BUG: unable to handle kernel NULL pointer dereference in get_next_nat_page

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 88e6c0207623 Merge branch 'work.misc' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1308df4f700000
kernel config: https://syzkaller.appspot.com/x/.config?x=bbf6d956ace94654
dashboard link: https://syzkaller.appspot.com/bug?extid=5e2426815f625f449a45
compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2
CC: [ch...@kernel.org jae...@kernel.org linux-f2...@lists.sourceforge.net linux-...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5e2426...@syzkaller.appspotmail.com

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 1b511067 P4D 1b511067 PUD 0
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 3595 Comm: syz-executor.4 Not tainted 5.17.0-syzkaller-13993-g88e6c0207623 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:0x0
Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
RSP: 0018:ffffc90003cdf4c0 EFLAGS: 00010296
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888018fc9d00
RDX: 0000000000000000 RSI: ffffea0000b36c80 RDI: ffff88803d1f24d8
RBP: ffffea000204d2c0 R08: ffffffff81b49c3b R09: fffff94000166d91
R10: fffff94000166d91 R11: 0000000000000000 R12: ffffea000204d2c0
R13: dffffc0000000000 R14: ffffea0000b36c80 R15: ffffea000204d2c8
FS: 0000555555c69400(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000020b85000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
get_next_nat_page+0x3a9/0x770 fs/f2fs/node.c:158
__flush_nat_entry_set fs/f2fs/node.c:3008 [inline]
f2fs_flush_nat_entries+0xa13/0x1b80 fs/f2fs/node.c:3112
f2fs_write_checkpoint+0x14d9/0x5b80 fs/f2fs/checkpoint.c:1677
f2fs_issue_checkpoint+0x361/0x4e0
sync_filesystem+0x1bc/0x220 fs/sync.c:66
generic_shutdown_super+0x6b/0x300 fs/super.c:445
kill_block_super+0x79/0xd0 fs/super.c:1394
kill_f2fs_super+0x2f9/0x3c0 fs/f2fs/super.c:4546
deactivate_locked_super+0xa7/0xf0 fs/super.c:332
cleanup_mnt+0x462/0x510 fs/namespace.c:1186
task_work_run+0x146/0x1c0 kernel/task_work.c:164
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop kernel/entry/common.c:183 [inline]
exit_to_user_mode_prepare+0x1d2/0x1f0 kernel/entry/common.c:215
__syscall_exit_to_user_mode_work kernel/entry/common.c:297 [inline]
syscall_exit_to_user_mode+0x2e/0x70 kernel/entry/common.c:308
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f347cc8a4b7
Code: ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd9e5e4d48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f347cc8a4b7
RDX: 00007ffd9e5e4e19 RSI: 000000000000000a RDI: 00007ffd9e5e4e10
RBP: 00007ffd9e5e4e10 R08: 00000000ffffffff R09: 00007ffd9e5e4be0
R10: 0000555555c6a8b3 R11: 0000000000000246 R12: 00007f347cce21ea
R13: 00007ffd9e5e5ed0 R14: 0000555555c6a810 R15: 00007ffd9e5e5f10
</TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
RSP: 0018:ffffc90003cdf4c0 EFLAGS: 00010296
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888018fc9d00
RDX: 0000000000000000 RSI: ffffea0000b36c80 RDI: ffff88803d1f24d8
RBP: ffffea000204d2c0 R08: ffffffff81b49c3b R09: fffff94000166d91
R10: fffff94000166d91 R11: 0000000000000000 R12: ffffea000204d2c0
R13: dffffc0000000000 R14: ffffea0000b36c80 R15: ffffea000204d2c8
FS: 0000555555c69400(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000020b85000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.