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BUG: KASAN: null-ptr-deref in test_and_set_bit include/asm-generic/bitops-instrumented.h:143 [inline]
BUG: KASAN: null-ptr-deref in queue_work_on+0xa6/0x210 kernel/workqueue.c:1517
Write of size 8 at addr 0000000000000050 by task syz-executor632/8580

CPU: 1 PID: 8580 Comm: syz-executor632 Not tainted 5.3.0-rc4-next-20190816 #67
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+0x5/0x36 mm/kasan/report.c:486
 kasan_report+0x12/0x17 mm/kasan/common.c:610
 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
 test_and_set_bit include/asm-generic/bitops-instrumented.h:143 [inline]
 queue_work_on+0xa6/0x210 kernel/workqueue.c:1517
 queue_work include/linux/workqueue.h:490 [inline]
 schedule_work include/linux/workqueue.h:548 [inline]
 slcan_write_wakeup+0x66/0x90 drivers/net/can/slcan.c:348
 tty_wakeup+0xe9/0x120 drivers/tty/tty_io.c:535
 pty_unthrottle+0x37/0x60 drivers/tty/pty.c:95
 tty_unthrottle+0xab/0x110 drivers/tty/tty_ioctl.c:139
 __tty_perform_flush+0x1b3/0x200 drivers/tty/tty_ioctl.c:861
 n_tty_ioctl_helper+0x1cc/0x3b0 drivers/tty/tty_ioctl.c:937
 n_tty_ioctl+0x59/0x370 drivers/tty/n_tty.c:2466
 tty_ioctl+0xaf9/0x14f0 drivers/tty/tty_io.c:2666
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446b69
Code: e8 8c 19 03 00 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 3b 0c fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2d185efd18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006dcc58 RCX: 0000000000446b69
RDX: 0000000000000000 RSI: 000000000000540b RDI: 0000000000000003
RBP: 00000000006dcc50 R08: 00007f2d185f0700 R09: 0000000000000000
R10: 00007f2d185f0700 R11: 0000000000000246 R12: 00000000006dcc5c
R13: 00007ffe0e48e94f R14: 00007f2d185f09c0 R15: 0000000000000001
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