Searched hist:bd36d3bab2e3d08f80766c86487090dbceed4651 (Results 1 – 1 of 1) sorted by relevance
| /linux/drivers/gpu/drm/ |
| H A D | drm_lease.c | diff d2a48e52541cdf474ef35d51e8d73ded5be33122 Thu Dec 21 07:54:24 CET 2017 Keith Packard <keithp@keithp.com> drm: move lease init after validation in drm_lease_create
Patch bd36d3bab2e3d08f80766c86487090dbceed4651 fixed a deadlock in the
failure path of drm_lease_create. This made the partially initialized
lease object visible for a short window of time.
To avoid having the lessee state appear transiently, I've rearranged
the code so that the lessor fields are not filled in until the
parameters are all validated and the function will succeed.
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171221065424.1304-1-keithp@keithp.com
diff bd36d3bab2e3d08f80766c86487090dbceed4651 Wed Dec 13 19:10:48 CET 2017 Marius Vlad <marius-cristian.vlad@nxp.com> drm/drm_lease: Prevent deadlock in case drm_lease_create() fails
This case can been seen when creating the lease with the same objects passed.
[ 605.515097] 2 locks held by testapp/3337:
[ 605.519027] #0: (&dev->mode_config.idr_mutex){......}, at: [<ffff0000085f1664>] drm_mode_create_lease_ioctl+0x384/0x858
[ 605.530045] #1: (&dev->mode_config.idr_mutex){......}, at: [<ffff0000085f11bc>] drm_lease_destroy+0x2c/0x110
Which was causing the process to hang:
[ 605.398827] [<ffff0000080856cc>] __switch_to+0x94/0xa8
[ 605.404030] [<ffff000008c05d00>] __schedule+0x1b0/0x698
[ 605.409322] [<ffff000008c06224>] schedule+0x3c/0xa8
[ 605.414260] [<ffff000008c06628>] schedule_preempt_disabled+0x20/0x38
[ 605.420677] [<ffff000008c07370>] mutex_lock_nested+0x158/0x340
[ 605.426572] [<ffff0000085f11bc>] drm_lease_destroy+0x2c/0x110
[ 605.432389] [<ffff0000085cecf0>] drm_master_put+0xc0/0xc8
[ 605.437845] [<ffff0000085f175c>] drm_mode_create_lease_ioctl+0x47c/0x858
[ 605.444612] [<ffff0000085d4460>] drm_ioctl+0x198/0x448
[ 605.449811] [<ffff000008201134>] do_vfs_ioctl+0xa4/0x748
[ 605.455192] [<ffff000008201864>] SyS_ioctl+0x8c/0xa0
[ 605.460216] [<ffff000008082f4c>] __sys_trace_return+0x0/0x4
drm_mode_create_lease_ioctl() calls drm_lease_create() which acquires a lock
on dev->mode_config.idr_mutex. In case of failure, drm_lease_create() calls
drm_master_put() which in turn tries to acquire the same lock when calling
drm_lease_destroy().
v2: - Reverse the order at exit in case of fail, so that unlocking takes place
before dropping the reference.
- Include detail information about deadlock (Daniel Vetter)
Signed-off-by: Marius Vlad <marius-cristian.vlad@nxp.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171213181048.32719-1-marius-cristian.vlad@nxp.com
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