syzbot
KASAN: use-after-free Read in __ext4_check_dir_entry
Status:
upstream: reported C repro on 2024/06/03 01:15
Bug presence:
origin:upstream
[Documentation on labels]
Reported-by: syzbot+618531929d48e32a4823@syzkaller.appspotmail.com
First crash: 794d, last: 72d
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Bug presence (1)
| Date |
Name |
Commit |
Repro |
Result |
| 2024/06/03 |
upstream (ToT) |
c3f38fa61af7 |
C
|
[report] KASAN: use-after-free Read in __ext4_check_dir_entry
|
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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 |
1d01h |
563d
|
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 |
515d |
668d
|
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 |
2142d |
2246d
|
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 |
803d |
813d
|
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 |
10 |
80d |
483d
|
0/2 |
upstream: reported C repro on 2025/04/09 15:24
|
| android-5-15 |
KASAN: use-after-free Read in __ext4_check_dir_entry
missing-backport
origin:upstream
|
19 |
syz, C |
|
error |
4 |
644d |
768d
|
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 |
165d |
165d
|
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 |
6 |
46d |
401d
|
0/29 |
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 |
3046d |
3049d
|
22/29 |
closed as dup on 2018/03/31 22:38
|
| android-5-10 |
KASAN: use-after-free Read in __ext4_check_dir_entry
|
19 |
syz, C |
|
error |
2 |
699d |
817d
|
0/2 |
auto-obsoleted due to no activity on 2024/12/26 18:56
|
| android-6-1 |
KASAN: use-after-free Read in __ext4_check_dir_entry
missing-backport
origin:upstream
|
19 |
syz, C |
|
error |
4 |
692d |
816d
|
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 |
757d |
794d
|
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 |
61d |
487d
|
0/2 |
upstream: reported C repro on 2025/04/05 13:22
|
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Last patch testing requests (6)
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Fix bisection attempts (7)
Sample crash report:
EXT4-fs warning (device loop0): dx_probe:965: inode #2: comm syz-executor581: Corrupt directory, running e2fsck is recommended
==================================================================
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x6f3/0x870 fs/ext4/dir.c:85
Read of size 2 at addr ffff8880708f6003 by task syz-executor581/3513
CPU: 1 PID: 3513 Comm: syz-executor581 Not tainted 5.15.160-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
print_address_description+0x63/0x3b0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0x16b/0x1c0 mm/kasan/report.c:451
__ext4_check_dir_entry+0x6f3/0x870 fs/ext4/dir.c:85
ext4_readdir+0x14a6/0x38e0 fs/ext4/dir.c:258
iterate_dir+0x224/0x570
__do_sys_getdents64 fs/readdir.c:369 [inline]
__se_sys_getdents64+0x209/0x4f0 fs/readdir.c:354
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fa96dc1e569
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 1b 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa96dbd0218 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007fa96dc9e608 RCX: 00007fa96dc1e569
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000008
RBP: 00007fa96dc9e600 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa96dc6b62c
R13: 00007fa96dc6b2e0 R14: 00007fa96dc6b528 R15: 6f6f6c2f7665642f
</TASK>
The buggy address belongs to the page:
page:ffffea0001c23d80 refcount:1 mapcount:1 mapping:0000000000000000 index:0x55b157b7a pfn:0x708f6
memcg:ffff888011e84000
anon flags: 0xfff00000080014(uptodate|lru|swapbacked|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000080014 ffffea0001589b48 ffffea0001c23dc8 ffff88801a9ea771
raw: 000000055b157b7a 0000000000000000 0000000100000000 ffff888011e84000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x1100cca(GFP_HIGHUSER_MOVABLE), pid 2964, ts 43131601451, free_ts 37232586833
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x322a/0x33c0 mm/page_alloc.c:4159
__alloc_pages+0x272/0x700 mm/page_alloc.c:5423
alloc_pages_vma+0x39a/0x800 mm/mempolicy.c:2146
wp_page_copy+0x24e/0x2070 mm/memory.c:3026
handle_pte_fault mm/memory.c:4639 [inline]
__handle_mm_fault mm/memory.c:4756 [inline]
handle_mm_fault+0x2a3d/0x5950 mm/memory.c:4854
do_user_addr_fault arch/x86/mm/fault.c:1388 [inline]
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x271/0x740 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1340 [inline]
free_pcp_prepare mm/page_alloc.c:1391 [inline]
free_unref_page_prepare+0xc34/0xcf0 mm/page_alloc.c:3317
free_unref_page_list+0x1f7/0x8e0 mm/page_alloc.c:3433
release_pages+0x1bb9/0x1f40 mm/swap.c:963
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:338
exit_mmap+0x3cd/0x670 mm/mmap.c:3188
__mmput+0x112/0x3b0 kernel/fork.c:1126
exit_mm+0x688/0x7f0 kernel/exit.c:548
do_exit+0x626/0x2480 kernel/exit.c:859
do_group_exit+0x144/0x310 kernel/exit.c:994
__do_sys_exit_group kernel/exit.c:1005 [inline]
__se_sys_exit_group kernel/exit.c:1003 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1003
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
Memory state around the buggy address:
ffff8880708f5f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8880708f5f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880708f6000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
^
ffff8880708f6080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8880708f6100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
* Struck through repros no longer work on HEAD.