On Wed, Aug 24, 2022 at 3:54 PM <crash-utility-requ...@redhat.com> wrote:
> Date: Wed, 24 Aug 2022 12:10:35 +0800
> From: Tao Liu <l...@redhat.com>
> To: crash-utility@redhat.com
> Subject: [Crash-utility] [PATCH 2/2] x86_64: Correct the identifier
> when locating the call instruction
> Message-ID: <20220824041033.40559-2-l...@redhat.com>
> Content-Type: text/plain; charset="US-ASCII"; x-default=true
>
> The previous implementation to locate the call instruction is
> to strstr "call", then check whether the previous char is ' '
> or '\t'. The implementation is problematic. For example it
> cannot resolve the following disassembly string:
>
> "0xffffffffc06e6399 <nfs_callback_up+118>:\tcall 0xffffffff9ac8792f
> <printk>"
>
> strstr will locate the "_call" and char check fails,
> as a result, extract_hex fail to get the calling address.
>
>
This looks like a potential corner bug. Did you see if it can be reproduced
without the [PATCH 1/2]?
Thanks.
Lianbo
This patch fix the issue by strstr "\tcall" and " call", to
> locate the correct call instruction.
>
> Signed-off-by: Tao Liu <l...@redhat.com>
> ---
> x86_64.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/x86_64.c b/x86_64.c
> index dfada48..74bd1bb 100644
> --- a/x86_64.c
> +++ b/x86_64.c
> @@ -4432,8 +4432,7 @@ x86_64_function_called_by(ulong rip)
> if (gdb_pass_through(buf, pc->tmpfile2, GNU_RETURN_ON_ERROR)) {
> rewind(pc->tmpfile2);
> while (fgets(buf, BUFSIZE, pc->tmpfile2)) {
> - if ((p1 = strstr(buf, "call")) &&
> - whitespace(*(p1-1))) {
> + if ((p1 = strstr(buf, " call")) || (p1 =
> strstr(buf, "\tcall"))) {
if (extract_hex(p1, &value, NULLCHAR,
> TRUE))
> break;
> }
> --
> 2.33.1
>
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