Messages in this thread | | | Subject | Re: [PATCH 1/5] ARM: stacktrace: Skip frame pointer boundary check for call_with_stack() | From | Li Huafei <> | Date | Tue, 26 Jul 2022 16:10:25 +0800 |
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Hi Linus, sorry for the late reply.
On 2022/7/18 16:57, Linus Walleij wrote: > On Tue, Jul 12, 2022 at 4:18 AM Li Huafei <lihuafei1@huawei.com> wrote: > >> When using the frame pointer unwinder, it was found that the stack trace >> output of stack_trace_save() is incomplete if the stack contains >> call_with_stack(): >> >> [0x7f00002c] dump_stack_task+0x2c/0x90 [hrtimer] >> [0x7f0000a0] hrtimer_hander+0x10/0x18 [hrtimer] >> [0x801a67f0] __hrtimer_run_queues+0x1b0/0x3b4 >> [0x801a7350] hrtimer_run_queues+0xc4/0xd8 >> [0x801a597c] update_process_times+0x3c/0x88 >> [0x801b5a98] tick_periodic+0x50/0xd8 >> [0x801b5bf4] tick_handle_periodic+0x24/0x84 >> [0x8010ffc4] twd_handler+0x38/0x48 >> [0x8017d220] handle_percpu_devid_irq+0xa8/0x244 >> [0x80176e9c] generic_handle_domain_irq+0x2c/0x3c >> [0x8052e3a8] gic_handle_irq+0x7c/0x90 >> [0x808ab15c] generic_handle_arch_irq+0x60/0x80 >> [0x8051191c] call_with_stack+0x1c/0x20 >> >> For the frame pointer unwinder, unwind_frame() checks stackframe::fp by >> stackframe::sp. Since call_with_stack() switches the SP from one stack >> to another, stackframe::fp and stackframe: :sp will point to different >> stacks, so we can no longer check stackframe::fp by stackframe::sp. Skip >> checking stackframe::fp at this point to avoid this problem. >> >> Signed-off-by: Li Huafei <lihuafei1@huawei.com> > Very nice catch! Took me some time to realize what was > going on here.
Yeah, it took me some time to discover the cause of the problem too.
> > Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Thanks!
> > Nitpick below: > >> + /* >> + * call_with_stack() is the only place we allow SP to jump from one >> + * stack to another, with FP and SP pointing to different stacks, >> + * skipping the FP boundary check at this point. >> + */ >> + if (pc >= (unsigned long)&call_with_stack && >> + pc < (unsigned long)&call_with_stack_end) >> + return 0; > Can we create a local helper macro to do this, if it needs to happen > some other time?
Hopefully this won't come up again.:(
Maybe it would be better to define a macro when this happens?
Thanks,
Huafei
> > #define ARM_PC_IN_FUNCTION(pc, func) (pc >=. ...) > > Yours, > Linus Walleij > .
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