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| author | Bob Peterson <rpeterso@redhat.com> | 2010-06-17 16:45:37 -0400 |
|---|---|---|
| committer | Steven Whitehouse <swhiteho@redhat.com> | 2010-07-15 09:06:25 +0100 |
| commit | b1becbdee776b447f203aa8da9a40488d5a75e1d (patch) | |
| tree | 1bf927adf4bf63cc39961cad2476774ab88b47ee /fs/gfs2/inode.c | |
| parent | b7dc2df5725fe7355fd76000ead7e39728e1b8a9 (diff) | |
| download | linux-b1becbdee776b447f203aa8da9a40488d5a75e1d.tar.bz2 | |
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.c | 12 |
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); |