From: syzbot <syzbot+baa24e4b7e349e388442@syzkaller.appspotmail.com>
To: code@tyhicks.com, ecryptfs@vger.kernel.org,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: [syzbot] [ecryptfs?] KASAN: slab-use-after-free Read in ecryptfs_destroy_mount_crypt_stat
Date: Wed, 16 Sep 2026 22:53:25 -0700 [thread overview]
Message-ID: <6aab8055.71f81b7d.278072.0015.GAE@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: 238650ef6c7c Merge tag 'powerpc-7.3-4' of git://git.kernel..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15684915580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8c5c3949d762a91f
dashboard link: https://syzkaller.appspot.com/bug?extid=baa24e4b7e349e388442
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13684915580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=122fdbf9580000
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-238650ef.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7608108a1c05/vmlinux-238650ef.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4d6d01769695/bzImage-238650ef.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+baa24e4b7e349e388442@syzkaller.appspotmail.com
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007f6210a25fac R14: 00007f6210a25fa0 R15: 00007f6210a25fa0
</TASK>
==================================================================
BUG: KASAN: slab-use-after-free in ecryptfs_destroy_mount_crypt_stat+0x28f/0x360 fs/ecryptfs/crypto.c:137
Read of size 4 at addr ffff88802b378610 by task syz.0.20/5927
CPU: 2 UID: 0 PID: 5927 Comm: syz.0.20 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
ecryptfs_destroy_mount_crypt_stat+0x28f/0x360 fs/ecryptfs/crypto.c:137
ecryptfs_get_tree+0x10b6/0x15b0 fs/ecryptfs/main.c:566
vfs_get_tree+0x92/0x320 fs/super.c:1933
fc_mount fs/namespace.c:1198 [inline]
do_new_mount_fc fs/namespace.c:3772 [inline]
do_new_mount fs/namespace.c:3848 [inline]
path_mount+0x7d0/0x24c0 fs/namespace.c:4168
do_mount fs/namespace.c:4181 [inline]
__do_sys_mount fs/namespace.c:4397 [inline]
__se_sys_mount fs/namespace.c:4374 [inline]
__x64_sys_mount+0x293/0x310 fs/namespace.c:4374
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f621079e159
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:00007fff0780ea08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f6210a25fa0 RCX: 00007f621079e159
RDX: 0000200000000480 RSI: 0000200000000000 RDI: 0000200000000400
RBP: 00007fff0780ea70 R08: 0000200000000500 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007f6210a25fac R14: 00007f6210a25fa0 R15: 00007f6210a25fa0
</TASK>
Allocated by task 5927:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4683 [inline]
slab_alloc_node mm/slub.c:4996 [inline]
kmem_cache_alloc_noprof+0x269/0x6a0 mm/slub.c:5010
ecryptfs_init_fs_context+0x6b/0x200 fs/ecryptfs/main.c:617
alloc_fs_context+0x60c/0xf40 fs/fs_context.c:295
do_new_mount fs/namespace.c:3828 [inline]
path_mount+0xdbd/0x24c0 fs/namespace.c:4168
do_mount fs/namespace.c:4181 [inline]
__do_sys_mount fs/namespace.c:4397 [inline]
__se_sys_mount fs/namespace.c:4374 [inline]
__x64_sys_mount+0x293/0x310 fs/namespace.c:4374
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 5927:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2748 [inline]
slab_free mm/slub.c:6508 [inline]
kmem_cache_free+0x127/0x6c0 mm/slub.c:6635
ecryptfs_kill_block_super+0x81/0xa0 fs/ecryptfs/main.c:586
deactivate_locked_super+0xbd/0x140 fs/super.c:589
ecryptfs_get_tree+0x10e9/0x15b0 fs/ecryptfs/main.c:563
vfs_get_tree+0x92/0x320 fs/super.c:1933
fc_mount fs/namespace.c:1198 [inline]
do_new_mount_fc fs/namespace.c:3772 [inline]
do_new_mount fs/namespace.c:3848 [inline]
path_mount+0x7d0/0x24c0 fs/namespace.c:4168
do_mount fs/namespace.c:4181 [inline]
__do_sys_mount fs/namespace.c:4397 [inline]
__se_sys_mount fs/namespace.c:4374 [inline]
__x64_sys_mount+0x293/0x310 fs/namespace.c:4374
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff88802b378600
which belongs to the cache ecryptfs_sb_cache of size 280
The buggy address is located 16 bytes inside of
freed 280-byte region [ffff88802b378600, ffff88802b378718)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b378
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 ffff888024ddadc0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000200150015 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff888024ddadc0 dead000000000100 dead000000000122
head: 0000000000000000 0000000200150015 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 5924, tgid 5924 (syz.0.17), ts 74770264892
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab mm/slub.c:3462 [inline]
new_slab+0xa9/0x6e0 mm/slub.c:3513
refill_objects+0xe3/0x410 mm/slub.c:7417
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
kmem_cache_alloc_noprof+0x4c4/0x6a0 mm/slub.c:5010
ecryptfs_init_fs_context+0x6b/0x200 fs/ecryptfs/main.c:617
alloc_fs_context+0x60c/0xf40 fs/fs_context.c:295
do_new_mount fs/namespace.c:3828 [inline]
path_mount+0xdbd/0x24c0 fs/namespace.c:4168
do_mount fs/namespace.c:4181 [inline]
__do_sys_mount fs/namespace.c:4397 [inline]
__se_sys_mount fs/namespace.c:4374 [inline]
__x64_sys_mount+0x293/0x310 fs/namespace.c:4374
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5862 tgid 5862 ts 74382051531 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
__free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4683 [inline]
slab_alloc_node mm/slub.c:4996 [inline]
kmem_cache_alloc_lru_noprof+0x265/0x6a0 mm/slub.c:5029
__d_alloc+0x35/0xa50 fs/dcache.c:1907
d_alloc+0x4a/0x1e0 fs/dcache.c:1986
lookup_one_qstr_excl+0x171/0x250 fs/namei.c:1806
__start_dirop fs/namei.c:2920 [inline]
start_dirop+0x59/0xb0 fs/namei.c:2942
simple_start_creating+0xf9/0x110 fs/libfs.c:2308
debugfs_start_creating.part.0+0x9f/0x180 fs/debugfs/inode.c:397
debugfs_start_creating fs/debugfs/inode.c:368 [inline]
__debugfs_create_file+0x86/0x4d0 fs/debugfs/inode.c:431
debugfs_create_file_full+0x41/0x60 fs/debugfs/inode.c:463
cfg80211_debugfs_rdev_add+0xce/0x250 net/wireless/debugfs.c:138
wiphy_register+0x242d/0x3110 net/wireless/core.c:1184
ieee80211_register_hw+0x3053/0x4580 net/mac80211/main.c:1626
Memory state around the buggy address:
ffff88802b378500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802b378580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802b378600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802b378680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802b378700: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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If the report is already addressed, let syzbot know by replying with:
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If you want syzbot to run the reproducer, reply with:
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next reply other threads:[~2026-09-17 5:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-17 5:53 syzbot [this message]
2026-09-17 9:01 ` Edward Adam Davis
2026-09-17 9:25 ` syzbot
2026-09-18 0:35 ` [PATCH] ecryptfs: reject destroy mount crypt stat if sb's active refer is 1 Edward Adam Davis
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