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Re: [Qemu-devel] qemu_futex_wait() lockups in ARM64: 2 possible issues
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] qemu_futex_wait() lockups in ARM64: 2 possible issues |
Date: |
Wed, 2 Oct 2019 11:45:19 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 |
On 02/10/19 11:23, Jan Glauber wrote:
> I've tried to verify me theory with this patch and didn't run into the
> issue for ~500 iterations (usually I would trigger the issue ~20 iterations).
Awesome! That would be a compiler bug though, as atomic_add and atomic_sub
are defined as sequentially consistent:
#define atomic_add(ptr, n) ((void) __atomic_fetch_add(ptr, n, __ATOMIC_SEQ_CST))
#define atomic_sub(ptr, n) ((void) __atomic_fetch_sub(ptr, n, __ATOMIC_SEQ_CST))
What compiler are you using and what distro? Can you compile util/aio-posix.c
with "-fdump-rtl-all -fdump-tree-all", zip the boatload of debugging files and
send them my way?
Thanks,
Paolo
Re: [Qemu-devel] qemu_futex_wait() lockups in ARM64: 2 possible issues, Paolo Bonzini, 2019/10/07