[Crash-utility] Re: [PATCH v2 0/5] gdb multi-stack unwinding support

Hi Tao, thanks for the update. Do you guys discuss it through some channels other than Crash-utility mailing list?

I tested your patches v2 on top of crash-9.0. It is directly applicable and no issues or concerns at runtime. And silent bt seems working. LGTM.

Regards, --Alexey On 4/30/25 9:22 PM, Tao Liu wrote: > Hi Alexey, > > The patchset needs to be rebased after upgrading the gdb into version > v16.2. If we put the "multi-stack unwinding" together with gdb > upgrading, there will be too much modification for one release. So we > decided to defer the "multi-stack unwinding" after gdb upgrading. I > think I will rebase and re-post the "multi-stack" patches later. > > Thanks, > Tao Liu > > On Thu, May 1, 2025 at 9:25 AM Alexey Makhalov > <alexey.makhalov(a)broadcom.com&gt; wrote: >> >> Hello Tao and folks! >> >> What is the status of this patchset? I expected to see it in 9.0. >> >> Thanks, >> --Alexey >> >> >> On 2/20/25 1:44 PM, Tao Liu wrote: >>> 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 >>> >>> 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 | 85 +++++++++++++++++++++++++++++++-- >>> crash_target.c | 49 +++++++++++++++++-- >>> defs.h | 3 +- >>> gdb_interface.c | 6 +-- >>> kernel.c | 43 +++++++++++++++++ >>> ppc64.c | 70 +++++++++++++++++++++++---- >>> task.c | 4 +- >>> x86_64.c | 123 +++++++++++++++++++++++++++++++++++++++++++++--- >>> 8 files changed, 354 insertions(+), 29 deletions(-) >>> >> -- >> 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 >