From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 629B347CA89; Sat, 12 Sep 2026 13:39:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789220382; cv=none; b=gt7EyG4rqaMwrz8kf6vd9wETgpaaXlxDsl7EbbOVhHNS4aVCA6jhQwToiIHMhCo5qIr0gTM/H9GUAaAztiarrEPMijwJ9xlqUWMimzO65q1nPatMo5wuwql9e17lpvJY2XwgE8GdwVh7weh/RtUI/4g7RjFuBUL2H7efUmpQf2U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789220382; c=relaxed/simple; bh=eClSGgIVl2DyekMXyWIptpe6PFEELWHyh4BEyYJ/LbE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LWfXRfBS80cq9v6i5/n7SJgawSF9eMQphpJ3CrlDSmayMXrmuwaT4fbgjKGb7grPVsbuNbA//ZMbZt/FJIq8jEmw9anwObOf4nHMLkPmNMkJRs/56NelzyuMYbZXozB0VoMvePqOzzVFSseE7jlurjMGqV9LNlBwo6DpQcYTheo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qzTOgZH7; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qzTOgZH7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C589C1F000FF; Sat, 12 Sep 2026 13:39:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789220378; bh=emjRaxOpZKGRLnpl6BgAh3KEtMy3EQ6VOAF6eb97XD0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=qzTOgZH7/UYUUBnfFyF3n2gYpcai3Pn4ZHNPjy2CM23TOyY2WjBeLW8M5BnpemSP1 TlgvCWoYmuL7p/KjsS3YiFULJvkYao6msdiCKj2NzY6/XFTAMpKKAmphcH//59yaYx G5U5QRzUNiOxQZcg3iiumpbVO2gx6gU8iGmO8Q4s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, liyouhong , Mikulas Patocka Subject: [PATCH 6.6 0123/1424] dm-era: fix shadowed superblock leak on take-snap failure Date: Sat, 12 Sep 2026 08:42:35 +0200 Message-ID: <20260912065610.056662031@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.279695368@linuxfoundation.org> References: <20260912065607.279695368@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: liyouhong commit 39c5aa3bd8ec3912d2cd0b3fe092642b0d2b0713 upstream. metadata_take_snap() bumps the live superblock refcount and then dm_tm_shadow_block() allocates a new block for the metadata snapshot. If the subsequent dm_sm_inc_block() of writeset_tree_root or era_array_root fails, the function only unlocks the clone and returns. The newly allocated shadow block is never returned to the metadata space map, so each failed take-snap permanently leaks one metadata block. Free the clone with dm_sm_dec_block() on those error paths, matching the final step of metadata_drop_snap(). Fixes: eec40579d848 ("dm: add era target") Cc: stable@vger.kernel.org Signed-off-by: liyouhong Signed-off-by: Mikulas Patocka Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-era-target.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/md/dm-era-target.c +++ b/drivers/md/dm-era-target.c @@ -1034,6 +1034,7 @@ static int metadata_checkpoint(struct er static int metadata_take_snap(struct era_metadata *md) { int r, inc; + dm_block_t location; struct dm_block *clone; if (md->metadata_snap != SUPERBLOCK_LOCATION) { @@ -1071,7 +1072,9 @@ static int metadata_take_snap(struct era r = dm_sm_inc_block(md->sm, md->writeset_tree_root); if (r) { DMERR("%s: couldn't inc writeset tree root", __func__); + location = dm_block_location(clone); dm_tm_unlock(md->tm, clone); + dm_sm_dec_block(md->sm, location); return r; } @@ -1079,7 +1082,9 @@ static int metadata_take_snap(struct era if (r) { DMERR("%s: couldn't inc era tree root", __func__); dm_sm_dec_block(md->sm, md->writeset_tree_root); + location = dm_block_location(clone); dm_tm_unlock(md->tm, clone); + dm_sm_dec_block(md->sm, location); return r; }