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authorPavel Begunkov <asml.silence@gmail.com>2020-07-30 18:43:47 +0300
committerJens Axboe <axboe@kernel.dk>2020-07-30 11:42:21 -0600
commitb2bd1cf99f3e7c8fbf12ea07af2c6998e1209e25 (patch)
treedc16e00563bdc1880c78dddfa067d78e10e11cbe /fs
parent81b68a5ca0ab5d92229a7b76332b9ce88bd6dbd1 (diff)
downloadlinux-b2bd1cf99f3e7c8fbf12ea07af2c6998e1209e25.tar.bz2
io_uring: fix racy overflow count reporting
All ->cq_overflow modifications should be under completion_lock, otherwise it can report a wrong number to the userspace. Fix it in io_uring_cancel_files(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
-rw-r--r--fs/io_uring.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 11f4ab87e08f..6e2322525da6 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7847,10 +7847,9 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx,
clear_bit(0, &ctx->cq_check_overflow);
ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW;
}
- spin_unlock_irq(&ctx->completion_lock);
-
WRITE_ONCE(ctx->rings->cq_overflow,
atomic_inc_return(&ctx->cached_cq_overflow));
+ spin_unlock_irq(&ctx->completion_lock);
/*
* Put inflight ref and overflow ref. If that's