From nobody Sat Jul 25 23:42:23 2026 Received: from m16.mail.126.com (m16.mail.126.com [220.197.31.8]) (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 58B403446C9 for ; Sat, 11 Jul 2026 10:06:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.8 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783764401; cv=none; b=Lj9Io88tCqD5EKJqrjtLGhBHVC0BCk6wkgtGZdaUXE162TBiq3bnBfWM4SCAKwDbTjATgAbwdWOgbpVFP/nIaOTXwsvOfxXEzg7mJPUEhNHDZ72fqesN4Rj97EJ3YEB1aMbzbM09ZswI33ax1X+wDEB/w2J9D8i0WKJmse4eRXw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783764401; c=relaxed/simple; bh=YRWY2l0mkRmrRt3rjfZMoLCj/5G52iPky2Dkh6MsXB0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=j989Oi6exicEPhMWmsDAa8HklbPXLpXMCW63F0OfCfIOF104qZHAZ9z8vNensZRt99cGvyasv3iWhJdKm04zbGdzQlpE1nnQfqklKLwFpQbUj8gxW5YzgLRsDuAS9FAxSb3wd3fZY4PfcsfwU6OnTvWJ8jcGmhfD5LyliufFhHI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=126.com; spf=pass smtp.mailfrom=126.com; dkim=pass (1024-bit key) header.d=126.com header.i=@126.com header.b=aPGCvFkM; arc=none smtp.client-ip=220.197.31.8 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=126.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=126.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=126.com header.i=@126.com header.b="aPGCvFkM" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=126.com; s=s110527; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=h2 nToSbHKBQZACrxjxyaVN+GI3bXXec2Ra3NMx0+bF0=; b=aPGCvFkMyH01mSbuQp kZhXfMlEsTSixvL9MbaOtahUF6NxgORJ8rtJ66BqyP1vEMSVnfcQNGATiFwjx58E r+F9eQf2c/hsSHvg0jslmO0IsLoMspeUEx6vWg1UwowMl4RULfTFK3+xjn9rAh4h 1PW4oyMV5zn5CoimrR/Ebrulw= Received: from LAPTOP-N9A9U1FG.lan (unknown []) by gzsmtp4 (Coremail) with SMTP id PykvCgD3f2FqFVJqlOIdCw--.28673S4; Sat, 11 Jul 2026 18:05:56 +0800 (CST) From: Genjian To: agk@redhat.com, snitzer@kernel.org, mpatocka@redhat.com, bmarzins@redhat.com, ejt@redhat.com Cc: dm-devel@lists.linux.dev, linux-kernel@vger.kernel.org, Genjian Zhang Subject: [PATCH] dm thin metadata: fix superblock refcount leak on snapshot shadow failure Date: Sat, 11 Jul 2026 18:05:26 +0800 Message-ID: <20260711100526.835027-1-zhanggenjian@126.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: PykvCgD3f2FqFVJqlOIdCw--.28673S4 X-Coremail-Antispam: 1Uf129KBjvdXoW7XFWrCF1ftw48Gr1kZFyftFb_yoWkArc_Wr 45XFWIqw1DCr4Yvw4xXws2vryIyr4Fgw4UWayjv3Wava4kXF4akry3CrZrtrn5Z3y5t34q kr4UZFyrJryxJjkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUvcSsGvfC2KfnxnUUI43ZEXa7IU19Xo3UUUUU== X-CM-SenderInfo: x2kd0wxjhqyxldq6ij2wof0z/xtbBtASVFGpSFYQbPAAA3- Content-Type: text/plain; charset="utf-8" From: Genjian Zhang __reserve_metadata_snap() increments THIN_SUPERBLOCK_LOCATION in the metadata space map before shadowing it. When dm_tm_shadow_block() fails, a reference is leaked in the metadata space map. Fix by adding the missing dm_sm_dec_block(). Fixes: cc8394d86f04 ("dm thin: provide userspace access to pool metadata") Signed-off-by: Genjian Zhang --- drivers/md/dm-thin-metadata.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c index b6a2d2081a24..b194fb57d158 100644 --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -1353,8 +1353,10 @@ static int __reserve_metadata_snap(struct dm_pool_me= tadata *pmd) dm_sm_inc_block(pmd->metadata_sm, THIN_SUPERBLOCK_LOCATION); r =3D dm_tm_shadow_block(pmd->tm, THIN_SUPERBLOCK_LOCATION, &sb_validator, ©, &inc); - if (r) + if (r) { + dm_sm_dec_block(pmd->metadata_sm, THIN_SUPERBLOCK_LOCATION); return r; + } =20 BUG_ON(!inc); =20 --=20 2.43.0