syzbot
KASAN: use-after-free Read in __ext4_check_dir_entry
Status:
auto-obsoleted due to no activity on 2024/12/26 18:56
Reported-by: syzbot+8f42da1dbf662eb1d6f0@syzkaller.appspotmail.com
First crash: 829d, last: 711d
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Similar bugs (13)
| Kernel |
Title |
Rank
🛈
|
Repro |
Cause bisect |
Fix bisect |
Count |
Last |
Reported |
Patched |
Status |
| android-5-10 |
KASAN: use-after-free Read in __ext4_check_dir_entry (2)
|
19 |
syz, C |
|
|
12 |
12d |
575d
|
0/2 |
upstream: reported C repro on 2025/01/19 16:52
|
| upstream |
KASAN: use-after-free Read in __ext4_check_dir_entry (3)
ext4
|
19 |
syz, C |
inconclusive |
done |
6 |
527d |
680d
|
0/29 |
auto-obsoleted due to no activity on 2025/06/16 07:57
|
| linux-4.14 |
KASAN: use-after-free Read in __ext4_check_dir_entry
|
19 |
syz, C |
|
inconclusive |
6 |
2154d |
2257d
|
0/1 |
upstream: reported C repro on 2020/06/12 02:23
|
| upstream |
KASAN: use-after-free Read in __ext4_check_dir_entry (2)
ext4
|
19 |
syz, C |
error |
|
1 |
815d |
825d
|
0/29 |
closed as dup on 2024/06/26 08:39
|
| android-5-15 |
KASAN: use-after-free Read in __ext4_check_dir_entry (2)
origin:lts
|
19 |
syz, C |
|
error |
11 |
11d |
495d
|
0/2 |
upstream: reported C repro on 2025/04/09 15:24
|
| linux-5.15 |
KASAN: use-after-free Read in __ext4_check_dir_entry
origin:upstream
|
19 |
syz, C |
|
error |
10 |
8d00h |
805d
|
0/3 |
upstream: reported C repro on 2024/06/03 01:15
|
| android-5-15 |
KASAN: use-after-free Read in __ext4_check_dir_entry
missing-backport
origin:upstream
|
19 |
syz, C |
|
error |
4 |
656d |
780d
|
0/2 |
auto-obsoleted due to no activity on 2025/02/07 07:57
|
| linux-6.6 |
KASAN: use-after-free Read in __ext4_check_dir_entry
origin:upstream
|
19 |
syz, C |
|
error |
1 |
176d |
176d
|
0/2 |
upstream: reported C repro on 2026/02/22 03:13
|
| upstream |
KASAN: slab-use-after-free Read in __ext4_check_dir_entry
prio:high
ext4
|
19 |
syz, C |
error |
error |
7 |
10d |
413d
|
2/29 |
upstream: reported C repro on 2025/06/30 17:28
|
| upstream |
KASAN: use-after-free Read in __ext4_check_dir_entry
ext4
|
19 |
syz, C |
|
|
8 |
3058d |
3061d
|
22/29 |
closed as dup on 2018/03/31 22:38
|
| android-6-1 |
KASAN: use-after-free Read in __ext4_check_dir_entry
missing-backport
origin:upstream
|
19 |
syz, C |
|
error |
4 |
704d |
828d
|
0/2 |
auto-obsoleted due to no activity on 2024/12/21 14:06
|
| linux-6.1 |
KASAN: use-after-free Read in __ext4_check_dir_entry
|
19 |
|
|
|
15 |
769d |
805d
|
0/3 |
auto-obsoleted due to no activity on 2024/09/17 20:54
|
| android-6-1 |
KASAN: use-after-free Read in __ext4_check_dir_entry (2)
origin:upstream
|
19 |
syz, C |
|
error |
9 |
73d |
499d
|
0/2 |
upstream: reported C repro on 2025/04/05 13:22
|
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Last patch testing requests (3)
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Fix bisection attempts (4)
Sample crash report:
EXT4-fs error (device loop0): dx_make_map:1302: inode #2: block 255: comm syz-executor926: bad entry in directory: inode out of bounds - offset=0, inode=1633771873, rec_len=1024, size=1024 fake=0
EXT4-fs error (device loop0) in do_split:2056: Corrupt filesystem
EXT4-fs warning (device loop0): dx_probe:817: inode #2: comm syz-executor926: Hash code is SIPHASH, but hash not in dirent
EXT4-fs warning (device loop0): dx_probe:945: inode #2: comm syz-executor926: Corrupt directory, running e2fsck is recommended
==================================================================
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x700/0x880 fs/ext4/dir.c:85
Read of size 2 at addr ffff88811ee9d003 by task syz-executor926/286
CPU: 0 PID: 286 Comm: syz-executor926 Not tainted 5.10.223-syzkaller-00011-g1c5354a314ea #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
print_address_description+0x81/0x3b0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:435 [inline]
kasan_report+0x179/0x1c0 mm/kasan/report.c:452
__asan_report_load2_noabort+0x14/0x20 mm/kasan/report_generic.c:307
__ext4_check_dir_entry+0x700/0x880 fs/ext4/dir.c:85
ext4_readdir+0x1402/0x37c0 fs/ext4/dir.c:258
iterate_dir+0x265/0x580
__do_sys_getdents64 fs/readdir.c:369 [inline]
__se_sys_getdents64+0x1c1/0x460 fs/readdir.c:354
__x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354
do_syscall_64+0x34/0x70
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f8b926ae7b9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 1c 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd956fba68 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8b926ae7b9
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f8b926f225b R08: 00007f8b926f227d R09: 00007f8b926f227d
R10: 00007f8b926f227d R11: 0000000000000246 R12: 00007f8b926f221b
R13: 00007f8b926f2072 R14: 00007ffd956fbad0 R15: 00007ffd956fbaa8
The buggy address belongs to the page:
page:ffffea00047ba740 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x11ee9d
flags: 0x4000000000000000()
raw: 4000000000000000 ffffea00047b4108 ffff8881f715ab70 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x8100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|0x8000000), pid 274, ts 19444317089, free_ts 19460513210
set_page_owner include/linux/page_owner.h:35 [inline]
post_alloc_hook mm/page_alloc.c:2456 [inline]
prep_new_page+0x166/0x180 mm/page_alloc.c:2462
get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254
__alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5348
__alloc_pages include/linux/gfp.h:544 [inline]
__alloc_pages_node include/linux/gfp.h:557 [inline]
alloc_pages_node include/linux/gfp.h:571 [inline]
alloc_pages include/linux/gfp.h:590 [inline]
do_anonymous_page mm/memory.c:3935 [inline]
handle_pte_fault+0x1782/0x3e30 mm/memory.c:4758
__handle_mm_fault mm/memory.c:4916 [inline]
handle_mm_fault+0x11d6/0x1a10 mm/memory.c:5330
do_user_addr_fault arch/x86/mm/fault.c:1362 [inline]
handle_page_fault arch/x86/mm/fault.c:1428 [inline]
exc_page_fault+0x2a6/0x5b0 arch/x86/mm/fault.c:1484
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:571
page last free stack trace:
reset_page_owner include/linux/page_owner.h:28 [inline]
free_pages_prepare mm/page_alloc.c:1349 [inline]
free_pcp_prepare mm/page_alloc.c:1421 [inline]
free_unref_page_prepare+0x2ae/0x2d0 mm/page_alloc.c:3336
free_unref_page_list+0x122/0xb20 mm/page_alloc.c:3443
release_pages+0xea0/0xef0 mm/swap.c:1103
free_pages_and_swap_cache+0x8a/0xa0 mm/swap_state.c:356
tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
tlb_flush_mmu mm/mmu_gather.c:247 [inline]
tlb_finish_mmu+0x177/0x320 mm/mmu_gather.c:326
unmap_region+0x31c/0x370 mm/mmap.c:2810
__do_munmap+0x699/0x8c0 mm/mmap.c:3041
__vm_munmap mm/mmap.c:3064 [inline]
__do_sys_munmap mm/mmap.c:3090 [inline]
__se_sys_munmap+0x120/0x1a0 mm/mmap.c:3086
__x64_sys_munmap+0x5b/0x70 mm/mmap.c:3086
do_syscall_64+0x34/0x70
entry_SYSCALL_64_after_hwframe+0x61/0xcb
Memory state around the buggy address:
ffff88811ee9cf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88811ee9cf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88811ee9d000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88811ee9d080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88811ee9d100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop0): ext4_readdir:260: inode #2: block 255: comm syz-executor926: path /file1: bad entry in directory: rec_len is smaller than minimal - offset=1023, inode=0, rec_len=0, size=1024 fake=0
EXT4-fs error (device loop0): ext4_readdir:260: inode #2: block 253: comm syz-executor926: path /file1: bad entry in directory: rec_len is smaller than minimal - offset=0, inode=0, rec_len=0, size=1024 fake=0
* Struck through repros no longer work on HEAD.