diff options
| author | Ilija Hadzic <ihadzic@research.bell-labs.com> | 2013-04-02 17:56:10 +0400 |
|---|---|---|
| committer | Dave Airlie <airlied@redhat.com> | 2013-04-03 00:44:38 +0400 |
| commit | a8ec3a662921220fc058ed6f7f3674697876d218 (patch) | |
| tree | e7c35670e35d4e5ace87b01c83652dfee006fdc4 | |
| parent | 7cebefe6cca5e8ff6ec9ba13ff9edb03d3c19fc7 (diff) | |
| download | linux-a8ec3a662921220fc058ed6f7f3674697876d218.tar.xz | |
drm: correctly restore mappings if drm_open fails
If first drm_open fails, the error-handling path will
incorrectly restore inode's mapping to NULL. This can
cause the crash later on. Fix by separately storing
away mapping pointers that drm_open can touch and
restore each from its own respective variable if the
call fails.
Fixes: https://bugzilla.novell.com/show_bug.cgi?id=807850
(thanks to Michal Hocko for investigating investigating and
finding the root cause of the bug)
Reference:
http://lists.freedesktop.org/archives/dri-devel/2013-March/036564.html
v2: Use one variable to store file and inode mapping
since they are the same at the function entry.
Fix spelling mistakes in commit message.
v3: Add reference to the original bug report.
Reported-by: Marco Munderloh <munderl@tnt.uni-hannover.de>
Tested-by: Marco Munderloh <munderl@tnt.uni-hannover.de>
Signed-off-by: Ilija Hadzic <ihadzic@research.bell-labs.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
| -rw-r--r-- | drivers/gpu/drm/drm_fops.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c index 13fdcd10a605..429e07d0b0f1 100644 --- a/drivers/gpu/drm/drm_fops.c +++ b/drivers/gpu/drm/drm_fops.c @@ -123,6 +123,7 @@ int drm_open(struct inode *inode, struct file *filp) int retcode = 0; int need_setup = 0; struct address_space *old_mapping; + struct address_space *old_imapping; minor = idr_find(&drm_minors_idr, minor_id); if (!minor) @@ -137,6 +138,7 @@ int drm_open(struct inode *inode, struct file *filp) if (!dev->open_count++) need_setup = 1; mutex_lock(&dev->struct_mutex); + old_imapping = inode->i_mapping; old_mapping = dev->dev_mapping; if (old_mapping == NULL) dev->dev_mapping = &inode->i_data; @@ -159,8 +161,8 @@ int drm_open(struct inode *inode, struct file *filp) err_undo: mutex_lock(&dev->struct_mutex); - filp->f_mapping = old_mapping; - inode->i_mapping = old_mapping; + filp->f_mapping = old_imapping; + inode->i_mapping = old_imapping; iput(container_of(dev->dev_mapping, struct inode, i_data)); dev->dev_mapping = old_mapping; mutex_unlock(&dev->struct_mutex); |