[Crash-utility] Re: [PATCH v4 0/5] gdb multi-stack unwinding support

On Wed, Jun 25, 2025 at 12:04 PM <devel-request(a)lists.crash-utility.osci.io&gt; wrote: > > Date: Wed, 25 Jun 2025 16:01:58 +1200 > From: Tao Liu <ltao(a)redhat.com&gt; > Subject: [Crash-utility] [PATCH v4 0/5] gdb multi-stack unwinding > support > To: devel(a)lists.crash-utility.osci.io > Cc: Tao Liu <ltao(a)redhat.com&gt; > Message-ID: <20250625040203.60334-1-ltao(a)redhat.com&gt; > Content-Type: text/plain; charset="US-ASCII"; x-default=true > > This patchset is based on Alexy's work [1], and is the follow-up of the > previous "gdb stack unwinding support for crash utility" patchset. > > Currently gdb target analyzes only one task at a time and it backtraces > only straight stack until end of the stack. If stacks were concatenated > during exceptions or interrupts, gdb bt will show only the topmost one. > > This patchset will introduce multiple stacks support for gdb stack unwinding, > which can be observed as a different threads from gdb perspective. A > short usage is as follows: > > 'set <PID>' - to switch to a specific task > 'gdb info threads' - to see list of in-kernel stacks of this task. > 'gdb thread <ID>' - to switch to the stack. > 'gdb bt' - to unwind it. > > E.g, with the patchset: > > crash> bt > PID: 17636 TASK: ffff88032e0742c0 CPU: 11 COMMAND: "kworker/11:4" > #0 [ffff88037fca6b58] machine_kexec at ffffffff8103cef2 > #1 [ffff88037fca6ba8] crash_kexec at ffffffff810c9aa3 > #2 [ffff88037fca6c70] panic at ffffffff815f0444 > ... > #9 [ffff88037fca6ec8] do_nmi at ffffffff815fd980 > #10 [ffff88037fca6ef0] end_repeat_nmi at ffffffff815fcec1 > [exception RIP: memcpy+13] > RIP: ffffffff812f5b1d RSP: ffff88034f2a9728 RFLAGS: 00010046 > RAX: ffffc900139fe000 RBX: ffff880374b7a1b0 RCX: 0000000000000030 > RBP: ffff88034f2a9778 R8: 000000007fffffff R9: 00000000ffffffff > ... > ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 > --- <NMI exception stack> --- > #11 [ffff88034f2a9728] memcpy at ffffffff812f5b1d > #12 [ffff88034f2a9728] mga_dirty_update at ffffffffa024ad2b [mgag200] > #13 [ffff88034f2a9780] mga_imageblit at ffffffffa024ae3f [mgag200] > #14 [ffff88034f2a97a0] bit_putcs at ffffffff813424ef > ... > > crash> info threads > Id Target Id Frame > * 1 17636 kworker/11:4 (stack 0) crash_setup_regs (oldregs=0x0, newregs=0xffff88037fca6bb0) > 2 17636 kworker/11:4 (stack 1) 0xffffffff812f5b1d in memcpy () > > crash> thread 2 > crash> gdb bt > #0 0xffffffff812f5b1d in memcpy () at arch/x86/lib/memcpy_64.S:69 > ... > > There are 2 stacks of the current task, and we can list/switch-to/unwind > each stack. > > [1]: https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg01204.html > > v2 -> v1: 1) Rebase this patchset onto gdb-16.2 [2]. > 2) Improved the silent_call_bt() to catch the error FATAL. > > [2]: https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg01354.html > > v3 -> v2: 1) Rebase this patchset to crash v9.0.0. > 2) Fix v2's segfault in cmd "bt -E". > 3) Elimit repeat stacks by adding constraints before > gdb_add_substack(). > > v4 -> v3: 1) Fix compiling warning of silent_call_bt() > 2) Add known issue link found in ppc arch. > Thank you for the update, Tao. For the v4: Ack Thanks Lianbo > Tao Liu (5): > Add multi-threads support in crash target > Call cmd_bt silently after "set pid" > x86_64: Add gdb multi-stack unwind support > arm64: Add gdb multi-stack unwind support > ppc64: Add gdb multi-stack unwind support > > arm64.c | 102 +++++++++++++++++++++++++++++++++-- > crash_target.c | 49 +++++++++++++++-- > defs.h | 3 +- > gdb_interface.c | 6 +-- > kernel.c | 44 +++++++++++++++ > ppc64.c | 78 ++++++++++++++++++++++++--- > task.c | 4 +- > x86_64.c | 138 +++++++++++++++++++++++++++++++++++++++++++++--- > 8 files changed, 394 insertions(+), 30 deletions(-) > > -- > 2.47.0 -- 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