From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5BF8D31748; Fri, 24 Nov 2023 18:50:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="e5tivaIJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF4DFC433C8; Fri, 24 Nov 2023 18:50:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700851858; bh=0VITVK+hBvY5QCKMlf4TTvmOQld067iQ7PAGL4FLtUo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=e5tivaIJSdr2eAC2SbJQNmAB+EC5yVyAV3ipk+rS/7ZGo9Dya5wanlJVgWrnQKSGe vjn2Oc2S82RZx6+ajJbX/iQSDFLhwYqSoXqkIaNLHSyZP5ebSrOpzkyg3SEpkJXjut W+IevOl4j47qJOD21mEKVk6hSvtKoNm+ad0e9Rwc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+3e5130844b0c0e2b4948@syzkaller.appspotmail.com, Andreas Gruenbacher , Sasha Levin Subject: [PATCH 6.1 124/372] gfs2: Silence "suspicious RCU usage in gfs2_permission" warning Date: Fri, 24 Nov 2023 17:48:31 +0000 Message-ID: <20231124172014.613150229@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231124172010.413667921@linuxfoundation.org> References: <20231124172010.413667921@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andreas Gruenbacher [ Upstream commit 074d7306a4fe22fcac0b53f699f92757ab1cee99 ] Commit 0abd1557e21c added rcu_dereference() for dereferencing ip->i_gl in gfs2_permission. This now causes lockdep to complain when gfs2_permission is called in non-RCU context: WARNING: suspicious RCU usage in gfs2_permission Switch to rcu_dereference_check() and check for the MAY_NOT_BLOCK flag to shut up lockdep when we know that dereferencing ip->i_gl is safe. Fixes: 0abd1557e21c ("gfs2: fix an oops in gfs2_permission") Reported-by: syzbot+3e5130844b0c0e2b4948@syzkaller.appspotmail.com Signed-off-by: Andreas Gruenbacher Signed-off-by: Sasha Levin --- fs/gfs2/inode.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c index d126b02893eb0..23e6962cdd6e3 100644 --- a/fs/gfs2/inode.c +++ b/fs/gfs2/inode.c @@ -1845,6 +1845,7 @@ static const char *gfs2_get_link(struct dentry *dentry, int gfs2_permission(struct user_namespace *mnt_userns, struct inode *inode, int mask) { + int may_not_block = mask & MAY_NOT_BLOCK; struct gfs2_inode *ip; struct gfs2_holder i_gh; struct gfs2_glock *gl; @@ -1852,14 +1853,14 @@ int gfs2_permission(struct user_namespace *mnt_userns, struct inode *inode, gfs2_holder_mark_uninitialized(&i_gh); ip = GFS2_I(inode); - gl = rcu_dereference(ip->i_gl); + gl = rcu_dereference_check(ip->i_gl, !may_not_block); if (unlikely(!gl)) { /* inode is getting torn down, must be RCU mode */ - WARN_ON_ONCE(!(mask & MAY_NOT_BLOCK)); + WARN_ON_ONCE(!may_not_block); return -ECHILD; } if (gfs2_glock_is_locked_by_me(gl) == NULL) { - if (mask & MAY_NOT_BLOCK) + if (may_not_block) return -ECHILD; error = gfs2_glock_nq_init(gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh); if (error) -- 2.42.0