WARNING in nilfs_btree_assign

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 41f36d7859a7 Linux 4.14.296
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10d5c2fc880000
kernel config: https://syzkaller.appspot.com/x/.config?x=20cc5ea0fe276fa6
dashboard link: https://syzkaller.appspot.com/bug?extid=5006fb4c22f32aa2d82f
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/941b591cedec/disk-41f36d78.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2eea2720f8fc/vmlinux-41f36d78.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7c3ce0be6b9a/bzImage-41f36d78.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5006fb...@syzkaller.appspotmail.com

kvm: emulating exchange as write
------------[ cut here ]------------
WARNING: CPU: 1 PID: 10430 at fs/nilfs2/btree.c:2285 nilfs_btree_assign+0x815/0xcc0 fs/nilfs2/btree.c:2285
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 10430 Comm: segctord Not tainted 4.14.296-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b2/0x281 lib/dump_stack.c:58
panic+0x1f9/0x42d kernel/panic.c:183
__warn.cold+0x20/0x44 kernel/panic.c:547
report_bug+0x208/0x250 lib/bug.c:183
fixup_bug arch/x86/kernel/traps.c:177 [inline]
fixup_bug arch/x86/kernel/traps.c:172 [inline]
do_error_trap+0x195/0x2d0 arch/x86/kernel/traps.c:295
invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:964
RIP: 0010:nilfs_btree_assign+0x815/0xcc0 fs/nilfs2/btree.c:2285
RSP: 0018:ffff88804c027a70 EFLAGS: 00010297
RAX: ffff88804de326c0 RBX: 0000000000000001 RCX: 0000000000000008
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffff88809bac2890
RBP: ffff88809bac2800 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000000 R11: ffff88804de326c0 R12: 00000000fffffffe
R13: ffff88804c027cc0 R14: ffff888048037950 R15: 0000000000040103
nilfs_bmap_assign+0x83/0x170 fs/nilfs2/bmap.c:391
nilfs_segctor_update_payload_blocknr fs/nilfs2/segment.c:1608 [inline]
nilfs_segctor_assign fs/nilfs2/segment.c:1642 [inline]
nilfs_segctor_do_construct+0x1931/0x79c0 fs/nilfs2/segment.c:2069
nilfs_segctor_construct+0x6db/0x8e0 fs/nilfs2/segment.c:2394
nilfs_segctor_thread_construct fs/nilfs2/segment.c:2502 [inline]
nilfs_segctor_thread+0x3ad/0xdb0 fs/nilfs2/segment.c:2586
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 41f36d7859a7 Linux 4.14.296
git tree: linux-4.14.y

console output: https://syzkaller.appspot.com/x/log.txt?x=12309be2880000

kernel config: https://syzkaller.appspot.com/x/.config?x=20cc5ea0fe276fa6
dashboard link: https://syzkaller.appspot.com/bug?extid=5006fb4c22f32aa2d82f
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=122ca95e880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=109650b6880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/941b591cedec/disk-41f36d78.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2eea2720f8fc/vmlinux-41f36d78.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7c3ce0be6b9a/bzImage-41f36d78.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/c1e2869b6a23/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5006fb...@syzkaller.appspotmail.com

NILFS (loop3): segctord starting. Construction interval = 5 seconds, CP frequency < 30 seconds
NILFS (loop0): segctord starting. Construction interval = 5 seconds, CP frequency < 30 seconds
NILFS (loop1): segctord starting. Construction interval = 5 seconds, CP frequency < 30 seconds
------------[ cut here ]------------
WARNING: CPU: 1 PID: 8135 at fs/nilfs2/btree.c:2285 nilfs_btree_assign+0x815/0xcc0 fs/nilfs2/btree.c:2285

Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 8135 Comm: segctord Not tainted 4.14.296-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b2/0x281 lib/dump_stack.c:58
panic+0x1f9/0x42d kernel/panic.c:183
__warn.cold+0x20/0x44 kernel/panic.c:547
report_bug+0x208/0x250 lib/bug.c:183
fixup_bug arch/x86/kernel/traps.c:177 [inline]
fixup_bug arch/x86/kernel/traps.c:172 [inline]
do_error_trap+0x195/0x2d0 arch/x86/kernel/traps.c:295
invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:964
RIP: 0010:nilfs_btree_assign+0x815/0xcc0 fs/nilfs2/btree.c:2285

RSP: 0018:ffff88808d0afa70 EFLAGS: 00010297
RAX: ffff888097b42080 RBX: 0000000000000001 RCX: 0000000000000008
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffff8880aa432110
RBP: ffff8880aa432080 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000000 R11: ffff888097b42080 R12: 00000000fffffffe
R13: ffff88808d0afcc0 R14: ffff888088d7a6d0 R15: 0000000000040103