[Crash-utility] Re: [PATCH] X86 64: fix a regression issue about kernel stack padding
Hi Lijiang & Kazu,
On Wed, Jun 12, 2024 at 1:03 PM lijiang <lijiang(a)redhat.com> wrote:
On Wed, Jun 12, 2024 at 12:29 PM HAGIO KAZUHITO(萩尾 一仁) <k-hagio-ab(a)nec.com> wrote:
>
>
> On 2024/06/12 12:42, Lianbo Jiang wrote:
> > The commit 48764a14bc58 may cause a regression issue when the CONFIG_X86_FRED
> > is not enabled, this is because the SIZE(fred_frame) will call the
> > SIZE_verify() to determine if the fred_frame is valid, otherwise it will
> > emit an error:
> >
> > crash> bt 1
> >
> > bt: invalid structure size: fred_frame
> > FILE: x86_64.c LINE: 4089 FUNCTION:
x86_64_low_budget_back_trace_cmd()
> >
> > [/home/k-hagio/bin/crash] error trace: 588df3 => 5cbc72 => 5eb3e1 =>
5eb366
> > PID: 1 TASK: ffff9f94c024b980 CPU: 2 COMMAND: "systemd"
> > #0 [ffffade44001bca8] __schedule at ffffffffb948ebbb
> > #1 [ffffade44001bd10] schedule at ffffffffb948f04d
> > #2 [ffffade44001bd20] schedule_hrtimeout_range_clock at ffffffffb9494fef
> > #3 [ffffade44001bda8] ep_poll at ffffffffb8c91be8
> > #4 [ffffade44001be48] do_epoll_wait at ffffffffb8c91d11
> > #5 [ffffade44001be80] __x64_sys_epoll_wait at ffffffffb8c92590
> > #6 [ffffade44001bed0] do_syscall_64 at ffffffffb947f459
> > #7 [ffffade44001bf50] entry_SYSCALL_64_after_hwframe at ffffffffb96000ea
> >
> > 5eb366: SIZE_verify.part.42+70
> > 5eb3e1: SIZE_verify+49
> > 5cbc72: x86_64_low_budget_back_trace_cmd+3010
> > 588df3: back_trace+1523
> >
> > bt: invalid structure size: fred_frame
> > FILE: x86_64.c LINE: 4089 FUNCTION:
x86_64_low_budget_back_trace_cmd()
> >
> > Let's replace the SIZE(fred_frame) with the VALID_SIZE(fred_frame) to
> > fix it.
> >
> > Fixes: 48764a14bc58 ("x86_64: fix for adding top_of_kernel_stack_padding
for kernel stack")
> > Reported-by: Kazuhito Hagio <k-hagio-ab(a)nec.com>
> > Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com>
> > ---
> > x86_64.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/x86_64.c b/x86_64.c
> > index 6777c93e6b47..469d26b05e24 100644
> > --- a/x86_64.c
> > +++ b/x86_64.c
> > @@ -4086,7 +4086,7 @@ in_exception_stack:
> >
> > if (!irq_eframe && !is_kernel_thread(bt->tc->task)
&&
> > (GET_STACKBASE(bt->tc->task) == bt->stackbase)) {
> > - long stack_padding_size = SIZE(fred_frame) > 0 ? (2*8) : 0;
> > + long stack_padding_size = VALID_SIZE(fred_frame) ? (2*8) : 0;
> > user_mode_eframe = bt->stacktop - SIZE(pt_regs);
> > if (last_process_stack_eframe < user_mode_eframe)
> > x86_64_exception_frame(EFRAME_PRINT, 0, bt->stackbuf +
> > @@ -4408,7 +4408,7 @@ in_exception_stack:
> >
> > if (!irq_eframe && !is_kernel_thread(bt->tc->task)
&&
> > (GET_STACKBASE(bt->tc->task) == bt->stackbase)) {
> > - long stack_padding_size = SIZE(fred_frame) > 0 ? (2*8) : 0;
> > + long stack_padding_size = VALID_SIZE(fred_frame) ? (2*8) : 0;
> > user_mode_eframe = bt->stacktop - SIZE(pt_regs);
> > if (last_process_stack_eframe < user_mode_eframe)
> > x86_64_exception_frame(EFRAME_PRINT, 0, bt->stackbuf +
>
> Thanks, tested ok with kernels configured without CONFIG_X86_FRED=y.
>
Thank you for helping with the test, Kazu.
Thanks for reporting and fixing the code. LGTM, so ack.
Thanks,
Tao Liu
Lianbo
>
> Thanks,
> Kazu