syzbot


kernel BUG in ext4_mb_release_inode_pa

Status: upstream: reported on 2025/05/15 07:16
Reported-by: syzbot+dd2667318936f5e8a162@syzkaller.appspotmail.com
First crash: 63d, last: 63d
Similar bugs (4)
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 C 6 30d 256d 0/2 upstream: reported C repro on 2024/11/03 14:27
android-5-15 kernel BUG in ext4_mb_release_inode_pa origin:lts -1 syz 7 17d 207d 0/2 premoderation: reported syz repro on 2024/12/22 22:32
upstream kernel BUG in ext4_mb_release_inode_pa ext4 -1 syz unreliable error 1 604d 600d 0/29 auto-obsoleted due to no activity on 2024/02/29 10:29
android-6-1 kernel BUG in ext4_mb_release_inode_pa origin:lts -1 C 6 27d 214d 0/2 upstream: reported C repro on 2024/12/15 14:57

Sample crash report:
EXT4-fs (loop4): encrypted files will use data=ordered instead of data journaling mode
EXT4-fs (loop4): 1 truncate cleaned up
EXT4-fs (loop4): mounted filesystem without journal. Quota mode: writeback.
------------[ cut here ]------------
kernel BUG at fs/ext4/mballoc.c:4854!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 9627 Comm: syz.4.1011 Not tainted 6.1.138-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:ext4_mb_release_inode_pa+0xaa4/0xab0 fs/ext4/mballoc.c:4854
Code: 80 c2 03 38 c2 0f 8c 3a fe ff ff 48 89 df 41 89 ce e8 e0 67 ab ff 44 89 f1 e9 27 fe ff ff e8 83 f4 59 ff 0f 0b e8 7c f4 59 ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 55 41 57 41 56 53 48 89 fb 49
RSP: 0018:ffffc90005346d00 EFLAGS: 00010287
RAX: ffffffff8226df34 RBX: 0000000000000020 RCX: 0000000000080000
RDX: ffffc90004b81000 RSI: 0000000000022459 RDI: 000000000002245a
RBP: ffffc90005346e50 R08: dffffc0000000000 R09: ffffed100e86e5fb
R10: ffffed100e86e5fb R11: 1ffff1100e86e5fa R12: dffffc0000000000
R13: ffff8880516c5488 R14: 0000000000000000 R15: 0000000000001153
FS:  00007f8eadfe96c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000002a000 CR3: 0000000053539000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000097 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ext4_mb_discard_group_preallocations+0xb62/0xdc0 fs/ext4/mballoc.c:5000
 ext4_mb_discard_preallocations fs/ext4/mballoc.c:5569 [inline]
 ext4_mb_discard_preallocations_should_retry+0x1f2/0x710 fs/ext4/mballoc.c:5590
 ext4_mb_new_blocks+0x3329/0x4720 fs/ext4/mballoc.c:5793
 ext4_alloc_branch fs/ext4/indirect.c:340 [inline]
 ext4_ind_map_blocks+0xe55/0x2220 fs/ext4/indirect.c:635
 ext4_map_blocks+0x970/0x1b60 fs/ext4/inode.c:681
 _ext4_get_block+0x1d7/0x4e0 fs/ext4/inode.c:822
 ext4_block_write_begin+0x637/0x12f0 fs/ext4/inode.c:1124
 ext4_write_begin+0x624/0xf50 fs/ext4/ext4_jbd2.h:-1
 generic_perform_write+0x2db/0x560 mm/filemap.c:3846
 ext4_buffered_write_iter+0x11a/0x3e0 fs/ext4/file.c:285
 ext4_file_write_iter+0x1d6/0x16e0 fs/ext4/file.c:-1
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x44c/0x960 fs/read_write.c:584
 ksys_write+0x143/0x240 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8ead18e969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8eadfe9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8ead3b5fa0 RCX: 00007f8ead18e969
RDX: 000000000208e24b RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007f8ead210ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f8ead3b5fa0 R15: 00007fffebe42c88
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_mb_release_inode_pa+0xaa4/0xab0 fs/ext4/mballoc.c:4854
Code: 80 c2 03 38 c2 0f 8c 3a fe ff ff 48 89 df 41 89 ce e8 e0 67 ab ff 44 89 f1 e9 27 fe ff ff e8 83 f4 59 ff 0f 0b e8 7c f4 59 ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 55 41 57 41 56 53 48 89 fb 49
RSP: 0018:ffffc90005346d00 EFLAGS: 00010287
RAX: ffffffff8226df34 RBX: 0000000000000020 RCX: 0000000000080000
RDX: ffffc90004b81000 RSI: 0000000000022459 RDI: 000000000002245a
RBP: ffffc90005346e50 R08: dffffc0000000000 R09: ffffed100e86e5fb
R10: ffffed100e86e5fb R11: 1ffff1100e86e5fa R12: dffffc0000000000
R13: ffff8880516c5488 R14: 0000000000000000 R15: 0000000000001153
FS:  00007f8eadfe96c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000002a000 CR3: 0000000053539000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000097 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/15 07:16 linux-6.1.y 02b72ccb5f9d d6b2ee52 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan kernel BUG in ext4_mb_release_inode_pa
* Struck through repros no longer work on HEAD.