kernel BUG in ext4_es_cache_extent

Status: auto-obsoleted due to no activity on 2026/09/19 12:03
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+69319f3f3c680030db3e@syzkaller.appspotmail.com
First crash: 198d, last: 151d
Fix bisection: failed (error log, bisect log)
  
Bug presence (5)
Date Name Commit Repro Result
2026/04/22 android14-6.1 (ToT) 15ea42c3d32a C [report] kernel BUG in ext4_es_cache_extent
2026/03/06 lts (merge base) 0182cb5b74ee C [report] kernel BUG in ext4_ext_insert_extent
2026/08/24 lts (merge base) [unknown] C Failed due to an error; will retry later
2026/03/06 upstream (ToT) 5ee8dbf54602 C [report] kernel BUG in ext4_es_cache_extent
2026/04/22 upstream (ToT) 6596a02b2078 C Didn't crash
Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream kernel BUG in ext4_es_cache_extent ext4 -1 syz, C inconclusive 6 1328d 1687d 22/29 fixed on 2023/02/24 13:50
android-54 kernel BUG in ext4_es_cache_extent ext4 -1 syz, C 16 794d 1484d 0/2 auto-obsoleted due to no activity on 2024/10/26 14:37
linux-6.1 kernel BUG in ext4_es_cache_extent -1 syz error 1 193d 193d 0/3 upstream: reported syz repro on 2026/03/11 08:55
upstream kernel BUG in ext4_es_cache_extent (4) prio:high ext4 -1 syz, C error error 15 180d 223d 0/29 auto-obsoleted due to no activity on 2026/09/15 14:07
android-5-15 kernel BUG in ext4_es_cache_extent origin:lts -1 syz, C error 7 198d 210d 0/2 auto-obsoleted due to no activity on 2026/09/01 07:59
android-5-10 kernel BUG in ext4_es_cache_extent -1 syz, C error 1 1484d 1484d 0/2 closed as invalid on 2022/09/13 19:49
upstream kernel BUG in ext4_es_cache_extent (3) ext4 -1 syz, C 4 367d 381d 29/29 fixed on 2025/11/18 08:45
android-5-10 kernel BUG in ext4_es_cache_extent (2) -1 syz, C done 9 161d 339d 0/2 auto-obsoleted due to no activity on 2026/08/28 15:54
upstream kernel BUG in ext4_es_cache_extent (2) ext4 -1 1 605d 601d 0/29 auto-obsoleted due to no activity on 2025/05/03 18:51
Last patch testing requests (3)
Created Duration User Patch Repo Result
2026/09/19 11:21 41m retest repro android14-6.1 no crash job log log
2026/07/02 20:51 15m retest repro android14-6.1 log
2026/03/22 17:09 7m retest repro android14-6.1 report log

Sample crash report:
------------[ cut here ]------------
kernel BUG at fs/ext4/extents_status.c:967!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 5066 Comm: syz.6.1258 Tainted: G        W          syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:ext4_es_cache_extent+0x57b/0x5d0 fs/ext4/extents_status.c:967
Code: e8 03 42 80 3c 38 00 74 08 48 89 df e8 de 27 cf ff 48 8b 3b 48 8b 74 24 28 48 8d 54 24 60 e8 3c fa 0c 00 eb 13 e8 45 f5 89 ff <0f> 0b e8 3e f5 89 ff eb 28 e8 37 f5 89 ff 31 f6 65 ff 0d f6 f5 1a
RSP: 0018:ffffc900033163e0 EFLAGS: 00010293
RAX: ffffffff81e777bb RBX: 0000000000000080 RCX: ffff88813e75d100
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 0000000000000070
RBP: ffffc900033164e8 R08: ffffc90003316457 R09: ffffc90003316440
R10: dffffc0000000000 R11: fffff52000662c8b R12: ffff8881289f03c8
R13: 47ffffffffffffff R14: 0000000000000070 R15: dffffc0000000000
FS:  00007f6dfa7c96c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f46d7348060 CR3: 000000011e205000 CR4: 00000000003506a0
Call Trace:
 <TASK>
 ext4_cache_extents fs/ext4/extents.c:536 [inline]
 __read_extent_tree_block+0x44b/0x790 fs/ext4/extents.c:583
 ext4_find_extent+0x8b9/0xe20 fs/ext4/extents.c:936
 ext4_ext_map_blocks+0x207/0x61d0 fs/ext4/extents.c:4166
 ext4_map_blocks+0x9d8/0x1b70 fs/ext4/inode.c:679
 _ext4_get_block+0x1ea/0x540 fs/ext4/inode.c:822
 ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:855
 ext4_block_write_begin+0x594/0x1280 fs/ext4/inode.c:1124
 ext4_write_begin+0x600/0xf90 fs/ext4/ext4_jbd2.h:-1
 ext4_da_write_begin+0x3e7/0x8c0 fs/ext4/inode.c:3001
 generic_perform_write+0x32d/0x740 mm/filemap.c:3903
 ext4_buffered_write_iter+0x367/0x630 fs/ext4/file.c:285
 ext4_file_write_iter+0x191/0x1500 fs/ext4/file.c:-1
 __kernel_write_iter+0x296/0x660 fs/read_write.c:517
 dump_emit_page fs/coredump.c:886 [inline]
 dump_user_range+0x40b/0x660 fs/coredump.c:913
 elf_core_dump+0x2b52/0x3060 fs/binfmt_elf.c:2354
 do_coredump+0x15d3/0x2240 fs/coredump.c:760
 get_signal+0x11db/0x1520 kernel/signal.c:2877
 arch_do_signal_or_restart+0xd1/0x1140 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x7a/0xb0 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x9/0x10 kernel/entry/common.c:316
 irqentry_exit+0x12/0x40 kernel/entry/common.c:419
 exc_page_fault+0x5e/0xb0 arch/x86/mm/fault.c:1520
 asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7f6df999c7a1
Code: 00 00 00 00 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 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:fffffffffffffe70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f6df9c15fa0 RCX: 00007f6df999c799
RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000
RBP: 00007f6df9a32bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f6df9c16038 R14: 00007f6df9c15fa0 R15: 00007ffd506df508
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_es_cache_extent+0x57b/0x5d0 fs/ext4/extents_status.c:967
Code: e8 03 42 80 3c 38 00 74 08 48 89 df e8 de 27 cf ff 48 8b 3b 48 8b 74 24 28 48 8d 54 24 60 e8 3c fa 0c 00 eb 13 e8 45 f5 89 ff <0f> 0b e8 3e f5 89 ff eb 28 e8 37 f5 89 ff 31 f6 65 ff 0d f6 f5 1a
RSP: 0018:ffffc900033163e0 EFLAGS: 00010293
RAX: ffffffff81e777bb RBX: 0000000000000080 RCX: ffff88813e75d100
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 0000000000000070
RBP: ffffc900033164e8 R08: ffffc90003316457 R09: ffffc90003316440
R10: dffffc0000000000 R11: fffff52000662c8b R12: ffff8881289f03c8
R13: 47ffffffffffffff R14: 0000000000000070 R15: dffffc0000000000
FS:  00007f6dfa7c96c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f17a35e82f8 CR3: 000000011e205000 CR4: 00000000003506b0

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/08 16:58 android14-6.1 6bfa51973214 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_es_cache_extent
2026/03/08 10:54 android14-6.1 6bfa51973214 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_es_cache_extent
2026/03/07 21:55 android14-6.1 6bfa51973214 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_es_cache_extent
2026/03/07 18:58 android14-6.1 6bfa51973214 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_es_cache_extent
2026/03/06 20:15 android14-6.1 6bfa51973214 41d8037d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_es_cache_extent
2026/03/06 15:54 android14-6.1 6bfa51973214 41d8037d .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-6-1 kernel BUG in ext4_es_cache_extent
2026/03/06 11:41 android14-6.1 6bfa51973214 31e9c887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_es_cache_extent
2026/03/06 11:40 android14-6.1 6bfa51973214 31e9c887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_es_cache_extent
2026/03/06 11:38 android14-6.1 6bfa51973214 31e9c887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_es_cache_extent
2026/03/06 11:36 android14-6.1 6bfa51973214 31e9c887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_es_cache_extent
2026/03/06 11:35 android14-6.1 6bfa51973214 31e9c887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in ext4_es_cache_extent
* Struck through repros no longer work on HEAD.