From: Pavel Begunkov <asml.silence@gmail.com>
To: Jens Axboe <axboe@kernel.dk>,
io-uring@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/1] io_uring: fix refcounting with OOM
Date: Sat, 25 Jan 2020 11:59:30 +0300 [thread overview]
Message-ID: <fa69cae513308ef3f681e13888a4f551c67ef3a2.1579942715.git.asml.silence@gmail.com> (raw)
In case of out of memory the second argument of percpu_ref_put_many() in
io_submit_sqes() may evaluate into "nr - (-EAGAIN)", that is clearly
wrong.
Fixes: 2b85edfc0c90 ("io_uring: batch getting pcpu references")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/io_uring.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index a4b496815783..744e8a90b543 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4912,8 +4912,11 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
break;
}
- if (submitted != nr)
- percpu_ref_put_many(&ctx->refs, nr - submitted);
+ if (unlikely(submitted != nr)) {
+ int ref_used = (submitted == -EAGAIN) ? 0 : submitted;
+
+ percpu_ref_put_many(&ctx->refs, nr - ref_used);
+ }
io_submit_end(ctx);
if (nr > IO_PLUG_THRESHOLD)
--
2.24.0
next reply other threads:[~2020-01-25 9:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-25 8:59 Pavel Begunkov [this message]
2020-01-25 16:46 ` [PATCH 1/1] io_uring: fix refcounting with OOM Jens Axboe
2020-01-25 19:27 ` Pavel Begunkov
2020-01-25 19:34 ` [PATCH v2] " Pavel Begunkov
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