From: "Gong, Sishuai" <sishuai@purdue.edu>
To: "viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>
Cc: "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
Subject: A data race on mnt->mnt.mnt_flags
Date: Mon, 29 May 2023 20:38:28 +0000 [thread overview]
Message-ID: <BE49328F-DC47-4509-AC7E-6DD6FEC2FF83@purdue.edu> (raw)
Hello,
We found a data race that could happen between clone_mnt() and
mnt_hold_writers() over mnt->mnt.mnt_flags.
The two functions can write to mnt->mnt.mnt_flags concurrently.
Although mnt_hold_writers() holds the lock_mount_hash(), clone_mnt() does not
respect this lock at this moment (it will apply for this lock later).
Thread-1 Thread-2
// clone_mnt() // mnt_hold_writers() holding lock_mount_hash()
mnt->mnt.mnt_flags &= ~(MNT_WRITE_HOLD|MNT_MARKED|MNT_INTERNAL);
mnt->mnt.mnt_flags |= MNT_WRITE_HOLD;
It is not clear whether this is a serious problem but we would like to report it
just in case.
Thanks,
Sishuai
reply other threads:[~2023-05-29 20:38 UTC|newest]
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