[v6.6] KASAN: slab-use-after-free Read in skb_queue_purge_reason
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syzbot
Jun 21, 2025, 4:51:24 AM6/21/25
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 6282921b6825 Linux 6.6.94
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17ffd370580000
kernel config: https://syzkaller.appspot.com/x/.config?x=96da6b2210cda427
dashboard link: https://syzkaller.appspot.com/bug?extid=a2f50896f15927de15b2
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a3bf0d8e22b2/disk-6282921b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1d442f782d0/vmlinux-6282921b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8378f4b7e1b/bzImage-6282921b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a2f508...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in __lock_acquire+0xff/0x7c80 kernel/locking/lockdep.c:5005
Read of size 8 at addr ffff888141261088 by task syz.3.2529/12100
CPU: 1 PID: 12100 Comm: syz.3.2529 Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:364 [inline]
print_report+0xac/0x230 mm/kasan/report.c:475
kasan_report+0x117/0x150 mm/kasan/report.c:588
__lock_acquire+0xff/0x7c80 kernel/locking/lockdep.c:5005
lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162
skb_dequeue net/core/skbuff.c:3693 [inline]
skb_queue_purge_reason+0x36/0x1c0 net/core/skbuff.c:3734
skb_queue_purge include/linux/skbuff.h:3203 [inline]
vhci_flush+0x44/0x50 drivers/bluetooth/hci_vhci.c:69
hci_dev_do_reset net/bluetooth/hci_core.c:574 [inline]
hci_dev_reset+0x44f/0x610 net/bluetooth/hci_core.c:614
sock_do_ioctl+0xd7/0x2f0 net/socket.c:1222
sock_ioctl+0x623/0x7a0 net/socket.c:1341
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f36bf58e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f36bf3ff038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f36bf7b5fa0 RCX: 00007f36bf58e929
RDX: 0000000000000000 RSI: 00000000400448cb RDI: 0000000000000009
RBP: 00007f36bf610b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f36bf7b5fa0 R15: 00007ffd550a7e58
</TASK>
Allocated by task 5768:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:374 [inline]
__kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:721 [inline]
vhci_open+0x57/0x360 drivers/bluetooth/hci_vhci.c:636
misc_open+0x2f9/0x370 drivers/char/misc.c:179
chrdev_open+0x59e/0x670 fs/char_dev.c:414
do_dentry_open+0x8c6/0x1500 fs/open.c:929
do_open fs/namei.c:3632 [inline]
path_openat+0x274b/0x3190 fs/namei.c:3789
do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
do_sys_open fs/open.c:1434 [inline]
__do_sys_openat fs/open.c:1450 [inline]
__se_sys_openat fs/open.c:1445 [inline]
__x64_sys_openat+0x139/0x160 fs/open.c:1445
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Freed by task 5768:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1806 [inline]
slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1832
slab_free mm/slub.c:3816 [inline]
__kmem_cache_free+0xba/0x1f0 mm/slub.c:3829
vhci_release+0xbf/0xd0 drivers/bluetooth/hci_vhci.c:672
__fput+0x234/0x970 fs/file_table.c:384
task_work_run+0x1ce/0x250 kernel/task_work.c:239
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0x903/0x23c0 kernel/exit.c:874
do_group_exit+0x21b/0x2d0 kernel/exit.c:1023
get_signal+0x12fc/0x1400 kernel/signal.c:2902
arch_do_signal_or_restart+0x96/0x780 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
The buggy address belongs to the object at ffff888141261000
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 136 bytes inside of
freed 1024-byte region [ffff888141261000, ffff888141261400)
The buggy address belongs to the physical page:
page:ffffea0005049800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x141260
head:ffffea0005049800 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000840(slab|head|node=1|zone=2|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 057ff00000000840 ffff888017841dc0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x52000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 0, tgid 0 (swapper/0), ts 1864618578, free_ts 0
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
prep_new_page mm/page_alloc.c:1561 [inline]
get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
__alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2120
alloc_slab_page+0x5d/0x170 mm/slub.c:1876
allocate_slab mm/slub.c:2023 [inline]
new_slab+0x87/0x2e0 mm/slub.c:2076
___slab_alloc+0xc6d/0x12f0 mm/slub.c:3230
__slab_alloc mm/slub.c:3329 [inline]
__slab_alloc_node mm/slub.c:3382 [inline]
slab_alloc_node mm/slub.c:3475 [inline]
__kmem_cache_alloc_node+0x1a2/0x260 mm/slub.c:3524
kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:721 [inline]
kernfs_create_root+0x5e/0x690 fs/kernfs/dir.c:967
cgroup_setup_root+0x26e/0xb30 kernel/cgroup/cgroup.c:2074
cgroup_init+0x19f/0xc50 kernel/cgroup/cgroup.c:6091
start_kernel+0x440/0x4e0 init/main.c:1065
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
copy_bootdata+0x0/0xe0 arch/x86/kernel/head64.c:536
secondary_startup_64_no_verify+0x179/0x17b
page_owner free stack trace missing
Memory state around the buggy address:
ffff888141260f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888141261000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888141261080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888141261100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888141261180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 6282921b6825 Linux 6.6.94
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17ffd370580000
kernel config: https://syzkaller.appspot.com/x/.config?x=96da6b2210cda427
dashboard link: https://syzkaller.appspot.com/bug?extid=a2f50896f15927de15b2
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a3bf0d8e22b2/disk-6282921b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1d442f782d0/vmlinux-6282921b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8378f4b7e1b/bzImage-6282921b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a2f508...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in __lock_acquire+0xff/0x7c80 kernel/locking/lockdep.c:5005
Read of size 8 at addr ffff888141261088 by task syz.3.2529/12100
CPU: 1 PID: 12100 Comm: syz.3.2529 Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:364 [inline]
print_report+0xac/0x230 mm/kasan/report.c:475
kasan_report+0x117/0x150 mm/kasan/report.c:588
__lock_acquire+0xff/0x7c80 kernel/locking/lockdep.c:5005
lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162
skb_dequeue net/core/skbuff.c:3693 [inline]
skb_queue_purge_reason+0x36/0x1c0 net/core/skbuff.c:3734
skb_queue_purge include/linux/skbuff.h:3203 [inline]
vhci_flush+0x44/0x50 drivers/bluetooth/hci_vhci.c:69
hci_dev_do_reset net/bluetooth/hci_core.c:574 [inline]
hci_dev_reset+0x44f/0x610 net/bluetooth/hci_core.c:614
sock_do_ioctl+0xd7/0x2f0 net/socket.c:1222
sock_ioctl+0x623/0x7a0 net/socket.c:1341
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f36bf58e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f36bf3ff038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f36bf7b5fa0 RCX: 00007f36bf58e929
RDX: 0000000000000000 RSI: 00000000400448cb RDI: 0000000000000009
RBP: 00007f36bf610b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f36bf7b5fa0 R15: 00007ffd550a7e58
</TASK>
Allocated by task 5768:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:374 [inline]
__kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:721 [inline]
vhci_open+0x57/0x360 drivers/bluetooth/hci_vhci.c:636
misc_open+0x2f9/0x370 drivers/char/misc.c:179
chrdev_open+0x59e/0x670 fs/char_dev.c:414
do_dentry_open+0x8c6/0x1500 fs/open.c:929
do_open fs/namei.c:3632 [inline]
path_openat+0x274b/0x3190 fs/namei.c:3789
do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
do_sys_open fs/open.c:1434 [inline]
__do_sys_openat fs/open.c:1450 [inline]
__se_sys_openat fs/open.c:1445 [inline]
__x64_sys_openat+0x139/0x160 fs/open.c:1445
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Freed by task 5768:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1806 [inline]
slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1832
slab_free mm/slub.c:3816 [inline]
__kmem_cache_free+0xba/0x1f0 mm/slub.c:3829
vhci_release+0xbf/0xd0 drivers/bluetooth/hci_vhci.c:672
__fput+0x234/0x970 fs/file_table.c:384
task_work_run+0x1ce/0x250 kernel/task_work.c:239
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0x903/0x23c0 kernel/exit.c:874
do_group_exit+0x21b/0x2d0 kernel/exit.c:1023
get_signal+0x12fc/0x1400 kernel/signal.c:2902
arch_do_signal_or_restart+0x96/0x780 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
The buggy address belongs to the object at ffff888141261000
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 136 bytes inside of
freed 1024-byte region [ffff888141261000, ffff888141261400)
The buggy address belongs to the physical page:
page:ffffea0005049800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x141260
head:ffffea0005049800 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000840(slab|head|node=1|zone=2|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 057ff00000000840 ffff888017841dc0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x52000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 0, tgid 0 (swapper/0), ts 1864618578, free_ts 0
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
prep_new_page mm/page_alloc.c:1561 [inline]
get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
__alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2120
alloc_slab_page+0x5d/0x170 mm/slub.c:1876
allocate_slab mm/slub.c:2023 [inline]
new_slab+0x87/0x2e0 mm/slub.c:2076
___slab_alloc+0xc6d/0x12f0 mm/slub.c:3230
__slab_alloc mm/slub.c:3329 [inline]
__slab_alloc_node mm/slub.c:3382 [inline]
slab_alloc_node mm/slub.c:3475 [inline]
__kmem_cache_alloc_node+0x1a2/0x260 mm/slub.c:3524
kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:721 [inline]
kernfs_create_root+0x5e/0x690 fs/kernfs/dir.c:967
cgroup_setup_root+0x26e/0xb30 kernel/cgroup/cgroup.c:2074
cgroup_init+0x19f/0xc50 kernel/cgroup/cgroup.c:6091
start_kernel+0x440/0x4e0 init/main.c:1065
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
copy_bootdata+0x0/0xe0 arch/x86/kernel/head64.c:536
secondary_startup_64_no_verify+0x179/0x17b
page_owner free stack trace missing
Memory state around the buggy address:
ffff888141260f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888141261000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888141261080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888141261100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888141261180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot
Sep 29, 2025, 4:51:19 AM9/29/25
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
Crashes did not happen for a while, no reproducer and no activity.
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