From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Andreas Gruenbacher <agruenba@redhat.com>,
Sasha Levin <sashal@kernel.org>,
gfs2@lists.linux.dev
Subject: [PATCH AUTOSEL 6.6 18/19] gfs2: Refcounting fix in gfs2_thaw_super
Date: Mon, 15 Jan 2024 19:23:53 -0500 [thread overview]
Message-ID: <20240116002413.215163-18-sashal@kernel.org> (raw)
In-Reply-To: <20240116002413.215163-1-sashal@kernel.org>
From: Andreas Gruenbacher <agruenba@redhat.com>
[ 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@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/gfs2/super.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 5f4ebe279aaa..8f229914c1e2 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -818,6 +818,7 @@ static int gfs2_thaw_super(struct super_block *sb, enum freeze_holder who)
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);
@@ -828,6 +829,7 @@ static int gfs2_thaw_super(struct super_block *sb, enum freeze_holder who)
}
out:
mutex_unlock(&sdp->sd_freeze_mutex);
+ deactivate_super(sb);
return error;
}
--
2.43.0
parent reply other threads:[~2024-01-16 0:24 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20240116002413.215163-1-sashal@kernel.org>]
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