[Crash-utility] Re: [PATCH] X86 64: fix a regression issue about kernel stack padding

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&gt; > Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com&gt; > --- > 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.

Thanks, Kazu