syzbot
kernel BUG in ext4_es_cache_extent
Status:
auto-obsoleted due to no activity on 2026/09/01 07:59
Bug presence:
origin:lts
[Documentation on labels]
Reported-by: syzbot+bd36204ef9201acb1b1e@syzkaller.appspotmail.com
First crash: 194d, last: 181d
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Bug presence (2)
| Date |
Name |
Commit |
Repro |
Result |
| 2026/02/22 |
lts (merge base) |
e45d5d41c134 |
C
|
[report] kernel BUG in ext4_ext_insert_extent
|
| 2026/02/22 |
upstream (ToT) |
fa5c82f4d2bb |
C
|
Didn't crash |
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Last patch testing requests (3)
Sample crash report:
kernel BUG at fs/ext4/extents_status.c:968!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 13836 Comm: syz.8.4128 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:968
Code: e8 03 42 80 3c 38 00 74 08 48 89 df e8 0e 51 d2 ff 48 8b 3b 48 8b 74 24 28 48 8d 54 24 60 e8 8c da 0c 00 eb 13 e8 85 22 93 ff <0f> 0b e8 7e 22 93 ff eb 28 e8 77 22 93 ff 31 f6 65 ff 0d f6 c2 2b
RSP: 0018:ffffc90000d760e0 EFLAGS: 00010293
RAX: ffffffff81d6aa7b RBX: 000000000000008f RCX: ffff8881282ce2c0
RDX: 0000000000000000 RSI: 000000000000008f RDI: 000000000000008d
RBP: ffffc90000d761e8 R08: ffffc90000d76157 R09: ffffc90000d76140
R10: dffffc0000000000 R11: fffff520001aec2b R12: ffff888147a603c8
R13: 47ffffffffffffff R14: 000000000000008d R15: dffffc0000000000
FS: 00007fd697dfb6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31f1eff8 CR3: 000000010f096000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ext4_cache_extents fs/ext4/extents.c:517 [inline]
__read_extent_tree_block+0x44b/0x790 fs/ext4/extents.c:564
ext4_find_extent+0x8b9/0xe20 fs/ext4/extents.c:929
ext4_ext_map_blocks+0x207/0x61e0 fs/ext4/extents.c:4166
ext4_map_blocks+0x988/0x1b30 fs/ext4/inode.c:674
_ext4_get_block+0x1ea/0x540 fs/ext4/inode.c:817
ext4_get_block_unwritten+0x2a/0x40 fs/ext4/inode.c:848
ext4_block_write_begin+0x563/0x1160 fs/ext4/inode.c:1102
ext4_write_begin+0x65a/0x12e0 fs/ext4/ext4_jbd2.h:-1
ext4_da_write_begin+0x321/0xbf0 fs/ext4/inode.c:2988
generic_perform_write+0x2b7/0x690 mm/filemap.c:3870
ext4_buffered_write_iter+0x4ed/0x670 fs/ext4/file.c:270
ext4_file_write_iter+0x440/0x1540 fs/ext4/file.c:-1
__kernel_write+0x510/0x950 fs/read_write.c:539
__dump_emit+0x246/0x370 fs/coredump.c:880
dump_emit+0x383/0x3f0 fs/coredump.c:917
dump_user_range+0x86/0x1c0 fs/coredump.c:954
elf_core_dump+0x2a8f/0x2fd0 fs/binfmt_elf.c:2285
do_coredump+0x1452/0x2950 fs/coredump.c:831
get_signal+0x38d/0x1480 kernel/signal.c:2893
arch_do_signal_or_restart+0xdf/0x11c0 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0xa7/0xe0 kernel/entry/common.c:178
exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:214
irqentry_exit_to_user_mode+0x9/0x10 kernel/entry/common.c:320
irqentry_exit+0x12/0x40 kernel/entry/common.c:411
exc_page_fault+0x5e/0xb0 arch/x86/mm/fault.c:1563
asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7fd6993a07a1
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: 00007fd699619fa0 RCX: 00007fd6993a0799
RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000
RBP: 00007fd699436bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fd69961a038 R14: 00007fd699619fa0 R15: 00007ffec70b8468
</TASK>
Modules linked in:
---[ end trace b807cabba16a6128 ]---
RIP: 0010:ext4_es_cache_extent+0x57b/0x5d0 fs/ext4/extents_status.c:968
Code: e8 03 42 80 3c 38 00 74 08 48 89 df e8 0e 51 d2 ff 48 8b 3b 48 8b 74 24 28 48 8d 54 24 60 e8 8c da 0c 00 eb 13 e8 85 22 93 ff <0f> 0b e8 7e 22 93 ff eb 28 e8 77 22 93 ff 31 f6 65 ff 0d f6 c2 2b
RSP: 0018:ffffc90000d760e0 EFLAGS: 00010293
RAX: ffffffff81d6aa7b RBX: 000000000000008f RCX: ffff8881282ce2c0
RDX: 0000000000000000 RSI: 000000000000008f RDI: 000000000000008d
RBP: ffffc90000d761e8 R08: ffffc90000d76157 R09: ffffc90000d76140
R10: dffffc0000000000 R11: fffff520001aec2b R12: ffff888147a603c8
R13: 47ffffffffffffff R14: 000000000000008d R15: dffffc0000000000
FS: 00007fd697dfb6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc1cd8a72f8 CR3: 000000010f096000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
* Struck through repros no longer work on HEAD.