kernel BUG in ext4_mb_release_inode_pa

Status: upstream: reported C repro on 2024/12/15 14:57
Bug presence: origin:lts
[Documentation on labels]
Reported-by: syzbot+17ceeb320d1a7e75cc60@syzkaller.appspotmail.com
First crash: 683d, last: 11d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2024/12/17 lts (merge base) b67dc5c9ade9 C [report] kernel BUG in ext4_mb_release_inode_pa
2024/12/17 upstream (ToT) 5529876063e1 C Didn't crash
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 kernel BUG in ext4_mb_release_inode_pa -1 syz, C error 9 4d14h 725d 0/2 upstream: reported C repro on 2024/11/03 14:27
android-5-15 kernel BUG in ext4_mb_release_inode_pa origin:upstream -1 syz, C error 11 16h41m 152d 0/2 upstream: reported C repro on 2026/05/30 09:25
linux-6.1 kernel BUG in ext4_mb_release_inode_pa -1 1 533d 533d 0/3 auto-obsoleted due to no activity on 2025/08/23 07:17
upstream kernel BUG in ext4_mb_release_inode_pa ext4 -1 syz unreliable error 1 1073d 1069d 0/29 auto-obsoleted due to no activity on 2024/02/29 10:29
linux-6.1 kernel BUG in ext4_mb_release_inode_pa (2) origin:upstream -1 syz, C error 2 284d 390d 0/3 upstream: reported C repro on 2025/10/04 09:03
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/10/18 23:32 11m retest repro android14-6.1 report job log log
2026/09/29 04:12 8m retest repro android14-6.1 report job log log
2026/09/29 04:12 9m retest repro android14-6.1 report job log log
2026/08/25 15:54 3m retest repro android14-6.1 error job log
2026/08/25 15:54 5m retest repro android14-6.1 error job log
2026/08/25 15:54 2m retest repro android14-6.1 error job log
2026/08/25 15:54 3m retest repro android14-6.1 error job log
2026/08/15 23:55 4m retest repro android14-6.1 error job log
2026/07/07 08:17 14m retest repro android14-6.1 log
2026/07/04 02:27 29m retest repro android14-6.1 log
▶ ▼ Fix bisection attempts (3)
Created Duration User Patch Repo Result
2026/04/28 04:29 19m bisect fix android14-6.1 error job log
2025/07/21 10:24 4h40m bisect fix android14-6.1 OK (0) job log log
2025/05/14 10:29 2h06m bisect fix android14-6.1 OK (0) job log log

Sample crash report:
EXT4-fs (loop0): Remounting filesystem read-only
------------[ cut here ]------------
kernel BUG at fs/ext4/mballoc.c:4867!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 313 Comm: syz-executor103 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:ext4_mb_release_inode_pa+0xa73/0xa80 fs/ext4/mballoc.c:4867
Code: e2 07 80 c2 03 38 c2 0f 8c 2c fe ff ff 4c 89 f7 89 cb e8 80 24 c8 ff 89 d9 e9 1b fe ff ff e8 84 99 82 ff 0f 0b e8 7d 99 82 ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000eb6c60 EFLAGS: 00010293
RAX: ffffffff81eed4c3 RBX: 00000000000013ee RCX: ffff8881215bbcc0
RDX: 0000000000000000 RSI: 0000000000000060 RDI: 0000000000000000
RBP: ffffc90000eb6db0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520001d6da8 R12: 1ffff920001d6da4
R13: dffffc0000000000 R14: 0000000000000060 R15: 0000000000000000
FS:  00007f058959b6c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559e6834cf60 CR3: 0000000122a65000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ext4_mb_discard_group_preallocations+0xbdb/0xe20 fs/ext4/mballoc.c:5013
 ext4_mb_discard_preallocations fs/ext4/mballoc.c:5582 [inline]
 ext4_mb_discard_preallocations_should_retry+0x15a/0x5e0 fs/ext4/mballoc.c:5603
 ext4_mb_new_blocks+0x2f60/0x4070 fs/ext4/mballoc.c:5806
 ext4_alloc_branch fs/ext4/indirect.c:340 [inline]
 ext4_ind_map_blocks+0xdd1/0x2040 fs/ext4/indirect.c:635
 ext4_map_blocks+0x97a/0x1a80 fs/ext4/inode.c:683
 _ext4_get_block+0x1ea/0x540 fs/ext4/inode.c:824
 ext4_get_block+0x39/0x50 fs/ext4/inode.c:841
 ext4_block_write_begin+0x59b/0x1240 fs/ext4/inode.c:1126
 ext4_write_begin+0x614/0xfc0 fs/ext4/ext4_jbd2.h:-1
 generic_perform_write+0x32d/0x740 mm/filemap.c:3927
 ext4_buffered_write_iter+0x38f/0x690 fs/ext4/file.c:285
 ext4_file_write_iter+0x4b2/0x1540 fs/ext4/file.c:-1
 call_write_iter include/linux/fs.h:2282 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x5ef/0xd00 fs/read_write.c:584
 ksys_write+0x14a/0x260 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:646
 x64_sys_call+0x27b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f05895c8239
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 d0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f058959b168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f058966ee28 RCX: 00007f05895c8239
RDX: 000000000208e24b RSI: 0000200000000040 RDI: 0000000000000005
RBP: 00007f058966ee20 R08: 00007f058959bcdc R09: 0000000000000000
R10: 00007f058959bcdc R11: 0000000000000246 R12: 00007f058966ee2c
R13: 0000000000000006 R14: 00007fff0234f910 R15: 00007fff0234f9f8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_mb_release_inode_pa+0xa73/0xa80 fs/ext4/mballoc.c:4867
Code: e2 07 80 c2 03 38 c2 0f 8c 2c fe ff ff 4c 89 f7 89 cb e8 80 24 c8 ff 89 d9 e9 1b fe ff ff e8 84 99 82 ff 0f 0b e8 7d 99 82 ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000eb6c60 EFLAGS: 00010293
RAX: ffffffff81eed4c3 RBX: 00000000000013ee RCX: ffff8881215bbcc0
RDX: 0000000000000000 RSI: 0000000000000060 RDI: 0000000000000000
RBP: ffffc90000eb6db0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520001d6da8 R12: 1ffff920001d6da4
R13: dffffc0000000000 R14: 0000000000000060 R15: 0000000000000000
FS:  00007f058959b6c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559e6834cf60 CR3: 0000000122a65000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/03 09:05 android14-6.1 6612ef9d0b09 57bbd979 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (clean fs)] [mounted in repro #2 (corrupt fs)] ci2-android-6-1 kernel BUG in ext4_mb_release_inode_pa
2026/06/18 17:01 android14-6.1 9f35ca3ff66c a776b0d0 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (clean fs)] [mounted in repro #2 (corrupt fs)] [mounted in repro #3 (clean fs)] ci2-android-6-1 kernel BUG in ext4_mb_release_inode_pa
2025/02/15 13:58 android14-6.1 ccc915784332 40a34ec9 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (clean fs)] ci2-android-6-1 kernel BUG in ext4_mb_release_inode_pa
2025/01/15 10:29 android14-6.1 e09bed30088f 7315a7cf .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in ext4_mb_release_inode_pa
2025/01/14 06:40 android14-6.1 770852bf7d99 b1f1cd88 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in ext4_mb_release_inode_pa
2024/12/15 14:56 android14-6.1 22b7ded8b55b 7cbfbb3a .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in ext4_mb_release_inode_pa
2025/01/17 05:15 android14-6.1 dbdf659cc65c f9e07a6e .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-android-6-1 kernel BUG in ext4_mb_release_inode_pa
2025/01/17 04:31 android14-6.1 dbdf659cc65c f9e07a6e .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-android-6-1 kernel BUG in ext4_mb_release_inode_pa
2026/07/20 09:41 android14-6.1 c7e15f0bdc49 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_mb_release_inode_pa
2026/07/20 09:40 android14-6.1 c7e15f0bdc49 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_mb_release_inode_pa
2026/07/20 09:39 android14-6.1 c7e15f0bdc49 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_mb_release_inode_pa
2026/07/20 09:39 android14-6.1 c7e15f0bdc49 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_mb_release_inode_pa
* Struck through repros no longer work on HEAD.