From: syzbot <syzbot+46bbbe175b7eea8036b8@syzkaller.appspotmail.com>
To: linux-kernel@vger.kernel.org, nsvatoslav515@gmail.com,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [ecryptfs?] KASAN: slab-out-of-bounds Read in md5_blocks
Date: Sat, 03 Oct 2026 04:48:03 -0700 [thread overview]
Message-ID: <6ac0eb73.34119e79.2f92f3.0014.GAE@google.com> (raw)
In-Reply-To: <20261003110632.121743-1-nsvatoslav515@gmail.com>
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in ecryptfs_write_tag_70_packet
==================================================================
BUG: KASAN: slab-use-after-free in ecryptfs_write_tag_70_packet+0x1260/0x1300 fs/ecryptfs/keystore.c:740
Read of size 4 at addr ffff88802600c298 by task syz.0.17/6331
CPU: 0 UID: 0 PID: 6331 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description+0x55/0x1e0 mm/kasan/report.c:378
print_report+0x58/0x70 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
ecryptfs_write_tag_70_packet+0x1260/0x1300 fs/ecryptfs/keystore.c:740
ecryptfs_encrypt_filename fs/ecryptfs/crypto.c:1378 [inline]
ecryptfs_encrypt_and_encode_filename+0x576/0x1580 fs/ecryptfs/crypto.c:1789
ecryptfs_lookup+0x20e/0x780 fs/ecryptfs/inode.c:402
lookup_one_qstr_excl+0x12d/0x360 fs/namei.c:1810
__start_dirop fs/namei.c:2920 [inline]
start_dirop fs/namei.c:2942 [inline]
filename_create+0x20e/0x370 fs/namei.c:5103
filename_mkdirat+0xd2/0x510 fs/namei.c:5449
__do_sys_mkdirat fs/namei.c:5477 [inline]
__se_sys_mkdirat+0x35/0x150 fs/namei.c:5474
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb17ed9e159
Code: ff c3 66 2e 0f 1f 84 00 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
RSP: 002b:00007fb17fcc2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fb17f025fa0 RCX: 00007fb17ed9e159
RDX: 0000000000000080 RSI: 0000200000000100 RDI: 0000000000000003
RBP: 00007fb17ee3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb17f026038 R14: 00007fb17f025fa0 R15: 00007ffe3c5b3ec8
</TASK>
Allocated by task 6330:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:409 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5531 [inline]
__kmalloc_noprof+0x366/0x710 mm/slub.c:5556
_kmalloc_noprof include/linux/slab.h:995 [inline]
_kmalloc_array_noprof include/linux/slab.h:1211 [inline]
security_inode_init_security+0x102/0x3e0 security/security.c:1386
shmem_symlink+0xe0/0x4d0 mm/shmem.c:4269
vfs_symlink+0x18e/0x330 fs/namei.c:5807
filename_symlinkat+0x1cd/0x410 fs/namei.c:5832
__do_sys_symlinkat fs/namei.c:5852 [inline]
__se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5847
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 6330:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:264 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2780 [inline]
slab_free mm/slub.c:6630 [inline]
kfree+0x1c5/0x650 mm/slub.c:6923
security_inode_init_security+0x34e/0x3e0 security/security.c:1413
shmem_symlink+0xe0/0x4d0 mm/shmem.c:4269
vfs_symlink+0x18e/0x330 fs/namei.c:5807
filename_symlinkat+0x1cd/0x410 fs/namei.c:5832
__do_sys_symlinkat fs/namei.c:5852 [inline]
__se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5847
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff88802600c200
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 152 bytes inside of
freed 256-byte region [ffff88802600c200, ffff88802600c300)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2600c
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813ff24b40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ff24b40 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 8442970623
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1854
prep_new_page mm/page_alloc.c:1862 [inline]
get_page_from_freelist+0x220f/0x2280 mm/page_alloc.c:3933
__alloc_frozen_pages_noprof+0x1fc/0x400 mm/page_alloc.c:5471
alloc_slab_page mm/slub.c:3384 [inline]
allocate_slab+0x7d/0x5e0 mm/slub.c:3499
new_slab mm/slub.c:3550 [inline]
refill_objects+0x2d5/0x350 mm/slub.c:7539
refill_sheaf mm/slub.c:2917 [inline]
__pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4811
alloc_from_pcs mm/slub.c:4887 [inline]
slab_alloc_node mm/slub.c:5021 [inline]
__kmalloc_cache_noprof+0x396/0x600 mm/slub.c:5676
_kmalloc_noprof include/linux/slab.h:991 [inline]
_kzalloc_noprof include/linux/slab.h:1312 [inline]
bus_add_driver+0x19d/0x6e0 drivers/base/bus.c:755
driver_register+0x23a/0x320 drivers/base/driver.c:174
do_one_initcall+0x250/0x870 init/main.c:1360
do_initcall_level+0x10a/0x1a0 init/main.c:1422
do_initcalls+0x59/0xa0 init/main.c:1438
kernel_init_freeable+0x29d/0x3e0 init/main.c:1673
kernel_init+0x22/0x1d0 init/main.c:1563
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing
Memory state around the buggy address:
ffff88802600c180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802600c200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802600c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802600c300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802600c380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
Tested on:
commit: f0406245 Add linux-next specific files for 20261002
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16672ec9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=dfd189b706ddeebe
dashboard link: https://syzkaller.appspot.com/bug?extid=46bbbe175b7eea8036b8
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=13bad035580000
next parent reply other threads:[~2026-10-03 11:48 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20261003110632.121743-1-nsvatoslav515@gmail.com>
2026-10-03 11:48 ` syzbot [this message]
[not found] <20261003131345.4325-1-nsvatoslav515@gmail.com>
2026-10-03 15:47 ` syzbot
[not found] <20261003130520.3743-1-nsvatoslav515@gmail.com>
2026-10-03 14:41 ` syzbot
2026-10-01 23:29 syzbot
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