bisecting fixing commit since e7c124bd04631973a3cc0df19ab881b56d8a2d50 building syzkaller on 6cc879d4712dbaf6e97f01250e2f4906c07b24b8 testing commit e7c124bd04631973a3cc0df19ab881b56d8a2d50 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 13be3ffc91bba911ea8cdb0cc757ac0c5d0041a3da935fb5ced93fbfbee0ac1f run #0: crashed: possible deadlock in vmci_qp_broker_detach run #1: crashed: possible deadlock in vmci_qp_broker_detach run #2: crashed: possible deadlock in vmci_qp_broker_detach run #3: crashed: possible deadlock in vmci_qp_broker_detach run #4: crashed: possible deadlock in vmci_qp_broker_detach run #5: crashed: possible deadlock in vmci_qp_broker_detach run #6: crashed: possible deadlock in vmci_qp_broker_detach run #7: crashed: possible deadlock in vmci_qp_broker_detach run #8: crashed: possible deadlock in vmci_qp_broker_detach run #9: crashed: possible deadlock in vmci_qp_broker_detach run #10: crashed: possible deadlock in vmci_qp_broker_detach run #11: crashed: possible deadlock in vmci_qp_broker_detach run #12: crashed: possible deadlock in vmci_qp_broker_detach run #13: crashed: possible deadlock in vmci_qp_broker_detach run #14: crashed: possible deadlock in vmci_qp_broker_detach run #15: crashed: possible deadlock in vmci_qp_broker_detach run #16: crashed: possible deadlock in vmci_qp_broker_detach run #17: crashed: possible deadlock in vmci_qp_broker_detach run #18: crashed: possible deadlock in vmci_qp_broker_detach run #19: OK testing current HEAD d569e86915b7f2f9795588591c8d5ea0b66481cb testing commit d569e86915b7f2f9795588591c8d5ea0b66481cb compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: fcb3140772d114cb66a2b7bd9fd9dd716e7798e72278eeee831485f906a8ea73 all runs: crashed: possible deadlock in vmci_qp_broker_detach revisions tested: 2, total time: 34m5.264076468s (build: 12m5.661318213s, test: 21m17.416903958s) the crash still happens on HEAD commit msg: Merge tag 'drm-fixes-2022-04-22' of git://anongit.freedesktop.org/drm/drm crash: possible deadlock in vmci_qp_broker_detach ============================================ WARNING: possible recursive locking detected 5.18.0-rc3-syzkaller #0 Not tainted -------------------------------------------- syz-executor393/7028 is trying to acquire lock: ffffffff8ba9cc98 (qp_broker_list.mutex){+.+.}-{3:3}, at: vmci_qp_broker_detach+0x11a/0x1390 drivers/misc/vmw_vmci/vmci_queue_pair.c:2093 but task is already holding lock: ffffffff8ba9cc98 (qp_broker_list.mutex){+.+.}-{3:3}, at: vmci_qp_broker_detach+0x11a/0x1390 drivers/misc/vmw_vmci/vmci_queue_pair.c:2093 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(qp_broker_list.mutex); lock(qp_broker_list.mutex); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by syz-executor393/7028: #0: ffffffff8ba9cc98 (qp_broker_list.mutex){+.+.}-{3:3}, at: vmci_qp_broker_detach+0x11a/0x1390 drivers/misc/vmw_vmci/vmci_queue_pair.c:2093 stack backtrace: CPU: 0 PID: 7028 Comm: syz-executor393 Not tainted 5.18.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x57/0x7d lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2958 [inline] check_deadlock kernel/locking/lockdep.c:3001 [inline] validate_chain kernel/locking/lockdep.c:3790 [inline] __lock_acquire.cold+0x149/0x399 kernel/locking/lockdep.c:5029 lock_acquire kernel/locking/lockdep.c:5641 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5606 __mutex_lock_common kernel/locking/mutex.c:600 [inline] __mutex_lock+0x12f/0x12f0 kernel/locking/mutex.c:733 vmci_qp_broker_detach+0x11a/0x1390 drivers/misc/vmw_vmci/vmci_queue_pair.c:2093 ctx_free_ctx+0x410/0xc10 drivers/misc/vmw_vmci/vmci_context.c:444 kref_put include/linux/kref.h:65 [inline] vmci_ctx_put drivers/misc/vmw_vmci/vmci_context.c:497 [inline] vmci_ctx_enqueue_datagram+0x3de/0x530 drivers/misc/vmw_vmci/vmci_context.c:360 dg_dispatch_as_host drivers/misc/vmw_vmci/vmci_datagram.c:275 [inline] vmci_datagram_dispatch+0x270/0x870 drivers/misc/vmw_vmci/vmci_datagram.c:339 qp_notify_peer+0x136/0x200 drivers/misc/vmw_vmci/vmci_queue_pair.c:1479 vmci_qp_broker_detach+0x85d/0x1390 drivers/misc/vmw_vmci/vmci_queue_pair.c:2186 ctx_free_ctx+0x410/0xc10 drivers/misc/vmw_vmci/vmci_context.c:444 vmci_host_close+0xf2/0x180 drivers/misc/vmw_vmci/vmci_host.c:143 __fput+0x1f5/0x8c0 fs/file_table.c:317 task_work_run+0xc0/0x160 kernel/task_work.c:164 exit_task_work include/linux/task_work.h:37 [inline] do_exit+0x986/0x2470 kernel/exit.c:795 do_group_exit+0xb2/0x2a0 kernel/exit.c:925 get_signal+0x1c12/0x1e50 kernel/signal.c:2864 arch_do_signal_or_restart+0x88/0x1a10 arch/x86/kernel/signal.c:867 exit_to_user_mode_loop kernel/entry/common.c:166 [inline] exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:294 do_syscall_64+0x42/0x80 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f98c630ba19 Code: Unable to access opcode bytes at RIP 0x7f98c630b9ef. RSP: 002b:00007f98c62bd308 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 00007f98c63933e8 RCX: 00007f98c630ba19 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f98c63933ec RBP: 00007f98c63933e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f98c63933ec R13: 00007f98c6361064 R14: 636d762f7665642f R15: 0000000000022000