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From: Dominique Martinet <asmadeus@codewreck.org>
To: unlisted-recipients:; (no To-header on input)
Cc: Jianyong Wu <jianyong.wu@arm.com>,
	lucho@ionkov.net, justin.he@arm.com, ericvh@gmail.com,
	qemu_oss@crudebyte.com, groug@kaod.org,
	linux-kernel@vger.kernel.org,
	v9fs-developer@lists.sourceforge.net,
	Dominique Martinet <asmadeus@codewreck.org>
Subject: [PATCH 2/2] 9p: Fix writeback fid incorrectly being attached to dentry
Date: Thu, 19 Nov 2020 17:06:52 +0100	[thread overview]
Message-ID: <1605802012-31133-3-git-send-email-asmadeus@codewreck.org> (raw)
In-Reply-To: <1605802012-31133-1-git-send-email-asmadeus@codewreck.org>

v9fs_dir_release needs fid->ilist to have been initialized for filp's
fid, not the inode's writeback fid's.

With refcounting this can be improved on later but this appears to fix
null deref issues.

Fixes: xxx ("fs/9p: track open fids")
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
---
(note: fixes tag can't be filled here, will be corrected later)
 fs/9p/vfs_file.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index b0ef225cecd0..c5e49c88688d 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -46,7 +46,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
 	int err;
 	struct v9fs_inode *v9inode;
 	struct v9fs_session_info *v9ses;
-	struct p9_fid *fid;
+	struct p9_fid *fid, *writeback_fid;
 	int omode;
 
 	p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);
@@ -85,13 +85,13 @@ int v9fs_file_open(struct inode *inode, struct file *file)
 		 * because we want write after unlink usecase
 		 * to work.
 		 */
-		fid = v9fs_writeback_fid(file_dentry(file));
+		writeback_fid = v9fs_writeback_fid(file_dentry(file));
 		if (IS_ERR(fid)) {
 			err = PTR_ERR(fid);
 			mutex_unlock(&v9inode->v_mutex);
 			goto out_error;
 		}
-		v9inode->writeback_fid = (void *) fid;
+		v9inode->writeback_fid = (void *) writeback_fid;
 	}
 	mutex_unlock(&v9inode->v_mutex);
 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
-- 
2.28.0


      parent reply	other threads:[~2020-11-19 16:07 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-23 14:11 [PATCH RFC v2 0/4] 9p: fix open-unlink-f*syscall bug Jianyong Wu
2020-09-23 14:11 ` [PATCH v2 1/4] fs/9p: fix create-unlink-getattr idiom Jianyong Wu
2020-09-23 14:11 ` [PATCH v2 2/4] fs/9p: track open fids Jianyong Wu
2020-09-23 14:11 ` [PATCH v2 3/4] fs/9p: search open fids first Jianyong Wu
2020-09-23 14:11 ` [PATCH RFC v2 4/4] 9p: fix race issue in fid contention Jianyong Wu
2020-09-23 14:49   ` Dominique Martinet
2020-09-24  8:38     ` Jianyong Wu
2020-09-24  8:56       ` Greg Kurz
2020-09-24  9:51       ` Dominique Martinet
2020-09-25  9:49         ` Jianyong Wu
2020-11-03 10:41   ` Dominique Martinet
2020-11-04 11:32     ` Christian Schoenebeck
2020-11-04 11:57       ` Dominique Martinet
2020-11-05 12:32         ` Christian Schoenebeck
2020-11-05  7:05     ` Jianyong Wu
2020-11-19 16:06     ` [PATCH 0/2] follow-up to " Dominique Martinet
2020-11-19 16:06       ` [PATCH 1/2] 9p: apply review requests for fid refcounting Dominique Martinet
2020-11-19 16:06       ` Dominique Martinet [this message]

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