bisecting fixing commit since f022814633e1c600507b3a99691b4d624c2813f0 building syzkaller on 89bc860804252dbacb8c2bea60b9204859f4afd7 testing commit f022814633e1c600507b3a99691b4d624c2813f0 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: ab5ab5b4fdb0647de6cec37b7a0ec679bca8b132e36d40c79c7c26619913c384 run #0: basic kernel testing failed: BUG: program execution failed: executor NUM: failed to write control pipe: write |NUM: broken pipe run #1: crashed: INFO: task hung in lock_sock_nested run #2: crashed: INFO: task hung in lock_sock_nested run #3: crashed: INFO: task hung in lock_sock_nested run #4: crashed: INFO: task hung in lock_sock_nested run #5: crashed: INFO: task hung in lock_sock_nested run #6: crashed: INFO: task hung in lock_sock_nested run #7: crashed: INFO: task hung in lock_sock_nested run #8: crashed: INFO: task hung in lock_sock_nested run #9: crashed: INFO: task hung in lock_sock_nested run #10: crashed: INFO: task hung in lock_sock_nested run #11: crashed: INFO: task hung in lock_sock_nested run #12: crashed: INFO: task hung in lock_sock_nested run #13: crashed: INFO: task hung in lock_sock_nested run #14: crashed: INFO: task hung in lock_sock_nested run #15: crashed: INFO: task hung in lock_sock_nested run #16: crashed: INFO: task hung in lock_sock_nested run #17: crashed: INFO: task hung in lock_sock_nested run #18: crashed: INFO: task hung in lock_sock_nested run #19: boot failed: WARNING in blk_release_queue testing current HEAD 72a8e05d4f66b5af7854df4490e3135168694b6b testing commit 72a8e05d4f66b5af7854df4490e3135168694b6b compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: ea1c9343678cb064e15c7f5e2ea2a09fec007ea19286694a4fa45eb50d63ff0b all runs: crashed: possible deadlock in rfcomm_sk_state_change revisions tested: 2, total time: 27m14.888913233s (build: 13m23.281657016s, test: 13m20.831639952s) the crash still happens on HEAD commit msg: Merge tag 'ovl-fixes-5.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs crash: possible deadlock in rfcomm_sk_state_change ============================================ WARNING: possible recursive locking detected 5.19.0-rc6-syzkaller #0 Not tainted -------------------------------------------- syz-executor.0/4088 is trying to acquire lock: ffff88807989f130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1677 [inline] ffff88807989f130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sk_state_change+0x99/0x320 net/bluetooth/rfcomm/sock.c:73 but task is already holding lock: ffff88807989f130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1677 [inline] ffff88807989f130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_shutdown+0x41/0x1b0 net/bluetooth/rfcomm/sock.c:902 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM); lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by syz-executor.0/4088: #0: ffff888073313810 (&sb->s_type->i_mutex_key#9){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:741 [inline] #0: ffff888073313810 (&sb->s_type->i_mutex_key#9){+.+.}-{3:3}, at: __sock_release+0x76/0x270 net/socket.c:649 #1: ffff88807989f130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1677 [inline] #1: ffff88807989f130 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sock_shutdown+0x41/0x1b0 net/bluetooth/rfcomm/sock.c:902 #2: ffffffff8c693ca8 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_close+0x25/0x200 net/bluetooth/rfcomm/core.c:507 #3: ffff88807a102128 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0xff/0x770 net/bluetooth/rfcomm/core.c:487 stack backtrace: CPU: 0 PID: 4088 Comm: syz-executor.0 Not tainted 5.19.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022 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:2988 [inline] check_deadlock kernel/locking/lockdep.c:3031 [inline] validate_chain kernel/locking/lockdep.c:3816 [inline] __lock_acquire.cold+0x1e0/0x3a9 kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5665 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5630 lock_sock_nested+0x2b/0xd0 net/core/sock.c:3389 lock_sock include/net/sock.h:1677 [inline] rfcomm_sk_state_change+0x99/0x320 net/bluetooth/rfcomm/sock.c:73 __rfcomm_dlc_close+0x153/0x770 net/bluetooth/rfcomm/core.c:489 rfcomm_dlc_close+0x1a4/0x200 net/bluetooth/rfcomm/core.c:520 __rfcomm_sock_close+0x80/0x1f0 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xb9/0x1b0 net/bluetooth/rfcomm/sock.c:905 rfcomm_sock_release+0x4a/0x120 net/bluetooth/rfcomm/sock.c:925 __sock_release+0xbb/0x270 net/socket.c:650 sock_close+0xf/0x20 net/socket.c:1365 __fput+0x1f5/0x8c0 fs/file_table.c:317 task_work_run+0xc0/0x160 kernel/task_work.c:177 get_signal+0x19a/0x1e40 kernel/signal.c:2634 arch_do_signal_or_restart+0x88/0x1b10 arch/x86/kernel/signal.c:869 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+0x19/0x50 kernel/entry/common.c:294 do_syscall_64+0x42/0x80 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f17a1289049 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f17a24d2168 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: fffffffffffffffc RBX: 00007f17a139bf60 RCX: 00007f17a1289049 RDX: 0000000000000080 RSI: 0000000020000000 RDI: 0000000000000004 RBP: 00007f17a12e308d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdc1ae530f R14: 00007f17a24d2300 R15: 0000000000022000