Messages in this thread | | | Date | Fri, 7 Apr 2023 21:56:19 -0700 | From | Josh Poimboeuf <> | Subject | Re: [PATCH 1/2] x86: make profile_pc() use arch_stack_walk() |
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On Thu, Mar 30, 2023 at 04:15:51PM +0800, Qi Zheng wrote: > The profile_pc() try to get pc by doing a trick to read > the contents of the stack. This may cause false positives > for KASAN, like the following: > > BUG: KASAN: stack-out-of-bounds in profile_pc+0x5b/0x90 > Read of size 8 at addr ffff8881062a7a00 by task id/130040
I don't think this was actually a false positive. The !FRAME_POINTER code in profile_pc() has been badly broken for many years.
BTW, there was a similar patch here:
https://lore.kernel.org/lkml/20230224021858.120078-1-chenzhongjin@huawei.com/
I thought CONFIG_PROFILING was obsolete but Andi said previously he wants to keep it for at least boot-time profiling.
Andi did suggest removing the lock profiling hacks, which means all the profile_pc() implementations can just be removed in favor of the generic instruction_pointer().
-- Josh
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