================================================================== BUG: KASAN: null-ptr-deref in set_bit include/asm-generic/bitops-instrumented.h:28 [inline] BUG: KASAN: null-ptr-deref in io_wq_cancel_all+0x28/0x2a0 fs/io-wq.c:574 Write of size 8 at addr 0000000000000004 by task syz-executor.5/9124 CPU: 1 PID: 9124 Comm: syz-executor.5 Not tainted 5.4.0-rc4-next-20191025 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 __kasan_report.cold+0x5/0x41 mm/kasan/report.c:510 kasan_report+0x12/0x20 mm/kasan/common.c:634 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192 __kasan_check_write+0x14/0x20 mm/kasan/common.c:98 set_bit include/asm-generic/bitops-instrumented.h:28 [inline] io_wq_cancel_all+0x28/0x2a0 fs/io-wq.c:574 io_ring_ctx_wait_and_kill+0x1e2/0x710 fs/io_uring.c:3679 io_uring_release+0x42/0x50 fs/io_uring.c:3691 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x904/0x2e60 kernel/exit.c:817 do_group_exit+0x135/0x360 kernel/exit.c:921 get_signal+0x47c/0x24f0 kernel/signal.c:2734 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:159 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x65f/0x760 arch/x86/entry/common.c:300 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459f39 Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f9b31a60cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 000000000075bfd0 RCX: 0000000000459f39 RDX: 00000000004c9c73 RSI: 0000000000000081 RDI: 000000000075bfd4 RBP: 000000000075bfc8 R08: 0000000000000009 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 000000000075bfd4 R13: 00007ffc2bbc8a7f R14: 00007f9b31a619c0 R15: 000000000075bfd4 ==================================================================