On Wed, Oct 02, 2019 at 11:45:19AM +0200, Paolo Bonzini wrote: > 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))
Compiler bug sounds kind of unlikely... > 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? This is on Ubuntu 18.04.3, gcc version 7.4.0 (Ubuntu/Linaro 7.4.0-1ubuntu1~18.04.1) I've uploaded the debug files to: https://bugs.launchpad.net/qemu/+bug/1805256/+attachment/5293619/+files/aio-posix.tar.xz Thanks, Jan > Thanks, > > Paolo
