linux-kernel - [PATCH AUTOSEL 5.16 18/19] io_uring: perform poll removal even if async work removal is successful

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Message-Id: <20220123001113.2460140-18-sashal@kernel.org>
Date:   Sat, 22 Jan 2022 19:11:11 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Jens Axboe <axboe@...nel.dk>,
        Florian Fischer <florian.fl.fischer@....de>,
        Sasha Levin <sashal@...nel.org>, io-uring@...r.kernel.org
Subject: [PATCH AUTOSEL 5.16 18/19] io_uring: perform poll removal even if async work removal is successful

From: Jens Axboe <axboe@...nel.dk>

[ Upstream commit ccbf726171b7328f800bc98005132fd77eb1a175 ]

An active work can have poll armed, hence it's not enough to just do
the async work removal and return the value if it's different from "not
found". Rather than make poll removal special, just fall through to do
the remaining type lookups and removals.

Reported-by: Florian Fischer <florian.fl.fischer@....de>
Link: https://lore.kernel.org/io-uring/20220118151337.fac6cthvbnu7icoc@pasture/
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/io_uring.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index fb2a0cb4aaf83..a958457b2af07 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6316,16 +6316,21 @@ static int io_try_cancel_userdata(struct io_kiocb *req, u64 sqe_addr)
 	WARN_ON_ONCE(!io_wq_current_is_worker() && req->task != current);
 
 	ret = io_async_cancel_one(req->task->io_uring, sqe_addr, ctx);
-	if (ret != -ENOENT)
-		return ret;
+	/*
+	 * Fall-through even for -EALREADY, as we may have poll armed
+	 * that need unarming.
+	 */
+	if (!ret)
+		return 0;
 
 	spin_lock(&ctx->completion_lock);
+	ret = io_poll_cancel(ctx, sqe_addr, false);
+	if (ret != -ENOENT)
+		goto out;
+
 	spin_lock_irq(&ctx->timeout_lock);
 	ret = io_timeout_cancel(ctx, sqe_addr);
 	spin_unlock_irq(&ctx->timeout_lock);
-	if (ret != -ENOENT)
-		goto out;
-	ret = io_poll_cancel(ctx, sqe_addr, false);
 out:
 	spin_unlock(&ctx->completion_lock);
 	return ret;
-- 
2.34.1