https://bugzilla.kernel.org/show_bug.cgi?id=83341 Bug ID: 83341 Summary: Failure to check return value leads to missed -EDEADLK and a kernel warning printout Product: Drivers Version: 2.5 Kernel Version: 3.16 and above Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) Assignee: drivers_video-dri@xxxxxxxxxxxxxxxxxxxx Reporter: thellstrom@xxxxxxxxxx Regression: No Please see https://bugzilla.redhat.com/show_bug.cgi?id=1114160 The error is in the following lines, where no error checking takes place on drm_modeset_lock(). drm_modeset_lock_all(dev); drm_modeset_lock_init(&crtc->mutex); /* dropped by _unlock_all(): */ drm_modeset_lock(&crtc->mutex, config->acquire_ctx); This is probably under the assumption that the lock is just initialized and will therefore always succeed. However, the ww_mutex subsystem has a fault injection option and when that kicks in, that lock may fail. Fixing this turns out to be a little involved. Personally I think a trylock() would be in order here, but that would mean extending the drm_modeset_lock() API. The error message copied from Redhat Bugzilla: [ 5.082609] ------------[ cut here ]------------ [ 5.083548] WARNING: CPU: 0 PID: 369 at drivers/gpu/drm/drm_modeset_lock.c:91 drm_modeset_drop_locks+0x71/0x80 [drm]() [ 5.084483] Modules linked in: vmwgfx(+) drm_kms_helper ttm drm mptspi scsi_transport_spi e1000 mptscsih mptbase i2c_core ata_generic pata_acpi [ 5.085536] CPU: 0 PID: 369 Comm: systemd-udevd Not tainted 3.16.0-0.rc2.git3.1.fc21.x86_64 #1 [ 5.086689] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013 [ 5.088693] 0000000000000000 0000000054dc8e0c ffff880036e27910 ffffffff81807c4c [ 5.090714] 0000000000000000 ffff880036e27948 ffffffff8109b3ed ffff880039073000 [ 5.091584] ffff8800391ee900 ffff8800391ee900 ffff88003890fe00 ffff880000400000 [ 5.092662] Call Trace: [ 5.093311] [<ffffffff81807c4c>] dump_stack+0x4d/0x66 [ 5.093867] [<ffffffff8109b3ed>] warn_slowpath_common+0x7d/0xa0 [ 5.094562] [<ffffffff8109b51a>] warn_slowpath_null+0x1a/0x20 [ 5.095241] [<ffffffffa00a8eb1>] drm_modeset_drop_locks+0x71/0x80 [drm] [ 5.095773] [<ffffffffa009996e>] drm_modeset_unlock_all+0x2e/0x70 [drm] [ 5.096196] [<ffffffffa009b557>] drm_crtc_init_with_planes+0xa7/0x110 [drm] [ 5.096659] [<ffffffffa00d7343>] drm_crtc_init+0x33/0x40 [drm_kms_helper] [ 5.097050] [<ffffffffa01135b9>] vmw_kms_init_screen_object_display+0x1a9/0x260 [vmwgfx] [ 5.098174] [<ffffffffa0105b69>] vmw_kms_init+0x59/0x70 [vmwgfx] [ 5.098725] [<ffffffffa0107dd0>] vmw_driver_load+0x8d0/0xda0 [vmwgfx] [ 5.099129] [<ffffffffa009424d>] drm_dev_register+0xad/0x100 [drm] [ 5.099486] [<ffffffffa009707d>] drm_get_pci_dev+0x8d/0x200 [drm] [ 5.099900] [<ffffffffa0106b25>] vmw_probe+0x15/0x20 [vmwgfx] [ 5.100274] [<ffffffff8142fee5>] local_pci_probe+0x45/0xa0 [ 5.100626] [<ffffffff814311c5>] ? pci_match_device+0xe5/0x110 [ 5.100959] [<ffffffff81431329>] pci_device_probe+0xf9/0x150 [ 5.101286] [<ffffffff8151fba3>] driver_probe_device+0xa3/0x400 [ 5.101589] [<ffffffff8151ffcb>] __driver_attach+0x8b/0x90 [ 5.101934] [<ffffffff8151ff40>] ? __device_attach+0x40/0x40 [ 5.102242] [<ffffffff8151d823>] bus_for_each_dev+0x73/0xc0 [ 5.102545] [<ffffffff8151f5fe>] driver_attach+0x1e/0x20 [ 5.102808] [<ffffffff8151f1c8>] bus_add_driver+0x188/0x260 [ 5.103075] [<ffffffff81520aa4>] driver_register+0x64/0xf0 [ 5.103352] [<ffffffff8142f790>] __pci_register_driver+0x60/0x70 [ 5.103616] [<ffffffffa00972fa>] drm_pci_init+0x10a/0x140 [drm] [ 5.103913] [<ffffffffa012e000>] ? 0xffffffffa012dfff [ 5.104176] [<ffffffffa012e018>] vmwgfx_init+0x18/0x1000 [vmwgfx] [ 5.104482] [<ffffffff81002148>] do_one_initcall+0xd8/0x210 [ 5.104745] [<ffffffff81206e8a>] ? __vunmap+0xba/0x120 [ 5.105015] [<ffffffff8113aff0>] load_module+0x2110/0x2740 [ 5.105275] [<ffffffff81136260>] ? store_uevent+0x70/0x70 [ 5.105551] [<ffffffff810fc23f>] ? lock_release_holdtime.part.28+0xf/0x200 [ 5.105951] [<ffffffff811025e6>] ? lock_release_non_nested+0x3c6/0x3d0 [ 5.106357] [<ffffffff8113b707>] SyS_init_module+0xe7/0x140 [ 5.106849] [<ffffffff81811869>] system_call_fastpath+0x16/0x1b [ 5.107162] ---[ end trace 225f20829bb0d8e8 ]--- -- You are receiving this mail because: You are watching the assignee of the bug. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
