Re: [Qemu-devel] [PATCH 12/12] WIP ucontext: annotate coroutine stack for ASAN

[Stefan Hajnoczi]

On Fri, Dec 08, 2017 at 01:58:25AM +0100, Marc-André Lureau wrote:
> Not strictly necessary, but it may help ASAN and remove some false
> positives.
> 
> Sadly, this annotation produces an ASAN error:
> 
> $ tests/test-coroutine -p /basic/lifecycle
> /basic/lifecycle: ==27655==WARNING: ASan doesn't fully support 
> makecontext/swapcontext functions and may produce false positives in some 
> cases!
> ==27655==AddressSanitizer CHECK failed: 
> /builddir/build/BUILD/compiler-rt-4.0.1.src/lib/asan/asan_poisoning.cc:38 
> "((AddrIsAlignedByGranularity(addr + size))) != (0)" (0x0, 0x0)
>     #0 0x55d1e4e8a695 in __asan::AsanCheckFailed(char const*, int, char 
> const*, unsigned long long, unsigned long long) 
> (/home/elmarco/src/qq/build/tests/test-coroutine+0x1c0695)
>     #1 0x55d1e4ea6235 in __sanitizer::CheckFailed(char const*, int, char 
> const*, unsigned long long, unsigned long long) 
> (/home/elmarco/src/qq/build/tests/test-coroutine+0x1dc235)
>     #2 0x55d1e4e82ea4 in __asan::PoisonShadow(unsigned long, unsigned long, 
> unsigned char) (/home/elmarco/src/qq/build/tests/test-coroutine+0x1b8ea4)
>     #3 0x55d1e4dde1e7 in __asan::FakeStack::Destroy(int) 
> (/home/elmarco/src/qq/build/tests/test-coroutine+0x1141e7)
>     #4 0x55d1e528b775 in qemu_coroutine_switch 
> /home/elmarco/src/qq/util/coroutine-ucontext.c:219:9
>     #5 0x55d1e528b18d in coroutine_trampoline 
> /home/elmarco/src/qq/util/coroutine-ucontext.c:114:9
>     #6 0x7fb3e0087bef  (/lib64/libc.so.6+0x50bef)

Looks like a step in the right direction.

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