Messages in this thread | | | Subject | Re: [PATCH v2] x86/entry/64: wipe KASAN stack shadow before rewind_stack_do_exit() | From | Andrey Ryabinin <> | Date | Wed, 29 Aug 2018 11:33:36 +0300 |
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On 08/28/2018 09:40 PM, Jann Horn wrote: > Reset the KASAN shadow state of the task stack before rewinding RSP. > Without this, a kernel oops will leave parts of the stack poisoned, and > code running under do_exit() can trip over such poisoned regions and cause > nonsensical false-positive KASAN reports about stack-out-of-bounds bugs. > > This patch does not wipe exception stacks; if you oops on an exception > stack, you might get random KASAN false-positives from other tasks > afterwards. This is probably relatively uninteresting, since if you're > oopsing on an exception stack, you likely have bigger things to worry > about. It'd be more interesting if vmapped stacks and KASAN were > compatible, since then handle_stack_overflow() would oops from exception > stack context. > > Fixes: 2deb4be28077 ("x86/dumpstack: When OOPSing, rewind the stack before do_exit()") > Signed-off-by: Jann Horn <jannh@google.com> > ---
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
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