[Crash-utility] Re: [PATCH v1 2/5] Call cmd_bt silently after "set pid"

Date: Fri, 3 Jan 2025 18:48:14 +1300 From: Tao Liu <ltao(a)redhat.com&gt; Subject: [Crash-utility] [PATCH v1 2/5] Call cmd_bt silently after "set pid" To: devel(a)lists.crash-utility.osci.io Cc: alexey.makhalov(a)broadcom.com Message-ID: <20250103054817.364053-3-ltao(a)redhat.com&gt; Content-Type: text/plain; charset="US-ASCII"; x-default=true Cmd bt will list multi-stacks of one task. After we "set <pid>" switch context to one task, we first need a bt call to detect the multi-stacks, however we don't want any console output from it, so a nullfp is used for output receive. The silent bt call is only triggered once as part of task context switch by cmd set. A array of user_regs pointers is reserved for each supported arch. If one extra stack found, a user_regs structure will be allocated for storing regs value of the stack. Co-developed-by: Alexey Makhalov <alexey.makhalov(a)broadcom.com&gt; Co-developed-by: Tao Liu <ltao(a)redhat.com&gt; Signed-off-by: Tao Liu <ltao(a)redhat.com&gt; --- arm64.c | 4 ++++ crash_target.c | 5 +++++ gdb-10.2.patch | 2 +- kernel.c | 20 ++++++++++++++++++++ ppc64.c | 4 ++++ x86_64.c | 3 +++ 6 files changed, 37 insertions(+), 1 deletion(-) diff --git a/arm64.c b/arm64.c index 1cdde5f..8291301 100644 --- a/arm64.c +++ b/arm64.c @@ -126,6 +126,10 @@ struct user_regs_bitmap_struct { ulong bitmap[32]; };

+ulong extra_stacks_idx = 0; +struct user_regs_bitmap_struct *extra_stacks_regs[MAX_EXCEPTION_STACKS] = {0}; +

{ /* check for ARM64_MTE enabled */ diff --git a/crash_target.c b/crash_target.c index c5ad1df..8cfa744 100644 --- a/crash_target.c +++ b/crash_target.c @@ -31,6 +31,9 @@ extern "C" int crash_get_current_task_reg (int regno, const char *regname, extern "C" int gdb_change_thread_context (void); extern "C" int gdb_add_substack (int); extern "C" void crash_get_current_task_info(unsigned long *pid, char **comm); +#if defined (TARGET_X86_64) || defined (TARGET_ARM64) || defined (TARGET_PPC64) +extern "C" void silent_call_bt(void); +#endif /* The crash target. */ @@ -164,6 +165,10 @@ gdb_change_thread_context (void) /* 3rd, refresh regcache for tid 0 */ target_fetch_registers(get_current_regcache(), -1); reinit_frame_cache(); +#if defined (TARGET_X86_64) || defined (TARGET_ARM64) || defined (TARGET_PPC64) + /* 4th, invoke bt silently to refresh the additional stacks */ + silent_call_bt();

return TRUE; } diff --git a/gdb-10.2.patch b/gdb-10.2.patch index c867660..7baa925 100644 --- a/gdb-10.2.patch +++ b/gdb-10.2.patch @@ -55,7 +55,7 @@ exit 0 # your system doesn't have fcntl.h in /usr/include (which is where it # should be according to Posix). -DEFS = @DEFS@ -+DEFS = -DCRASH_MERGE @DEFS@ ++DEFS = -DCRASH_MERGE -DTARGET_${CRASH_TARGET} @DEFS@ GDB_CFLAGS = -I. -I$(srcdir) -I$(srcdir)/config \ -DLOCALEDIR="\"$(localedir)\"" $(DEFS) diff --git a/kernel.c b/kernel.c index 8c2e0ca..1c8f500 100644 --- a/kernel.c +++ b/kernel.c @@ -12001,3 +12001,23 @@ int get_linux_banner_from_vmlinux(char *buf, size_t size) return TRUE; } + +#if defined(X86_64) || defined(ARM64) || defined(PPC64) +extern ulong extra_stacks_idx; +extern void *extra_stacks_regs[]; +void silent_call_bt(void) +{ + FILE *fp_save = fp; + fp = pc->nullfp; + + for (int i = 0; i < extra_stacks_idx; i++) { + FREEBUF(extra_stacks_regs[i]); + extra_stacks_regs[i] = NULL; + } + sprintf(pc->command_line, "bt\n"); + argcnt = parse_line(pc->command_line, args); + optind = 1; + cmd_bt(); + fp = fp_save; +} +#endif \ No newline at end of file diff --git a/ppc64.c b/ppc64.c index 7ac12fe..532eb3f 100644 --- a/ppc64.c +++ b/ppc64.c @@ -80,6 +80,10 @@ struct user_regs_bitmap_struct { ulong bitmap[32]; }; +#define MAX_EXCEPTION_STACKS 7 +ulong extra_stacks_idx = 0; +struct user_regs_bitmap_struct *extra_stacks_regs[MAX_EXCEPTION_STACKS] = {0}; + static int is_opal_context(ulong sp, ulong nip) { uint64_t opal_start, opal_end; diff --git a/x86_64.c b/x86_64.c index 53ae3ef..e544be8 100644 --- a/x86_64.c +++ b/x86_64.c @@ -160,6 +160,9 @@ struct user_regs_bitmap_struct { ulong bitmap[32]; }; +ulong extra_stacks_idx = 0; +struct user_regs_bitmap_struct *extra_stacks_regs[MAX_EXCEPTION_STACKS] = {0}; + /* * Do all necessary machine-specific setup here. This is called several * times during initialization. -- 2.47.0