From: syzbot <syzbot+f20755f37da70df33a16@syzkaller.appspotmail.com>
To: hdanton@sina.com, igorpetindev@gmail.com,
linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org,
luiz.dentz@gmail.com, marcel@holtmann.org,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in mesh_send_sync
Date: Sun, 15 Nov 2026 02:58:23 -0800 [thread overview]
Message-ID: <6af9904f.84fe3b82.798c4.0000.GAE@google.com> (raw)
In-Reply-To: <6ac5b02e.fe639fcc.32b100.000f.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 23c62304dde2 Merge tag 'for-linus-7.4a-rc3-tag' of git://g..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=17227da1580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c210800cfc8f61e
dashboard link: https://syzkaller.appspot.com/bug?extid=f20755f37da70df33a16
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
userspace arch: i386
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13ceb769580000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f20755f37da70df33a16@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in mesh_send_sync+0x3d9/0x430 net/bluetooth/mgmt.c:2343
Read of size 1 at addr ffff88804f72623b by task kworker/u34:0/67
CPU: 3 UID: 0 PID: 67 Comm: kworker/u34:0 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
Workqueue: hci0 hci_cmd_sync_work
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
mesh_send_sync+0x3d9/0x430 net/bluetooth/mgmt.c:2343
hci_cmd_sync_work+0x1b6/0x4c0 net/bluetooth/hci_sync.c:338
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3495
process_scheduled_works kernel/workqueue.c:3578 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Allocated by task 6696:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:409 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:426
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x2f8/0x6d0 mm/slub.c:5680
_kmalloc_noprof include/linux/slab.h:991 [inline]
_kzalloc_noprof include/linux/slab.h:1312 [inline]
mgmt_mesh_add+0x54/0x410 net/bluetooth/mgmt_util.c:413
mesh_send+0x2b4/0x770 net/bluetooth/mgmt.c:2536
hci_mgmt_cmd net/bluetooth/hci_sock.c:1739 [inline]
hci_sock_sendmsg+0x159f/0x26f0 net/bluetooth/hci_sock.c:1859
sock_sendmsg_nosec net/socket.c:800 [inline]
__sock_sendmsg net/socket.c:818 [inline]
__sys_sendto+0x492/0x4e0 net/socket.c:2283
__do_sys_sendto net/socket.c:2290 [inline]
__se_sys_sendto net/socket.c:2286 [inline]
__ia32_sys_sendto+0xdd/0x1b0 net/socket.c:2286
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
__do_fast_syscall_32+0x14d/0x8e0 arch/x86/entry/syscall_32.c:286
do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:311
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
Freed by task 67:
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:264 [inline]
__kasan_slab_free+0x5f/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+0x22b/0x6d0 mm/slub.c:6923
mesh_send_complete net/bluetooth/mgmt.c:1095 [inline]
mesh_send_start_complete+0x1a1/0x210 net/bluetooth/mgmt.c:2319
hci_cmd_sync_work+0x20a/0x4c0 net/bluetooth/hci_sync.c:340
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3495
process_scheduled_works kernel/workqueue.c:3578 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
The buggy address belongs to the object at ffff88804f726200
which belongs to the cache kmalloc-96 of size 96
The buggy address is located 59 bytes inside of
freed 96-byte region [ffff88804f726200, ffff88804f726260)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88804f726c80 pfn:0x4f726
flags: 0x4fff00000000200(workingset|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000200 ffff88801d442280 ffffea000114bb10 ffffea000105ef90
raw: ffff88804f726c80 000000000020001e 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 37, tgid 37 (kworker/u33:0), ts 11020237037
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1860
prep_new_page mm/page_alloc.c:1868 [inline]
get_page_from_freelist+0xdae/0x2c80 mm/page_alloc.c:3950
__alloc_frozen_pages_noprof+0x2ad/0x31e0 mm/page_alloc.c:5492
alloc_slab_page mm/slub.c:3384 [inline]
allocate_slab mm/slub.c:3499 [inline]
new_slab+0xb1/0x6d0 mm/slub.c:3550
refill_objects+0xe3/0x410 mm/slub.c:7539
refill_sheaf mm/slub.c:2917 [inline]
__pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4811
alloc_from_pcs mm/slub.c:4887 [inline]
slab_alloc_node mm/slub.c:5021 [inline]
__kmalloc_cache_node_noprof+0x517/0x710 mm/slub.c:5695
_kmalloc_node_noprof include/linux/slab.h:1196 [inline]
__get_vm_area_node+0x124/0x350 mm/vmalloc.c:3270
__vmalloc_node_range_noprof+0x2ad/0x1440 mm/vmalloc.c:4112
__vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4213
alloc_thread_stack_node kernel/fork.c:359 [inline]
dup_task_struct kernel/fork.c:931 [inline]
copy_process+0x80b/0x88e0 kernel/fork.c:2150
kernel_clone+0x176/0x9d0 kernel/fork.c:2798
user_mode_thread+0xd1/0x120 kernel/fork.c:2875
call_usermodehelper_exec_work kernel/umh.c:169 [inline]
call_usermodehelper_exec_work+0xcb/0x180 kernel/umh.c:155
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3495
process_scheduled_works kernel/workqueue.c:3578 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659
page last free pid 37 tgid 37 ts 11020040140 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1402 [inline]
__free_frozen_pages+0x7b1/0x10f0 mm/page_alloc.c:2958
___free_pages_bulk mm/kasan/shadow.c:333 [inline]
__kasan_populate_vmalloc_do mm/kasan/shadow.c:385 [inline]
__kasan_populate_vmalloc+0x164/0x210 mm/kasan/shadow.c:424
kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
alloc_vmap_area+0x963/0x2bc0 mm/vmalloc.c:2151
__get_vm_area_node+0x1ed/0x350 mm/vmalloc.c:3281
__vmalloc_node_range_noprof+0x2ad/0x1440 mm/vmalloc.c:4112
__vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4213
alloc_thread_stack_node kernel/fork.c:359 [inline]
dup_task_struct kernel/fork.c:931 [inline]
copy_process+0x80b/0x88e0 kernel/fork.c:2150
kernel_clone+0x176/0x9d0 kernel/fork.c:2798
user_mode_thread+0xd1/0x120 kernel/fork.c:2875
call_usermodehelper_exec_work kernel/umh.c:169 [inline]
call_usermodehelper_exec_work+0xcb/0x180 kernel/umh.c:155
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3495
process_scheduled_works kernel/workqueue.c:3578 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Memory state around the buggy address:
ffff88804f726100: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
ffff88804f726180: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
>ffff88804f726200: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
^
ffff88804f726280: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
ffff88804f726300: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
==================================================================
next prev parent reply other threads:[~2026-11-15 10:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-07 2:36 syzbot
2026-11-15 10:58 ` syzbot [this message]
2026-10-15 0:38 [PATCH] Bluetooth: mgmt: Fix UAF in mesh_send_sync caused by race in mesh queue Hillf Danton
2026-10-15 0:58 ` [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in mesh_send_sync syzbot
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