On Mon, Sep 16, 2024 at 3:46 PM <devel-requ...@lists.crash-utility.osci.io>
wrote:
> Date: Mon, 16 Sep 2024 19:44:58 +1200
> From: Tao Liu <l...@redhat.com>
> Subject: [Crash-utility] [PATCH] x86_64: Fix the bug of getting
> incorrect framesize
> To: devel@lists.crash-utility.osci.io
> Cc: mycomplexl...@gmail.com
> Message-ID: <20240916074458.105832-1-l...@redhat.com>
> Content-Type: text/plain; charset="US-ASCII"; x-default=true
>
> Previously, "retq" is used to determine the end of a function, so the end
> of framesize calculation. However "ret" might be outputted by gdb rather
> than "retq", as a result, the framesize is returned incorrectly, and bogus
> stack trace will be outputted.
>
> Without the patch:
>
> $ crash -d 3 vmcore vmlinux
> crash> bt
> 0xffffffff92da7545 <copy_process+5>: push %rbp [framesize: 8]
> ...
> 0xffffffff92da7561 <copy_process+33>: sub $0x238,%rsp
> [framesize: 624]
> ...
> 0xffffffff92da776a <copy_process+554>: pop %r15
> [framesize: 8]
> 0xffffffff92da776c <copy_process+556>: pop %rbp
> [framesize: 0]
> 0xffffffff92da776d <copy_process+557>: ret
>
> crash> bt -D dump
> framesize_cache_entries:
> ...
> [ 3]: ffffffff92dadcbd 0 CF (copy_process+26493)
>
> crash> bt
> ...
> #9 [ffff888263157bc0] copy_process at ffffffff92dadcbd
> #10 [ffff888263157d20] __mutex_init at ffffffff92ed8dd5
> #11 [ffff888263157d38] __alloc_file at ffffffff93458397
> #12 [ffff888263157d60] alloc_empty_file at ffffffff934585d2
> #13 [ffff888263157da8] __alloc_fd at ffffffff934b5ead
> #14 [ffff888263157e38] _do_fork at ffffffff92dae7a1
> #15 [ffff888263157f28] do_syscall_64 at ffffffff92c085f4
>
> Stack #10 ~ #13 are bogus and misleading.
>
> With the patch:
> ...
> 0xffffffff92da776d <copy_process+557>: ret [framesize
> restored to: 624]
>
> crash> bt -D dump
> ...
> [ 3]: ffffffff92dadcbd 624 CF (copy_process+26493)
>
> crash> bt
> ...
> #9 [ffff888263157bc0] copy_process at ffffffff92dadcbd
> #10 [ffff888263157e38] _do_fork at ffffffff92dae7a1
> #11 [ffff888263157f28] do_syscall_64 at ffffffff92c085f4
>
> Signed-off-by: Tao Liu <l...@redhat.com>
> ---
> x86_64.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/x86_64.c b/x86_64.c
> index 469d26b..7aa9430 100644
> --- a/x86_64.c
> +++ b/x86_64.c
> @@ -8781,7 +8781,8 @@ x86_64_get_framesize(struct bt_info *bt, ulong
> textaddr, ulong rsp, char *stack_
> if (CRASHDEBUG(2) || (bt->flags &
> BT_FRAMESIZE_DEBUG))
> fprintf(fp, "%s\t[framesize: %d]\n",
> strip_linefeeds(buf2), framesize);
> - } else if (STRNEQ(arglist[instr], "retq")) {
> + } else if (STRNEQ(arglist[instr], "retq") ||
> + STRNEQ(arglist[instr], "ret")) {
>
Thank you for the fix, Tao.
This looks good. Applied:
https://github.com/crash-utility/crash/commit/0d2ad774532db3c4dad6cda05d51db74d0e3fa86
Lianbo
if (!exception) {
> framesize = max;
> if (CRASHDEBUG(2) || (bt->flags &
> BT_FRAMESIZE_DEBUG))
> --
> 2.40.1
>
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