• Maarten Lankhorst's avatar
    drm/atomic: Fix double free in drm_atomic_state_default_clear · 4cd462c7
    Maarten Lankhorst authored
    commit 92c715fc upstream.
    
    drm_atomic_helper_page_flip and drm_atomic_ioctl set their own events
    in crtc_state->event. But when it's set the event is freed in 2 places.
    
    Solve this by only freeing the event in the atomic ioctl when it
    allocated its own event.
    
    This has been broken twice. The first time when the code was introduced,
    but only in the corner case when an event is allocated, but more crtc's
    were included by atomic check and then failing. This can mostly
    happen when you do an atomic modeset in i915 and the display clock is
    changed, which forces all crtc's to be included to the state.
    
    This has been broken worse by adding in-fences support, which caused
    the double free to be done unconditionally.
    
    [IGT] kms_rotation_crc: starting subtest primary-rotation-180
    =============================================================================
    BUG kmalloc-128 (Tainted: G     U         ): Object already free
    -----------------------------------------------------------------------------
    
    Disabling lock debugging due to kernel taint
    INFO: Allocated in drm_atomic_helper_setup_commit+0x285/0x2f0 [drm_kms_helper] age=0 cpu=3 pid=1529
     ___slab_alloc+0x308/0x3b0
     __slab_alloc+0xd/0x20
     kmem_cache_alloc_trace+0x92/0x1c0
     drm_atomic_helper_setup_commit+0x285/0x2f0 [drm_kms_helper]
     intel_atomic_commit+0x35/0x4f0 [i915]
     drm_atomic_commit+0x46/0x50 [drm]
     drm_mode_atomic_ioctl+0x7d4/0xab0 [drm]
     drm_ioctl+0x2b3/0x490 [drm]
     do_vfs_ioctl+0x69c/0x700
     SyS_ioctl+0x4e/0x80
     entry_SYSCALL_64_fastpath+0x13/0x94
    INFO: Freed in drm_event_cancel_free+0xa3/0xb0 [drm] age=0 cpu=3 pid=1529
     __slab_free+0x48/0x2e0
     kfree+0x159/0x1a0
     drm_event_cancel_free+0xa3/0xb0 [drm]
     drm_mode_atomic_ioctl+0x86d/0xab0 [drm]
     drm_ioctl+0x2b3/0x490 [drm]
     do_vfs_ioctl+0x69c/0x700
     SyS_ioctl+0x4e/0x80
     entry_SYSCALL_64_fastpath+0x13/0x94
    INFO: Slab 0xffffde1f0997b080 objects=17 used=2 fp=0xffff92fb65ec2578 flags=0x200000000008101
    INFO: Object 0xffff92fb65ec2578 @offset=1400 fp=0xffff92fb65ec2ae8
    
    Redzone ffff92fb65ec2570: bb bb bb bb bb bb bb bb                          ........
    Object ffff92fb65ec2578: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
    Object ffff92fb65ec2588: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
    Object ffff92fb65ec2598: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
    Object ffff92fb65ec25a8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
    Object ffff92fb65ec25b8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
    Object ffff92fb65ec25c8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
    Object ffff92fb65ec25d8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
    Object ffff92fb65ec25e8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5  kkkkkkkkkkkkkkk.
    Redzone ffff92fb65ec25f8: bb bb bb bb bb bb bb bb                          ........
    Padding ffff92fb65ec2738: 5a 5a 5a 5a 5a 5a 5a 5a                          ZZZZZZZZ
    CPU: 3 PID: 180 Comm: kworker/3:2 Tainted: G    BU          4.10.0-rc6-patser+ #5039
    Hardware name:                  /NUC5PPYB, BIOS PYBSWCEL.86A.0031.2015.0601.1712 06/01/2015
    Workqueue: events intel_atomic_helper_free_state [i915]
    Call Trace:
     dump_stack+0x4d/0x6d
     print_trailer+0x20c/0x220
     free_debug_processing+0x1c6/0x330
     ? drm_atomic_state_default_clear+0xf7/0x1c0 [drm]
     __slab_free+0x48/0x2e0
     ? drm_atomic_state_default_clear+0xf7/0x1c0 [drm]
     kfree+0x159/0x1a0
     drm_atomic_state_default_clear+0xf7/0x1c0 [drm]
     ? drm_atomic_state_clear+0x30/0x30 [drm]
     intel_atomic_state_clear+0xd/0x20 [i915]
     drm_atomic_state_clear+0x1a/0x30 [drm]
     __drm_atomic_state_free+0x13/0x60 [drm]
     intel_atomic_helper_free_state+0x5d/0x70 [i915]
     process_one_work+0x260/0x4a0
     worker_thread+0x2d1/0x4f0
     kthread+0x127/0x130
     ? process_one_work+0x4a0/0x4a0
     ? kthread_stop+0x120/0x120
     ret_from_fork+0x29/0x40
    FIX kmalloc-128: Object at 0xffff92fb65ec2578 not freed
    
    Fixes: 3b24f7d6 ("drm/atomic: Add struct drm_crtc_commit to track async updates")
    Fixes: 96260142 ("drm/fence: add in-fences support")
    Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
    Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
    Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
    Reviewed-by: default avatarGustavo Padovan <gustavo.padovan@collabora.com>
    Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
    Link: http://patchwork.freedesktop.org/patch/msgid/1485854725-27640-1-git-send-email-maarten.lankhorst@linux.intel.com
    CC: koos vriezen <koos.vriezen@gmail.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    4cd462c7
drm_atomic.c 51 KB