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kernel BUG in bch2_bkey_pack_pos_lossy (2)

Status: upstream: reported C repro on 2025/06/02 13:54
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+a6af6dbf934175da5161@syzkaller.appspotmail.com
First crash: 51d, last: 40d
Cause bisection: introduced by (bisect log) :
commit cd3cdb1ef706a1ac725194d81858d58375739b25
Author: Kent Overstreet <kent.overstreet@linux.dev>
Date: Tue Apr 22 13:14:19 2025 +0000

  bcachefs: Single err message for btree node reads

Crash: kernel BUG in bch2_bkey_pack_pos_lossy (log)
Repro: C syz .config
  
Fix bisection: fixed by (bisect log) :
commit 263561649ee5875a922f4358e96d3deb17a91021
Author: Kent Overstreet <kent.overstreet@linux.dev>
Date: Sat Jun 7 18:27:35 2025 +0000

  bcachefs: Don't persistently run scan_for_btree_nodes

  
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bcachefs?] kernel BUG in bch2_bkey_pack_pos_lossy (2) 0 (2) 2025/07/12 08:11
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream kernel BUG in bch2_bkey_pack_pos_lossy bcachefs -1 C 7 254d 266d 28/29 fixed on 2024/12/16 09:50
▶ ▼ Last patch testing requests (4)
Created Duration User Patch Repo Result
2025/06/24 14:47 2h05m retest repro upstream OK log
2025/06/24 14:47 1h50m retest repro upstream OK log
2025/06/23 18:30 20m retest repro upstream OK log
2025/06/23 18:30 20m retest repro upstream OK log

Sample crash report:
------------[ cut here ]------------
kernel BUG at fs/bcachefs/bkey.c:389!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 6853 Comm: read_btree_node Not tainted 6.15.0-syzkaller-13659-g5b032cac6225 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:set_inc_field_lossy fs/bcachefs/bkey.c:389 [inline]
RIP: 0010:bch2_bkey_pack_pos_lossy+0x13de/0x24e0 fs/bcachefs/bkey.c:518
Code: e8 87 2b 09 fe 48 ba 00 00 00 00 00 fc ff df e9 a5 f8 ff ff e8 63 de a7 fd 90 0f 0b e8 5b de a7 fd 90 0f 0b e8 53 de a7 fd 90 <0f> 0b e8 4b de a7 fd 90 0f 0b e8 43 de a7 fd 90 0f 0b f3 0f 1e fa
RSP: 0018:ffffc9000385eb20 EFLAGS: 00010293
RAX: ffffffff84186ccd RBX: 0024000000000000 RCX: ffff88802228da00
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0024000000000000
RBP: ffffc9000385ed58 R08: ffffffffffffffff R09: ffffffffffffffff
R10: ffffffffffffffff R11: ffffffffffffffff R12: ffff88807b6300c4
R13: ffdc0000ffffffff R14: 0000000000000000 R15: fffffffffffffffe
FS:  0000000000000000(0000) GS:ffff888125d84000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd53acc1000 CR3: 0000000032062000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 bkey_pack_pos fs/bcachefs/bkey.h:382 [inline]
 __build_ro_aux_tree+0xb21/0x1800 fs/bcachefs/bset.c:743
 bch2_bset_build_aux_tree+0x3f5/0x570 fs/bcachefs/bset.c:787
 bch2_btree_node_read_done+0x3ae8/0x5150 fs/bcachefs/btree_io.c:1322
 btree_node_read_work+0x426/0xe30 fs/bcachefs/btree_io.c:1399
 bch2_btree_node_read+0x887/0x2a00 fs/bcachefs/btree_io.c:-1
 bch2_btree_node_fill+0xd12/0x14f0 fs/bcachefs/btree_cache.c:994
 bch2_btree_node_get_noiter+0xa2c/0x1000 fs/bcachefs/btree_cache.c:1261
 found_btree_node_is_readable fs/bcachefs/btree_node_scan.c:85 [inline]
 try_read_btree_node fs/bcachefs/btree_node_scan.c:220 [inline]
 read_btree_nodes_worker+0x1319/0x1e20 fs/bcachefs/btree_node_scan.c:269
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:set_inc_field_lossy fs/bcachefs/bkey.c:389 [inline]
RIP: 0010:bch2_bkey_pack_pos_lossy+0x13de/0x24e0 fs/bcachefs/bkey.c:518
Code: e8 87 2b 09 fe 48 ba 00 00 00 00 00 fc ff df e9 a5 f8 ff ff e8 63 de a7 fd 90 0f 0b e8 5b de a7 fd 90 0f 0b e8 53 de a7 fd 90 <0f> 0b e8 4b de a7 fd 90 0f 0b e8 43 de a7 fd 90 0f 0b f3 0f 1e fa
RSP: 0018:ffffc9000385eb20 EFLAGS: 00010293
RAX: ffffffff84186ccd RBX: 0024000000000000 RCX: ffff88802228da00
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0024000000000000
RBP: ffffc9000385ed58 R08: ffffffffffffffff R09: ffffffffffffffff
R10: ffffffffffffffff R11: ffffffffffffffff R12: ffff88807b6300c4
R13: ffdc0000ffffffff R14: 0000000000000000 R15: fffffffffffffffe
FS:  0000000000000000(0000) GS:ffff888125d84000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0add749000 CR3: 0000000032062000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (25):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/07 18:50 upstream 5b032cac6225 4826c28e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in bch2_bkey_pack_pos_lossy
2025/06/03 02:51 upstream d00a83477e7a a30356b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in bch2_bkey_pack_pos_lossy
2025/06/01 19:26 upstream 7d4e49a77d99 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in bch2_bkey_pack_pos_lossy
2025/05/30 16:30 upstream f66bc387efbe 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in bch2_bkey_pack_pos_lossy
2025/05/29 15:10 upstream 90b83efa6701 3d2f584d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs kernel BUG in bch2_bkey_pack_pos_lossy
2025/05/29 14:44 upstream 90b83efa6701 3d2f584d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs kernel BUG in bch2_bkey_pack_pos_lossy
2025/06/09 18:25 upstream 19272b37aa4f 4826c28e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/06/08 14:05 upstream 8630c59e9936 4826c28e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/06/08 12:18 upstream 8630c59e9936 4826c28e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/06/06 19:38 upstream e271ed52b344 3d899f2c .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/06/05 17:08 upstream ec7714e49479 6b6b5f21 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/06/04 20:15 upstream 1af80d00e1e0 e565f08d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/06/04 03:24 upstream 5abc7438f1e9 a30356b7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/06/01 17:29 upstream 7d4e49a77d99 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/06/01 16:42 upstream 7d4e49a77d99 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/06/01 09:43 upstream 4cb6c8af8591 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/05/31 15:48 upstream 0f70f5b08a47 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/05/31 08:09 upstream 8477ab143069 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/05/31 02:05 upstream 8477ab143069 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/05/30 15:43 upstream f66bc387efbe 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/05/30 01:18 upstream e0797d3b91de 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/05/30 01:07 upstream e0797d3b91de 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/05/29 14:28 upstream 90b83efa6701 3d2f584d .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/05/29 14:08 upstream 90b83efa6701 3d2f584d .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2 (corrupt fs)] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
2025/05/29 13:46 upstream 90b83efa6701 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_bkey_pack_pos_lossy
* Struck through repros no longer work on HEAD.