syzbot


kernel BUG in ext4_es_cache_extent (2)

Status: premoderation: reported syz repro on 2025/09/23 23:29
Reported-by: syzbot+861c094488598cff0422@syzkaller.appspotmail.com
First crash: 14d, last: 14d
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream kernel BUG in ext4_es_cache_extent ext4 -1 C inconclusive 6 981d 1340d 22/29 fixed on 2023/02/24 13:50
android-54 kernel BUG in ext4_es_cache_extent ext4 -1 C 16 447d 1137d 0/2 auto-obsoleted due to no activity on 2024/10/26 14:37
android-5-10 kernel BUG in ext4_es_cache_extent -1 C error 1 1137d 1137d 0/2 closed as invalid on 2022/09/13 19:49
upstream kernel BUG in ext4_es_cache_extent (3) ext4 -1 C 4 20d 34d 0/29 upstream: reported C repro on 2025/09/04 09:44
upstream kernel BUG in ext4_es_cache_extent (2) ext4 -1 1 258d 254d 0/29 auto-obsoleted due to no activity on 2025/05/03 18:51

Sample crash report:
------------[ cut here ]------------
kernel BUG at fs/ext4/extents_status.c:968!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 1227 Comm: syz.3.50 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025
RIP: 0010:ext4_es_cache_extent+0x57f/0x5d0 fs/ext4/extents_status.c:968
Code: 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 08 ef d2 ff 48 8b 3b 48 8b 74 24 28 4c 89 f2 e8 a8 4d 0c 00 eb 13 e8 a1 01 99 ff <0f> 0b e8 9a 01 99 ff eb 28 e8 93 01 99 ff 31 f6 65 ff 0d 06 c9 37
RSP: 0018:ffffc90004986380 EFLAGS: 00010293
RAX: ffffffff81caa46f RBX: 000000000000002c RCX: ffff888126b662c0
RDX: 0000000000000000 RSI: 000000000000002c RDI: 000000000000002a
RBP: ffffc90004986488 R08: dffffc0000000000 R09: ffffc900049863e0
R10: fffff52000930c7f R11: 1ffff92000930c7c R12: 00000000ffffffff
R13: 47ffffffffffffff R14: 000000000000002a R15: dffffc0000000000
FS:  000055557364a500(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe53e3db80 CR3: 00000001079a7000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ext4_cache_extents fs/ext4/extents.c:516 [inline]
 __read_extent_tree_block+0x44b/0x790 fs/ext4/extents.c:563
 ext4_find_extent+0x8b9/0xe20 fs/ext4/extents.c:928
 ext4_ext_map_blocks+0x1de/0x5d40 fs/ext4/extents.c:4160
 ext4_map_blocks+0x978/0x1bc0 fs/ext4/inode.c:674
 mpage_map_one_extent fs/ext4/inode.c:2452 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2505 [inline]
 ext4_writepages+0x11d5/0x2e00 fs/ext4/inode.c:2873
 do_writepages+0x12a/0x270 mm/page-writeback.c:2380
 __filemap_fdatawrite_range+0x2bc/0x360 mm/filemap.c:427
 file_write_and_wait_range+0x8c/0x110 mm/filemap.c:766
 ext4_sync_file+0x1a9/0x9f0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x190/0x1a0 fs/sync.c:202
 generic_write_sync include/linux/fs.h:2920 [inline]
 ext4_buffered_write_iter+0x59b/0x640 fs/ext4/file.c:278
 ext4_file_write_iter+0x536/0x1980 fs/ext4/file.c:-1
 __kernel_write+0x55a/0x910 fs/read_write.c:550
 dump_emit+0x240/0x360 fs/coredump.c:855
 dump_user_range+0x6a/0x1a0 fs/coredump.c:908
 elf_core_dump+0x278a/0x2bc0 fs/binfmt_elf.c:2290
 do_coredump+0x1ac9/0x27f0 fs/coredump.c:817
 get_signal+0xf23/0x12e0 kernel/signal.c:2779
 arch_do_signal_or_restart+0xbf/0x10f0 arch/x86/kernel/signal.c:805
 handle_signal_work kernel/entry/common.c:145 [inline]
 exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169
 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199
 irqentry_exit_to_user_mode+0x9/0x10 kernel/entry/common.c:287
 irqentry_exit+0x12/0x60 kernel/entry/common.c:375
 exc_page_fault+0x67/0xc0 arch/x86/mm/fault.c:1487
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:571
RIP: 0033:0x7f940ac57ec9
Code: Unable to access opcode bytes at RIP 0x7f940ac57e9f.
RSP: 002b:00007ffe53e3df48 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 00007f940aeaefa0 RCX: 00007f940ac57ec9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000a000
RBP: 00007f940acdaf91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f940aeaefa0 R14: 00007f940aeaefa0 R15: 0000000000000006
Modules linked in:
---[ end trace 6bd1003e24c991dd ]---
RIP: 0010:ext4_es_cache_extent+0x57f/0x5d0 fs/ext4/extents_status.c:968
Code: 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 08 ef d2 ff 48 8b 3b 48 8b 74 24 28 4c 89 f2 e8 a8 4d 0c 00 eb 13 e8 a1 01 99 ff <0f> 0b e8 9a 01 99 ff eb 28 e8 93 01 99 ff 31 f6 65 ff 0d 06 c9 37
RSP: 0018:ffffc90004986380 EFLAGS: 00010293
RAX: ffffffff81caa46f RBX: 000000000000002c RCX: ffff888126b662c0
RDX: 0000000000000000 RSI: 000000000000002c RDI: 000000000000002a
RBP: ffffc90004986488 R08: dffffc0000000000 R09: ffffc900049863e0
R10: fffff52000930c7f R11: 1ffff92000930c7c R12: 00000000ffffffff
R13: 47ffffffffffffff R14: 000000000000002a R15: dffffc0000000000
FS:  000055557364a500(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f940ac57e9f CR3: 00000001079a7000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 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
2025/09/23 23:28 android13-5.10-lts 911f602c2237 e667a34f .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-5-10 kernel BUG in ext4_es_cache_extent
* Struck through repros no longer work on HEAD.