Messages in this thread | | | Date | Thu, 2 May 2024 08:16:41 -0400 | From | Steven Rostedt <> | Subject | [BUG][v6.9-rc6] Deadlock with: Revert "drm/qxl: simplify qxl_fence_wait" |
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I went to run my tests on my VMs and the tests hung on boot up. Unfortunately, the most I ever got out was:
[ 93.607888] Testing event system initcall: OK [ 93.667730] Running tests on all trace events: [ 93.669757] Testing all events: OK [ 95.631064] ------------[ cut here ]------------ Timed out after 60 seconds
I ran a bisect and it came up with:
# first bad commit: [07ed11afb68d94eadd4ffc082b97c2331307c5ea] Revert "drm/qxl: simplify qxl_fence_wait"
I checked out 07ed11afb68d94eadd4ffc082b97c2331307c5ea~1 and it booted fine. Added back that commit, it failed to boot. I did this twice, and got the same results.
But the last time I ran it, it did trigger this:
------------[ cut here ]------------ ====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc1-test-00021-g07ed11afb68d #5 Not tainted ------------------------------------------------------ kworker/u24:3/119 is trying to acquire lock: ffffffff95aa4600 (console_owner){....}-{0:0}, at: console_flush_all+0x1f5/0x530 but task is already holding lock: ffff93c4bbd37218 (&pool->lock){-.-.}-{2:2}, at: __flush_work+0xc1/0x440 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&pool->lock){-.-.}-{2:2}: _raw_spin_lock+0x33/0x40 __queue_work+0xd6/0x610 queue_work_on+0x8a/0x90 soft_cursor+0x1a0/0x230 bit_cursor+0x386/0x5f0 hide_cursor+0x27/0xb0 vt_console_print+0x474/0x490 console_flush_all+0x22e/0x530 console_unlock+0x56/0x160 vprintk_emit+0x160/0x390 dev_printk_emit+0xa5/0xd0 _dev_info+0x79/0xa0 __drm_fb_helper_initial_config_and_unlock+0x3a9/0x5f0 drm_fbdev_generic_client_hotplug+0x69/0xc0 drm_client_register+0x7b/0xc0 qxl_pci_probe+0x107/0x1a0 local_pci_probe+0x45/0xa0 pci_device_probe+0xc7/0x240 really_probe+0xd6/0x390 __driver_probe_device+0x78/0x150 driver_probe_device+0x1f/0x90 __driver_attach+0xd6/0x1d0 bus_for_each_dev+0x8f/0xe0 bus_add_driver+0x119/0x220 driver_register+0x59/0x100 do_one_initcall+0x76/0x3c0 kernel_init_freeable+0x3a5/0x5b0 kernel_init+0x1a/0x1c0 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1a/0x30 -> #0 (console_owner){....}-{0:0}: __lock_acquire+0x13e7/0x2180 lock_acquire+0xd9/0x300 console_flush_all+0x212/0x530 console_unlock+0x56/0x160 vprintk_emit+0x160/0x390 _printk+0x64/0x80 __warn_printk+0x8e/0x180 check_flush_dependency+0xfd/0x120 __flush_work+0xfa/0x440 qxl_queue_garbage_collect+0x83/0x90 qxl_fence_wait+0xa4/0x1a0 dma_fence_wait_timeout+0x98/0x1e0 dma_resv_wait_timeout+0x7f/0xe0 ttm_bo_delayed_delete+0x2b/0x90 process_one_work+0x228/0x740 worker_thread+0x1dc/0x3c0 kthread+0xf2/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1a/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&pool->lock); lock(console_owner); lock(&pool->lock); lock(console_owner); *** DEADLOCK *** 6 locks held by kworker/u24:3/119: #0: ffff93c440245948 ((wq_completion)ttm){+.+.}-{0:0}, at: process_one_work+0x43a/0x740 #1: ffffa01380d83e60 ((work_completion)(&bo->delayed_delete)){+.+.}-{0:0}, at: process_one_work+0x1e2/0x740 #2: ffffffff95b17880 (rcu_read_lock){....}-{1:2}, at: __flush_work+0x86/0x440 #3: ffff93c4bbd37218 (&pool->lock){-.-.}-{2:2}, at: __flush_work+0xc1/0x440 #4: ffffffff95b149c0 (console_lock){+.+.}-{0:0}, at: _printk+0x64/0x80 #5: ffffffff95b14a10 (console_srcu){....}-{0:0}, at: console_flush_all+0x7b/0x530 stack backtrace: CPU: 2 PID: 119 Comm: kworker/u24:3 Not tainted 6.9.0-rc1-test-00021-g07ed11afb68d #5 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: ttm ttm_bo_delayed_delete Call Trace: <TASK> dump_stack_lvl+0x77/0xb0 check_noncircular+0x148/0x160 __lock_acquire+0x13e7/0x2180 lock_acquire+0xd9/0x300 ? console_flush_all+0x1f5/0x530 ? lock_release+0x147/0x2c0 ? console_flush_all+0x1f5/0x530 console_flush_all+0x212/0x530 ? console_flush_all+0x1f5/0x530 console_unlock+0x56/0x160 vprintk_emit+0x160/0x390 _printk+0x64/0x80 ? __pfx_ttm_bo_delayed_delete+0x10/0x10 ? __pfx_qxl_gc_work+0x10/0x10 __warn_printk+0x8e/0x180 ? __pfx_ttm_bo_delayed_delete+0x10/0x10 ? __pfx_qxl_gc_work+0x10/0x10 ? __pfx_qxl_gc_work+0x10/0x10 check_flush_dependency+0xfd/0x120 __flush_work+0xfa/0x440 qxl_queue_garbage_collect+0x83/0x90 qxl_fence_wait+0xa4/0x1a0 dma_fence_wait_timeout+0x98/0x1e0 dma_resv_wait_timeout+0x7f/0xe0 ttm_bo_delayed_delete+0x2b/0x90 process_one_work+0x228/0x740 worker_thread+0x1dc/0x3c0 ? __pfx_worker_thread+0x10/0x10 kthread+0xf2/0x120 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x34/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> workqueue: WQ_MEM_RECLAIM ttm:ttm_bo_delayed_delete is flushing !WQ_MEM_RECLAIM events:qxl_gc_work WARNING: CPU: 2 PID: 119 at kernel/workqueue.c:3728 check_flush_dependency+0xfd/0x120 Modules linked in: CPU: 2 PID: 119 Comm: kworker/u24:3 Not tainted 6.9.0-rc1-test-00021-g07ed11afb68d #5 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: ttm ttm_bo_delayed_delete RIP: 0010:check_flush_dependency+0xfd/0x120 Code: 8b 45 18 48 8d b2 70 01 00 00 49 89 e8 48 8d 8b 70 01 00 00 48 c7 c7 60 46 7b 95 c6 05 48 67 d2 01 01 48 89 c2 e8 63 40 fd ff <0f> 0b e9 1e ff ff ff 80 3d 33 67 d2 01 00 75 93 e9 4a ff ff ff 66 RSP: 0000:ffffa01380d83c28 EFLAGS: 00010086 RAX: 0000000000000000 RBX: ffff93c44004ee00 RCX: 0000000000000000 RDX: 0000000080000003 RSI: 00000000ffffefff RDI: 0000000000000001 RBP: ffffffff9497b100 R08: 0000000000000000 R09: 0000000000000003 R10: ffffa01380d83ab8 R11: ffffffff95b14828 R12: ffff93c443980000 R13: ffff93c440fbe300 R14: 0000000000000001 R15: ffff93c44004ee00 FS: 0000000000000000(0000) GS:ffff93c4bbd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000007c864001 CR4: 0000000000170ef0 Call Trace: <TASK> ? __warn+0x8c/0x180 ? check_flush_dependency+0xfd/0x120 ? report_bug+0x191/0x1c0 ? prb_read_valid+0x1b/0x30 ? handle_bug+0x3c/0x80 ? exc_invalid_op+0x17/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? __pfx_qxl_gc_work+0x10/0x10 ? check_flush_dependency+0xfd/0x120 ? check_flush_dependency+0xfd/0x120 __flush_work+0xfa/0x440 qxl_queue_garbage_collect+0x83/0x90 qxl_fence_wait+0xa4/0x1a0 dma_fence_wait_timeout+0x98/0x1e0 dma_resv_wait_timeout+0x7f/0xe0 ttm_bo_delayed_delete+0x2b/0x90 process_one_work+0x228/0x740 worker_thread+0x1dc/0x3c0 ? __pfx_worker_thread+0x10/0x10 kthread+0xf2/0x120 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x34/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> irq event stamp: 58 hardirqs last enabled at (57): [<ffffffff93fede30>] queue_work_on+0x60/0x90 hardirqs last disabled at (58): [<ffffffff94ea7f66>] _raw_spin_lock_irq+0x56/0x60 softirqs last enabled at (0): [<ffffffff93fbae27>] copy_process+0xc07/0x2c60 softirqs last disabled at (0): [<0000000000000000>] 0x0 ---[ end trace 0000000000000000 ]---
So there's an issue with dma_fence and a workqueue.
-- Steve
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