From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Pavel Begunkov <asml.silence@gmail.com>,
Jens Axboe <axboe@kernel.dk>, Sasha Levin <sashal@kernel.org>,
io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH AUTOSEL 5.8 61/64] io_uring: fix racy overflow count reporting
Date: Mon, 10 Aug 2020 15:08:56 -0400 [thread overview]
Message-ID: <20200810190859.3793319-61-sashal@kernel.org> (raw)
In-Reply-To: <20200810190859.3793319-1-sashal@kernel.org>
From: Pavel Begunkov <asml.silence@gmail.com>
[ Upstream commit b2bd1cf99f3e7c8fbf12ea07af2c6998e1209e25 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/io_uring.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index acd98df1f7d44..73f5e0a9bf2bd 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7529,10 +7529,9 @@ 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
--
2.25.1
next prev parent reply other threads:[~2020-08-10 19:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200810190859.3793319-1-sashal@kernel.org>
2020-08-10 19:08 ` [PATCH AUTOSEL 5.8 07/64] io_uring: fix req->work corruption Sasha Levin
2020-08-10 19:08 ` Sasha Levin [this message]
2020-08-10 19:08 ` [PATCH AUTOSEL 5.8 62/64] io_uring: fix stalled deferred requests Sasha Levin
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