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authorBob Peterson <rpeterso@redhat.com>2010-06-17 16:45:37 -0400
committerSteven Whitehouse <swhiteho@redhat.com>2010-07-15 09:06:25 +0100
commitb1becbdee776b447f203aa8da9a40488d5a75e1d (patch)
tree1bf927adf4bf63cc39961cad2476774ab88b47ee /fs/gfs2/inode.c
parentb7dc2df5725fe7355fd76000ead7e39728e1b8a9 (diff)
GFS2: Fix kernel NULL pointer dereference by dlm_astd
This patch fixes a problem in an error path when looking up dinodes. There are two sister-functions, gfs2_inode_lookup and gfs2_process_unlinked_inode. Both functions acquire and hold the i_iopen glock for the dinode being looked up. The last thing they try to do is hold the i_gl glock for the dinode. If that glock fails for some reason, the error path was incorrectly calling gfs2_glock_put for the i_iopen glock twice. This resulted in the glock being prematurely freed. The "minimum hold time" usually kept the glock in memory, but the lock interface to dlm (aka lock_dlm) freed its memory for the glock. In some circumstances, it would cause dlm's dlm_astd daemon to try to call the bast function for the freed lock_dlm memory, which resulted in a NULL pointer dereference. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'fs/gfs2/inode.c')
-rw-r--r--fs/gfs2/inode.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index b5612cbb62a5..f03afd9c44bc 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -169,7 +169,7 @@ struct inode *gfs2_inode_lookup(struct super_block *sb,
{
struct inode *inode;
struct gfs2_inode *ip;
- struct gfs2_glock *io_gl;
+ struct gfs2_glock *io_gl = NULL;
int error;
inode = gfs2_iget(sb, no_addr);
@@ -198,6 +198,7 @@ struct inode *gfs2_inode_lookup(struct super_block *sb,
ip->i_iopen_gh.gh_gl->gl_object = ip;
gfs2_glock_put(io_gl);
+ io_gl = NULL;
if ((type == DT_UNKNOWN) && (no_formal_ino == 0))
goto gfs2_nfsbypass;
@@ -228,7 +229,8 @@ gfs2_nfsbypass:
fail_glock:
gfs2_glock_dq(&ip->i_iopen_gh);
fail_iopen:
- gfs2_glock_put(io_gl);
+ if (io_gl)
+ gfs2_glock_put(io_gl);
fail_put:
if (inode->i_state & I_NEW)
ip->i_gl->gl_object = NULL;
@@ -256,7 +258,7 @@ void gfs2_process_unlinked_inode(struct super_block *sb, u64 no_addr)
{
struct gfs2_sbd *sdp;
struct gfs2_inode *ip;
- struct gfs2_glock *io_gl;
+ struct gfs2_glock *io_gl = NULL;
int error;
struct gfs2_holder gh;
struct inode *inode;
@@ -293,6 +295,7 @@ void gfs2_process_unlinked_inode(struct super_block *sb, u64 no_addr)
ip->i_iopen_gh.gh_gl->gl_object = ip;
gfs2_glock_put(io_gl);
+ io_gl = NULL;
inode->i_mode = DT2IF(DT_UNKNOWN);
@@ -319,7 +322,8 @@ void gfs2_process_unlinked_inode(struct super_block *sb, u64 no_addr)
fail_glock:
gfs2_glock_dq(&ip->i_iopen_gh);
fail_iopen:
- gfs2_glock_put(io_gl);
+ if (io_gl)
+ gfs2_glock_put(io_gl);
fail_put:
ip->i_gl->gl_object = NULL;
gfs2_glock_put(ip->i_gl);