This is a note to let you know that I've just added the patch titled
gfs2: Refcounting fix in gfs2_thaw_super
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
gfs2-refcounting-fix-in-gfs2_thaw_super.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit cac69531b06595b4fc0945bf6a8dd8348b7f119d
Author: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
Date: Mon Dec 25 20:07:46 2023 +0100
gfs2: Refcounting fix in gfs2_thaw_super
[ Upstream commit 4e58543e7da4859c4ba61d15493e3522b6ad71fd ]
It turns out that the .freeze_super and .thaw_super operations require
the filesystem to manage the superblock refcount itself. We are using
the freeze_super() and thaw_super() helpers to mostly take care of that
for us, but this means that the superblock may no longer be around by
when thaw_super() returns, and gfs2_thaw_super() will then access freed
memory. Take an extra superblock reference in gfs2_thaw_super() to fix
that.
Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index f9b47df485d17..aff8cdc61eff7 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -814,6 +814,7 @@ static int gfs2_thaw_super(struct super_block *sb)
if (!test_bit(SDF_FREEZE_INITIATOR, &sdp->sd_flags))
goto out;
+ atomic_inc(&sb->s_active);
gfs2_freeze_unlock(&sdp->sd_freeze_gh);
error = gfs2_do_thaw(sdp);
@@ -824,6 +825,7 @@ static int gfs2_thaw_super(struct super_block *sb)
}
out:
mutex_unlock(&sdp->sd_freeze_mutex);
+ deactivate_super(sb);
return error;
}
