[Crash-utility] Re: [PATCH v2] Fix a segfault issue due to the incorrect irq_stack_size on ARM64

Hi Tao, I have tested this new patch-v2, and it works well in both branches.

Thanks, Yeping Tao Liu <ltao(a)redhat.com&gt; 于2024年8月14日周三 07:41写道： > > See the following stack trace: > (gdb) bt > #0 0x00005635ac2b166b in arm64_unwind_frame (frame=0x7ffdaf35cb70, > bt=0x7ffdaf35d430) at arm64.c:2821 > #1 arm64_back_trace_cmd (bt=0x7ffdaf35d430) at arm64.c:3306 > #2 0x00005635ac27b108 in back_trace (bt=bt@entry=0x7ffdaf35d430) at > kernel.c:3239 > #3 0x00005635ac2880ae in cmd_bt () at kernel.c:2863 > #4 0x00005635ac1f16dc in exec_command () at main.c:893 > #5 0x00005635ac1f192a in main_loop () at main.c:840 > #6 0x00005635ac50df81 in captured_main (data=<optimized out>) at main.c:1284 > #7 gdb_main (args=<optimized out>) at main.c:1313 > #8 0x00005635ac50e000 in gdb_main_entry (argc=<optimized out>, > argv=<optimized out>) at main.c:1338 > #9 0x00005635ac1ea2a5 in main (argc=5, argv=0x7ffdaf35dde8) at main.c:721 > > The issue may be encountered when thread_union symbol not found in vmlinux > due to compiling optimization. > > This patch will try the following 2 methods to get the irq_stack_size > when thread_union symbol unavailable: > > 1. change the thread_shift when KASAN is enabled and with vmcoreinfo. > In arm64/include/asm/memory.h: > > #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) > ... > #define IRQ_STACK_SIZE THREAD_SIZE > > Since enabling the KASAN will affect the final value, > this patch reset IRQ_STACK_SIZE according to the calculation process in > kernel code. > > 2. Try getting the value from kernel code disassembly, to get > THREAD_SHIFT directly from tbnz instruction. > > In arch/arm64/kernel/entry.S: > .macro kernel_ventry, el:req, ht:req, regsize:req, label:req > ... > add sp, sp, x0 > sub x0, sp, x0 > tbnz x0, #THREAD_SHIFT, 0f > > $ gdb vmlinux > (gdb) disass vectors > Dump of assembler code for function vectors: > ... > 0xffff800080010804 <+4>: add sp, sp, x0 > 0xffff800080010808 <+8>: sub x0, sp, x0 > 0xffff80008001080c <+12>: tbnz w0, #16, 0xffff80008001081c <vectors+28> > > Signed-off-by: yeping.zheng <yeping.zheng(a)nio.com&gt; > Improved-by: Tao Liu <ltao(a)redhat.com&gt; > --- > > v2 -> v1: Add stack_vm_area member check for task_struct, and kernel > file reference. > > Hi Yeping & lianbo, > > Please have a test on this version of patch, I guess this will be the > last version if test is passed. Thanks in advance! > > Thanks, > Tao Liu > > --- > arm64.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 61 insertions(+), 2 deletions(-) > > diff --git a/arm64.c b/arm64.c > index 067c879..332e3f0 100644 > --- a/arm64.c > +++ b/arm64.c > @@ -95,6 +95,7 @@ static int arm64_is_uvaddr(ulong, struct task_context *); > static void arm64_calc_KERNELPACMASK(void); > static void arm64_recalc_KERNELPACMASK(void); > static int arm64_get_vmcoreinfo(unsigned long *vaddr, const char *label, int base); > +static ulong arm64_set_irq_stack_size(void); > > struct kernel_range { > unsigned long modules_vaddr, modules_end; > @@ -2340,8 +2341,10 @@ arm64_irq_stack_init(void) > if (MEMBER_EXISTS("thread_union", "stack")) { > if ((sz = MEMBER_SIZE("thread_union", "stack")) > 0) > ms->irq_stack_size = sz; > - } else > - ms->irq_stack_size = ARM64_IRQ_STACK_SIZE; > + } else { > + ulong res = arm64_set_irq_stack_size(); > + ms->irq_stack_size = (res > 0) ? res : ARM64_IRQ_STACK_SIZE; > + } > > machdep->flags |= IRQ_STACKS; > > @@ -5056,6 +5059,62 @@ static void arm64_recalc_KERNELPACMASK(void){ > } > } > > +static ulong arm64_set_irq_stack_size(void) > +{ > + int min_thread_shift = 14; > + ulong thread_shift = 0; > + char buf1[BUFSIZE]; > + char *pos1, *pos2; > + int errflag = 0; > + > + if (kernel_symbol_exists("vmcoreinfo_data") && > + kernel_symbol_exists("vmcoreinfo_size")) { > + /* > + * Referring to arch/arm64/include/asm/memory.h > + */ > + if (kernel_symbol_exists("kasan_enable_current")) { > + min_thread_shift += 1; > + } > + if (MEMBER_EXISTS("task_struct", "stack_vm_area") && > + min_thread_shift < machdep->pageshift) { > + thread_shift = machdep->pageshift; > + } else { > + thread_shift = min_thread_shift; > + } > + } else { > + sprintf(buf1, "x/32i vectors"); > + open_tmpfile(); > + if (!gdb_pass_through(buf1, pc->tmpfile, GNU_RETURN_ON_ERROR)) { > + goto out; > + } > + rewind(pc->tmpfile); > + while (fgets(buf1, BUFSIZE, pc->tmpfile)) { > + if ((pos1 = strstr(buf1, "tbnz"))) { > + if ((pos2 = strchr(pos1, '#'))) { > + pos2 += 1; > + for (pos1 = pos2; > + *pos2 != '\0' && *pos2 != ','; > + pos2++); > + *pos2 = '\0'; > + thread_shift = stol(pos1, > + RETURN_ON_ERROR|QUIET, &errflag); > + if (errflag) { > + thread_shift = 0; > + } > + break; > + } > + } > + } > +out: > + close_tmpfile(); > + } > + > + if (thread_shift) > + return ((1UL) << thread_shift); > + else > + return 0; > +} > + > #endif /* ARM64 */ > > > -- > 2.40.1 > -- > Crash-utility mailing list -- devel(a)lists.crash-utility.osci.io > To unsubscribe send an email to devel-leave(a)lists.crash-utility.osci.io > https://${domain_name}/admin/lists/devel.lists.crash-utility.osci.io/ > Contribution Guidelines: https://github.com/crash-utility/crash/wiki