syzbot
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
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Last patch testing requests (3)
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
* Struck through repros no longer work on HEAD.