syzbot

==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: slab-use-after-free in atomic_long_read include/linux/atomic/atomic-instrumented.h:3188 [inline]
BUG: KASAN: slab-use-after-free in __mutex_unlock_slowpath+0xd4/0x700 kernel/locking/mutex.c:918
Read of size 8 at addr ffff88807dfd42d0 by task kworker/1:0/24

CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0 Not tainted 6.16.0-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events l2cap_chan_timeout
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
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 atomic_long_read include/linux/atomic/atomic-instrumented.h:3188 [inline]
 __mutex_unlock_slowpath+0xd4/0x700 kernel/locking/mutex.c:918
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 9191:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 l2cap_conn_add+0xaa/0x8d0 net/bluetooth/l2cap_core.c:6886
 l2cap_chan_connect+0x6c8/0xe30 net/bluetooth/l2cap_core.c:7077
 l2cap_sock_connect+0x5c5/0x7a0 net/bluetooth/l2cap_sock.c:256
 kernel_connect+0x116/0x180 net/socket.c:3608
 rfcomm_session_create net/bluetooth/rfcomm/core.c:811 [inline]
 __rfcomm_dlc_open net/bluetooth/rfcomm/core.c:388 [inline]
 rfcomm_dlc_open+0x8fe/0xed0 net/bluetooth/rfcomm/core.c:431
 rfcomm_sock_connect+0x2f7/0x610 net/bluetooth/rfcomm/sock.c:409
 __sys_connect_file net/socket.c:2038 [inline]
 __sys_connect+0x316/0x440 net/socket.c:2057
 __do_sys_connect net/socket.c:2063 [inline]
 __se_sys_connect net/socket.c:2060 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2060
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5838:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x18e/0x440 mm/slub.c:4842
 hci_disconn_cfm include/net/bluetooth/hci_core.h:2074 [inline]
 hci_conn_hash_flush+0x10d/0x230 net/bluetooth/hci_conn.c:2560
 hci_dev_close_sync+0xaef/0x1330 net/bluetooth/hci_sync.c:5294
 hci_dev_do_close net/bluetooth/hci_core.c:501 [inline]
 hci_error_reset+0x127/0x3e0 net/bluetooth/hci_core.c:1034
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff88807dfd4000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 720 bytes inside of
 freed 1024-byte region [ffff88807dfd4000, ffff88807dfd4400)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7dfd0
head: order:3 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 ffff88801a441dc0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801a441dc0 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001f7f401 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 61, tgid 61 (kworker/u8:4), ts 198670135432, free_ts 198657878790
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21d5/0x22b0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2619
 new_slab mm/slub.c:2673 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3859
 __slab_alloc mm/slub.c:3949 [inline]
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_noprof+0x305/0x4f0 mm/slub.c:4340
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 ieee802_11_parse_elems_full+0x152/0x2aa0 net/mac80211/parse.c:1011
 ieee802_11_parse_elems_crc net/mac80211/ieee80211_i.h:2414 [inline]
 ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2421 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1569 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x462/0x2ae0 net/mac80211/ibss.c:1600
 ieee80211_iface_process_skb net/mac80211/iface.c:1670 [inline]
 ieee80211_iface_work+0x806/0xfe0 net/mac80211/iface.c:1724
 cfg80211_wiphy_work+0x2dc/0x460 net/wireless/core.c:435
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page last free pid 926 tgid 926 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0xc65/0xe60 mm/page_alloc.c:2706
 discard_slab mm/slub.c:2717 [inline]
 __put_partials+0x161/0x1c0 mm/slub.c:3186
 put_cpu_partial+0x17c/0x250 mm/slub.c:3261
 __slab_free+0x2f7/0x400 mm/slub.c:4513
 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:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0 mm/slub.c:4249
 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:660
 alloc_skb include/linux/skbuff.h:1336 [inline]
 mld_newpack+0x13c/0xc40 net/ipv6/mcast.c:1788
 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1899
 add_grec+0x13b2/0x1670 net/ipv6/mcast.c:2037
 mld_send_cr net/ipv6/mcast.c:2163 [inline]
 mld_ifc_work+0x6e6/0xde0 net/ipv6/mcast.c:2702
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464

Memory state around the buggy address:
 ffff88807dfd4180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807dfd4200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807dfd4280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff88807dfd4300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807dfd4380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================