linux-kernel - [PATCH 16/19] VFS: use GFP_NOFS rather than GFP_KERNEL in __d

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140416040337.10604.61837.stgit@notabene.brown>
Date:	Wed, 16 Apr 2014 14:03:37 +1000
From:	NeilBrown <neilb@...e.de>
To:	linux-mm@...ck.org, linux-nfs@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc:	xfs@....sgi.com
Subject: [PATCH 16/19] VFS: use GFP_NOFS rather than GFP_KERNEL in __d_alloc.

__d_alloc can be called with i_mutex held, so it is safer to
use GFP_NOFS.

lockdep reports this can deadlock when loop-back NFS is in use,
as nfsd may be required to write out for reclaim, and nfsd certainly
takes i_mutex.

Signed-off-by: NeilBrown <neilb@...e.de>
---
 fs/dcache.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index ca02c13a84aa..3651ff6185b4 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1483,7 +1483,7 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
 	struct dentry *dentry;
 	char *dname;
 
-	dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL);
+	dentry = kmem_cache_alloc(dentry_cache, GFP_NOFS);
 	if (!dentry)
 		return NULL;
 
@@ -1495,7 +1495,7 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
 	 */
 	dentry->d_iname[DNAME_INLINE_LEN-1] = 0;
 	if (name->len > DNAME_INLINE_LEN-1) {
-		dname = kmalloc(name->len + 1, GFP_KERNEL);
+		dname = kmalloc(name->len + 1, GFP_NOFS);
 		if (!dname) {
 			kmem_cache_free(dentry_cache, dentry); 
 			return NULL;


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/