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From:   Edward AD <twuufnxlz@gmail.com>
To:     syzbot+9704e6f099d952508943@syzkaller.appspotmail.com
Cc:     davem@davemloft.net, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, reibax@gmail.com, richardcochran@gmail.com,
        syzkaller-bugs@googlegroups.com
Subject: [PATCH] ptp: ptp_read should not release queue
Date:   Mon, 23 Oct 2023 10:46:23 +0800
Message-ID: <20231023024622.323905-2-twuufnxlz@gmail.com>
In-Reply-To: <0000000000002e8d4a06085267f3@google.com>
References: <0000000000002e8d4a06085267f3@google.com>
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Firstly, queue is not the memory allocated in ptp_read;
Secondly, other processes may block at ptp_read and wait for conditions to be 
met to perform read operations.

Reported-and-tested-by: syzbot+9704e6f099d952508943@syzkaller.appspotmail.com
Fixes: 8f5de6fb2453 ("ptp: support multiple timestamp event readers")
Signed-off-by: Edward AD <twuufnxlz@gmail.com>
---
 drivers/ptp/ptp_chardev.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 282cd7d24077..27c1ef493617 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -585,7 +585,5 @@ ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags,
 free_event:
 	kfree(event);
 exit:
-	if (result < 0)
-		ptp_release(pccontext);
 	return result;
 }
-- 
2.25.1