_do_fork+0x339/0xfb0 kernel/fork.c:2168 kernel_thread+0xc6/0xe0 kernel/fork.c:2227 create_kthread kernel/kthread.c:270 [inline] kthreadd+0x59c/0x900 kernel/kthread.c:589 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:416 BUG: unable to handle kernel NULL pointer dereference at 00000000000008f4 PGD 80000001b51c1067 P4D 80000001b51c1067 PUD 1b518f067 PMD 0 Oops: 0002 [#1] SMP PTI CPU: 0 PID: 14179 Comm: syz-executor1 Not tainted 4.19.0-rc1+ #42 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:65 Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 RSP: 0018:ffff8801b5f2f268 EFLAGS: 00010046 RAX: 0000000000000000 RBX: fffffffffffffff4 RCX: 0000000000000fb0 RDX: 0000000000000fb0 RSI: 0000000000000000 RDI: 00000000000008f4 RBP: ffff8801b5f2f278 R08: 0000000000000000 R09: 00000000000008f4 R10: 0000000000000000 R11: ffffffff81355350 R12: 00000000e5000113 R13: 0000000000000000 R14: 0000000000000286 R15: fffffffffffffff4 FS: 00007fc0826e1700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000008f4 CR3: 000000004731a000 CR4: 00000000001406f0 DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: kmsan_thread_create+0x4b/0x90 mm/kmsan/kmsan_hooks.c:30 __kthread_create_on_node+0x71b/0x810 kernel/kthread.c:345 kthread_create_on_node+0x23f/0x270 kernel/kthread.c:381 init_rescuer+0x334/0x6f0 kernel/workqueue.c:4033 __alloc_workqueue_key+0x1d90/0x2300 kernel/workqueue.c:4109 ucma_open+0x122/0x4f0 drivers/infiniband/core/ucma.c:1716 misc_open+0x6e2/0x8b0 drivers/char/misc.c:141 chrdev_open+0xc26/0xdb0 fs/char_dev.c:417 do_dentry_open+0xce6/0x1740 fs/open.c:771 vfs_open+0xaf/0xe0 fs/open.c:880 do_last fs/namei.c:3418 [inline] path_openat+0x1799/0x6870 fs/namei.c:3534 do_filp_open+0x259/0x610 fs/namei.c:3564 do_sys_open+0x630/0x940 fs/open.c:1063 __do_sys_openat fs/open.c:1090 [inline] __se_sys_openat+0xcb/0xe0 fs/open.c:1084 __x64_sys_openat+0x56/0x70 fs/open.c:1084 do_syscall_64+0xb8/0x100 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 RIP: 0033:0x457099 Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc0826e0c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fc0826e16d4 RCX: 0000000000457099 RDX: 0000000000000002 RSI: 0000000020000200 RDI: ffffffffffffff9c RBP: 0000000000930140 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d3948 R14: 00000000004c8588 R15: 0000000000000001 Modules linked in: Dumping ftrace buffer: (ftrace buffer empty) CR2: 00000000000008f4 ---[ end trace d5cbc005a3d7d796 ]--- RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:65 Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 RSP: 0018:ffff8801b5f2f268 EFLAGS: 00010046 RAX: 0000000000000000 RBX: fffffffffffffff4 RCX: 0000000000000fb0 RDX: 0000000000000fb0 RSI: 0000000000000000 RDI: 00000000000008f4 RBP: ffff8801b5f2f278 R08: 0000000000000000 R09: 00000000000008f4 R10: 0000000000000000 R11: ffffffff81355350 R12: 00000000e5000113 R13: 0000000000000000 R14: 0000000000000286 R15: fffffffffffffff4 FS: 00007fc0826e1700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000008f4 CR3: 000000004731a000 CR4: 00000000001406f0 DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600