On 31/8/21 3:24 am, Desmond Cheong Zhi Xi wrote:
Sorry for the noise, rebasing on top of drm-misc-next. Please ignore the
v9 series.
Hi,
I updated the patch set with some suggestions by Daniel Vetter, and
dropped the patches after patch 4 so that we can stick the landing for
avoiding races
ned-off-by: Desmond Cheong Zhi Xi
Reviewed-by: Daniel Vetter
---
drivers/gpu/drm/drm_auth.c | 4
drivers/gpu/drm/drm_ioctl.c | 20 +++-
drivers/gpu/drm/drm_lease.c | 35 ---
include/drm/drm_device.h| 6 ++
4 files changed, 49 inserti
ctl permissions.
Signed-off-by: Desmond Cheong Zhi Xi
Reviewed-by: Daniel Vetter
---
drivers/gpu/drm/drm_ioctl.c | 21 -
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 9fc00e36c5d6..fe9c4c026
, convert master_mutex into a rwsem to enable
concurrent readers.
Signed-off-by: Desmond Cheong Zhi Xi
Reviewed-by: Daniel Vetter
---
drivers/gpu/drm/drm_auth.c| 35 ++-
drivers/gpu/drm/drm_debugfs.c | 4 ++--
drivers/gpu/drm/drm_drv.c | 3 +--
drivers/gpu
s set up in drm_open_helper through the call to
drm_master_open, so we mirror it with a call to drm_master_release in
drm_close_helper, and remove drm_master_release from drm_file_free to
avoid the null ptr dereference.
Fixes: 7eeaeb90a6a5 ("drm/file: Don't set master on in-kernel clien
ting a new
DRM_MASTER_FLUSH ioctl flag.
Best wishes,
Desmond
Desmond Cheong Zhi Xi (4):
drm: fix null ptr dereference in drm_master_release
drm: convert drm_device.master_mutex into a rwsem
drm: lock drm_global_mutex earlier in the ioctl handler
drm: avoid races with modesetting rights
ned-off-by: Desmond Cheong Zhi Xi
Reviewed-by: Daniel Vetter
---
drivers/gpu/drm/drm_auth.c | 4
drivers/gpu/drm/drm_ioctl.c | 20 +++-
drivers/gpu/drm/drm_lease.c | 35 ---
include/drm/drm_device.h| 6 ++
4 files changed, 49 inserti
ctl permissions.
Signed-off-by: Desmond Cheong Zhi Xi
Reviewed-by: Daniel Vetter
---
drivers/gpu/drm/drm_ioctl.c | 21 -
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index d25713b09b80..59c5aa850
, convert master_mutex into a rwsem to enable
concurrent readers.
Signed-off-by: Desmond Cheong Zhi Xi
Reviewed-by: Daniel Vetter
---
drivers/gpu/drm/drm_auth.c| 35 ++-
drivers/gpu/drm/drm_debugfs.c | 4 ++--
drivers/gpu/drm/drm_drv.c | 3 +--
drivers/gpu
s set up in drm_open_helper through the call to
drm_master_open, so we mirror it with a call to drm_master_release in
drm_close_helper, and remove drm_master_release from drm_file_free to
avoid the null ptr dereference.
Fixes: 7eeaeb90a6a5 ("drm/file: Don't set master on in-kernel clien
nise readers and writers.
- Implement drm_master_flush with task_work so that flushes can be
queued to run before returning to userspace without creating a new
DRM_MASTER_FLUSH ioctl flag.
Best wishes,
Desmond
Desmond Cheong Zhi Xi (4):
drm: fix null ptr dereference in drm_maste
On 26/8/21 9:21 pm, Daniel Vetter wrote:
On Thu, Aug 26, 2021 at 10:01:22AM +0800, Desmond Cheong Zhi Xi wrote:
Previously, master_lookup_lock was introduced in
commit 0b0860a3cf5e ("drm: serialize drm_file.master with a new
spinlock") to serialize accesses to drm_file.master. This th
On 26/8/21 8:59 pm, Daniel Vetter wrote:
On Thu, Aug 26, 2021 at 10:01:19AM +0800, Desmond Cheong Zhi Xi wrote:
In drm_client_modeset.c and drm_fb_helper.c,
drm_master_internal_{acquire,release} are used to avoid races with DRM
userspace. These functions hold onto drm_device.master_rwsem while
On 26/8/21 5:58 pm, Daniel Vetter wrote:
On Thu, Aug 26, 2021 at 10:01:18AM +0800, Desmond Cheong Zhi Xi wrote:
In a future patch, a read lock on drm_device.master_rwsem is
held in the ioctl handler before the check for ioctl
permissions. However, this inverts the lock hierarchy of
On 26/8/21 5:53 pm, Daniel Vetter wrote:
On Thu, Aug 26, 2021 at 10:01:16AM +0800, Desmond Cheong Zhi Xi wrote:
drm_master_release can be called on a drm_file without a master, which
results in a null ptr dereference of file_priv->master->magic_map. The
three cases are:
1. Error p
take this opportunity to clean up the locking design by
replacing master_lookup_lock with drm_device.master_rwsem.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 19 +++
drivers/gpu/drm/drm_file.c | 1 -
drivers/gpu/drm/drm_internal.h | 1 +
dr
inversion of the
master_rwsem --> modeset_mutex lock hierarchy.
To fix this, we create a new drm_lease_held_master helper function
that enables us to avoid calling drm_file_get_master after locking
master_rwsem or modeset_mutex.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_aut
unlocked versions that call
__drm_mode_object_find and drm_mode_object_find respectively.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_atomic_uapi.c| 7 ++---
drivers/gpu/drm/drm_color_mgmt.c | 2 +-
drivers/gpu/drm/drm_crtc.c | 5 ++--
dri
ned-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 4
drivers/gpu/drm/drm_ioctl.c | 20 +++-
drivers/gpu/drm/drm_lease.c | 35 ---
include/drm/drm_device.h| 5 +
4 files changed, 48 insertions(+), 16 deletions(-)
di
ctl permissions.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_ioctl.c | 18 +-
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index d25713b09b80..158629d88319 100644
--- a/drivers/gpu/
, convert master_mutex into a rwsem to enable
concurrent readers.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c| 35 ++-
drivers/gpu/drm/drm_debugfs.c | 4 ++--
drivers/gpu/drm/drm_drv.c | 3 +--
drivers/gpu/drm/drm_ioctl.c | 10
s set up in drm_open_helper through the call to
drm_master_open, so we mirror it with a call to drm_master_release in
drm_close_helper, and remove drm_master_release from drm_file_free to
avoid the null ptr dereference.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_file.c | 6 +
rk so that flushes can be
queued to run before returning to userspace without creating a new
DRM_MASTER_FLUSH ioctl flag.
Best wishes,
Desmond
Desmond Cheong Zhi Xi (7):
drm: fix null ptr dereference in drm_master_release
drm: convert drm_device.master_mutex into a rwsem
drm: lock drm_global_m
take this opportunity to clean up the locking design by
replacing master_lookup_lock with drm_device.master_rwsem.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 19 +++
drivers/gpu/drm/drm_file.c | 1 -
drivers/gpu/drm/drm_internal.h | 1 +
dr
chy.
To fix this, we create a new drm_lease_held_master helper function
that enables us to avoid calling drm_file_get_master after locking
modeset_mutex.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c| 3 +++
drivers/gpu/drm/drm_encoder.c | 7 ++-
drivers/gpu/
unlocked versions that call
__drm_mode_object_find and drm_mode_object_find respectively.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_atomic_uapi.c| 7 ++---
drivers/gpu/drm/drm_color_mgmt.c | 2 +-
drivers/gpu/drm/drm_crtc.c | 5 ++--
dri
ned-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 4
drivers/gpu/drm/drm_ioctl.c | 20 +++-
drivers/gpu/drm/drm_lease.c | 35 ---
include/drm/drm_device.h| 5 +
4 files changed, 48 insertions(+), 16 deletions(-)
di
ctl permissions.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_ioctl.c | 18 +-
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index d25713b09b80..158629d88319 100644
--- a/drivers/gpu/
, convert master_mutex into a rwsem to enable
concurrent readers.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c| 35 ++-
drivers/gpu/drm/drm_debugfs.c | 4 ++--
drivers/gpu/drm/drm_drv.c | 3 +--
drivers/gpu/drm/drm_ioctl.c | 10
s set up in drm_open_helper through the call to
drm_master_open, so we mirror it with a call to drm_master_release in
drm_close_helper, and remove drm_master_release from drm_file_free to
avoid the null ptr dereference.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_file.c | 6 +
ace without creating a new
DRM_MASTER_FLUSH ioctl flag.
Best wishes,
Desmond
Desmond Cheong Zhi Xi (7):
drm: fix null ptr dereference in drm_master_release
drm: convert drm_device.master_mutex into a rwsem
drm: lock drm_global_mutex earlier in the ioctl handler
drm: avoid races with modes
take this opportunity to clean up the locking design by
replacing master_lookup_lock with drm_device.master_rwsem.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 19 +++
drivers/gpu/drm/drm_file.c | 1 -
drivers/gpu/drm/drm_internal.h | 1 +
dr
chy.
To fix this, we create a new drm_lease_held_master helper function
that enables us to avoid calling drm_file_get_master after locking
modeset_mutex.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c| 3 +++
drivers/gpu/drm/drm_encoder.c | 7 ++-
drivers/gpu/
unlocked versions that call
__drm_mode_object_find and drm_mode_object_find respectively.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_atomic_uapi.c| 7 +++---
drivers/gpu/drm/drm_color_mgmt.c | 2 +-
drivers/gpu/drm/drm_crtc.c | 5 +++--
ned-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 4
drivers/gpu/drm/drm_ioctl.c | 20 +++-
drivers/gpu/drm/drm_lease.c | 35 ---
include/drm/drm_device.h| 5 +
4 files changed, 48 insertions(+), 16 deletions(-)
di
ctl permissions.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_ioctl.c | 18 +-
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index d25713b09b80..158629d88319 100644
--- a/drivers/gpu/
, convert master_mutex into a rwsem to enable
concurrent readers.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c| 35 ++-
drivers/gpu/drm/drm_debugfs.c | 4 ++--
drivers/gpu/drm/drm_drv.c | 3 +--
drivers/gpu/drm/drm_ioctl.c | 10
s set up in drm_open_helper through the call to
drm_master_open, so we mirror it with a call to drm_master_release in
drm_close_helper, and remove drm_master_release from drm_file_free to
avoid the null ptr dereference.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_file.c | 6 +
o userspace without creating a new
DRM_MASTER_FLUSH ioctl flag.
Best wishes,
Desmond
Desmond Cheong Zhi Xi (7):
drm: fix null ptr dereference in drm_master_release
drm: convert drm_device.master_mutex into a rwsem
drm: lock drm_global_mutex earlier in the ioctl handler
drm: avoid races with
revious patch fixed other remaining inversions
involving master_rwsem and modeset_mutex.
Hence, we can take this opportunity to clean up the locking design by
replacing master_lookup_lock with drm_device.master_rwsem.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gp
Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_atomic_uapi.c | 4 +++-
drivers/gpu/drm/drm_auth.c| 3 +++
drivers/gpu/drm/drm_encoder.c | 7 ++-
drivers/gpu/drm/drm_framebuffer.c | 2 +-
drivers/gpu/drm/drm_lease.c | 34 ---
drivers
ned-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 4
drivers/gpu/drm/drm_ioctl.c | 20 +++-
drivers/gpu/drm/drm_lease.c | 35 ---
include/drm/drm_device.h| 5 +
4 files changed, 48 insertions(+), 16 deletions(-)
di
ctl permissions.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_ioctl.c | 18 +-
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index d25713b09b80..158629d88319 100644
--- a/drivers/gpu/
, convert master_mutex into a rwsem to enable
concurrent readers.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c| 35 ++-
drivers/gpu/drm/drm_debugfs.c | 4 ++--
drivers/gpu/drm/drm_drv.c | 3 +--
drivers/gpu/drm/drm_ioctl.c | 10
s set up in drm_open_helper through the call to
drm_master_open, so we mirror it with a call to drm_master_release in
drm_close_helper, and remove drm_master_release from drm_file_free to
avoid the null ptr dereference.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_file.c | 6 +
ers.
- Implement drm_master_flush with task_work so that flushes can be
queued to run before returning to userspace without creating a new
DRM_MASTER_FLUSH ioctl flag.
Best wishes,
Desmond
Desmond Cheong Zhi Xi (6):
drm: fix null ptr dereference in drm_master_release
drm: convert drm_device.mas
ter_rwsem while holding onto
mode_config.idr_mutex), then remove master_lookup_lock.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c| 19 ++--
drivers/gpu/drm/drm_file.c| 1 -
drivers/gpu/drm/drm_internal.h| 1 +
drivers/gpu/drm/drm_ioctl.c
ned-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 4
drivers/gpu/drm/drm_ioctl.c | 20 +++-
drivers/gpu/drm/drm_lease.c | 35 ---
include/drm/drm_device.h| 5 +
4 files changed, 48 insertions(+), 16 deletions(-)
di
ctl permissions.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_ioctl.c | 18 +-
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index d25713b09b80..158629d88319 100644
--- a/drivers/gpu/
, convert master_mutex into a rwsem to enable
concurrent readers.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c| 35 ++-
drivers/gpu/drm/drm_debugfs.c | 4 ++--
drivers/gpu/drm/drm_drv.c | 3 +--
drivers/gpu/drm/drm_ioctl.c | 10
s set up in drm_open_helper through the call to
drm_master_open, so we mirror it with a call to drm_master_release in
drm_close_helper, and remove drm_master_release from drm_file_free to
avoid the null ptr dereference.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_file.c | 6 +
reating a new
DRM_MASTER_FLUSH ioctl flag.
Best wishes,
Desmond
Desmond Cheong Zhi Xi (5):
drm: fix null ptr dereference in drm_master_release
drm: convert drm_device.master_mutex into a rwsem
drm: lock drm_global_mutex earlier in the ioctl handler
drm: avoid races with modesetting rig
On 18/8/21 7:02 pm, Daniel Vetter wrote:
On Wed, Aug 18, 2021 at 03:38:22PM +0800, Desmond Cheong Zhi Xi wrote:
In a future patch, a read lock on drm_device.master_rwsem is
held in the ioctl handler before the check for ioctl
permissions. However, this produces the following lockdep splat
On 19/8/21 5:26 pm, Christoph Hellwig wrote:
On Wed, Aug 18, 2021 at 03:38:23PM +0800, Desmond Cheong Zhi Xi wrote:
+EXPORT_SYMBOL(task_work_add);
EXPORT_SYMBOL_GPL for this kinds of functionality, please.
Thanks, I wasn't aware of the GPL-only export. I'll update this in a
fut
On 19/8/21 12:33 am, Daniel Vetter wrote:
On Wed, Aug 18, 2021 at 5:37 PM Desmond Cheong Zhi Xi
wrote:
On 18/8/21 6:11 pm, Daniel Vetter wrote:
On Wed, Aug 18, 2021 at 03:38:19PM +0800, Desmond Cheong Zhi Xi wrote:
There are three areas where we dereference struct drm_master without
On 18/8/21 6:11 pm, Daniel Vetter wrote:
On Wed, Aug 18, 2021 at 03:38:19PM +0800, Desmond Cheong Zhi Xi wrote:
There are three areas where we dereference struct drm_master without
checking if the pointer is non-NULL.
1. drm_getmagic is called from the ioctl_handler. Since
DRM_IOCTL_GET_MAGIC
On 18/8/21 6:05 pm, Daniel Vetter wrote:
On Wed, Aug 18, 2021 at 03:38:17PM +0800, Desmond Cheong Zhi Xi wrote:
When drm_file.master changes value, the corresponding
drm_device.master_lookup_lock should be held.
In drm_master_release, a call to drm_master_put sets the
file_priv->master to N
sem: users that
perform modesetting should hold a read lock on the new
drm_device.master_rwsem, and users that change these permissions
should either hold a write lock, or should flush readers before
returning to userspace.
Reported-by: Daniel Vetter
Signed-off-by: Desmond Cheong Zhi Xi
---
drive
:
ERROR: modpost: "task_work_add" [drivers/gpu/drm/drm.ko] undefined!
Reported-by: kernel test robot
Signed-off-by: Desmond Cheong Zhi Xi
---
kernel/task_work.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/task_work.c b/kernel/task_work.c
index 1698fbe6f0e1..9404af2b 10
At the same time, we update the check for the global mutex to use the
drm_dev_needs_global_mutex helper function.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_ioctl.c | 18 +-
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/drm_ioctl.
. Hence, convert master_mutex into a rwsem to enable
concurrent readers.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c| 27 ++-
drivers/gpu/drm/drm_debugfs.c | 4 ++--
drivers/gpu/drm/drm_drv.c | 3 +--
drivers/gpu/drm/drm_ioctl.c | 4
serialize access to drm_master.magic_map and
drm_master.unique{_len} using drm_device.master_lookup_lock which is
an inner lock.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 12 +++-
drivers/gpu/drm/drm_ioctl.c | 10 ++
include/drm/drm_auth.h | 6
is
non-NULl to guard against this scenario.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index 8c0e0dba1611..f9267b21556e 100644
--- a/drivers/gpu/
cking if the master pointers are NULL before use.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 16 ++--
drivers/gpu/drm/drm_ioctl.c | 5 +
2 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_
When drm_file.master changes value, the corresponding
drm_device.master_lookup_lock should be held.
In drm_master_release, a call to drm_master_put sets the
file_priv->master to NULL, so we protect this section with
drm_device.master_lookup_lock.
Signed-off-by: Desmond Cheong Zhi
drm_device allows us to use it for structures that
are accessed by multiple drm_files, such as drm_master.magic_map.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 18 +-
drivers/gpu/drm/drm_drv.c | 1 +
drivers/gpu/drm/drm_file.c | 1 -
include/drm
nt drm_master_flush with task_work so that flushes can be
queued to run before returning to userspace without creating a new
DRM_MASTER_FLUSH ioctl flag.
Best wishes,
Desmond
Desmond Cheong Zhi Xi (9):
drm: move master_lookup_lock into drm_device
drm: hold master_lookup_lock when releasing a drm_file&#
On 16/8/21 9:59 pm, Daniel Vetter wrote:
On Mon, Aug 16, 2021 at 12:31 PM Desmond Cheong Zhi Xi
wrote:
On 16/8/21 5:04 pm, Daniel Vetter wrote:
On Mon, Aug 16, 2021 at 10:53 AM Desmond Cheong Zhi Xi
wrote:
On 16/8/21 2:47 am, kernel test robot wrote:
Hi Desmond,
Thank you for the patch
On 16/8/21 5:04 pm, Daniel Vetter wrote:
On Mon, Aug 16, 2021 at 10:53 AM Desmond Cheong Zhi Xi
wrote:
On 16/8/21 2:47 am, kernel test robot wrote:
Hi Desmond,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on next-20210813]
[also build test ERROR on v5.14-rc5
, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url:
https://github.com/0day-ci/linux/commits/Desmond-Cheong-Zhi-Xi/drm-avoid-races-with-modesetting-rights/20210815-2
git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url:
https://github.com/0day-ci/linux/commits/Desmond-Cheong-Zhi-Xi/drm-avoid-races-with-modesetting-rights/20210815-2
by: Daniel Vetter
Signed-off-by: Desmond Cheong Zhi Xi
---
Hi,
I opted to leave the drm_master_unlock_and_flush helper out of this
patch, but happy to add it in if it'd be useful. Imo, when comparing it
with a mutex_unlock followed by drm_master_flush, it didn't add clarity.
And since we d
On 13/8/21 11:49 pm, Daniel Vetter wrote:
On Fri, Aug 13, 2021 at 04:54:49PM +0800, Desmond Cheong Zhi Xi wrote:
In drm_client_modeset.c and drm_fb_helper.c,
drm_master_internal_{acquire,release} are used to avoid races with DRM
userspace. These functions hold onto drm_device.master_mutex while
()
Thoughts and comments would be very appreciated.
Link: https://lore.kernel.org/lkml/YN9kAFcfGoB13x7f@phenom.ffwll.local/ [1]
Best wishes,
Desmond
Desmond Cheong Zhi Xi (2):
drm: avoid races with modesetting rights
drm: unexport drm_ioctl_permit
drivers/gpu/drm/drm_auth.c | 17
Since the last user of drm_ioctl_permit was removed, and it's now only
used in drm_ioctl.c, unexport the symbol.
Reported-by: Daniel Vetter
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_ioctl.c | 15 +--
include/drm/drm_ioctl.h | 1 -
2 files chang
return
to userspace.
Reported-by: Daniel Vetter
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 17 ++---
drivers/gpu/drm/drm_client_modeset.c | 10 ++
drivers/gpu/drm/drm_drv.c| 2 ++
drivers/gpu/drm/drm_fb_helper.c
ion is now convenient. So we add in the
assertion and explain this lock design in the kerneldoc.
Signed-off-by: Desmond Cheong Zhi Xi
Acked-by: Boqun Feng
Acked-by: Waiman Long
Acked-by: Peter Zijlstra (Intel)
---
drivers/gpu/drm/drm_auth.c | 6 +++---
include/drm/drm_file.h | 4 +++
Zijlstra (Intel)
Signed-off-by: Desmond Cheong Zhi Xi
Acked-by: Boqun Feng
Acked-by: Waiman Long
Acked-by: Peter Zijlstra (Intel)
---
include/linux/lockdep.h | 41 +
1 file changed, 21 insertions(+), 20 deletions(-)
diff --git a/include/linux/lockdep.h b
in
the use of lockdep_assert(). As suggested by Boqun Feng.
Link:
https://lore.kernel.org/lkml/20210722092929.244629-2-desmondcheon...@gmail.com/
[1]
Best wishes,
Desmond
Desmond Cheong Zhi Xi (1):
drm: add lockdep assert to drm_is_current_master_locked
Peter Zijlstra (1):
locking/lockdep: Provide l
On 2/8/21 4:26 pm, Daniel Vetter wrote:
On Sat, Jul 31, 2021 at 04:24:56PM +0800, Desmond Cheong Zhi Xi wrote:
Hi,
Following a discussion on the patch ("drm: use the lookup lock in
drm_is_current_master") [1], Peter Zijlstra proposed new lockdep_assert
helpers to make it convenient
ion is now convenient. So we add in the
assertion and explain this lock design in the kerneldoc.
Signed-off-by: Desmond Cheong Zhi Xi
Acked-by: Boqun Feng
Acked-by: Waiman Long
---
drivers/gpu/drm/drm_auth.c | 6 +++---
include/drm/drm_file.h | 4
2 files changed, 7 insertions(+), 3
Zijlstra (Intel)
Signed-off-by: Desmond Cheong Zhi Xi
Acked-by: Boqun Feng
Acked-by: Waiman Long
---
include/linux/lockdep.h | 41 +
1 file changed, 21 insertions(+), 20 deletions(-)
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 5cf3
-desmondcheon...@gmail.com/
[1]
Best wishes,
Desmond
Desmond Cheong Zhi Xi (1):
drm: add lockdep assert to drm_is_current_master_locked
Peter Zijlstra (1):
locking/lockdep: Provide lockdep_assert{,_once}() helpers
drivers/gpu/drm/drm_auth.c | 6 +++---
include/drm/drm_file.h | 4
On 30/7/21 2:08 pm, Boqun Feng wrote:
On Fri, Jul 30, 2021 at 12:15:15PM +0800, Desmond Cheong Zhi Xi wrote:
In drm_is_current_master_locked, accessing drm_file.master should be
protected by either drm_file.master_lookup_lock or
drm_device.master_mutex. This was previously awkward to assert
summary retained to clarify that it's the leased objects that
are returned, not the lease structure.
drm_mode_revoke_lease_ioctl:
Kerneldoc removed, but useful function details retained.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_lease.c | 131 +++---
ion is now convenient so we add it in.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/drm_auth.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index 9c24b8cc8e36..6f4d7ff23c80 100644
--- a/drive
Zijlstra (Intel)
Signed-off-by: Desmond Cheong Zhi Xi
---
include/linux/lockdep.h | 41 +
1 file changed, 21 insertions(+), 20 deletions(-)
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 5cf387813754..9fe165beb0f9 100644
--- a/inclu
n utilizes these helpers in drm_is_current_master_locked in the
following patch.
Link:
https://lore.kernel.org/lkml/20210722092929.244629-2-desmondcheon...@gmail.com/
[1]
Best wishes,
Desmond
Desmond Cheong Zhi Xi (1):
drm: add lockdep assert to drm_is_current_master_locked
Peter Zijlstra (1):
On 29/7/21 3:00 pm, Daniel Vetter wrote:
On Tue, Jul 27, 2021 at 04:37:22PM +0200, Peter Zijlstra wrote:
On Thu, Jul 22, 2021 at 12:38:10PM +0200, Daniel Vetter wrote:
On Thu, Jul 22, 2021 at 05:29:27PM +0800, Desmond Cheong Zhi Xi wrote:
Inside drm_is_current_master, using the outer
g, and explains how leases work and why
they're used.
Signed-off-by: Desmond Cheong Zhi Xi
Reviewed-by: Daniel Vetter
---
v2 -> v3 (suggestions from Daniel Vetter):
- Clarified that device owners are changed through SETMASTER or
DROPMASTER IOCTL.
- Removed unneccessary includes for d
On 27/7/21 9:04 pm, Daniel Vetter wrote:
On Sat, Jul 24, 2021 at 07:18:23PM +0800, Desmond Cheong Zhi Xi wrote:
We make the following changes to the documentation of drm leases to
make it easier to reason about their usage. In particular, we clarify
the lifetime and locking rules of lease
ing drm_master_get with drm_file_get_master.
Signed-off-by: Desmond Cheong Zhi Xi
Reviewed-by: Daniel Vetter
Reviewed-by: Zack Rusin
---
drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
b/drivers/
g, and explains how leases work and why
they're used.
4. Clean up function documentation in drm_lease.c to use kernel-doc
formatting.
Signed-off-by: Desmond Cheong Zhi Xi
---
Hi,
After I updated the formatting for comments in drm_lease.c, I noticed
that none of these were driver interfaces
Signed-off-by: Desmond Cheong Zhi Xi
Reviewed-by: Daniel Vetter
---
drivers/gpu/drm/drm_auth.c | 9 +
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index f00354bec3fb..9c24b8cc8e36 100644
--- a/drivers/gpu/drm
in drm_master with suggestions from
Daniel Vetter.
- Added an overview DOC: section for drm leases in drm-uapi.rst.
- Cleaned up function documentation in drm_lease.c to use kernel-doc formatting.
Best wishes,
Desmond
Desmond Cheong Zhi Xi (3):
drm: use the lookup lock in drm_is_current_master
On 23/7/21 3:17 am, Zack Rusin wrote:
On 7/22/21 5:29 AM, Desmond Cheong Zhi Xi wrote:
drm_file.master should be protected by either drm_device.master_mutex
or drm_file.master_lookup_lock when being dereferenced. However,
drm_master_get is called on unprotected file_priv->master pointers
On 22/7/21 6:35 pm, Daniel Vetter wrote:
On Thu, Jul 22, 2021 at 05:29:28PM +0800, Desmond Cheong Zhi Xi wrote:
In particular, we make it clear that &drm_device.mode_config.idr_mutex
protects the lease idr and list structures for drm_master. The lessor
field itself doesn't need to be
On 21/7/21 9:23 pm, Daniel Vetter wrote:
On Wed, Jul 21, 2021 at 2:44 PM Desmond Cheong Zhi Xi
wrote:
On 21/7/21 6:29 pm, Daniel Vetter wrote:
On Wed, Jul 21, 2021 at 6:12 AM Desmond Cheong Zhi Xi
wrote:
On 21/7/21 2:24 am, Daniel Vetter wrote:
On Mon, Jul 12, 2021 at 12:35:03PM +0800
ing drm_master_get with drm_file_get_master.
Signed-off-by: Desmond Cheong Zhi Xi
---
drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index 0eba47762
for the lifetime of lessors and
leases to make it easier to reason about them.
Signed-off-by: Desmond Cheong Zhi Xi
---
include/drm/drm_auth.h | 62 ++
1 file changed, 51 insertions(+), 11 deletions(-)
diff --git a/include/drm/drm_auth.h b/include/d
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