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(parent: e523a29) | patch
io_uring: fix race condition when sq threads goes sleeping
authorStefan Bühler <source@stbuehler.de>
Fri, 19 Apr 2019 09:57:45 +0000 (11:57 +0200)
committerJens Axboe <axboe@kernel.dk>
Mon, 22 Apr 2019 17:00:56 +0000 (11:00 -0600)
commit0d7bae69c574c5f25802f8a71252e7d66933a3ab
tree9c6bd0dd0456a51080c7ed95350768452385aecbtree | snapshot
parente523a29c4f2703bdb98f68ce1bb256e259fd8d5fcommit | diff
io_uring: fix race condition when sq threads goes sleeping

Reading the SQ tail needs to come after setting IORING_SQ_NEED_WAKEUP in
flags; there is no cheap barrier for ordering a store before a load, a
full memory barrier is required.

Userspace needs a full memory barrier between updating SQ tail and
checking for the IORING_SQ_NEED_WAKEUP too.

Signed-off-by: Stefan Bühler <source@stbuehler.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
fs/io_uring.c diff | blob | history
Domain: System / Kernel;