Process accounting resumed
minix_free_inode: bit 1 already cleared
Process accounting resumed
minix_free_inode: bit 1 already cleared
Process accounting resumed
BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: test_and_set_bit arch/x86/include/asm/bitops.h:220 [inline]
IP: test_and_set_bit_lock arch/x86/include/asm/bitops.h:234 [inline]
IP: trylock_buffer include/linux/buffer_head.h:367 [inline]
IP: lock_buffer include/linux/buffer_head.h:373 [inline]
IP: alloc_branch fs/minix/itree_common.c:88 [inline]
IP: get_block+0x6a3/0x1100 fs/minix/itree_common.c:191
PGD 87e0f067 P4D 87e0f067 PUD 9ff1f067 PMD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 15990 Comm: syz-executor.2 Not tainted 4.14.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88809f1ec6c0 task.stack: ffff888089190000
RIP: 0010:test_and_set_bit arch/x86/include/asm/bitops.h:220 [inline]
RIP: 0010:test_and_set_bit_lock arch/x86/include/asm/bitops.h:234 [inline]
RIP: 0010:trylock_buffer include/linux/buffer_head.h:367 [inline]
RIP: 0010:lock_buffer include/linux/buffer_head.h:373 [inline]
RIP: 0010:alloc_branch fs/minix/itree_common.c:88 [inline]
RIP: 0010:get_block+0x6a3/0x1100 fs/minix/itree_common.c:191
RSP: 0018:ffff8880891975a8 EFLAGS: 00010246
RAX: 0000000000000007 RBX: ffff8880891976b0 RCX: 1ffffffff0fe794c
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff88809f1ec6e4
RBP: ffff888089197728 R08: 0000000000000001 R09: 0000000000000003
R10: ffff88809f1ecfc0 R11: ffff88809f1ec6c0 R12: ffff88808278d200
R13: ffff888089197674 R14: dffffc0000000000 R15: 0000000000000000
FS:  00007fa59fb0c700(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000005987d000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 minix_get_block+0xd6/0x100 fs/minix/inode.c:379
 __block_write_begin_int+0x33a/0x1000 fs/buffer.c:2038
 __block_write_begin fs/buffer.c:2088 [inline]
 block_write_begin+0x58/0x260 fs/buffer.c:2147
 minix_write_begin+0x35/0xc0 fs/minix/inode.c:415
 generic_perform_write+0x1c9/0x420 mm/filemap.c:3047
 __generic_file_write_iter+0x227/0x590 mm/filemap.c:3172
 generic_file_write_iter+0x36f/0x650 mm/filemap.c:3200
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x44e/0x630 fs/read_write.c:482
 __kernel_write+0xf5/0x330 fs/read_write.c:501
 do_acct_process+0xb49/0xf60 kernel/acct.c:520
 acct_pin_kill+0x28/0xe0 kernel/acct.c:174
 pin_kill+0x147/0x650 fs/fs_pin.c:50
 mnt_pin_kill+0x62/0x170 fs/fs_pin.c:87
 cleanup_mnt+0x110/0x140 fs/namespace.c:1180
 task_work_run+0x113/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca69
RSP: 002b:00007fa59fb0bc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 000000000050ac40 RCX: 000000000045ca69
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000500
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000c69 R14: 00000000004cec47 R15: 00007fa59fb0c6d4
Code: ef 08 00 00 49 8b bf 28 01 00 00 b9 08 00 00 00 e8 13 57 c6 ff 31 d2 be 74 01 00 00 48 c7 c7 a0 ea 99 86 49 89 c7 e8 ad 27 6d ff <f0> 49 0f ba 2f 02 0f 83 1e fe ff ff e8 0c c8 89 ff 4c 89 ff e8 
RIP: test_and_set_bit arch/x86/include/asm/bitops.h:220 [inline] RSP: ffff8880891975a8
RIP: test_and_set_bit_lock arch/x86/include/asm/bitops.h:234 [inline] RSP: ffff8880891975a8
RIP: trylock_buffer include/linux/buffer_head.h:367 [inline] RSP: ffff8880891975a8
RIP: lock_buffer include/linux/buffer_head.h:373 [inline] RSP: ffff8880891975a8
RIP: alloc_branch fs/minix/itree_common.c:88 [inline] RSP: ffff8880891975a8
RIP: get_block+0x6a3/0x1100 fs/minix/itree_common.c:191 RSP: ffff8880891975a8
CR2: 0000000000000000
---[ end trace 7bfa345dece1e49c ]---