[Crash-utility] Re: [PATCH] x86_64: filter unwanted warning message for "bt -T" cmd

Hi, Tao Thank you for the patch. On 7/9/25 13:41, devel-request(a)lists.crash-utility.osci.io wrote: > Date: Wed, 9 Jul 2025 17:41:12 +1200 > From: Tao Liu&lt;ltao(a)redhat.com&gt; > Subject: [Crash-utility] [PATCH] x86_64: filter unwanted warning > message for "bt -T" cmd > To:devel@lists.crash-utility.osci.io > Cc: Tao Liu&lt;ltao(a)redhat.com&gt; > Message-ID:<20250709054112.145454-1-ltao@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&lt;ltao(a)redhat.com&gt; > --- > 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 -- 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