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> 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(-)
>
--
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