applied:
https://github.com/crash-utility/crash/commit/145cc6a75f24dfce2e644b620b3afb6de04cadfd
On Wed, Jul 23, 2025 at 9:16 PM Lianbo Jiang <liji...@redhat.com> wrote:
>
> Hi, Tao
>
> Thank you for the patch.
>
> On 7/9/25 13:41, devel-requ...@lists.crash-utility.osci.io wrote:
> > Date: Wed, 9 Jul 2025 17:41:12 +1200
> > From: Tao Liu<l...@redhat.com>
> > Subject: [Crash-utility] [PATCH] x86_64: filter unwanted warning
> > message for "bt -T" cmd
> > To:devel@lists.crash-utility.osci.io
> > Cc: Tao Liu<l...@redhat.com>
> > Message-ID:<20250709054112.145454-1-l...@redhat.com>
> > Content-Type: text/plain; charset="US-ASCII"; x-default=true
> >
> > After patch "x86_64: Add gdb multi-stack unwind support" applied, a
> > warning message is observed for "bt -T" cmd:
> >
> > crash> bt -T
> > bt: seek error: kernel virtual address: fffffffffffffffb type:
> > "gdb_readmem_callback"
> > [ffffbaebc60d6fa8] srso_return_thunk at ffffffff82246fa5
> > ...
> >
> > The root cause is, "bt -T" will set BT_TEXT_SYMBOLS_ALL for bt->flags,
> > and eip is set to be 0 in kernel.c:back_trace(). Later in
> > x86_64_low_budget_back_trace_cmd(), eip - 5, or 0xfffffffffffffffb is
> > used for address disassembly by gdb "x/1i 0x%lx". This address is invalid so
> > the warning message is output.
> >
> > In fact, multi-stack unwind isn't designed for "bt -T" and eip = 0 case.
> > To avoid the warning message, let's simply bypass the "bt -T" case for
> > x86_64. Other archs(arm64/ppc64) aren't affected by the issue because
> > the gdb "x/1i 0x%lx" are not applied on those archs.
>
> For the patch: Ack.
>
>
> Thanks
>
> Lianbo
>
> > After apply the patch:
> >
> > crash> bt -T
> > [ffffbaebc60d6fa8] srso_return_thunk at ffffffff82246fa5
> > ...
> >
> > 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 cfefe3f..d7da536 100644
> > --- a/x86_64.c
> > +++ b/x86_64.c
> > @@ -3636,7 +3636,8 @@ x86_64_low_budget_back_trace_cmd(struct bt_info
> > *bt_in)
> > level++;
> > }
> >
> > - if (is_task_active(bt->task) && bt->flags & BT_DUMPFILE_SEARCH) {
> > + if (is_task_active(bt->task) && bt->flags & BT_DUMPFILE_SEARCH &&
> > + !(bt->flags & BT_TEXT_SYMBOLS_ALL)) {
> > if (!extra_stacks_regs[extra_stacks_idx]) {
> > extra_stacks_regs[extra_stacks_idx] =
> > (struct user_regs_bitmap_struct *)
> > -- 2.47.0
> --
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