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Date:   Fri, 3 Nov 2023 16:24:48 -0700
From:   Richard Cochran <richardcochran@gmail.com>
To:     Edward Adam Davis <eadavis@qq.com>
Cc:     jeremy@jcline.org, davem@davemloft.net, habetsm.xilinx@gmail.com,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        reibax@gmail.com,
        syzbot+df3f3ef31f60781fa911@syzkaller.appspotmail.com
Subject: Re: [PATCH net-next V3] ptp: fix corrupted list in ptp_open
Message-ID: <ZUWBQE7vfBXAVADq@hoboy.vegasvil.org>
References: <tencent_97D1BA12BBF933129EC01B1D4BB71BE92508@qq.com>
 <ZUV_1CZRUQTiANTT@hoboy.vegasvil.org>
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On Fri, Nov 03, 2023 at 04:18:44PM -0700, Richard Cochran wrote:
> On Fri, Nov 03, 2023 at 09:15:03PM +0800, Edward Adam Davis wrote:
> > There is no lock protection when writing ptp->tsevqs in ptp_open(),
> > ptp_release(), which can cause data corruption, use mutex lock to avoid this
> > issue.
> 
> The problem is the bogus call to ptp_release() in ptp_read().
> 
> Just delete that.

Like this...

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;
 }