Dear Linux Developer, Recently when using our tool to fuzz kernel, the following crash was triggered: HEAD commit: 64570fbc14f8 Linux 5.15-rc5 git tree: upstream compiler: gcc 8.0.1 console output: https://drive.google.com/file/d/1QcXGrdd3Li0ylo1WBfswWukWV__QZS4h/view?usp=share_link kernel config: https://drive.google.com/file/d/1uDOeEYgJDcLiSOrx9W8v2bqZ6uOA_55t/view?usp=share_link Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: Wei Chen <harperchen1110@xxxxxxxxx> INFO: task syz-executor.0:29056 blocked for more than 143 seconds. Not tainted 5.15.0-rc5 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:14632 pid:29056 ppid: 6574 flags:0x00000004 Call Trace: __schedule+0x4a1/0x1720 schedule+0x36/0xe0 rwsem_down_write_slowpath+0x322/0x7a0 fscrypt_ioctl_set_policy+0x11f/0x2a0 __f2fs_ioctl+0x1a9f/0x5780 f2fs_ioctl+0x89/0x3a0 __x64_sys_ioctl+0xe8/0x140 do_syscall_64+0x34/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4692c9 RSP: 002b:00007f9fecafbc38 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004692c9 RDX: 0000000020002900 RSI: 00000000800c6613 RDI: 0000000000000003 RBP: 000000000119c1d8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119c1d4 R13: 0000000000000000 R14: 000000000119c1c8 R15: 00007fffbfabbc40 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff8641dee0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x15/0x17a 1 lock held by kswapd0/269: 1 lock held by in:imklog/6194: #0: ffff888100174ef0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x92/0xa0 1 lock held by systemd-udevd/16539: 3 locks held by syz-executor.0/29046: 2 locks held by syz-executor.0/29056: #0: ffff88811912f460 (sb_writers#22){.+.+}-{0:0}, at: fscrypt_ioctl_set_policy+0xfc/0x2a0 #1: ffff88810a98e3f8 (&type->i_mutex_dir_key#12){++++}-{3:3}, at: fscrypt_ioctl_set_policy+0x11f/0x2a0 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 29 Comm: khungtaskd Not tainted 5.15.0-rc5 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack_lvl+0xcd/0x134 nmi_cpu_backtrace.cold.8+0xf3/0x118 nmi_trigger_cpumask_backtrace+0x18f/0x1c0 watchdog+0x9a0/0xb10 kthread+0x1a6/0x1e0 ret_from_fork+0x1f/0x30 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2973 Comm: systemd-journal Not tainted 5.15.0-rc5 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org 04/01/2014 RIP: 0010:lock_is_held_type+0xff/0x140 Code: 10 00 00 ba ff ff ff ff 65 0f c1 15 cb 92 43 7b 83 fa 01 75 28 9c 58 f6 c4 02 75 3c 41 f7 c7 00 02 00 00 74 01 fb 48 83 c4 08 <44> 89 e8 5b 5d 41 5c 41 5d 41 5e 41 5f c3 45 31 ed eb ba 0f 0b 48 RSP: 0018:ffffc9000079bd80 EFLAGS: 00000292 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffffff8641dea0 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff86462280 R11: 0000000000000000 R12: ffff8881050bd280 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000246 FS: 00007f0a317238c0(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0a2d3c2000 CR3: 0000000012f8f000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ___might_sleep+0x21/0x150 kmem_cache_alloc+0x279/0x310 getname_flags+0x5f/0x2c0 do_sys_openat2+0x3c8/0x6a0 do_sys_open+0x84/0xe0 do_syscall_64+0x34/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f0a30cb385d Code: bb 20 00 00 75 10 b8 02 00 00 00 0f 05 48 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 1e f6 ff ff 48 89 04 24 b8 02 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 67 f6 ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007fff8f43b630 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007fff8f43b940 RCX: 00007f0a30cb385d RDX: 00000000000001a0 RSI: 0000000000080042 RDI: 0000555919efe460 RBP: 000000000000000d R08: 000000000000ffc0 R09: 00000000ffffffff R10: 0000000000000069 R11: 0000000000000293 R12: 00000000ffffffff R13: 0000555919ef1040 R14: 00007fff8f43b900 R15: 0000555919efe280 ---------------- Code disassembly (best guess): 0: 10 00 adc %al,(%rax) 2: 00 ba ff ff ff ff add %bh,-0x1(%rdx) 8: 65 0f c1 15 cb 92 43 xadd %edx,%gs:0x7b4392cb(%rip) # 0x7b4392db f: 7b 10: 83 fa 01 cmp $0x1,%edx 13: 75 28 jne 0x3d 15: 9c pushfq 16: 58 pop %rax 17: f6 c4 02 test $0x2,%ah 1a: 75 3c jne 0x58 1c: 41 f7 c7 00 02 00 00 test $0x200,%r15d 23: 74 01 je 0x26 25: fb sti 26: 48 83 c4 08 add $0x8,%rsp * 2a: 44 89 e8 mov %r13d,%eax <-- trapping instruction 2d: 5b pop %rbx 2e: 5d pop %rbp 2f: 41 5c pop %r12 31: 41 5d pop %r13 33: 41 5e pop %r14 35: 41 5f pop %r15 37: c3 retq 38: 45 31 ed xor %r13d,%r13d 3b: eb ba jmp 0xfffffff7 3d: 0f 0b ud2 3f: 48 rex.W Best, Wei