bisecting fixing commit since a35d65bedfbc38cffe2701798cd6810bbdf07892 building syzkaller on 6e821dbf79b49f1952fc147f237aa0f396790edc testing commit a35d65bedfbc38cffe2701798cd6810bbdf07892 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: ee5bcc789de25e4f9c002099e46fdb8eb6f81a5e3f10de531fa7d6aaf700bb29 run #0: crashed: inconsistent lock state in sync_timeline_debug_remove run #1: crashed: unregister_netdevice: waiting for DEV to become free run #2: crashed: unregister_netdevice: waiting for DEV to become free run #3: crashed: unregister_netdevice: waiting for DEV to become free run #4: crashed: unregister_netdevice: waiting for DEV to become free run #5: crashed: unregister_netdevice: waiting for DEV to become free run #6: crashed: unregister_netdevice: waiting for DEV to become free run #7: crashed: inconsistent lock state in sync_timeline_debug_remove run #8: crashed: inconsistent lock state in sync_timeline_debug_remove run #9: crashed: unregister_netdevice: waiting for DEV to become free run #10: crashed: inconsistent lock state in sync_timeline_debug_remove run #11: crashed: unregister_netdevice: waiting for DEV to become free run #12: crashed: unregister_netdevice: waiting for DEV to become free run #13: crashed: unregister_netdevice: waiting for DEV to become free run #14: crashed: unregister_netdevice: waiting for DEV to become free run #15: crashed: unregister_netdevice: waiting for DEV to become free run #16: crashed: unregister_netdevice: waiting for DEV to become free run #17: crashed: unregister_netdevice: waiting for DEV to become free run #18: crashed: unregister_netdevice: waiting for DEV to become free run #19: crashed: inconsistent lock state in sync_timeline_debug_remove testing current HEAD 004bfaafc45ccc95366b37c9b9e7844cd5156368 testing commit 004bfaafc45ccc95366b37c9b9e7844cd5156368 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: b6fa9dfac32843cd52ef819ade8dba6c0656fa95f101d65ae7084c802d0dbacb run #0: crashed: unregister_netdevice: waiting for DEV to become free run #1: crashed: unregister_netdevice: waiting for DEV to become free run #2: crashed: unregister_netdevice: waiting for DEV to become free run #3: crashed: inconsistent lock state in sync_timeline_debug_remove run #4: crashed: inconsistent lock state in sync_timeline_debug_remove run #5: crashed: inconsistent lock state in sync_timeline_debug_remove run #6: crashed: unregister_netdevice: waiting for DEV to become free run #7: crashed: unregister_netdevice: waiting for DEV to become free run #8: crashed: unregister_netdevice: waiting for DEV to become free run #9: crashed: unregister_netdevice: waiting for DEV to become free revisions tested: 2, total time: 26m57.808357511s (build: 19m23.854602365s, test: 6m52.016758822s) the crash still happens on HEAD commit msg: Linux 4.14.273 crash: unregister_netdevice: waiting for DEV to become free IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready syz-executor.0 (7959) used greatest stack depth: 24088 bytes left can: request_module (can-proto-0) failed. can: request_module (can-proto-0) failed. can: request_module (can-proto-0) failed. unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 ================================ WARNING: inconsistent lock state 4.14.273-syzkaller #0 Not tainted -------------------------------- inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage. syz-executor271/8290 [HC1[1]:SC0[0]:HE0:SE1] takes: (sync_timeline_list_lock){?.+.}, at: [] sync_timeline_debug_remove+0x27/0x1b0 drivers/dma-buf/sync_debug.c:40 {HARDIRQ-ON-W} state was registered at: mark_held_locks+0xc7/0x130 kernel/locking/lockdep.c:2854 __trace_hardirqs_on_caller kernel/locking/lockdep.c:2875 [inline] trace_hardirqs_on_caller+0x296/0x570 kernel/locking/lockdep.c:2930 trace_hardirqs_on+0xd/0x10 kernel/locking/lockdep.c:2937 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] _raw_spin_unlock_irq+0x27/0x90 kernel/locking/spinlock.c:200 spin_unlock_irq include/linux/spinlock.h:367 [inline] sync_print_obj drivers/dma-buf/sync_debug.c:127 [inline] sync_debugfs_show+0xed/0x1f0 drivers/dma-buf/sync_debug.c:162 seq_read+0x4ad/0x12c0 fs/seq_file.c:240 __vfs_read+0xdb/0x840 fs/read_write.c:411 vfs_read+0xff/0x310 fs/read_write.c:447 SYSC_read fs/read_write.c:574 [inline] SyS_read+0x100/0x250 fs/read_write.c:567 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb irq event stamp: 9120 hardirqs last enabled at (9119): [] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] hardirqs last enabled at (9119): [] _raw_spin_unlock_irq+0x27/0x90 kernel/locking/spinlock.c:200 hardirqs last disabled at (9120): [] irq_work_interrupt+0x95/0xa0 arch/x86/entry/entry_64.S:824 softirqs last enabled at (5298): [] __do_softirq+0x644/0x9a2 kernel/softirq.c:314 softirqs last disabled at (5271): [] invoke_softirq kernel/softirq.c:368 [inline] softirqs last disabled at (5271): [] irq_exit+0x15f/0x1a0 kernel/softirq.c:409 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(sync_timeline_list_lock); lock(sync_timeline_list_lock); *** DEADLOCK *** no locks held by syz-executor271/8290. stack backtrace: CPU: 1 PID: 8290 Comm: syz-executor271 Not tainted 4.14.273-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x14b/0x1e7 lib/dump_stack.c:58 print_usage_bug.cold.46+0x433/0x563 kernel/locking/lockdep.c:2589 valid_state kernel/locking/lockdep.c:2602 [inline] mark_lock_irq kernel/locking/lockdep.c:2796 [inline] mark_lock+0xc00/0x11a0 kernel/locking/lockdep.c:3194 mark_irqflags kernel/locking/lockdep.c:3069 [inline] __lock_acquire+0x1214/0x42d0 kernel/locking/lockdep.c:3448 lock_acquire+0x17e/0x3e0 kernel/locking/lockdep.c:3998 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:160 sync_timeline_debug_remove+0x27/0x1b0 drivers/dma-buf/sync_debug.c:40 sync_timeline_free drivers/dma-buf/sw_sync.c:113 [inline] kref_put include/linux/kref.h:70 [inline] sync_timeline_put+0x18/0x30 drivers/dma-buf/sw_sync.c:125 timeline_fence_release+0x1ca/0x2d0 drivers/dma-buf/sw_sync.c:153 dma_fence_release+0xb7/0x290 drivers/dma-buf/dma-fence.c:178 kref_put include/linux/kref.h:70 [inline] dma_fence_put include/linux/dma-fence.h:197 [inline] dma_fence_array_release+0x139/0x200 drivers/dma-buf/dma-fence-array.c:96 dma_fence_release+0xb7/0x290 drivers/dma-buf/dma-fence.c:178 kref_put include/linux/kref.h:70 [inline] dma_fence_put include/linux/dma-fence.h:197 [inline] irq_dma_fence_array_work+0x3a/0x40 drivers/dma-buf/dma-fence-array.c:39 irq_work_run_list+0xe6/0x150 kernel/irq_work.c:156 irq_work_run+0x4d/0xc0 kernel/irq_work.c:171 smp_irq_work_interrupt+0xab/0x4d0 arch/x86/kernel/irq_work.c:21 irq_work_interrupt+0x9a/0xa0 arch/x86/entry/entry_64.S:824 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x56/0x90 kernel/locking/spinlock.c:200 RSP: 0018:ffff888095f37c00 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff09 RAX: dffffc0000000000 RBX: ffff8880a92aa250 RCX: 0000000000000000 RDX: 1ffffffff11e1153 RSI: 0000000000000001 RDI: ffffffff88f08a98 RBP: ffff888095f37c08 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880a92aa100 R13: ffff8880a92aa240 R14: ffff8880a92aa200 R15: dffffc0000000000 spin_unlock_irq include/linux/spinlock.h:367 [inline] sw_sync_debugfs_release+0x110/0x180 drivers/dma-buf/sw_sync.c:331 __fput+0x232/0x740 fs/file_table.c:210 ____fput+0x9/0x10 fs/file_table.c:244 task_work_run+0xe5/0x170 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x98b/0x2c90 kernel/exit.c:868 do_group_exit+0xf8/0x2c0 kernel/exit.c:965 SYSC_exit_group kernel/exit.c:976 [inline] SyS_exit_group+0x18/0x20 kernel/exit.c:974 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f1543c5c969 RSP: 002b:00007ffc30196e78 EFLAGS: 00000246 ORIG_RAX: 0000000000000