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From: Sasha Levin <[email protected]>
To: [email protected], [email protected]
Cc: Pavel Begunkov <[email protected]>,
	Jens Axboe <[email protected]>, Sasha Levin <[email protected]>,
	[email protected], [email protected]
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: <[email protected]> (raw)
In-Reply-To: <[email protected]>

From: Pavel Begunkov <[email protected]>

[ 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 <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 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


  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] <[email protected]>
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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