The patch titled
Subject: ufs: fix deadlocks introduced by sb mutex merge
has been added to the -mm tree. Its filename is
ufs-fix-deadlocks-introduced-by-sb-mutex-merge.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ufs-fix-deadlocks-introduced-by-sb-mutex-merge.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ufs-fix-deadlocks-introduced-by-sb-mutex-merge.patch
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------------------------------------------------------
From: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
Subject: ufs: fix deadlocks introduced by sb mutex merge
Commit 0244756edc4b ("ufs: sb mutex merge + mutex_destroy") introduces
deadlocks in ufs_new_inode() and ufs_free_inode().
Most callers of those functions acquire the mutex by themselves and
ufs_{new,free}_inode() do that via lock_ufs(), i.e we have an unavoidable
double lock.
The patch resolves the issue by making sure that ufs_{new,free}_inode()
are not called with the mutex held.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
Cc: Fabian Frederick <fabf@xxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Evgeniy Dushistov <dushistov@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ufs/inode.c | 7 ++-----
fs/ufs/namei.c | 14 ++++++--------
2 files changed, 8 insertions(+), 13 deletions(-)
diff -puN fs/ufs/inode.c~ufs-fix-deadlocks-introduced-by-sb-mutex-merge fs/ufs/inode.c
--- a/fs/ufs/inode.c~ufs-fix-deadlocks-introduced-by-sb-mutex-merge
+++ a/fs/ufs/inode.c
@@ -902,9 +902,6 @@ void ufs_evict_inode(struct inode * inod
invalidate_inode_buffers(inode);
clear_inode(inode);
- if (want_delete) {
- lock_ufs(inode->i_sb);
- ufs_free_inode (inode);
- unlock_ufs(inode->i_sb);
- }
+ if (want_delete)
+ ufs_free_inode(inode);
}
diff -puN fs/ufs/namei.c~ufs-fix-deadlocks-introduced-by-sb-mutex-merge fs/ufs/namei.c
--- a/fs/ufs/namei.c~ufs-fix-deadlocks-introduced-by-sb-mutex-merge
+++ a/fs/ufs/namei.c
@@ -126,12 +126,12 @@ static int ufs_symlink (struct inode * d
if (l > sb->s_blocksize)
goto out_notlocked;
- lock_ufs(dir->i_sb);
inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
err = PTR_ERR(inode);
if (IS_ERR(inode))
- goto out;
+ goto out_notlocked;
+ lock_ufs(dir->i_sb);
if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
/* slow symlink */
inode->i_op = &ufs_symlink_inode_operations;
@@ -181,13 +181,9 @@ static int ufs_mkdir(struct inode * dir,
struct inode * inode;
int err;
- lock_ufs(dir->i_sb);
- inode_inc_link_count(dir);
-
inode = ufs_new_inode(dir, S_IFDIR|mode);
- err = PTR_ERR(inode);
if (IS_ERR(inode))
- goto out_dir;
+ return PTR_ERR(inode);
inode->i_op = &ufs_dir_inode_operations;
inode->i_fop = &ufs_dir_operations;
@@ -195,6 +191,9 @@ static int ufs_mkdir(struct inode * dir,
inode_inc_link_count(inode);
+ lock_ufs(dir->i_sb);
+ inode_inc_link_count(dir);
+
err = ufs_make_empty(inode, dir);
if (err)
goto out_fail;
@@ -212,7 +211,6 @@ out_fail:
inode_dec_link_count(inode);
inode_dec_link_count(inode);
iput (inode);
-out_dir:
inode_dec_link_count(dir);
unlock_ufs(dir->i_sb);
goto out;
_
Patches currently in -mm which might be from khoroshilov@xxxxxxxxx are
ufs-fix-deadlocks-introduced-by-sb-mutex-merge.patch
linux-next.patch
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