2:38 a.m.
Hi, Aditya
Thank you for the great job.
The v6 patch set looks good to me, and I did not see any new issues in
my tests.
So for the v6: Ack.
Thanks
Lianbo
On 1/5/24 15:31, devel-request(a)lists.crash-utility.osci.io wrote:
Date: Fri, 5 Jan 2024 13:00:23 +0530
From: Aditya Gupta<adityag(a)linux.ibm.com>
Subject: [Crash-utility] [PATCH v6 1/5] ppc64: correct gdb
passthroughs by implementing machdep->get_cpu_reg
To:<devel@lists.crash-utility.osci.io>,<lijiang@redhat.com>,
Tao Liu<ltao(a)redhat.com>
Cc: Mahesh J Salgaonkar<mahesh(a)linux.ibm.com>, "Naveen N. Rao"
<naveen.n.rao(a)linux.vnet.ibm.com>
Message-ID:<20240105073027.378928-2-adityag@linux.ibm.com>
Content-Type: text/plain; charset=UTF-8
Currently, gdb passthroughs of 'bt', 'frame', 'up',
'down', 'info
locals' don't work. This is due to gdb not knowing the register values to
unwind the stack frames
Every gdb passthrough goes through `gdb_interface`. And then, gdb expects
`crash_target::fetch_registers` to give it the register values, which is
dependent on `machdep->get_cpu_reg` to read the register values for
specific architecture.
┌────────────────────────┐
gdb passthrough (eg. "bt") │ │
crash ─────────────────────────▶│ │
│ gdb_interface │
│ │
│ │
│ ┌────────────────────┐ │
fetch_registers │ │ │ │
crash_target◀────────────────────────┼─┤ gdb │ │
─────────────────────────┼▶│ │ │
Registers (SP,NIP, etc.)│ │ │ │
│ │ │ │
│ └────────────────────┘ │
└────────────────────────┘
Implement `machdep->get_cpu_reg` on PPC64, so that crash provides the
register values to gdb to unwind stack frames properly
With these changes, on powerpc, 'bt' command output in gdb mode, will look
like this:
gdb> bt
#0 0xc0000000002a53e8 in crash_setup_regs (oldregs=<optimized out>,
newregs=0xc00000000486f8d8) at ./arch/powerpc/include/asm/kexec.h:69
#1 __crash_kexec (regs=<optimized out>) at kernel/kexec_core.c:974
#2 0xc000000000168918 in panic (fmt=<optimized out>) at kernel/panic.c:358
#3 0xc000000000b735f8 in sysrq_handle_crash (key=<optimized out>) at
drivers/tty/sysrq.c:155
#4 0xc000000000b742cc in __handle_sysrq (key=key@entry=99,
check_mask=check_mask@entry=false) at drivers/tty/sysrq.c:602
#5 0xc000000000b7506c in write_sysrq_trigger (file=<optimized out>,
buf=<optimized out>, count=2, ppos=<optimized out>) at
drivers/tty/sysrq.c:1163
#6 0xc00000000069a7bc in pde_write (ppos=<optimized out>, count=<optimized
out>, buf=<optimized out>, file=<optimized out>, pde=0xc000000009ed3a80) at
fs/proc/inode.c:340
#7 proc_reg_write (file=<optimized out>, buf=<optimized out>,
count=<optimized out>, ppos=<optimized out>) at fs/proc/inode.c:352
#8 0xc0000000005b3bbc in vfs_write (file=file@entry=0xc00000009dda7d00,
buf=buf@entry=0xebcfc7c6040 <error: Cannot access memory at address 0xebcfc7c6040>,
count=count@entry=2, pos=pos@entry=0xc00000000486fda0) at fs/read_write.c:582
instead of earlier output without this patch:
gdb> bt
#0 <unavailable> in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
Also, 'get_dumpfile_regs' has been introduced to get registers from
multiple supported vmcore formats. Correspondingly a flag 'BT_NO_PRINT_REGS'
has been introduced to tell helper functions to get registers, to not
print registers with every call to backtrace in gdb.
Note: This feature to support GDB unwinding doesn't support live debugging
Signed-off-by: Aditya Gupta<adityag(a)linux.ibm.com>
---
defs.h | 122 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
kernel.c | 33 +++++++++++++++
ppc64.c | 105 +++++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 257 insertions(+), 3 deletions(-)
diff --git a/defs.h b/defs.h
index 5218a94fe4a4..615f3a37935a 100644
--- a/defs.h
+++ b/defs.h
@@ -6023,6 +6023,7 @@ int load_module_symbols_helper(char *);
void unlink_module(struct load_module *);
int check_specified_module_tree(char *, char *);
int is_system_call(char *, ulong);
+void get_dumpfile_regs(struct bt_info*, ulong*, ulong*);
void generic_dump_irq(int);
void generic_get_irq_affinity(int);
void generic_show_interrupts(int, ulong *);
@@ -6121,6 +6122,7 @@ ulong cpu_map_addr(const char *type);
#define BT_REGS_NOT_FOUND (0x4000000000000ULL)
#define BT_OVERFLOW_STACK (0x8000000000000ULL)
#define BT_SKIP_IDLE (0x10000000000000ULL)
+#define BT_NO_PRINT_REGS (0x20000000000000ULL)
#define BT_SYMBOL_OFFSET (BT_SYMBOLIC_ARGS)
#define BT_REF_HEXVAL (0x1)
@@ -7854,4 +7856,124 @@ enum x86_64_regnum {
LAST_REGNUM
};
+/*
+ * Register numbers to make crash_target->fetch_registers()
+ * ---> machdep->get_cpu_reg() work properly.
+ *
+ * These register numbers and names are given according to output of
+ * `rs6000_register_name`, because that is what was being used by
+ * crash_target::fetch_registers in case of PPC64
+ */
+enum ppc64_regnum {
+ PPC64_R0_REGNUM = 0,
+ PPC64_R1_REGNUM,
+ PPC64_R2_REGNUM,
+ PPC64_R3_REGNUM,
+ PPC64_R4_REGNUM,
+ PPC64_R5_REGNUM,
+ PPC64_R6_REGNUM,
+ PPC64_R7_REGNUM,
+ PPC64_R8_REGNUM,
+ PPC64_R9_REGNUM,
+ PPC64_R10_REGNUM,
+ PPC64_R11_REGNUM,
+ PPC64_R12_REGNUM,
+ PPC64_R13_REGNUM,
+ PPC64_R14_REGNUM,
+ PPC64_R15_REGNUM,
+ PPC64_R16_REGNUM,
+ PPC64_R17_REGNUM,
+ PPC64_R18_REGNUM,
+ PPC64_R19_REGNUM,
+ PPC64_R20_REGNUM,
+ PPC64_R21_REGNUM,
+ PPC64_R22_REGNUM,
+ PPC64_R23_REGNUM,
+ PPC64_R24_REGNUM,
+ PPC64_R25_REGNUM,
+ PPC64_R26_REGNUM,
+ PPC64_R27_REGNUM,
+ PPC64_R28_REGNUM,
+ PPC64_R29_REGNUM,
+ PPC64_R30_REGNUM,
+ PPC64_R31_REGNUM,
+
+ PPC64_F0_REGNUM = 32,
+ PPC64_F1_REGNUM,
+ PPC64_F2_REGNUM,
+ PPC64_F3_REGNUM,
+ PPC64_F4_REGNUM,
+ PPC64_F5_REGNUM,
+ PPC64_F6_REGNUM,
+ PPC64_F7_REGNUM,
+ PPC64_F8_REGNUM,
+ PPC64_F9_REGNUM,
+ PPC64_F10_REGNUM,
+ PPC64_F11_REGNUM,
+ PPC64_F12_REGNUM,
+ PPC64_F13_REGNUM,
+ PPC64_F14_REGNUM,
+ PPC64_F15_REGNUM,
+ PPC64_F16_REGNUM,
+ PPC64_F17_REGNUM,
+ PPC64_F18_REGNUM,
+ PPC64_F19_REGNUM,
+ PPC64_F20_REGNUM,
+ PPC64_F21_REGNUM,
+ PPC64_F22_REGNUM,
+ PPC64_F23_REGNUM,
+ PPC64_F24_REGNUM,
+ PPC64_F25_REGNUM,
+ PPC64_F26_REGNUM,
+ PPC64_F27_REGNUM,
+ PPC64_F28_REGNUM,
+ PPC64_F29_REGNUM,
+ PPC64_F30_REGNUM,
+ PPC64_F31_REGNUM,
+
+ PPC64_PC_REGNUM = 64,
+ PPC64_MSR_REGNUM = 65,
+ PPC64_CR_REGNUM = 66,
+ PPC64_LR_REGNUM = 67,
+ PPC64_CTR_REGNUM = 68,
+ PPC64_XER_REGNUM = 69,
+ PPC64_FPSCR_REGNUM = 70,
+
+ PPC64_VR0_REGNUM = 106,
+ PPC64_VR1_REGNUM,
+ PPC64_VR2_REGNUM,
+ PPC64_VR3_REGNUM,
+ PPC64_VR4_REGNUM,
+ PPC64_VR5_REGNUM,
+ PPC64_VR6_REGNUM,
+ PPC64_VR7_REGNUM,
+ PPC64_VR8_REGNUM,
+ PPC64_VR9_REGNUM,
+ PPC64_VR10_REGNUM,
+ PPC64_VR11_REGNUM,
+ PPC64_VR12_REGNUM,
+ PPC64_VR13_REGNUM,
+ PPC64_VR14_REGNUM,
+ PPC64_VR15_REGNUM,
+ PPC64_VR16_REGNUM,
+ PPC64_VR17_REGNUM,
+ PPC64_VR18_REGNUM,
+ PPC64_VR19_REGNUM,
+ PPC64_VR20_REGNUM,
+ PPC64_VR21_REGNUM,
+ PPC64_VR22_REGNUM,
+ PPC64_VR23_REGNUM,
+ PPC64_VR24_REGNUM,
+ PPC64_VR25_REGNUM,
+ PPC64_VR26_REGNUM,
+ PPC64_VR27_REGNUM,
+ PPC64_VR28_REGNUM,
+ PPC64_VR29_REGNUM,
+ PPC64_VR30_REGNUM,
+ PPC64_VR31_REGNUM,
+
+ PPC64_VSCR_REGNUM = 138,
+ PPC64_VRSAVE_REGNU = 139
+};
+
#endif /* !GDB_COMMON */
diff --git a/kernel.c b/kernel.c
index 6dcf414693e6..52b7ba09f390 100644
--- a/kernel.c
+++ b/kernel.c
@@ -3533,6 +3533,39 @@ get_lkcd_regs(struct bt_info *bt, ulong *eip, ulong *esp)
machdep->get_stack_frame(bt, eip, esp);
}
+void
+get_dumpfile_regs(struct bt_info *bt, ulong *eip, ulong *esp)
+{
+ bt->flags |= BT_NO_PRINT_REGS;
+
+ if (NETDUMP_DUMPFILE())
+ get_netdump_regs(bt, eip, esp);
+ else if (KDUMP_DUMPFILE())
+ get_kdump_regs(bt, eip, esp);
+ else if (DISKDUMP_DUMPFILE())
+ get_diskdump_regs(bt, eip, esp);
+ else if (KVMDUMP_DUMPFILE())
+ get_kvmdump_regs(bt, eip, esp);
+ else if (LKCD_DUMPFILE())
+ get_lkcd_regs(bt, eip, esp);
+ else if (XENDUMP_DUMPFILE())
+ get_xendump_regs(bt, eip, esp);
+ else if (SADUMP_DUMPFILE())
+ get_sadump_regs(bt, eip, esp);
+ else if (VMSS_DUMPFILE())
+ get_vmware_vmss_regs(bt, eip, esp);
+ else if (REMOTE_PAUSED()) {
+ if (!is_task_active(bt->task) || !get_remote_regs(bt, eip, esp))
+ machdep->get_stack_frame(bt, eip, esp);
+ } else
+ machdep->get_stack_frame(bt, eip, esp);
+
+ bt->flags &= ~BT_NO_PRINT_REGS;
+
+ bt->instptr = *eip;
+ bt->stkptr = *esp;
+}
+
/*
* Store the head of the kernel module list for future use.
diff --git a/ppc64.c b/ppc64.c
index e8930a139e0d..ea4821d86b9e 100644
--- a/ppc64.c
+++ b/ppc64.c
@@ -55,6 +55,8 @@ static void ppc64_set_bt_emergency_stack(enum emergency_stack_type
type,
static char * ppc64_check_eframe(struct ppc64_pt_regs *);
static void ppc64_print_eframe(char *, struct ppc64_pt_regs *,
struct bt_info *);
+static int ppc64_get_cpu_reg(int cpu, int regno, const char *name, int size,
+ void *value);
static void parse_cmdline_args(void);
static int ppc64_paca_percpu_offset_init(int);
static void ppc64_init_cpu_info(void);
@@ -704,6 +706,8 @@ ppc64_init(int when)
error(FATAL, "cannot malloc hwirqstack buffer space.");
}
+ machdep->get_cpu_reg = ppc64_get_cpu_reg;
+
ppc64_init_paca_info();
if (!machdep->hz) {
@@ -2501,6 +2505,99 @@ ppc64_print_eframe(char *efrm_str, struct ppc64_pt_regs *regs,
ppc64_print_nip_lr(regs, 1);
}
+static int
+ppc64_get_cpu_reg(int cpu, int regno, const char *name, int size,
+ void *value)
+{
+ struct bt_info bt_info, bt_setup;
+ struct task_context *tc;
+ struct ppc64_pt_regs *pt_regs;
+ ulong ip, sp;
+
+ if (LIVE()) {
+ /* doesn't support reading registers in live dump */
+ return FALSE;
+ }
+
+ /* Currently only handling registers available in ppc64_pt_regs:
+ *
+ * 0-31: r0-r31
+ * 64: pc/nip
+ * 65: msr
+ *
+ * 67: lr
+ * 68: ctr
+ */
+ switch (regno) {
+ case PPC64_R0_REGNUM ... PPC64_R31_REGNUM:
+
+ case PPC64_PC_REGNUM:
+ case PPC64_MSR_REGNUM:
+ case PPC64_LR_REGNUM:
+ case PPC64_CTR_REGNUM:
+ break;
+
+ default:
+ // return false if we can't get that register
+ if (CRASHDEBUG(1))
+ error(WARNING, "unsupported register, regno=%d\n", regno);
+ return FALSE;
+ }
+
+ tc = CURRENT_CONTEXT();
+ BZERO(&bt_setup, sizeof(struct bt_info));
+ clone_bt_info(&bt_setup, &bt_info, tc);
+ fill_stackbuf(&bt_info);
+
+ // reusing the get_dumpfile_regs function to get pt regs structure
+ get_dumpfile_regs(&bt_info, &sp, &ip);
+ pt_regs = (struct ppc64_pt_regs *)bt_info.machdep;
+
+ if (!pt_regs) {
+ error(WARNING, "pt_regs not available for cpu %d\n", cpu);
+ return FALSE;
+ }
+
+ switch (regno) {
+ case PPC64_R0_REGNUM ... PPC64_R31_REGNUM:
+ if (size != sizeof(pt_regs->gpr[regno]))
+ return FALSE; // size mismatch
+
+ memcpy(value, &pt_regs->gpr[regno], size);
+ break;
+
+ case PPC64_PC_REGNUM:
+ if (size != sizeof(pt_regs->nip))
+ return FALSE; // size mismatch
+
+ memcpy(value, &pt_regs->nip, size);
+ break;
+
+ case PPC64_MSR_REGNUM:
+ if (size != sizeof(pt_regs->msr))
+ return FALSE; // size mismatch
+
+ memcpy(value, &pt_regs->msr, size);
+ break;
+
+ case PPC64_LR_REGNUM:
+ if (size != sizeof(pt_regs->link))
+ return FALSE; // size mismatch
+
+ memcpy(value, &pt_regs->link, size);
+ break;
+
+ case PPC64_CTR_REGNUM:
+ if (size != sizeof(pt_regs->ctr))
+ return FALSE; // size mismatch
+
+ memcpy(value, &pt_regs->ctr, size);
+ break;
+ }
+
+ return TRUE;
+}
+
/*
* For vmcore typically saved with KDump or FADump, get SP and IP values
* from the saved ptregs.
@@ -2613,9 +2710,11 @@ ppc64_get_dumpfile_stack_frame(struct bt_info *bt_in, ulong *nip,
ulong *ksp)
pt_regs = (struct ppc64_pt_regs *)bt->machdep;
ur_nip = pt_regs->nip;
ur_ksp = pt_regs->gpr[1];
- /* Print the collected regs for panic task. */
- ppc64_print_regs(pt_regs);
- ppc64_print_nip_lr(pt_regs, 1);
+ if (!(bt->flags & BT_NO_PRINT_REGS)) {
+ /* Print the collected regs for panic task. */
+ ppc64_print_regs(pt_regs);
+ ppc64_print_nip_lr(pt_regs, 1);
+ }
} else if ((pc->flags & KDUMP) ||
((pc->flags & DISKDUMP) &&
(*diskdump_flags & KDUMP_CMPRS_LOCAL))) {
-- 2.43.0
2:41 a.m.
New subject: [PATCH v6 1/5] ppc64: correct gdb passthroughs by implementing machdep->get_cpu_reg
On Mon, Jan 08, 2024 at 04:38:20PM +0800, Lianbo Jiang wrote:
Hi, Aditya
Thank you for the great job.
The v6 patch set looks good to me, and I did not see any new issues in my
tests.
So for the v6: Ack.
Thanks for your continuous reviews and this ack, Lianbo.
- Aditya Gupta
>
> Thanks
>
> Lianbo
>
> On 1/5/24 15:31, devel-request(a)lists.crash-utility.osci.io wrote:
>
> > Date: Fri, 5 Jan 2024 13:00:23 +0530
> > From: Aditya Gupta<adityag(a)linux.ibm.com>
> > Subject: [Crash-utility] [PATCH v6 1/5] ppc64: correct gdb
> > passthroughs by implementing machdep->get_cpu_reg
> > To:<devel@lists.crash-utility.osci.io>,<lijiang@redhat.com>,
> > Tao Liu<ltao(a)redhat.com>
> > Cc: Mahesh J Salgaonkar<mahesh(a)linux.ibm.com>, "Naveen N. Rao"
> > <naveen.n.rao(a)linux.vnet.ibm.com>
> > Message-ID:<20240105073027.378928-2-adityag@linux.ibm.com>
> > Content-Type: text/plain; charset=UTF-8
> >
> > Currently, gdb passthroughs of 'bt', 'frame', 'up',
'down', 'info
> > locals' don't work. This is due to gdb not knowing the register values
to
> > unwind the stack frames
> >
> > Every gdb passthrough goes through `gdb_interface`. And then, gdb expects
> > `crash_target::fetch_registers` to give it the register values, which is
> > dependent on `machdep->get_cpu_reg` to read the register values for
> > specific architecture.
> >
> > ┌────────────────────────┐
> > gdb passthrough (eg. "bt") │ │
> > crash ─────────────────────────▶│ │
> > │ gdb_interface │
> > │ │
> > │ │
> > │ ┌────────────────────┐ │
> > fetch_registers │ │ │ │
> > crash_target◀────────────────────────┼─┤ gdb │ │
> > ─────────────────────────┼▶│ │ │
> > Registers (SP,NIP, etc.)│ │ │ │
> > │ │ │ │
> > │ └────────────────────┘ │
> > └────────────────────────┘
> >
> > Implement `machdep->get_cpu_reg` on PPC64, so that crash provides the
> > register values to gdb to unwind stack frames properly
> >
> > With these changes, on powerpc, 'bt' command output in gdb mode, will
look
> > like this:
> >
> > gdb> bt
> > #0 0xc0000000002a53e8 in crash_setup_regs (oldregs=<optimized out>,
newregs=0xc00000000486f8d8) at ./arch/powerpc/include/asm/kexec.h:69
> > #1 __crash_kexec (regs=<optimized out>) at kernel/kexec_core.c:974
> > #2 0xc000000000168918 in panic (fmt=<optimized out>) at
kernel/panic.c:358
> > #3 0xc000000000b735f8 in sysrq_handle_crash (key=<optimized out>) at
drivers/tty/sysrq.c:155
> > #4 0xc000000000b742cc in __handle_sysrq (key=key@entry=99,
check_mask=check_mask@entry=false) at drivers/tty/sysrq.c:602
> > #5 0xc000000000b7506c in write_sysrq_trigger (file=<optimized out>,
buf=<optimized out>, count=2, ppos=<optimized out>) at
drivers/tty/sysrq.c:1163
> > #6 0xc00000000069a7bc in pde_write (ppos=<optimized out>,
count=<optimized out>, buf=<optimized out>, file=<optimized out>,
pde=0xc000000009ed3a80) at fs/proc/inode.c:340
> > #7 proc_reg_write (file=<optimized out>, buf=<optimized out>,
count=<optimized out>, ppos=<optimized out>) at fs/proc/inode.c:352
> > #8 0xc0000000005b3bbc in vfs_write (file=file@entry=0xc00000009dda7d00,
buf=buf@entry=0xebcfc7c6040 <error: Cannot access memory at address 0xebcfc7c6040>,
count=count@entry=2, pos=pos@entry=0xc00000000486fda0) at fs/read_write.c:582
> >
> > instead of earlier output without this patch:
> >
> > gdb> bt
> > #0 <unavailable> in ?? ()
> > Backtrace stopped: previous frame identical to this frame (corrupt stack?)
> >
> > Also, 'get_dumpfile_regs' has been introduced to get registers from
> > multiple supported vmcore formats. Correspondingly a flag
'BT_NO_PRINT_REGS'
> > has been introduced to tell helper functions to get registers, to not
> > print registers with every call to backtrace in gdb.
> >
> > Note: This feature to support GDB unwinding doesn't support live
debugging
> >
> > Signed-off-by: Aditya Gupta<adityag(a)linux.ibm.com>
> > ---
> > defs.h | 122 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > kernel.c | 33 +++++++++++++++
> > ppc64.c | 105 +++++++++++++++++++++++++++++++++++++++++++++--
> > 3 files changed, 257 insertions(+), 3 deletions(-)
> >
> > diff --git a/defs.h b/defs.h
> > index 5218a94fe4a4..615f3a37935a 100644
> > --- a/defs.h
> > +++ b/defs.h
> > @@ -6023,6 +6023,7 @@ int load_module_symbols_helper(char *);
> > void unlink_module(struct load_module *);
> > int check_specified_module_tree(char *, char *);
> > int is_system_call(char *, ulong);
> > +void get_dumpfile_regs(struct bt_info*, ulong*, ulong*);
> > void generic_dump_irq(int);
> > void generic_get_irq_affinity(int);
> > void generic_show_interrupts(int, ulong *);
> > @@ -6121,6 +6122,7 @@ ulong cpu_map_addr(const char *type);
> > #define BT_REGS_NOT_FOUND (0x4000000000000ULL)
> > #define BT_OVERFLOW_STACK (0x8000000000000ULL)
> > #define BT_SKIP_IDLE (0x10000000000000ULL)
> > +#define BT_NO_PRINT_REGS (0x20000000000000ULL)
> > #define BT_SYMBOL_OFFSET (BT_SYMBOLIC_ARGS)
> > #define BT_REF_HEXVAL (0x1)
> > @@ -7854,4 +7856,124 @@ enum x86_64_regnum {
> > LAST_REGNUM
> > };
> > +/*
> > + * Register numbers to make crash_target->fetch_registers()
> > + * ---> machdep->get_cpu_reg() work properly.
> > + *
> > + * These register numbers and names are given according to output of
> > + * `rs6000_register_name`, because that is what was being used by
> > + * crash_target::fetch_registers in case of PPC64
> > + */
> > +enum ppc64_regnum {
> > + PPC64_R0_REGNUM = 0,
> > + PPC64_R1_REGNUM,
> > + PPC64_R2_REGNUM,
> > + PPC64_R3_REGNUM,
> > + PPC64_R4_REGNUM,
> > + PPC64_R5_REGNUM,
> > + PPC64_R6_REGNUM,
> > + PPC64_R7_REGNUM,
> > + PPC64_R8_REGNUM,
> > + PPC64_R9_REGNUM,
> > + PPC64_R10_REGNUM,
> > + PPC64_R11_REGNUM,
> > + PPC64_R12_REGNUM,
> > + PPC64_R13_REGNUM,
> > + PPC64_R14_REGNUM,
> > + PPC64_R15_REGNUM,
> > + PPC64_R16_REGNUM,
> > + PPC64_R17_REGNUM,
> > + PPC64_R18_REGNUM,
> > + PPC64_R19_REGNUM,
> > + PPC64_R20_REGNUM,
> > + PPC64_R21_REGNUM,
> > + PPC64_R22_REGNUM,
> > + PPC64_R23_REGNUM,
> > + PPC64_R24_REGNUM,
> > + PPC64_R25_REGNUM,
> > + PPC64_R26_REGNUM,
> > + PPC64_R27_REGNUM,
> > + PPC64_R28_REGNUM,
> > + PPC64_R29_REGNUM,
> > + PPC64_R30_REGNUM,
> > + PPC64_R31_REGNUM,
> > +
> > + PPC64_F0_REGNUM = 32,
> > + PPC64_F1_REGNUM,
> > + PPC64_F2_REGNUM,
> > + PPC64_F3_REGNUM,
> > + PPC64_F4_REGNUM,
> > + PPC64_F5_REGNUM,
> > + PPC64_F6_REGNUM,
> > + PPC64_F7_REGNUM,
> > + PPC64_F8_REGNUM,
> > + PPC64_F9_REGNUM,
> > + PPC64_F10_REGNUM,
> > + PPC64_F11_REGNUM,
> > + PPC64_F12_REGNUM,
> > + PPC64_F13_REGNUM,
> > + PPC64_F14_REGNUM,
> > + PPC64_F15_REGNUM,
> > + PPC64_F16_REGNUM,
> > + PPC64_F17_REGNUM,
> > + PPC64_F18_REGNUM,
> > + PPC64_F19_REGNUM,
> > + PPC64_F20_REGNUM,
> > + PPC64_F21_REGNUM,
> > + PPC64_F22_REGNUM,
> > + PPC64_F23_REGNUM,
> > + PPC64_F24_REGNUM,
> > + PPC64_F25_REGNUM,
> > + PPC64_F26_REGNUM,
> > + PPC64_F27_REGNUM,
> > + PPC64_F28_REGNUM,
> > + PPC64_F29_REGNUM,
> > + PPC64_F30_REGNUM,
> > + PPC64_F31_REGNUM,
> > +
> > + PPC64_PC_REGNUM = 64,
> > + PPC64_MSR_REGNUM = 65,
> > + PPC64_CR_REGNUM = 66,
> > + PPC64_LR_REGNUM = 67,
> > + PPC64_CTR_REGNUM = 68,
> > + PPC64_XER_REGNUM = 69,
> > + PPC64_FPSCR_REGNUM = 70,
> > +
> > + PPC64_VR0_REGNUM = 106,
> > + PPC64_VR1_REGNUM,
> > + PPC64_VR2_REGNUM,
> > + PPC64_VR3_REGNUM,
> > + PPC64_VR4_REGNUM,
> > + PPC64_VR5_REGNUM,
> > + PPC64_VR6_REGNUM,
> > + PPC64_VR7_REGNUM,
> > + PPC64_VR8_REGNUM,
> > + PPC64_VR9_REGNUM,
> > + PPC64_VR10_REGNUM,
> > + PPC64_VR11_REGNUM,
> > + PPC64_VR12_REGNUM,
> > + PPC64_VR13_REGNUM,
> > + PPC64_VR14_REGNUM,
> > + PPC64_VR15_REGNUM,
> > + PPC64_VR16_REGNUM,
> > + PPC64_VR17_REGNUM,
> > + PPC64_VR18_REGNUM,
> > + PPC64_VR19_REGNUM,
> > + PPC64_VR20_REGNUM,
> > + PPC64_VR21_REGNUM,
> > + PPC64_VR22_REGNUM,
> > + PPC64_VR23_REGNUM,
> > + PPC64_VR24_REGNUM,
> > + PPC64_VR25_REGNUM,
> > + PPC64_VR26_REGNUM,
> > + PPC64_VR27_REGNUM,
> > + PPC64_VR28_REGNUM,
> > + PPC64_VR29_REGNUM,
> > + PPC64_VR30_REGNUM,
> > + PPC64_VR31_REGNUM,
> > +
> > + PPC64_VSCR_REGNUM = 138,
> > + PPC64_VRSAVE_REGNU = 139
> > +};
> > +
> > #endif /* !GDB_COMMON */
> > diff --git a/kernel.c b/kernel.c
> > index 6dcf414693e6..52b7ba09f390 100644
> > --- a/kernel.c
> > +++ b/kernel.c
> > @@ -3533,6 +3533,39 @@ get_lkcd_regs(struct bt_info *bt, ulong *eip, ulong
*esp)
> > machdep->get_stack_frame(bt, eip, esp);
> > }
> > +void
> > +get_dumpfile_regs(struct bt_info *bt, ulong *eip, ulong *esp)
> > +{
> > + bt->flags |= BT_NO_PRINT_REGS;
> > +
> > + if (NETDUMP_DUMPFILE())
> > + get_netdump_regs(bt, eip, esp);
> > + else if (KDUMP_DUMPFILE())
> > + get_kdump_regs(bt, eip, esp);
> > + else if (DISKDUMP_DUMPFILE())
> > + get_diskdump_regs(bt, eip, esp);
> > + else if (KVMDUMP_DUMPFILE())
> > + get_kvmdump_regs(bt, eip, esp);
> > + else if (LKCD_DUMPFILE())
> > + get_lkcd_regs(bt, eip, esp);
> > + else if (XENDUMP_DUMPFILE())
> > + get_xendump_regs(bt, eip, esp);
> > + else if (SADUMP_DUMPFILE())
> > + get_sadump_regs(bt, eip, esp);
> > + else if (VMSS_DUMPFILE())
> > + get_vmware_vmss_regs(bt, eip, esp);
> > + else if (REMOTE_PAUSED()) {
> > + if (!is_task_active(bt->task) || !get_remote_regs(bt, eip, esp))
> > + machdep->get_stack_frame(bt, eip, esp);
> > + } else
> > + machdep->get_stack_frame(bt, eip, esp);
> > +
> > + bt->flags &= ~BT_NO_PRINT_REGS;
> > +
> > + bt->instptr = *eip;
> > + bt->stkptr = *esp;
> > +}
> > +
> > /*
> > * Store the head of the kernel module list for future use.
> > diff --git a/ppc64.c b/ppc64.c
> > index e8930a139e0d..ea4821d86b9e 100644
> > --- a/ppc64.c
> > +++ b/ppc64.c
> > @@ -55,6 +55,8 @@ static void ppc64_set_bt_emergency_stack(enum
emergency_stack_type type,
> > static char * ppc64_check_eframe(struct ppc64_pt_regs *);
> > static void ppc64_print_eframe(char *, struct ppc64_pt_regs *,
> > struct bt_info *);
> > +static int ppc64_get_cpu_reg(int cpu, int regno, const char *name, int size,
> > + void *value);
> > static void parse_cmdline_args(void);
> > static int ppc64_paca_percpu_offset_init(int);
> > static void ppc64_init_cpu_info(void);
> > @@ -704,6 +706,8 @@ ppc64_init(int when)
> > error(FATAL, "cannot malloc hwirqstack buffer space.");
> > }
> > + machdep->get_cpu_reg = ppc64_get_cpu_reg;
> > +
> > ppc64_init_paca_info();
> > if (!machdep->hz) {
> > @@ -2501,6 +2505,99 @@ ppc64_print_eframe(char *efrm_str, struct ppc64_pt_regs
*regs,
> > ppc64_print_nip_lr(regs, 1);
> > }
> > +static int
> > +ppc64_get_cpu_reg(int cpu, int regno, const char *name, int size,
> > + void *value)
> > +{
> > + struct bt_info bt_info, bt_setup;
> > + struct task_context *tc;
> > + struct ppc64_pt_regs *pt_regs;
> > + ulong ip, sp;
> > +
> > + if (LIVE()) {
> > + /* doesn't support reading registers in live dump */
> > + return FALSE;
> > + }
> > +
> > + /* Currently only handling registers available in ppc64_pt_regs:
> > + *
> > + * 0-31: r0-r31
> > + * 64: pc/nip
> > + * 65: msr
> > + *
> > + * 67: lr
> > + * 68: ctr
> > + */
> > + switch (regno) {
> > + case PPC64_R0_REGNUM ... PPC64_R31_REGNUM:
> > +
> > + case PPC64_PC_REGNUM:
> > + case PPC64_MSR_REGNUM:
> > + case PPC64_LR_REGNUM:
> > + case PPC64_CTR_REGNUM:
> > + break;
> > +
> > + default:
> > + // return false if we can't get that register
> > + if (CRASHDEBUG(1))
> > + error(WARNING, "unsupported register, regno=%d\n", regno);
> > + return FALSE;
> > + }
> > +
> > + tc = CURRENT_CONTEXT();
> > + BZERO(&bt_setup, sizeof(struct bt_info));
> > + clone_bt_info(&bt_setup, &bt_info, tc);
> > + fill_stackbuf(&bt_info);
> > +
> > + // reusing the get_dumpfile_regs function to get pt regs structure
> > + get_dumpfile_regs(&bt_info, &sp, &ip);
> > + pt_regs = (struct ppc64_pt_regs *)bt_info.machdep;
> > +
> > + if (!pt_regs) {
> > + error(WARNING, "pt_regs not available for cpu %d\n", cpu);
> > + return FALSE;
> > + }
> > +
> > + switch (regno) {
> > + case PPC64_R0_REGNUM ... PPC64_R31_REGNUM:
> > + if (size != sizeof(pt_regs->gpr[regno]))
> > + return FALSE; // size mismatch
> > +
> > + memcpy(value, &pt_regs->gpr[regno], size);
> > + break;
> > +
> > + case PPC64_PC_REGNUM:
> > + if (size != sizeof(pt_regs->nip))
> > + return FALSE; // size mismatch
> > +
> > + memcpy(value, &pt_regs->nip, size);
> > + break;
> > +
> > + case PPC64_MSR_REGNUM:
> > + if (size != sizeof(pt_regs->msr))
> > + return FALSE; // size mismatch
> > +
> > + memcpy(value, &pt_regs->msr, size);
> > + break;
> > +
> > + case PPC64_LR_REGNUM:
> > + if (size != sizeof(pt_regs->link))
> > + return FALSE; // size mismatch
> > +
> > + memcpy(value, &pt_regs->link, size);
> > + break;
> > +
> > + case PPC64_CTR_REGNUM:
> > + if (size != sizeof(pt_regs->ctr))
> > + return FALSE; // size mismatch
> > +
> > + memcpy(value, &pt_regs->ctr, size);
> > + break;
> > + }
> > +
> > + return TRUE;
> > +}
> > +
> > /*
> > * For vmcore typically saved with KDump or FADump, get SP and IP values
> > * from the saved ptregs.
> > @@ -2613,9 +2710,11 @@ ppc64_get_dumpfile_stack_frame(struct bt_info *bt_in,
ulong *nip, ulong *ksp)
> > pt_regs = (struct ppc64_pt_regs *)bt->machdep;
> > ur_nip = pt_regs->nip;
> > ur_ksp = pt_regs->gpr[1];
> > - /* Print the collected regs for panic task. */
> > - ppc64_print_regs(pt_regs);
> > - ppc64_print_nip_lr(pt_regs, 1);
> > + if (!(bt->flags & BT_NO_PRINT_REGS)) {
> > + /* Print the collected regs for panic task. */
> > + ppc64_print_regs(pt_regs);
> > + ppc64_print_nip_lr(pt_regs, 1);
> > + }
> > } else if ((pc->flags & KDUMP) ||
> > ((pc->flags & DISKDUMP) &&
> > (*diskdump_flags & KDUMP_CMPRS_LOCAL))) {
> > -- 2.43.0
>
3:24 a.m.
New subject: [PATCH v6 1/5] ppc64: correct gdb passthroughs by implementing machdep->get_cpu_reg
Hi Lianbo,
Just a ping for the series. Any pending reviews for upstreaming it ?
Thanks,
Aditya Gupta
On Mon, Jan 08, 2024 at 04:38:20PM +0800, Lianbo Jiang wrote:
> Hi, Aditya
>
> Thank you for the great job.
>
> The v6 patch set looks good to me, and I did not see any new issues in my
> tests.
>
> So for the v6: Ack.
>
>
> Thanks
>
> Lianbo
>
> On 1/5/24 15:31, devel-request(a)lists.crash-utility.osci.io wrote:
>
> > Date: Fri, 5 Jan 2024 13:00:23 +0530
> > From: Aditya Gupta<adityag(a)linux.ibm.com>
> > Subject: [Crash-utility] [PATCH v6 1/5] ppc64: correct gdb
> > passthroughs by implementing machdep->get_cpu_reg
> > To:<devel@lists.crash-utility.osci.io>,<lijiang@redhat.com>,
> > Tao Liu<ltao(a)redhat.com>
> > Cc: Mahesh J Salgaonkar<mahesh(a)linux.ibm.com>, "Naveen N. Rao"
> > <naveen.n.rao(a)linux.vnet.ibm.com>
> > Message-ID:<20240105073027.378928-2-adityag@linux.ibm.com>
> > Content-Type: text/plain; charset=UTF-8
> >
> > Currently, gdb passthroughs of 'bt', 'frame', 'up',
'down', 'info
> > locals' don't work. This is due to gdb not knowing the register values
to
> > unwind the stack frames
> >
> > Every gdb passthrough goes through `gdb_interface`. And then, gdb expects
> > `crash_target::fetch_registers` to give it the register values, which is
> > dependent on `machdep->get_cpu_reg` to read the register values for
> > specific architecture.
> >
> > ┌────────────────────────┐
> > gdb passthrough (eg. "bt") │ │
> > crash ─────────────────────────▶│ │
> > │ gdb_interface │
> > │ │
> > │ │
> > │ ┌────────────────────┐ │
> > fetch_registers │ │ │ │
> > crash_target◀────────────────────────┼─┤ gdb │ │
> > ─────────────────────────┼▶│ │ │
> > Registers (SP,NIP, etc.)│ │ │ │
> > │ │ │ │
> > │ └────────────────────┘ │
> > └────────────────────────┘
> >
> > Implement `machdep->get_cpu_reg` on PPC64, so that crash provides the
> > register values to gdb to unwind stack frames properly
> >
> > With these changes, on powerpc, 'bt' command output in gdb mode, will
look
> > like this:
> >
> > gdb> bt
> > #0 0xc0000000002a53e8 in crash_setup_regs (oldregs=<optimized out>,
newregs=0xc00000000486f8d8) at ./arch/powerpc/include/asm/kexec.h:69
> > #1 __crash_kexec (regs=<optimized out>) at kernel/kexec_core.c:974
> > #2 0xc000000000168918 in panic (fmt=<optimized out>) at
kernel/panic.c:358
> > #3 0xc000000000b735f8 in sysrq_handle_crash (key=<optimized out>) at
drivers/tty/sysrq.c:155
> > #4 0xc000000000b742cc in __handle_sysrq (key=key@entry=99,
check_mask=check_mask@entry=false) at drivers/tty/sysrq.c:602
> > #5 0xc000000000b7506c in write_sysrq_trigger (file=<optimized out>,
buf=<optimized out>, count=2, ppos=<optimized out>) at
drivers/tty/sysrq.c:1163
> > #6 0xc00000000069a7bc in pde_write (ppos=<optimized out>,
count=<optimized out>, buf=<optimized out>, file=<optimized out>,
pde=0xc000000009ed3a80) at fs/proc/inode.c:340
> > #7 proc_reg_write (file=<optimized out>, buf=<optimized out>,
count=<optimized out>, ppos=<optimized out>) at fs/proc/inode.c:352
> > #8 0xc0000000005b3bbc in vfs_write (file=file@entry=0xc00000009dda7d00,
buf=buf@entry=0xebcfc7c6040 <error: Cannot access memory at address 0xebcfc7c6040>,
count=count@entry=2, pos=pos@entry=0xc00000000486fda0) at fs/read_write.c:582
> >
> > instead of earlier output without this patch:
> >
> > gdb> bt
> > #0 <unavailable> in ?? ()
> > Backtrace stopped: previous frame identical to this frame (corrupt stack?)
> >
> > Also, 'get_dumpfile_regs' has been introduced to get registers from
> > multiple supported vmcore formats. Correspondingly a flag
'BT_NO_PRINT_REGS'
> > has been introduced to tell helper functions to get registers, to not
> > print registers with every call to backtrace in gdb.
> >
> > Note: This feature to support GDB unwinding doesn't support live
debugging
> >
> > Signed-off-by: Aditya Gupta<adityag(a)linux.ibm.com>
> > ---
> > defs.h | 122 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > kernel.c | 33 +++++++++++++++
> > ppc64.c | 105 +++++++++++++++++++++++++++++++++++++++++++++--
> > 3 files changed, 257 insertions(+), 3 deletions(-)
> >
> > diff --git a/defs.h b/defs.h
> > index 5218a94fe4a4..615f3a37935a 100644
> > --- a/defs.h
> > +++ b/defs.h
> > @@ -6023,6 +6023,7 @@ int load_module_symbols_helper(char *);
> > void unlink_module(struct load_module *);
> > int check_specified_module_tree(char *, char *);
> > int is_system_call(char *, ulong);
> > +void get_dumpfile_regs(struct bt_info*, ulong*, ulong*);
> > void generic_dump_irq(int);
> > void generic_get_irq_affinity(int);
> > void generic_show_interrupts(int, ulong *);
> > @@ -6121,6 +6122,7 @@ ulong cpu_map_addr(const char *type);
> > #define BT_REGS_NOT_FOUND (0x4000000000000ULL)
> > #define BT_OVERFLOW_STACK (0x8000000000000ULL)
> > #define BT_SKIP_IDLE (0x10000000000000ULL)
> > +#define BT_NO_PRINT_REGS (0x20000000000000ULL)
> > #define BT_SYMBOL_OFFSET (BT_SYMBOLIC_ARGS)
> > #define BT_REF_HEXVAL (0x1)
> > @@ -7854,4 +7856,124 @@ enum x86_64_regnum {
> > LAST_REGNUM
> > };
> > +/*
> > + * Register numbers to make crash_target->fetch_registers()
> > + * ---> machdep->get_cpu_reg() work properly.
> > + *
> > + * These register numbers and names are given according to output of
> > + * `rs6000_register_name`, because that is what was being used by
> > + * crash_target::fetch_registers in case of PPC64
> > + */
> > +enum ppc64_regnum {
> > + PPC64_R0_REGNUM = 0,
> > + PPC64_R1_REGNUM,
> > + PPC64_R2_REGNUM,
> > + PPC64_R3_REGNUM,
> > + PPC64_R4_REGNUM,
> > + PPC64_R5_REGNUM,
> > + PPC64_R6_REGNUM,
> > + PPC64_R7_REGNUM,
> > + PPC64_R8_REGNUM,
> > + PPC64_R9_REGNUM,
> > + PPC64_R10_REGNUM,
> > + PPC64_R11_REGNUM,
> > + PPC64_R12_REGNUM,
> > + PPC64_R13_REGNUM,
> > + PPC64_R14_REGNUM,
> > + PPC64_R15_REGNUM,
> > + PPC64_R16_REGNUM,
> > + PPC64_R17_REGNUM,
> > + PPC64_R18_REGNUM,
> > + PPC64_R19_REGNUM,
> > + PPC64_R20_REGNUM,
> > + PPC64_R21_REGNUM,
> > + PPC64_R22_REGNUM,
> > + PPC64_R23_REGNUM,
> > + PPC64_R24_REGNUM,
> > + PPC64_R25_REGNUM,
> > + PPC64_R26_REGNUM,
> > + PPC64_R27_REGNUM,
> > + PPC64_R28_REGNUM,
> > + PPC64_R29_REGNUM,
> > + PPC64_R30_REGNUM,
> > + PPC64_R31_REGNUM,
> > +
> > + PPC64_F0_REGNUM = 32,
> > + PPC64_F1_REGNUM,
> > + PPC64_F2_REGNUM,
> > + PPC64_F3_REGNUM,
> > + PPC64_F4_REGNUM,
> > + PPC64_F5_REGNUM,
> > + PPC64_F6_REGNUM,
> > + PPC64_F7_REGNUM,
> > + PPC64_F8_REGNUM,
> > + PPC64_F9_REGNUM,
> > + PPC64_F10_REGNUM,
> > + PPC64_F11_REGNUM,
> > + PPC64_F12_REGNUM,
> > + PPC64_F13_REGNUM,
> > + PPC64_F14_REGNUM,
> > + PPC64_F15_REGNUM,
> > + PPC64_F16_REGNUM,
> > + PPC64_F17_REGNUM,
> > + PPC64_F18_REGNUM,
> > + PPC64_F19_REGNUM,
> > + PPC64_F20_REGNUM,
> > + PPC64_F21_REGNUM,
> > + PPC64_F22_REGNUM,
> > + PPC64_F23_REGNUM,
> > + PPC64_F24_REGNUM,
> > + PPC64_F25_REGNUM,
> > + PPC64_F26_REGNUM,
> > + PPC64_F27_REGNUM,
> > + PPC64_F28_REGNUM,
> > + PPC64_F29_REGNUM,
> > + PPC64_F30_REGNUM,
> > + PPC64_F31_REGNUM,
> > +
> > + PPC64_PC_REGNUM = 64,
> > + PPC64_MSR_REGNUM = 65,
> > + PPC64_CR_REGNUM = 66,
> > + PPC64_LR_REGNUM = 67,
> > + PPC64_CTR_REGNUM = 68,
> > + PPC64_XER_REGNUM = 69,
> > + PPC64_FPSCR_REGNUM = 70,
> > +
> > + PPC64_VR0_REGNUM = 106,
> > + PPC64_VR1_REGNUM,
> > + PPC64_VR2_REGNUM,
> > + PPC64_VR3_REGNUM,
> > + PPC64_VR4_REGNUM,
> > + PPC64_VR5_REGNUM,
> > + PPC64_VR6_REGNUM,
> > + PPC64_VR7_REGNUM,
> > + PPC64_VR8_REGNUM,
> > + PPC64_VR9_REGNUM,
> > + PPC64_VR10_REGNUM,
> > + PPC64_VR11_REGNUM,
> > + PPC64_VR12_REGNUM,
> > + PPC64_VR13_REGNUM,
> > + PPC64_VR14_REGNUM,
> > + PPC64_VR15_REGNUM,
> > + PPC64_VR16_REGNUM,
> > + PPC64_VR17_REGNUM,
> > + PPC64_VR18_REGNUM,
> > + PPC64_VR19_REGNUM,
> > + PPC64_VR20_REGNUM,
> > + PPC64_VR21_REGNUM,
> > + PPC64_VR22_REGNUM,
> > + PPC64_VR23_REGNUM,
> > + PPC64_VR24_REGNUM,
> > + PPC64_VR25_REGNUM,
> > + PPC64_VR26_REGNUM,
> > + PPC64_VR27_REGNUM,
> > + PPC64_VR28_REGNUM,
> > + PPC64_VR29_REGNUM,
> > + PPC64_VR30_REGNUM,
> > + PPC64_VR31_REGNUM,
> > +
> > + PPC64_VSCR_REGNUM = 138,
> > + PPC64_VRSAVE_REGNU = 139
> > +};
> > +
> > #endif /* !GDB_COMMON */
> > diff --git a/kernel.c b/kernel.c
> > index 6dcf414693e6..52b7ba09f390 100644
> > --- a/kernel.c
> > +++ b/kernel.c
> > @@ -3533,6 +3533,39 @@ get_lkcd_regs(struct bt_info *bt, ulong *eip, ulong
*esp)
> > machdep->get_stack_frame(bt, eip, esp);
> > }
> > +void
> > +get_dumpfile_regs(struct bt_info *bt, ulong *eip, ulong *esp)
> > +{
> > + bt->flags |= BT_NO_PRINT_REGS;
> > +
> > + if (NETDUMP_DUMPFILE())
> > + get_netdump_regs(bt, eip, esp);
> > + else if (KDUMP_DUMPFILE())
> > + get_kdump_regs(bt, eip, esp);
> > + else if (DISKDUMP_DUMPFILE())
> > + get_diskdump_regs(bt, eip, esp);
> > + else if (KVMDUMP_DUMPFILE())
> > + get_kvmdump_regs(bt, eip, esp);
> > + else if (LKCD_DUMPFILE())
> > + get_lkcd_regs(bt, eip, esp);
> > + else if (XENDUMP_DUMPFILE())
> > + get_xendump_regs(bt, eip, esp);
> > + else if (SADUMP_DUMPFILE())
> > + get_sadump_regs(bt, eip, esp);
> > + else if (VMSS_DUMPFILE())
> > + get_vmware_vmss_regs(bt, eip, esp);
> > + else if (REMOTE_PAUSED()) {
> > + if (!is_task_active(bt->task) || !get_remote_regs(bt, eip, esp))
> > + machdep->get_stack_frame(bt, eip, esp);
> > + } else
> > + machdep->get_stack_frame(bt, eip, esp);
> > +
> > + bt->flags &= ~BT_NO_PRINT_REGS;
> > +
> > + bt->instptr = *eip;
> > + bt->stkptr = *esp;
> > +}
> > +
> > /*
> > * Store the head of the kernel module list for future use.
> > diff --git a/ppc64.c b/ppc64.c
> > index e8930a139e0d..ea4821d86b9e 100644
> > --- a/ppc64.c
> > +++ b/ppc64.c
> > @@ -55,6 +55,8 @@ static void ppc64_set_bt_emergency_stack(enum
emergency_stack_type type,
> > static char * ppc64_check_eframe(struct ppc64_pt_regs *);
> > static void ppc64_print_eframe(char *, struct ppc64_pt_regs *,
> > struct bt_info *);
> > +static int ppc64_get_cpu_reg(int cpu, int regno, const char *name, int size,
> > + void *value);
> > static void parse_cmdline_args(void);
> > static int ppc64_paca_percpu_offset_init(int);
> > static void ppc64_init_cpu_info(void);
> > @@ -704,6 +706,8 @@ ppc64_init(int when)
> > error(FATAL, "cannot malloc hwirqstack buffer space.");
> > }
> > + machdep->get_cpu_reg = ppc64_get_cpu_reg;
> > +
> > ppc64_init_paca_info();
> > if (!machdep->hz) {
> > @@ -2501,6 +2505,99 @@ ppc64_print_eframe(char *efrm_str, struct ppc64_pt_regs
*regs,
> > ppc64_print_nip_lr(regs, 1);
> > }
> > +static int
> > +ppc64_get_cpu_reg(int cpu, int regno, const char *name, int size,
> > + void *value)
> > +{
> > + struct bt_info bt_info, bt_setup;
> > + struct task_context *tc;
> > + struct ppc64_pt_regs *pt_regs;
> > + ulong ip, sp;
> > +
> > + if (LIVE()) {
> > + /* doesn't support reading registers in live dump */
> > + return FALSE;
> > + }
> > +
> > + /* Currently only handling registers available in ppc64_pt_regs:
> > + *
> > + * 0-31: r0-r31
> > + * 64: pc/nip
> > + * 65: msr
> > + *
> > + * 67: lr
> > + * 68: ctr
> > + */
> > + switch (regno) {
> > + case PPC64_R0_REGNUM ... PPC64_R31_REGNUM:
> > +
> > + case PPC64_PC_REGNUM:
> > + case PPC64_MSR_REGNUM:
> > + case PPC64_LR_REGNUM:
> > + case PPC64_CTR_REGNUM:
> > + break;
> > +
> > + default:
> > + // return false if we can't get that register
> > + if (CRASHDEBUG(1))
> > + error(WARNING, "unsupported register, regno=%d\n", regno);
> > + return FALSE;
> > + }
> > +
> > + tc = CURRENT_CONTEXT();
> > + BZERO(&bt_setup, sizeof(struct bt_info));
> > + clone_bt_info(&bt_setup, &bt_info, tc);
> > + fill_stackbuf(&bt_info);
> > +
> > + // reusing the get_dumpfile_regs function to get pt regs structure
> > + get_dumpfile_regs(&bt_info, &sp, &ip);
> > + pt_regs = (struct ppc64_pt_regs *)bt_info.machdep;
> > +
> > + if (!pt_regs) {
> > + error(WARNING, "pt_regs not available for cpu %d\n", cpu);
> > + return FALSE;
> > + }
> > +
> > + switch (regno) {
> > + case PPC64_R0_REGNUM ... PPC64_R31_REGNUM:
> > + if (size != sizeof(pt_regs->gpr[regno]))
> > + return FALSE; // size mismatch
> > +
> > + memcpy(value, &pt_regs->gpr[regno], size);
> > + break;
> > +
> > + case PPC64_PC_REGNUM:
> > + if (size != sizeof(pt_regs->nip))
> > + return FALSE; // size mismatch
> > +
> > + memcpy(value, &pt_regs->nip, size);
> > + break;
> > +
> > + case PPC64_MSR_REGNUM:
> > + if (size != sizeof(pt_regs->msr))
> > + return FALSE; // size mismatch
> > +
> > + memcpy(value, &pt_regs->msr, size);
> > + break;
> > +
> > + case PPC64_LR_REGNUM:
> > + if (size != sizeof(pt_regs->link))
> > + return FALSE; // size mismatch
> > +
> > + memcpy(value, &pt_regs->link, size);
> > + break;
> > +
> > + case PPC64_CTR_REGNUM:
> > + if (size != sizeof(pt_regs->ctr))
> > + return FALSE; // size mismatch
> > +
> > + memcpy(value, &pt_regs->ctr, size);
> > + break;
> > + }
> > +
> > + return TRUE;
> > +}
> > +
> > /*
> > * For vmcore typically saved with KDump or FADump, get SP and IP values
> > * from the saved ptregs.
> > @@ -2613,9 +2710,11 @@ ppc64_get_dumpfile_stack_frame(struct bt_info *bt_in,
ulong *nip, ulong *ksp)
> > pt_regs = (struct ppc64_pt_regs *)bt->machdep;
> > ur_nip = pt_regs->nip;
> > ur_ksp = pt_regs->gpr[1];
> > - /* Print the collected regs for panic task. */
> > - ppc64_print_regs(pt_regs);
> > - ppc64_print_nip_lr(pt_regs, 1);
> > + if (!(bt->flags & BT_NO_PRINT_REGS)) {
> > + /* Print the collected regs for panic task. */
> > + ppc64_print_regs(pt_regs);
> > + ppc64_print_nip_lr(pt_regs, 1);
> > + }
> > } else if ((pc->flags & KDUMP) ||
> > ((pc->flags & DISKDUMP) &&
> > (*diskdump_flags & KDUMP_CMPRS_LOCAL))) {
> > -- 2.43.0
>
3:48 a.m.
New subject: [PATCH v6 1/5] ppc64: correct gdb passthroughs by implementing machdep->get_cpu_reg
Hi, Aditya
On 1/22/24 17:24, Aditya Gupta wrote:
Hi Lianbo,
Just a ping for the series. Any pending reviews for upstreaming it ?
Please wait for another ack.
Maybe Kazu is doing some tests for the patch set or reviewing it.
Thanks
Lianbo
Thanks,
Aditya Gupta
On Mon, Jan 08, 2024 at 04:38:20PM +0800, Lianbo Jiang wrote:
> Hi, Aditya
>
> Thank you for the great job.
>
> The v6 patch set looks good to me, and I did not see any new issues in my
> tests.
>
> So for the v6: Ack.
>
>
> Thanks
>
> Lianbo
>
> On 1/5/24 15:31, devel-request(a)lists.crash-utility.osci.io wrote:
>
>> Date: Fri, 5 Jan 2024 13:00:23 +0530
>> From: Aditya Gupta<adityag(a)linux.ibm.com>
>> Subject: [Crash-utility] [PATCH v6 1/5] ppc64: correct gdb
>> passthroughs by implementing machdep->get_cpu_reg
>> To:<devel@lists.crash-utility.osci.io>,<lijiang@redhat.com>,
>> Tao Liu<ltao(a)redhat.com>
>> Cc: Mahesh J Salgaonkar<mahesh(a)linux.ibm.com>, "Naveen N. Rao"
>> <naveen.n.rao(a)linux.vnet.ibm.com>
>> Message-ID:<20240105073027.378928-2-adityag@linux.ibm.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> Currently, gdb passthroughs of 'bt', 'frame', 'up',
'down', 'info
>> locals' don't work. This is due to gdb not knowing the register values
to
>> unwind the stack frames
>>
>> Every gdb passthrough goes through `gdb_interface`. And then, gdb expects
>> `crash_target::fetch_registers` to give it the register values, which is
>> dependent on `machdep->get_cpu_reg` to read the register values for
>> specific architecture.
>>
>> ┌────────────────────────┐
>> gdb passthrough (eg. "bt") │ │
>> crash ─────────────────────────▶│ │
>> │ gdb_interface │
>> │ │
>> │ │
>> │ ┌────────────────────┐ │
>> fetch_registers │ │ │ │
>> crash_target◀────────────────────────┼─┤ gdb │ │
>> ─────────────────────────┼▶│ │ │
>> Registers (SP,NIP, etc.)│ │ │ │
>> │ │ │ │
>> │ └────────────────────┘ │
>> └────────────────────────┘
>>
>> Implement `machdep->get_cpu_reg` on PPC64, so that crash provides the
>> register values to gdb to unwind stack frames properly
>>
>> With these changes, on powerpc, 'bt' command output in gdb mode, will
look
>> like this:
>>
>> gdb> bt
>> #0 0xc0000000002a53e8 in crash_setup_regs (oldregs=<optimized out>,
newregs=0xc00000000486f8d8) at ./arch/powerpc/include/asm/kexec.h:69
>> #1 __crash_kexec (regs=<optimized out>) at kernel/kexec_core.c:974
>> #2 0xc000000000168918 in panic (fmt=<optimized out>) at
kernel/panic.c:358
>> #3 0xc000000000b735f8 in sysrq_handle_crash (key=<optimized out>) at
drivers/tty/sysrq.c:155
>> #4 0xc000000000b742cc in __handle_sysrq (key=key@entry=99,
check_mask=check_mask@entry=false) at drivers/tty/sysrq.c:602
>> #5 0xc000000000b7506c in write_sysrq_trigger (file=<optimized out>,
buf=<optimized out>, count=2, ppos=<optimized out>) at
drivers/tty/sysrq.c:1163
>> #6 0xc00000000069a7bc in pde_write (ppos=<optimized out>,
count=<optimized out>, buf=<optimized out>, file=<optimized out>,
pde=0xc000000009ed3a80) at fs/proc/inode.c:340
>> #7 proc_reg_write (file=<optimized out>, buf=<optimized out>,
count=<optimized out>, ppos=<optimized out>) at fs/proc/inode.c:352
>> #8 0xc0000000005b3bbc in vfs_write (file=file@entry=0xc00000009dda7d00,
buf=buf@entry=0xebcfc7c6040 <error: Cannot access memory at address 0xebcfc7c6040>,
count=count@entry=2, pos=pos@entry=0xc00000000486fda0) at fs/read_write.c:582
>>
>> instead of earlier output without this patch:
>>
>> gdb> bt
>> #0 <unavailable> in ?? ()
>> Backtrace stopped: previous frame identical to this frame (corrupt stack?)
>>
>> Also, 'get_dumpfile_regs' has been introduced to get registers from
>> multiple supported vmcore formats. Correspondingly a flag
'BT_NO_PRINT_REGS'
>> has been introduced to tell helper functions to get registers, to not
>> print registers with every call to backtrace in gdb.
>>
>> Note: This feature to support GDB unwinding doesn't support live
debugging
>>
>> Signed-off-by: Aditya Gupta<adityag(a)linux.ibm.com>
>> ---
>> defs.h | 122 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> kernel.c | 33 +++++++++++++++
>> ppc64.c | 105 +++++++++++++++++++++++++++++++++++++++++++++--
>> 3 files changed, 257 insertions(+), 3 deletions(-)
>>
>> diff --git a/defs.h b/defs.h
>> index 5218a94fe4a4..615f3a37935a 100644
>> --- a/defs.h
>> +++ b/defs.h
>> @@ -6023,6 +6023,7 @@ int load_module_symbols_helper(char *);
>> void unlink_module(struct load_module *);
>> int check_specified_module_tree(char *, char *);
>> int is_system_call(char *, ulong);
>> +void get_dumpfile_regs(struct bt_info*, ulong*, ulong*);
>> void generic_dump_irq(int);
>> void generic_get_irq_affinity(int);
>> void generic_show_interrupts(int, ulong *);
>> @@ -6121,6 +6122,7 @@ ulong cpu_map_addr(const char *type);
>> #define BT_REGS_NOT_FOUND (0x4000000000000ULL)
>> #define BT_OVERFLOW_STACK (0x8000000000000ULL)
>> #define BT_SKIP_IDLE (0x10000000000000ULL)
>> +#define BT_NO_PRINT_REGS (0x20000000000000ULL)
>> #define BT_SYMBOL_OFFSET (BT_SYMBOLIC_ARGS)
>> #define BT_REF_HEXVAL (0x1)
>> @@ -7854,4 +7856,124 @@ enum x86_64_regnum {
>> LAST_REGNUM
>> };
>> +/*
>> + * Register numbers to make crash_target->fetch_registers()
>> + * ---> machdep->get_cpu_reg() work properly.
>> + *
>> + * These register numbers and names are given according to output of
>> + * `rs6000_register_name`, because that is what was being used by
>> + * crash_target::fetch_registers in case of PPC64
>> + */
>> +enum ppc64_regnum {
>> + PPC64_R0_REGNUM = 0,
>> + PPC64_R1_REGNUM,
>> + PPC64_R2_REGNUM,
>> + PPC64_R3_REGNUM,
>> + PPC64_R4_REGNUM,
>> + PPC64_R5_REGNUM,
>> + PPC64_R6_REGNUM,
>> + PPC64_R7_REGNUM,
>> + PPC64_R8_REGNUM,
>> + PPC64_R9_REGNUM,
>> + PPC64_R10_REGNUM,
>> + PPC64_R11_REGNUM,
>> + PPC64_R12_REGNUM,
>> + PPC64_R13_REGNUM,
>> + PPC64_R14_REGNUM,
>> + PPC64_R15_REGNUM,
>> + PPC64_R16_REGNUM,
>> + PPC64_R17_REGNUM,
>> + PPC64_R18_REGNUM,
>> + PPC64_R19_REGNUM,
>> + PPC64_R20_REGNUM,
>> + PPC64_R21_REGNUM,
>> + PPC64_R22_REGNUM,
>> + PPC64_R23_REGNUM,
>> + PPC64_R24_REGNUM,
>> + PPC64_R25_REGNUM,
>> + PPC64_R26_REGNUM,
>> + PPC64_R27_REGNUM,
>> + PPC64_R28_REGNUM,
>> + PPC64_R29_REGNUM,
>> + PPC64_R30_REGNUM,
>> + PPC64_R31_REGNUM,
>> +
>> + PPC64_F0_REGNUM = 32,
>> + PPC64_F1_REGNUM,
>> + PPC64_F2_REGNUM,
>> + PPC64_F3_REGNUM,
>> + PPC64_F4_REGNUM,
>> + PPC64_F5_REGNUM,
>> + PPC64_F6_REGNUM,
>> + PPC64_F7_REGNUM,
>> + PPC64_F8_REGNUM,
>> + PPC64_F9_REGNUM,
>> + PPC64_F10_REGNUM,
>> + PPC64_F11_REGNUM,
>> + PPC64_F12_REGNUM,
>> + PPC64_F13_REGNUM,
>> + PPC64_F14_REGNUM,
>> + PPC64_F15_REGNUM,
>> + PPC64_F16_REGNUM,
>> + PPC64_F17_REGNUM,
>> + PPC64_F18_REGNUM,
>> + PPC64_F19_REGNUM,
>> + PPC64_F20_REGNUM,
>> + PPC64_F21_REGNUM,
>> + PPC64_F22_REGNUM,
>> + PPC64_F23_REGNUM,
>> + PPC64_F24_REGNUM,
>> + PPC64_F25_REGNUM,
>> + PPC64_F26_REGNUM,
>> + PPC64_F27_REGNUM,
>> + PPC64_F28_REGNUM,
>> + PPC64_F29_REGNUM,
>> + PPC64_F30_REGNUM,
>> + PPC64_F31_REGNUM,
>> +
>> + PPC64_PC_REGNUM = 64,
>> + PPC64_MSR_REGNUM = 65,
>> + PPC64_CR_REGNUM = 66,
>> + PPC64_LR_REGNUM = 67,
>> + PPC64_CTR_REGNUM = 68,
>> + PPC64_XER_REGNUM = 69,
>> + PPC64_FPSCR_REGNUM = 70,
>> +
>> + PPC64_VR0_REGNUM = 106,
>> + PPC64_VR1_REGNUM,
>> + PPC64_VR2_REGNUM,
>> + PPC64_VR3_REGNUM,
>> + PPC64_VR4_REGNUM,
>> + PPC64_VR5_REGNUM,
>> + PPC64_VR6_REGNUM,
>> + PPC64_VR7_REGNUM,
>> + PPC64_VR8_REGNUM,
>> + PPC64_VR9_REGNUM,
>> + PPC64_VR10_REGNUM,
>> + PPC64_VR11_REGNUM,
>> + PPC64_VR12_REGNUM,
>> + PPC64_VR13_REGNUM,
>> + PPC64_VR14_REGNUM,
>> + PPC64_VR15_REGNUM,
>> + PPC64_VR16_REGNUM,
>> + PPC64_VR17_REGNUM,
>> + PPC64_VR18_REGNUM,
>> + PPC64_VR19_REGNUM,
>> + PPC64_VR20_REGNUM,
>> + PPC64_VR21_REGNUM,
>> + PPC64_VR22_REGNUM,
>> + PPC64_VR23_REGNUM,
>> + PPC64_VR24_REGNUM,
>> + PPC64_VR25_REGNUM,
>> + PPC64_VR26_REGNUM,
>> + PPC64_VR27_REGNUM,
>> + PPC64_VR28_REGNUM,
>> + PPC64_VR29_REGNUM,
>> + PPC64_VR30_REGNUM,
>> + PPC64_VR31_REGNUM,
>> +
>> + PPC64_VSCR_REGNUM = 138,
>> + PPC64_VRSAVE_REGNU = 139
>> +};
>> +
>> #endif /* !GDB_COMMON */
>> diff --git a/kernel.c b/kernel.c
>> index 6dcf414693e6..52b7ba09f390 100644
>> --- a/kernel.c
>> +++ b/kernel.c
>> @@ -3533,6 +3533,39 @@ get_lkcd_regs(struct bt_info *bt, ulong *eip, ulong *esp)
>> machdep->get_stack_frame(bt, eip, esp);
>> }
>> +void
>> +get_dumpfile_regs(struct bt_info *bt, ulong *eip, ulong *esp)
>> +{
>> + bt->flags |= BT_NO_PRINT_REGS;
>> +
>> + if (NETDUMP_DUMPFILE())
>> + get_netdump_regs(bt, eip, esp);
>> + else if (KDUMP_DUMPFILE())
>> + get_kdump_regs(bt, eip, esp);
>> + else if (DISKDUMP_DUMPFILE())
>> + get_diskdump_regs(bt, eip, esp);
>> + else if (KVMDUMP_DUMPFILE())
>> + get_kvmdump_regs(bt, eip, esp);
>> + else if (LKCD_DUMPFILE())
>> + get_lkcd_regs(bt, eip, esp);
>> + else if (XENDUMP_DUMPFILE())
>> + get_xendump_regs(bt, eip, esp);
>> + else if (SADUMP_DUMPFILE())
>> + get_sadump_regs(bt, eip, esp);
>> + else if (VMSS_DUMPFILE())
>> + get_vmware_vmss_regs(bt, eip, esp);
>> + else if (REMOTE_PAUSED()) {
>> + if (!is_task_active(bt->task) || !get_remote_regs(bt, eip, esp))
>> + machdep->get_stack_frame(bt, eip, esp);
>> + } else
>> + machdep->get_stack_frame(bt, eip, esp);
>> +
>> + bt->flags &= ~BT_NO_PRINT_REGS;
>> +
>> + bt->instptr = *eip;
>> + bt->stkptr = *esp;
>> +}
>> +
>> /*
>> * Store the head of the kernel module list for future use.
>> diff --git a/ppc64.c b/ppc64.c
>> index e8930a139e0d..ea4821d86b9e 100644
>> --- a/ppc64.c
>> +++ b/ppc64.c
>> @@ -55,6 +55,8 @@ static void ppc64_set_bt_emergency_stack(enum
emergency_stack_type type,
>> static char * ppc64_check_eframe(struct ppc64_pt_regs *);
>> static void ppc64_print_eframe(char *, struct ppc64_pt_regs *,
>> struct bt_info *);
>> +static int ppc64_get_cpu_reg(int cpu, int regno, const char *name, int size,
>> + void *value);
>> static void parse_cmdline_args(void);
>> static int ppc64_paca_percpu_offset_init(int);
>> static void ppc64_init_cpu_info(void);
>> @@ -704,6 +706,8 @@ ppc64_init(int when)
>> error(FATAL, "cannot malloc hwirqstack buffer space.");
>> }
>> + machdep->get_cpu_reg = ppc64_get_cpu_reg;
>> +
>> ppc64_init_paca_info();
>> if (!machdep->hz) {
>> @@ -2501,6 +2505,99 @@ ppc64_print_eframe(char *efrm_str, struct ppc64_pt_regs
*regs,
>> ppc64_print_nip_lr(regs, 1);
>> }
>> +static int
>> +ppc64_get_cpu_reg(int cpu, int regno, const char *name, int size,
>> + void *value)
>> +{
>> + struct bt_info bt_info, bt_setup;
>> + struct task_context *tc;
>> + struct ppc64_pt_regs *pt_regs;
>> + ulong ip, sp;
>> +
>> + if (LIVE()) {
>> + /* doesn't support reading registers in live dump */
>> + return FALSE;
>> + }
>> +
>> + /* Currently only handling registers available in ppc64_pt_regs:
>> + *
>> + * 0-31: r0-r31
>> + * 64: pc/nip
>> + * 65: msr
>> + *
>> + * 67: lr
>> + * 68: ctr
>> + */
>> + switch (regno) {
>> + case PPC64_R0_REGNUM ... PPC64_R31_REGNUM:
>> +
>> + case PPC64_PC_REGNUM:
>> + case PPC64_MSR_REGNUM:
>> + case PPC64_LR_REGNUM:
>> + case PPC64_CTR_REGNUM:
>> + break;
>> +
>> + default:
>> + // return false if we can't get that register
>> + if (CRASHDEBUG(1))
>> + error(WARNING, "unsupported register, regno=%d\n", regno);
>> + return FALSE;
>> + }
>> +
>> + tc = CURRENT_CONTEXT();
>> + BZERO(&bt_setup, sizeof(struct bt_info));
>> + clone_bt_info(&bt_setup, &bt_info, tc);
>> + fill_stackbuf(&bt_info);
>> +
>> + // reusing the get_dumpfile_regs function to get pt regs structure
>> + get_dumpfile_regs(&bt_info, &sp, &ip);
>> + pt_regs = (struct ppc64_pt_regs *)bt_info.machdep;
>> +
>> + if (!pt_regs) {
>> + error(WARNING, "pt_regs not available for cpu %d\n", cpu);
>> + return FALSE;
>> + }
>> +
>> + switch (regno) {
>> + case PPC64_R0_REGNUM ... PPC64_R31_REGNUM:
>> + if (size != sizeof(pt_regs->gpr[regno]))
>> + return FALSE; // size mismatch
>> +
>> + memcpy(value, &pt_regs->gpr[regno], size);
>> + break;
>> +
>> + case PPC64_PC_REGNUM:
>> + if (size != sizeof(pt_regs->nip))
>> + return FALSE; // size mismatch
>> +
>> + memcpy(value, &pt_regs->nip, size);
>> + break;
>> +
>> + case PPC64_MSR_REGNUM:
>> + if (size != sizeof(pt_regs->msr))
>> + return FALSE; // size mismatch
>> +
>> + memcpy(value, &pt_regs->msr, size);
>> + break;
>> +
>> + case PPC64_LR_REGNUM:
>> + if (size != sizeof(pt_regs->link))
>> + return FALSE; // size mismatch
>> +
>> + memcpy(value, &pt_regs->link, size);
>> + break;
>> +
>> + case PPC64_CTR_REGNUM:
>> + if (size != sizeof(pt_regs->ctr))
>> + return FALSE; // size mismatch
>> +
>> + memcpy(value, &pt_regs->ctr, size);
>> + break;
>> + }
>> +
>> + return TRUE;
>> +}
>> +
>> /*
>> * For vmcore typically saved with KDump or FADump, get SP and IP values
>> * from the saved ptregs.
>> @@ -2613,9 +2710,11 @@ ppc64_get_dumpfile_stack_frame(struct bt_info *bt_in,
ulong *nip, ulong *ksp)
>> pt_regs = (struct ppc64_pt_regs *)bt->machdep;
>> ur_nip = pt_regs->nip;
>> ur_ksp = pt_regs->gpr[1];
>> - /* Print the collected regs for panic task. */
>> - ppc64_print_regs(pt_regs);
>> - ppc64_print_nip_lr(pt_regs, 1);
>> + if (!(bt->flags & BT_NO_PRINT_REGS)) {
>> + /* Print the collected regs for panic task. */
>> + ppc64_print_regs(pt_regs);
>> + ppc64_print_nip_lr(pt_regs, 1);
>> + }
>> } else if ((pc->flags & KDUMP) ||
>> ((pc->flags & DISKDUMP) &&
>> (*diskdump_flags & KDUMP_CMPRS_LOCAL))) {
>> -- 2.43.0
6:33 a.m.
New subject: [PATCH v6 1/5] ppc64: correct gdb passthroughs by implementing machdep->get_cpu_reg
Hello Lianbo,
On 22/01/24 15:18, Lianbo Jiang wrote:
Hi, Aditya
On 1/22/24 17:24, Aditya Gupta wrote:
> Hi Lianbo,
>
> Just a ping for the series. Any pending reviews for upstreaming it ?
Please wait for another ack.
Maybe Kazu is doing some tests for the patch set or reviewing it.
Sure Lianbo, thanks for the update.
Thanks,
Aditya Gupta
>
> Thanks
>
> Lianbo
>
>>
>> Thanks,
>> Aditya Gupta
>>
>> On Mon, Jan 08, 2024 at 04:38:20PM +0800, Lianbo Jiang wrote:
>>> Hi, Aditya
>>>
>>> Thank you for the great job.
>>>
>>> The v6 patch set looks good to me, and I did not see any new issues
>>> in my
>>> tests.
>>>
>>> So for the v6: Ack.
>>>
>>>
>>> Thanks
>>>
>>> Lianbo
>>>
>>> On 1/5/24 15:31, devel-request(a)lists.crash-utility.osci.io wrote:
>>>
>>>> Date: Fri, 5 Jan 2024 13:00:23 +0530
>>>> From: Aditya Gupta<adityag(a)linux.ibm.com>
>>>> Subject: [Crash-utility] [PATCH v6 1/5] ppc64: correct gdb
>>>> passthroughs by implementing machdep->get_cpu_reg
>>>> To:<devel@lists.crash-utility.osci.io>,<lijiang@redhat.com>,
>>>> Tao Liu<ltao(a)redhat.com>
>>>> Cc: Mahesh J Salgaonkar<mahesh(a)linux.ibm.com>, "Naveen N.
Rao"
>>>> <naveen.n.rao(a)linux.vnet.ibm.com>
>>>> Message-ID:<20240105073027.378928-2-adityag@linux.ibm.com>
>>>> Content-Type: text/plain; charset=UTF-8
>>>>
>>>> Currently, gdb passthroughs of 'bt', 'frame',
'up', 'down', 'info
>>>> locals' don't work. This is due to gdb not knowing the register
>>>> values to
>>>> unwind the stack frames
>>>>
>>>> Every gdb passthrough goes through `gdb_interface`. And then, gdb
>>>> expects
>>>> `crash_target::fetch_registers` to give it the register values,
>>>> which is
>>>> dependent on `machdep->get_cpu_reg` to read the register values for
>>>> specific architecture.
>>>>
>>>> ┌────────────────────────┐
>>>> gdb passthrough (eg. "bt")
│ │
>>>> crash ─────────────────────────▶│ │
>>>> │ gdb_interface │
>>>> │ │
>>>> │ │
>>>> │ ┌────────────────────┐ │
>>>> fetch_registers │ │ │ │
>>>> crash_target◀────────────────────────┼─┤ gdb │ │
>>>> ─────────────────────────┼▶│ │ │
>>>> Registers (SP,NIP, etc.)│ │ │ │
>>>> │ │ │ │
>>>> │ └────────────────────┘ │
>>>> └────────────────────────┘
>>>>
>>>> Implement `machdep->get_cpu_reg` on PPC64, so that crash provides the
>>>> register values to gdb to unwind stack frames properly
>>>>
>>>> With these changes, on powerpc, 'bt' command output in gdb mode,
>>>> will look
>>>> like this:
>>>>
>>>> gdb> bt
>>>> #0 0xc0000000002a53e8 in crash_setup_regs
>>>> (oldregs=<optimized out>, newregs=0xc00000000486f8d8) at
>>>> ./arch/powerpc/include/asm/kexec.h:69
>>>> #1 __crash_kexec (regs=<optimized out>) at
>>>> kernel/kexec_core.c:974
>>>> #2 0xc000000000168918 in panic (fmt=<optimized out>) at
>>>> kernel/panic.c:358
>>>> #3 0xc000000000b735f8 in sysrq_handle_crash (key=<optimized
>>>> out>) at drivers/tty/sysrq.c:155
>>>> #4 0xc000000000b742cc in __handle_sysrq (key=key@entry=99,
>>>> check_mask=check_mask@entry=false) at drivers/tty/sysrq.c:602
>>>> #5 0xc000000000b7506c in write_sysrq_trigger
>>>> (file=<optimized out>, buf=<optimized out>, count=2,
>>>> ppos=<optimized out>) at drivers/tty/sysrq.c:1163
>>>> #6 0xc00000000069a7bc in pde_write (ppos=<optimized out>,
>>>> count=<optimized out>, buf=<optimized out>,
file=<optimized out>,
>>>> pde=0xc000000009ed3a80) at fs/proc/inode.c:340
>>>> #7 proc_reg_write (file=<optimized out>, buf=<optimized
>>>> out>, count=<optimized out>, ppos=<optimized out>) at
>>>> fs/proc/inode.c:352
>>>> #8 0xc0000000005b3bbc in vfs_write
>>>> (file=file@entry=0xc00000009dda7d00, buf=buf@entry=0xebcfc7c6040
>>>> <error: Cannot access memory at address 0xebcfc7c6040>,
>>>> count=count@entry=2, pos=pos@entry=0xc00000000486fda0) at
>>>> fs/read_write.c:582
>>>>
>>>> instead of earlier output without this patch:
>>>>
>>>> gdb> bt
>>>> #0 <unavailable> in ?? ()
>>>> Backtrace stopped: previous frame identical to this frame
>>>> (corrupt stack?)
>>>>
>>>> Also, 'get_dumpfile_regs' has been introduced to get registers
from
>>>> multiple supported vmcore formats. Correspondingly a flag
>>>> 'BT_NO_PRINT_REGS'
>>>> has been introduced to tell helper functions to get registers, to not
>>>> print registers with every call to backtrace in gdb.
>>>>
>>>> Note: This feature to support GDB unwinding doesn't support live
>>>> debugging
>>>>
>>>> Signed-off-by: Aditya Gupta<adityag(a)linux.ibm.com>
>>>> ---
>>>> defs.h | 122
>>>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>> kernel.c | 33 +++++++++++++++
>>>> ppc64.c | 105 +++++++++++++++++++++++++++++++++++++++++++++--
>>>> 3 files changed, 257 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/defs.h b/defs.h
>>>> index 5218a94fe4a4..615f3a37935a 100644
>>>> --- a/defs.h
>>>> +++ b/defs.h
>>>> @@ -6023,6 +6023,7 @@ int load_module_symbols_helper(char *);
>>>> void unlink_module(struct load_module *);
>>>> int check_specified_module_tree(char *, char *);
>>>> int is_system_call(char *, ulong);
>>>> +void get_dumpfile_regs(struct bt_info*, ulong*, ulong*);
>>>> void generic_dump_irq(int);
>>>> void generic_get_irq_affinity(int);
>>>> void generic_show_interrupts(int, ulong *);
>>>> @@ -6121,6 +6122,7 @@ ulong cpu_map_addr(const char *type);
>>>> #define BT_REGS_NOT_FOUND (0x4000000000000ULL)
>>>> #define BT_OVERFLOW_STACK (0x8000000000000ULL)
>>>> #define BT_SKIP_IDLE (0x10000000000000ULL)
>>>> +#define BT_NO_PRINT_REGS (0x20000000000000ULL)
>>>> #define BT_SYMBOL_OFFSET (BT_SYMBOLIC_ARGS)
>>>> #define BT_REF_HEXVAL (0x1)
>>>> @@ -7854,4 +7856,124 @@ enum x86_64_regnum {
>>>> LAST_REGNUM
>>>> };
>>>> +/*
>>>> + * Register numbers to make crash_target->fetch_registers()
>>>> + * ---> machdep->get_cpu_reg() work properly.
>>>> + *
>>>> + * These register numbers and names are given according to output of
>>>> + * `rs6000_register_name`, because that is what was being used by
>>>> + * crash_target::fetch_registers in case of PPC64
>>>> + */
>>>> +enum ppc64_regnum {
>>>> + PPC64_R0_REGNUM = 0,
>>>> + PPC64_R1_REGNUM,
>>>> + PPC64_R2_REGNUM,
>>>> + PPC64_R3_REGNUM,
>>>> + PPC64_R4_REGNUM,
>>>> + PPC64_R5_REGNUM,
>>>> + PPC64_R6_REGNUM,
>>>> + PPC64_R7_REGNUM,
>>>> + PPC64_R8_REGNUM,
>>>> + PPC64_R9_REGNUM,
>>>> + PPC64_R10_REGNUM,
>>>> + PPC64_R11_REGNUM,
>>>> + PPC64_R12_REGNUM,
>>>> + PPC64_R13_REGNUM,
>>>> + PPC64_R14_REGNUM,
>>>> + PPC64_R15_REGNUM,
>>>> + PPC64_R16_REGNUM,
>>>> + PPC64_R17_REGNUM,
>>>> + PPC64_R18_REGNUM,
>>>> + PPC64_R19_REGNUM,
>>>> + PPC64_R20_REGNUM,
>>>> + PPC64_R21_REGNUM,
>>>> + PPC64_R22_REGNUM,
>>>> + PPC64_R23_REGNUM,
>>>> + PPC64_R24_REGNUM,
>>>> + PPC64_R25_REGNUM,
>>>> + PPC64_R26_REGNUM,
>>>> + PPC64_R27_REGNUM,
>>>> + PPC64_R28_REGNUM,
>>>> + PPC64_R29_REGNUM,
>>>> + PPC64_R30_REGNUM,
>>>> + PPC64_R31_REGNUM,
>>>> +
>>>> + PPC64_F0_REGNUM = 32,
>>>> + PPC64_F1_REGNUM,
>>>> + PPC64_F2_REGNUM,
>>>> + PPC64_F3_REGNUM,
>>>> + PPC64_F4_REGNUM,
>>>> + PPC64_F5_REGNUM,
>>>> + PPC64_F6_REGNUM,
>>>> + PPC64_F7_REGNUM,
>>>> + PPC64_F8_REGNUM,
>>>> + PPC64_F9_REGNUM,
>>>> + PPC64_F10_REGNUM,
>>>> + PPC64_F11_REGNUM,
>>>> + PPC64_F12_REGNUM,
>>>> + PPC64_F13_REGNUM,
>>>> + PPC64_F14_REGNUM,
>>>> + PPC64_F15_REGNUM,
>>>> + PPC64_F16_REGNUM,
>>>> + PPC64_F17_REGNUM,
>>>> + PPC64_F18_REGNUM,
>>>> + PPC64_F19_REGNUM,
>>>> + PPC64_F20_REGNUM,
>>>> + PPC64_F21_REGNUM,
>>>> + PPC64_F22_REGNUM,
>>>> + PPC64_F23_REGNUM,
>>>> + PPC64_F24_REGNUM,
>>>> + PPC64_F25_REGNUM,
>>>> + PPC64_F26_REGNUM,
>>>> + PPC64_F27_REGNUM,
>>>> + PPC64_F28_REGNUM,
>>>> + PPC64_F29_REGNUM,
>>>> + PPC64_F30_REGNUM,
>>>> + PPC64_F31_REGNUM,
>>>> +
>>>> + PPC64_PC_REGNUM = 64,
>>>> + PPC64_MSR_REGNUM = 65,
>>>> + PPC64_CR_REGNUM = 66,
>>>> + PPC64_LR_REGNUM = 67,
>>>> + PPC64_CTR_REGNUM = 68,
>>>> + PPC64_XER_REGNUM = 69,
>>>> + PPC64_FPSCR_REGNUM = 70,
>>>> +
>>>> + PPC64_VR0_REGNUM = 106,
>>>> + PPC64_VR1_REGNUM,
>>>> + PPC64_VR2_REGNUM,
>>>> + PPC64_VR3_REGNUM,
>>>> + PPC64_VR4_REGNUM,
>>>> + PPC64_VR5_REGNUM,
>>>> + PPC64_VR6_REGNUM,
>>>> + PPC64_VR7_REGNUM,
>>>> + PPC64_VR8_REGNUM,
>>>> + PPC64_VR9_REGNUM,
>>>> + PPC64_VR10_REGNUM,
>>>> + PPC64_VR11_REGNUM,
>>>> + PPC64_VR12_REGNUM,
>>>> + PPC64_VR13_REGNUM,
>>>> + PPC64_VR14_REGNUM,
>>>> + PPC64_VR15_REGNUM,
>>>> + PPC64_VR16_REGNUM,
>>>> + PPC64_VR17_REGNUM,
>>>> + PPC64_VR18_REGNUM,
>>>> + PPC64_VR19_REGNUM,
>>>> + PPC64_VR20_REGNUM,
>>>> + PPC64_VR21_REGNUM,
>>>> + PPC64_VR22_REGNUM,
>>>> + PPC64_VR23_REGNUM,
>>>> + PPC64_VR24_REGNUM,
>>>> + PPC64_VR25_REGNUM,
>>>> + PPC64_VR26_REGNUM,
>>>> + PPC64_VR27_REGNUM,
>>>> + PPC64_VR28_REGNUM,
>>>> + PPC64_VR29_REGNUM,
>>>> + PPC64_VR30_REGNUM,
>>>> + PPC64_VR31_REGNUM,
>>>> +
>>>> + PPC64_VSCR_REGNUM = 138,
>>>> + PPC64_VRSAVE_REGNU = 139
>>>> +};
>>>> +
>>>> #endif /* !GDB_COMMON */
>>>> diff --git a/kernel.c b/kernel.c
>>>> index 6dcf414693e6..52b7ba09f390 100644
>>>> --- a/kernel.c
>>>> +++ b/kernel.c
>>>> @@ -3533,6 +3533,39 @@ get_lkcd_regs(struct bt_info *bt, ulong
>>>> *eip, ulong *esp)
>>>> machdep->get_stack_frame(bt, eip, esp);
>>>> }
>>>> +void
>>>> +get_dumpfile_regs(struct bt_info *bt, ulong *eip, ulong *esp)
>>>> +{
>>>> + bt->flags |= BT_NO_PRINT_REGS;
>>>> +
>>>> + if (NETDUMP_DUMPFILE())
>>>> + get_netdump_regs(bt, eip, esp);
>>>> + else if (KDUMP_DUMPFILE())
>>>> + get_kdump_regs(bt, eip, esp);
>>>> + else if (DISKDUMP_DUMPFILE())
>>>> + get_diskdump_regs(bt, eip, esp);
>>>> + else if (KVMDUMP_DUMPFILE())
>>>> + get_kvmdump_regs(bt, eip, esp);
>>>> + else if (LKCD_DUMPFILE())
>>>> + get_lkcd_regs(bt, eip, esp);
>>>> + else if (XENDUMP_DUMPFILE())
>>>> + get_xendump_regs(bt, eip, esp);
>>>> + else if (SADUMP_DUMPFILE())
>>>> + get_sadump_regs(bt, eip, esp);
>>>> + else if (VMSS_DUMPFILE())
>>>> + get_vmware_vmss_regs(bt, eip, esp);
>>>> + else if (REMOTE_PAUSED()) {
>>>> + if (!is_task_active(bt->task) || !get_remote_regs(bt, eip,
>>>> esp))
>>>> + machdep->get_stack_frame(bt, eip, esp);
>>>> + } else
>>>> + machdep->get_stack_frame(bt, eip, esp);
>>>> +
>>>> + bt->flags &= ~BT_NO_PRINT_REGS;
>>>> +
>>>> + bt->instptr = *eip;
>>>> + bt->stkptr = *esp;
>>>> +}
>>>> +
>>>> /*
>>>> * Store the head of the kernel module list for future use.
>>>> diff --git a/ppc64.c b/ppc64.c
>>>> index e8930a139e0d..ea4821d86b9e 100644
>>>> --- a/ppc64.c
>>>> +++ b/ppc64.c
>>>> @@ -55,6 +55,8 @@ static void ppc64_set_bt_emergency_stack(enum
>>>> emergency_stack_type type,
>>>> static char * ppc64_check_eframe(struct ppc64_pt_regs *);
>>>> static void ppc64_print_eframe(char *, struct ppc64_pt_regs *,
>>>> struct bt_info *);
>>>> +static int ppc64_get_cpu_reg(int cpu, int regno, const char *name,
>>>> int size,
>>>> + void *value);
>>>> static void parse_cmdline_args(void);
>>>> static int ppc64_paca_percpu_offset_init(int);
>>>> static void ppc64_init_cpu_info(void);
>>>> @@ -704,6 +706,8 @@ ppc64_init(int when)
>>>> error(FATAL, "cannot malloc hwirqstack buffer
>>>> space.");
>>>> }
>>>> + machdep->get_cpu_reg = ppc64_get_cpu_reg;
>>>> +
>>>> ppc64_init_paca_info();
>>>> if (!machdep->hz) {
>>>> @@ -2501,6 +2505,99 @@ ppc64_print_eframe(char *efrm_str, struct
>>>> ppc64_pt_regs *regs,
>>>> ppc64_print_nip_lr(regs, 1);
>>>> }
>>>> +static int
>>>> +ppc64_get_cpu_reg(int cpu, int regno, const char *name, int size,
>>>> + void *value)
>>>> +{
>>>> + struct bt_info bt_info, bt_setup;
>>>> + struct task_context *tc;
>>>> + struct ppc64_pt_regs *pt_regs;
>>>> + ulong ip, sp;
>>>> +
>>>> + if (LIVE()) {
>>>> + /* doesn't support reading registers in live dump */
>>>> + return FALSE;
>>>> + }
>>>> +
>>>> + /* Currently only handling registers available in ppc64_pt_regs:
>>>> + *
>>>> + * 0-31: r0-r31
>>>> + * 64: pc/nip
>>>> + * 65: msr
>>>> + *
>>>> + * 67: lr
>>>> + * 68: ctr
>>>> + */
>>>> + switch (regno) {
>>>> + case PPC64_R0_REGNUM ... PPC64_R31_REGNUM:
>>>> +
>>>> + case PPC64_PC_REGNUM:
>>>> + case PPC64_MSR_REGNUM:
>>>> + case PPC64_LR_REGNUM:
>>>> + case PPC64_CTR_REGNUM:
>>>> + break;
>>>> +
>>>> + default:
>>>> + // return false if we can't get that register
>>>> + if (CRASHDEBUG(1))
>>>> + error(WARNING, "unsupported register, regno=%d\n",
>>>> regno);
>>>> + return FALSE;
>>>> + }
>>>> +
>>>> + tc = CURRENT_CONTEXT();
>>>> + BZERO(&bt_setup, sizeof(struct bt_info));
>>>> + clone_bt_info(&bt_setup, &bt_info, tc);
>>>> + fill_stackbuf(&bt_info);
>>>> +
>>>> + // reusing the get_dumpfile_regs function to get pt regs
>>>> structure
>>>> + get_dumpfile_regs(&bt_info, &sp, &ip);
>>>> + pt_regs = (struct ppc64_pt_regs *)bt_info.machdep;
>>>> +
>>>> + if (!pt_regs) {
>>>> + error(WARNING, "pt_regs not available for cpu %d\n",
cpu);
>>>> + return FALSE;
>>>> + }
>>>> +
>>>> + switch (regno) {
>>>> + case PPC64_R0_REGNUM ... PPC64_R31_REGNUM:
>>>> + if (size != sizeof(pt_regs->gpr[regno]))
>>>> + return FALSE; // size mismatch
>>>> +
>>>> + memcpy(value, &pt_regs->gpr[regno], size);
>>>> + break;
>>>> +
>>>> + case PPC64_PC_REGNUM:
>>>> + if (size != sizeof(pt_regs->nip))
>>>> + return FALSE; // size mismatch
>>>> +
>>>> + memcpy(value, &pt_regs->nip, size);
>>>> + break;
>>>> +
>>>> + case PPC64_MSR_REGNUM:
>>>> + if (size != sizeof(pt_regs->msr))
>>>> + return FALSE; // size mismatch
>>>> +
>>>> + memcpy(value, &pt_regs->msr, size);
>>>> + break;
>>>> +
>>>> + case PPC64_LR_REGNUM:
>>>> + if (size != sizeof(pt_regs->link))
>>>> + return FALSE; // size mismatch
>>>> +
>>>> + memcpy(value, &pt_regs->link, size);
>>>> + break;
>>>> +
>>>> + case PPC64_CTR_REGNUM:
>>>> + if (size != sizeof(pt_regs->ctr))
>>>> + return FALSE; // size mismatch
>>>> +
>>>> + memcpy(value, &pt_regs->ctr, size);
>>>> + break;
>>>> + }
>>>> +
>>>> + return TRUE;
>>>> +}
>>>> +
>>>> /*
>>>> * For vmcore typically saved with KDump or FADump, get SP and
>>>> IP values
>>>> * from the saved ptregs.
>>>> @@ -2613,9 +2710,11 @@ ppc64_get_dumpfile_stack_frame(struct
>>>> bt_info *bt_in, ulong *nip, ulong *ksp)
>>>> pt_regs = (struct ppc64_pt_regs *)bt->machdep;
>>>> ur_nip = pt_regs->nip;
>>>> ur_ksp = pt_regs->gpr[1];
>>>> - /* Print the collected regs for panic task. */
>>>> - ppc64_print_regs(pt_regs);
>>>> - ppc64_print_nip_lr(pt_regs, 1);
>>>> + if (!(bt->flags & BT_NO_PRINT_REGS)) {
>>>> + /* Print the collected regs for panic task. */
>>>> + ppc64_print_regs(pt_regs);
>>>> + ppc64_print_nip_lr(pt_regs, 1);
>>>> + }
>>>> } else if ((pc->flags & KDUMP) ||
>>>> ((pc->flags & DISKDUMP) &&
>>>> (*diskdump_flags & KDUMP_CMPRS_LOCAL))) {
>>>> -- 2.43.0
>
12:57 a.m.
New subject: [PATCH v6 1/5] ppc64: correct gdb passthroughs by implementing machdep->get_cpu_reg
On 2024/01/22 21:33, Aditya Gupta wrote:
Hello Lianbo,
On 22/01/24 15:18, Lianbo Jiang wrote:
> Hi, Aditya
>
> On 1/22/24 17:24, Aditya Gupta wrote:
>
>> Hi Lianbo,
>>
>> Just a ping for the series. Any pending reviews for upstreaming it ?
Hi Aditya,
sorry for the delay.
Is it possible to upload a sample ppc64le vmcore and vmlinux somewhere
off-list? I would like to check the behavior at my end, probably
ppc64le vmcores can be processed by x86_64 crash for ppc64 vmcore.
Thanks,
Kazu
2:29 a.m.
New subject: [PATCH v6 1/5] ppc64: correct gdb passthroughs by implementing machdep->get_cpu_reg
On 2024/01/24 15:57, HAGIO KAZUHITO(萩尾 一仁) wrote:
Is it possible to upload a sample ppc64le vmcore and vmlinux
somewhere
off-list? I would like to check the behavior at my end, probably
ppc64le vmcores can be processed by x86_64 crash for ppc64 vmcore.
Thanks for the sample vmlinux and vmcore.
I'm still reviewing the patches and "gdb bt" looks good to me, but it
looks like "gdb info threads" calls GETBUF() too much. and the next
same command fails.
$ crash-ppc64 vmlinux vmcore
...
crash-ppc64> gdb info threads
Id Target Id Frame
1 CPU 0 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
2 CPU 1 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
3 CPU 2 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
...
42 CPU 41 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
* 43 CPU 42 0xc00000000005ae44 in crash_fadump (regs=0x0,
str=0xc000000002c0a6a0 <buf> "sysrq triggered crash") at
arch/powerpc/kernel/fadump.c:728
44 CPU 43 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
...
54 CPU 53 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
55 CPU 54 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
buf_1K_used: 50
buf_2K_used: 10
buf_4K_used: 2
buf_8K_used: 0
buf_32K_used: 3
...
malloc_bp[1997]: 8f3db90
malloc_bp[1998]: 8f41ba0
malloc_bp[1999]: 8f45bb0
smallest: 24
largest: 2883584
embedded: 2003
max_embedded: 2003
mallocs: 2162
frees: 162
reqs/total: 2228/41701642
average size: 18717
gdb: cannot allocate any more memory!
crash-ppc64>
crash-ppc64> gdb info threads
ui-out.c:357: internal-error: tables cannot be nested; table_begin found before previous
table_end.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
Doesn't this happen on ppc64 machines?
There might be lack of FREEBUF() somewhere.
Thanks,
Kazu
12:03 a.m.
New subject: [PATCH v6 1/5] ppc64: correct gdb passthroughs by implementing machdep->get_cpu_reg
Hi Kazu,
On Thu, Feb 01, 2024 at 08:29:01AM +0000, HAGIO KAZUHITO(萩尾 一仁) wrote:
On 2024/01/24 15:57, HAGIO KAZUHITO(萩尾 一仁) wrote:
> Is it possible to upload a sample ppc64le vmcore and vmlinux somewhere
> off-list? I would like to check the behavior at my end, probably
> ppc64le vmcores can be processed by x86_64 crash for ppc64 vmcore.
Thanks for the sample vmlinux and vmcore.
I'm still reviewing the patches and "gdb bt" looks good to me, but it
looks like "gdb info threads" calls GETBUF() too much. and the next
same command fails.
$ crash-ppc64 vmlinux vmcore
...
crash-ppc64> gdb info threads
Id Target Id Frame
1 CPU 0 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
2 CPU 1 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
3 CPU 2 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
...
42 CPU 41 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
* 43 CPU 42 0xc00000000005ae44 in crash_fadump (regs=0x0,
str=0xc000000002c0a6a0 <buf> "sysrq triggered crash") at
arch/powerpc/kernel/fadump.c:728
44 CPU 43 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
...
54 CPU 53 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
55 CPU 54 plpar_hcall_norets_notrace () at
arch/powerpc/platforms/pseries/hvCall.S:114
buf_1K_used: 50
buf_2K_used: 10
buf_4K_used: 2
buf_8K_used: 0
buf_32K_used: 3
...
malloc_bp[1997]: 8f3db90
malloc_bp[1998]: 8f41ba0
malloc_bp[1999]: 8f45bb0
smallest: 24
largest: 2883584
embedded: 2003
max_embedded: 2003
mallocs: 2162
frees: 162
reqs/total: 2228/41701642
average size: 18717
gdb: cannot allocate any more memory!
crash-ppc64>
crash-ppc64> gdb info threads
ui-out.c:357: internal-error: tables cannot be nested; table_begin found before previous
table_end.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
Doesn't this happen on ppc64 machines?
There might be lack of FREEBUF() somewhere.
Thanks for the hint about missing FREEBUF, yes, a FREEBUF was missing
in `ppc64_get_cpu_reg`, where the stack memory was allocated a buffer,
everytime `ppc64_get_cpu_reg` was called.
I have fixed in v7. I don't know why I didn't hit it before.
Thanks,
Aditya Gupta
>
> Thanks,
> Kazu
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devel@lists.crash-utility.osci.io
7 comments
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participants (3)
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Aditya Gupta -
HAGIO KAZUHITO(萩尾 一仁) -
Lianbo Jiang