syzbot


WARNING in read_block_bitmap

Status: upstream: reported C repro on 2025/09/09 14:40
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+4278b025fa75f41c8b4b@syzkaller.appspotmail.com
First crash: 143d, last: 25d
Fix bisection: failed (error log)
  
Bug presence (2)
Date Name Commit Repro Result
2025/09/13 upstream (ToT) 22f20375f5b7 C [report] WARNING in read_block_bitmap
2026/01/29 upstream (ToT) 8dfce8991b95 C Failed due to an error; will retry later
Fix bisection attempts (2)
Created Duration User Patch Repo Result
2025/11/18 21:26 0m bisect fix linux-6.1.y error
2025/10/16 17:50 2h25m bisect fix linux-6.1.y OK (0) job log log

Sample crash report:
EXT2-fs (loop0): error: ext2_free_blocks: Freeing blocks not in datazone - block = 1635278706, count = 1
------------[ cut here ]------------
block_group >= groups_count - block_group = 8096, groups_count = 1
WARNING: CPU: 1 PID: 4537 at fs/ext2/balloc.c:51 ext2_get_group_desc fs/ext2/balloc.c:-1 [inline]
WARNING: CPU: 1 PID: 4537 at fs/ext2/balloc.c:51 read_block_bitmap+0x1ec/0x754 fs/ext2/balloc.c:136
Modules linked in:
CPU: 1 PID: 4537 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : ext2_get_group_desc fs/ext2/balloc.c:-1 [inline]
pc : read_block_bitmap+0x1ec/0x754 fs/ext2/balloc.c:136
lr : ext2_get_group_desc fs/ext2/balloc.c:49 [inline]
lr : read_block_bitmap+0x1e8/0x754 fs/ext2/balloc.c:136
sp : ffff8000211d7550
x29: ffff8000211d7580 x28: dfff800000000000 x27: 1fffe0001bd704cf
x26: 0000000000000001 x25: ffff0000d5411000 x24: 0000000000001fa0
x23: ffff0000deb82678 x22: 0000000000000001 x21: ffff0000deb82678
x20: ffff0000deb82000 x19: 0000000000001fa0 x18: ffff800011a5bd40
x17: 1fffe00033eebd7e x16: ffff8000082d3a08 x15: 0000000040000000
x14: 0000000000000002 x13: 1ffff00002a0a0b1 x12: 0000000000ff0100
x11: ff0080000a895d54 x10: 0000000000000003 x9 : 451fe19a32d0a100
x8 : 451fe19a32d0a100 x7 : ffff8000082532dc x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000006 x1 : ffff800011a5d840 x0 : 0000000000000000
Call trace:
 ext2_get_group_desc fs/ext2/balloc.c:-1 [inline]
 read_block_bitmap+0x1ec/0x754 fs/ext2/balloc.c:136
 ext2_free_blocks+0x288/0x988 fs/ext2/balloc.c:521
 ext2_free_data fs/ext2/inode.c:1099 [inline]
 __ext2_truncate_blocks+0x2a8/0xbc0 fs/ext2/inode.c:1190
 ext2_truncate_blocks fs/ext2/inode.c:1259 [inline]
 ext2_write_failed+0x1fc/0x270 fs/ext2/inode.c:65
 ext2_write_begin+0x70/0x88 fs/ext2/inode.c:905
 generic_perform_write+0x230/0x4e4 mm/filemap.c:3862
 __generic_file_write_iter+0x130/0x250 mm/filemap.c:3960
 generic_file_write_iter+0xb4/0x2b0 mm/filemap.c:3989
 ext2_file_write_iter+0xc4/0x404 fs/ext2/file.c:179
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x5ac/0x7c4 fs/read_write.c:584
 ksys_pwrite64 fs/read_write.c:699 [inline]
 __do_sys_pwrite64 fs/read_write.c:709 [inline]
 __se_sys_pwrite64 fs/read_write.c:706 [inline]
 __arm64_sys_pwrite64+0x170/0x200 fs/read_write.c:706
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
irq event stamp: 8642
hardirqs last  enabled at (8641): [<ffff800008253370>] raw_spin_rq_unlock_irq kernel/sched/sched.h:1367 [inline]
hardirqs last  enabled at (8641): [<ffff800008253370>] finish_lock_switch+0xb0/0x1c4 kernel/sched/core.c:5003
hardirqs last disabled at (8642): [<ffff8000118fa220>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last  enabled at (8366): [<ffff8000080309e0>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (8364): [<ffff8000080309ac>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---
EXT2-fs (loop0): error: ext2_free_blocks: Freeing blocks not in datazone - block = 29554, count = 1

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/05 15:28 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-linux-6-1-kasan-arm64 WARNING in read_block_bitmap
2025/09/09 16:57 linux-6.1.y 28c695c365e1 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-linux-6-1-kasan-arm64 WARNING in read_block_bitmap
2025/09/09 16:15 linux-6.1.y 28c695c365e1 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-linux-6-1-kasan-arm64 WARNING in read_block_bitmap
2025/09/09 15:28 linux-6.1.y 28c695c365e1 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-linux-6-1-kasan-arm64 WARNING in read_block_bitmap
2026/01/05 14:41 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in read_block_bitmap
2025/09/11 04:52 linux-6.1.y f97f1002271b fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in read_block_bitmap
2025/09/09 14:40 linux-6.1.y 28c695c365e1 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in read_block_bitmap
* Struck through repros no longer work on HEAD.