[syzbot] [bluetooth?] KASAN: slab-use-after-free Read in mgmt_pending_remove

[syzbot <syzbot+9aa47cd4633a3cf92a80@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    4001bda0cc91 Merge branch 'selftests-vsock-refactor-and-im..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17f2897c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4dda49799a90cd0f
dashboard link: https://syzkaller.appspot.com/bug?extid=9aa47cd4633a3cf92a80
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11a21c12580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f1a9e5dda198/disk-4001bda0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e0d7f0aa5468/vmlinux-4001bda0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9cef7d2ebe50/bzImage-4001bda0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9aa47cd4633a3cf92a80@syzkaller.appspotmail.com

RAX: ffffffffffffffda RBX: 00007f5543fe5fa0 RCX: 00007f5543d8f6c9
RDX: 0000000000000007 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007f5544b69090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f5543fe6038 R14: 00007f5543fe5fa0 R15: 00007ffe72e0a568
 </TASK>
Bluetooth: hci0: no memory for command
==================================================================
BUG: KASAN: slab-use-after-free in mgmt_pending_remove+0x3b/0x210 net/bluetooth/mgmt_util.c:316
Read of size 8 at addr ffff888077164818 by task syz.0.17/5989

CPU: 0 UID: 0 PID: 5989 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 mgmt_pending_remove+0x3b/0x210 net/bluetooth/mgmt_util.c:316
 set_link_security+0x5c2/0x710 net/bluetooth/mgmt.c:1918
 hci_mgmt_cmd+0x9c9/0xef0 net/bluetooth/hci_sock.c:1719
 hci_sock_sendmsg+0x6ca/0xef0 net/bluetooth/hci_sock.c:1839
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 sock_write_iter+0x279/0x360 net/socket.c:1195
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5c9/0xb30 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5543d8f6c9
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:00007f5544b69038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5543fe5fa0 RCX: 00007f5543d8f6c9
RDX: 0000000000000007 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007f5544b69090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f5543fe6038 R14: 00007f5543fe5fa0 R15: 00007ffe72e0a568
 </TASK>

Allocated by task 5989:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __kmalloc_cache_noprof+0x3d5/0x6f0 mm/slub.c:5763
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 mgmt_pending_new+0x65/0x1e0 net/bluetooth/mgmt_util.c:269
 mgmt_pending_add+0x35/0x140 net/bluetooth/mgmt_util.c:296
 set_link_security+0x557/0x710 net/bluetooth/mgmt.c:1910
 hci_mgmt_cmd+0x9c9/0xef0 net/bluetooth/hci_sock.c:1719
 hci_sock_sendmsg+0x6ca/0xef0 net/bluetooth/hci_sock.c:1839
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 sock_write_iter+0x279/0x360 net/socket.c:1195
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5c9/0xb30 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5991:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587
 kasan_save_free_info mm/kasan/kasan.h:406 [inline]
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2539 [inline]
 slab_free mm/slub.c:6630 [inline]
 kfree+0x19a/0x6d0 mm/slub.c:6837
 mgmt_pending_free net/bluetooth/mgmt_util.c:311 [inline]
 mgmt_pending_foreach+0x30d/0x380 net/bluetooth/mgmt_util.c:257
 mgmt_index_removed+0x112/0x2f0 net/bluetooth/mgmt.c:9477
 hci_sock_bind+0xbe9/0x1000 net/bluetooth/hci_sock.c:1314
 __sys_bind_socket net/socket.c:1874 [inline]
 __sys_bind+0x2c6/0x3e0 net/socket.c:1905
 __do_sys_bind net/socket.c:1910 [inline]
 __se_sys_bind net/socket.c:1908 [inline]
 __x64_sys_bind+0x7a/0x90 net/socket.c:1908
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888077164800
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 24 bytes inside of
 freed 96-byte region [ffff888077164800, ffff888077164860)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x77164
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801a026280 dead000000000122 0000000000000000
raw: 0000000000000000 0000000080200020 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 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1098, tgid 1098 (kworker/u8:6), ts 87994876358, free_ts 87976357652
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3055 [inline]
 allocate_slab+0x96/0x350 mm/slub.c:3228
 new_slab mm/slub.c:3282 [inline]
 ___slab_alloc+0xe94/0x18a0 mm/slub.c:4651
 __slab_alloc+0x65/0x100 mm/slub.c:4770
 __slab_alloc_node mm/slub.c:4846 [inline]
 slab_alloc_node mm/slub.c:5268 [inline]
 __kmalloc_cache_noprof+0x411/0x6f0 mm/slub.c:5758
 kmalloc_noprof include/linux/slab.h:957 [inline]
 dst_cow_metrics_generic+0x56/0x1c0 net/core/dst.c:193
 dst_metrics_write_ptr include/net/dst.h:136 [inline]
 dst_metric_set include/net/dst.h:197 [inline]
 icmp6_dst_alloc+0x264/0x420 net/ipv6/route.c:3335
 ndisc_send_skb+0x3f1/0x1510 net/ipv6/ndisc.c:491
 ndisc_send_ns+0xcb/0x150 net/ipv6/ndisc.c:670
 addrconf_dad_work+0xaae/0x14b0 net/ipv6/addrconf.c:4282
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
page last free pid 1113 tgid 1113 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2906
 __slab_free+0x2e7/0x390 mm/slub.c:5962
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4970 [inline]
 slab_alloc_node mm/slub.c:5280 [inline]
 kmem_cache_alloc_node_noprof+0x433/0x710 mm/slub.c:5332
 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:664
 alloc_skb include/linux/skbuff.h:1383 [inline]
 nlmsg_new include/net/netlink.h:1055 [inline]
 nl80211_send_ibss_bssid+0x8d/0x430 net/wireless/nl80211.c:19952
 __cfg80211_ibss_joined+0x34a/0x440 net/wireless/ibss.c:50
 cfg80211_process_wdev_events+0x38a/0x4f0 net/wireless/util.c:1143
 cfg80211_process_rdev_events+0xa1/0x110 net/wireless/util.c:1170
 cfg80211_event_work+0x31/0x70 net/wireless/core.c:334
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158

Memory state around the buggy address:
 ffff888077164700: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
 ffff888077164780: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
>ffff888077164800: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                            ^
 ffff888077164880: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
 ffff888077164900: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
==================================================================


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