Message-ID: <673f2a35.050a0220.3c9d61.016f.GAE@google.com>
Date: Thu, 21 Nov 2024 04:40:21 -0800
From: syzbot <syzbot+78d82470c16a49702682@...kaller.appspotmail.com>
To: kent.overstreet@...ux.dev, linux-bcachefs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bcachefs?] kernel BUG in bch2_btree_node_lock_write

Hello,

syzbot found the following issue on:

HEAD commit:    ac24e26aa08f Add linux-next specific files for 20241120
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1471bae8580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=45719eec4c74e6ba
dashboard link: https://syzkaller.appspot.com/bug?extid=78d82470c16a49702682
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17e61930580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13e126c0580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9c6bcf3605c7/disk-ac24e26a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4ce96eb398a9/vmlinux-ac24e26a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9a22aac22c90/bzImage-ac24e26a.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/6a6e3ddf526a/mount_0.gz

The issue was bisected to:

commit feb21a9b4c1a8527e0a61c85eec4c078c558aee9
Author: Kent Overstreet <kent.overstreet@...ux.dev>
Date:   Sun Oct 27 04:40:43 2024 +0000

    bcachefs: try_alloc_bucket() now uses bch2_check_discard_freespace_key()

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=17b79930580000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=14779930580000
console output: https://syzkaller.appspot.com/x/log.txt?x=10779930580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+78d82470c16a49702682@...kaller.appspotmail.com
Fixes: feb21a9b4c1a ("bcachefs: try_alloc_bucket() now uses bch2_check_discard_freespace_key()")

  stripe            0
  stripe_redundancy 0
  io_time[READ]     0
  io_time[WRITE]    0
  fragmentation     0
  bp_start          8
  incorrectly set at freespace:0:24:0 (free 0, genbits 0 should be 0), fixing
------------[ cut here ]------------
kernel BUG at fs/bcachefs/btree_locking.h:306!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 UID: 0 PID: 11 Comm: kworker/u8:0 Not tainted 6.12.0-next-20241120-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Workqueue: btree_node_rewrite async_btree_node_rewrite_work
RIP: 0010:__btree_node_lock_write fs/bcachefs/btree_locking.h:306 [inline]
RIP: 0010:bch2_btree_node_lock_write+0x400/0x430 fs/bcachefs/btree_locking.h:327
Code: 06 be 03 00 00 00 48 c7 c7 80 97 f2 8e 48 89 da e8 a5 c3 d4 00 49 bf 00 00 00 00 00 fc ff df e9 f2 fd ff ff e8 b1 69 79 fd 90 <0f> 0b e8 a9 69 79 fd 90 0f 0b e8 a1 69 79 fd 90 0f 0b 48 8b 4c 24
RSP: 0018:ffffc90000107778 EFLAGS: 00010293
RAX: ffffffff8426110f RBX: ffff88803485c288 RCX: ffff88801befbc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: ffff88803485c000 R08: ffffffff84260d65 R09: 1ffffffff2030b7e
R10: dffffc0000000000 R11: fffffbfff2030b7f R12: ffff88803485c268
R13: 1ffff110061a4b13 R14: ffff888030d25800 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055976c6126b8 CR3: 000000007b348000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 bch2_btree_set_root+0x1d8/0xd10 fs/bcachefs/btree_update_interior.c:1323
 bch2_btree_node_rewrite+0x69d/0x1280 fs/bcachefs/btree_update_interior.c:2172
 async_btree_node_rewrite_trans fs/bcachefs/btree_update_interior.c:2236 [inline]
 async_btree_node_rewrite_work+0x31e/0xdf0 fs/bcachefs/btree_update_interior.c:2249
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__btree_node_lock_write fs/bcachefs/btree_locking.h:306 [inline]
RIP: 0010:bch2_btree_node_lock_write+0x400/0x430 fs/bcachefs/btree_locking.h:327
Code: 06 be 03 00 00 00 48 c7 c7 80 97 f2 8e 48 89 da e8 a5 c3 d4 00 49 bf 00 00 00 00 00 fc ff df e9 f2 fd ff ff e8 b1 69 79 fd 90 <0f> 0b e8 a9 69 79 fd 90 0f 0b e8 a1 69 79 fd 90 0f 0b 48 8b 4c 24
RSP: 0018:ffffc90000107778 EFLAGS: 00010293
RAX: ffffffff8426110f RBX: ffff88803485c288 RCX: ffff88801befbc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: ffff88803485c000 R08: ffffffff84260d65 R09: 1ffffffff2030b7e
R10: dffffc0000000000 R11: fffffbfff2030b7f R12: ffff88803485c268
R13: 1ffff110061a4b13 R14: ffff888030d25800 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055976c6126b8 CR3: 000000000e736000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
This report is generated by a bot. It may contain errors.
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the report is already addressed, let syzbot know by replying with:
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