On Fri, Apr 28, 2017 at 8:05 PM, Rob Clark <robdclark@xxxxxxxxx> wrote: > The ->preclose() hook is a good place to block for pending atomic > updates. We can't do this in ->postclose(), as it needs to happen > before drm_fb_release(). Otherwise, since we have already swapped > state (in the case of a non-blocking atomic update), this means that > the plane_state->fb will be released and cleared before we wait for > fences from the atomic-commit wq. > > There are probably more complex solutions possible. But since already > scheduled atomic update, possibly blocking on already scheduled gpu/etc > fences, will complete eventually (assuming nothing catches fire), so > the sanest thing seems to be just block until already scheduled atomic > updates complete before tearing things down. > > Fixes: > > WARNING: CPU: 1 PID: 69 at ../drivers/gpu/drm/drm_atomic_helper.c:1061 drm_atomic_helper_wait_for_fences+0xe0/0xf8 > Modules linked in: > > CPU: 1 PID: 69 Comm: kworker/1:1 Tainted: G W 4.11.0-rc8+ #1187 > Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) > Workqueue: events drm_mode_rmfb_work_fn > task: ffffffc036560d00 task.stack: ffffffc036550000 > PC is at drm_atomic_helper_wait_for_fences+0xe0/0xf8 > LR is at complete_commit.isra.1+0x44/0x1c0 > pc : [<ffffff80084f6040>] lr : [<ffffff800854176c>] pstate: 20000145 > sp : ffffffc036553b60 > x29: ffffffc036553b60 x28: ffffffc0264e6a00 > x27: ffffffc035659000 x26: 0000000000000000 > x25: ffffffc0240e8000 x24: 0000000000000038 > x23: 0000000000000000 x22: ffffff800858f200 > x21: ffffffc0240e8000 x20: ffffffc02f56a800 > x19: 0000000000000000 x18: 0000000000000000 > x17: 0000000000000000 x16: 0000000000000000 > x15: 0000000000000000 x14: ffffffc00a192700 > x13: 0000000000000004 x12: 0000000000000000 > x11: ffffff80089a1690 x10: 00000000000008f0 > x9 : ffffffc036553b20 x8 : ffffffc036561650 > x7 : ffffffc03fe6cb40 x6 : 0000000000000000 > x5 : 0000000000000001 x4 : 0000000000000002 > x3 : ffffffc035659000 x2 : ffffffc0240e8c80 > x1 : 0000000000000000 x0 : ffffffc02adbe588 > > ---[ end trace 13aeec77c3fb55e2 ]--- > Call trace: > Exception stack(0xffffffc036553990 to 0xffffffc036553ac0) > 3980: 0000000000000000 0000008000000000 > 39a0: ffffffc036553b60 ffffff80084f6040 0000000000004ff0 0000000000000038 > 39c0: ffffffc0365539d0 ffffff800857e098 ffffffc036553a00 ffffff800857e1b0 > 39e0: ffffffc036553a10 ffffff800857c554 ffffffc0365e8400 ffffffc0365e8400 > 3a00: ffffffc036553a20 ffffff8008103358 000000000001aad7 ffffff800851b72c > 3a20: ffffffc036553a50 ffffff80080e9228 ffffffc02adbe588 0000000000000000 > 3a40: ffffffc0240e8c80 ffffffc035659000 0000000000000002 0000000000000001 > 3a60: 0000000000000000 ffffffc03fe6cb40 ffffffc036561650 ffffffc036553b20 > 3a80: 00000000000008f0 ffffff80089a1690 0000000000000000 0000000000000004 > 3aa0: ffffffc00a192700 0000000000000000 0000000000000000 0000000000000000 > [<ffffff80084f6040>] drm_atomic_helper_wait_for_fences+0xe0/0xf8 > [<ffffff800854176c>] complete_commit.isra.1+0x44/0x1c0 > [<ffffff8008541c64>] msm_atomic_commit+0x32c/0x350 > [<ffffff8008516230>] drm_atomic_commit+0x50/0x60 > [<ffffff8008517548>] drm_atomic_remove_fb+0x158/0x250 > [<ffffff80085186d0>] drm_framebuffer_remove+0x50/0x158 > [<ffffff8008518818>] drm_mode_rmfb_work_fn+0x40/0x58 > [<ffffff80080d5668>] process_one_work+0x1d0/0x378 > [<ffffff80080d5a54>] worker_thread+0x244/0x488 > [<ffffff80080db7fc>] kthread+0xfc/0x128 > [<ffffff8008082ec0>] ret_from_fork+0x10/0x50 > > Reported-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx> > Signed-off-by: Rob Clark <robdclark@xxxxxxxxx> > --- > The hunk that removes the comment about ->preclose() included in this > patch to challenge the assumption that ->preclose() shouldn't exist ;-) And I'm going to challenge your patch here. Both fences and framebuffers and atomic commits are refcounted. If you go boom on them when userspace closes the fd, you have a refcount bug. We don't fix those by flusing stuff :-) Please add a pair of get/put() calls at the right place instead. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
