================================================================== BUG: KASAN: slab-use-after-free in __mutex_waiter_is_first kernel/locking/mutex.c:182 [inline] BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:680 [inline] BUG: KASAN: slab-use-after-free in __mutex_lock+0xa65/0xb90 kernel/locking/mutex.c:746 Read of size 8 at addr ffff88805afc1b20 by task kworker/2:4/6016 CPU: 2 UID: 0 PID: 6016 Comm: kworker/2:4 Not tainted 6.15.0-rc7-syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Workqueue: events l2cap_chan_timeout Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xc3/0x670 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 __mutex_waiter_is_first kernel/locking/mutex.c:182 [inline] __mutex_lock_common kernel/locking/mutex.c:680 [inline] __mutex_lock+0xa65/0xb90 kernel/locking/mutex.c:746 l2cap_chan_timeout+0x6d/0x310 net/bluetooth/l2cap_core.c:417 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 11696: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] l2cap_conn_add.part.0+0x60/0xa60 net/bluetooth/l2cap_core.c:6861 l2cap_conn_add include/net/bluetooth/hci_core.h:1637 [inline] l2cap_chan_connect+0x15e5/0x2020 net/bluetooth/l2cap_core.c:7052 bt_6lowpan_connect net/bluetooth/6lowpan.c:900 [inline] lowpan_control_write+0x3c9/0x740 net/bluetooth/6lowpan.c:1135 full_proxy_write+0x13f/0x200 fs/debugfs/file.c:398 vfs_write+0x25c/0x1180 fs/read_write.c:682 ksys_write+0x12a/0x240 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 12855: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2380 [inline] slab_free mm/slub.c:4642 [inline] kfree+0x2b6/0x4d0 mm/slub.c:4841 l2cap_conn_free net/bluetooth/l2cap_core.c:1810 [inline] kref_put include/linux/kref.h:65 [inline] l2cap_conn_put net/bluetooth/l2cap_core.c:1822 [inline] l2cap_conn_del+0x59c/0x730 net/bluetooth/l2cap_core.c:1802 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:7300 [inline] l2cap_disconn_cfm+0x96/0xd0 net/bluetooth/l2cap_core.c:7293 hci_disconn_cfm include/net/bluetooth/hci_core.h:2068 [inline] hci_conn_hash_flush+0x10e/0x260 net/bluetooth/hci_conn.c:2534 hci_dev_close_sync+0x602/0x11d0 net/bluetooth/hci_sync.c:5225 hci_dev_do_close+0x2e/0x90 net/bluetooth/hci_core.c:483 hci_dev_close+0x183/0x1e0 net/bluetooth/hci_core.c:508 hci_sock_ioctl+0x2b3/0x7d0 net/bluetooth/hci_sock.c:1128 sock_do_ioctl+0x115/0x280 net/socket.c:1190 sock_ioctl+0x227/0x6b0 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88805afc1800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 800 bytes inside of freed 1024-byte region [ffff88805afc1800, ffff88805afc1c00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5afc0 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 ffff88801b442dc0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b442dc0 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea00016bf001 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 11465, tgid 11463 (syz.2.1600), ts 192065421322, free_ts 192019882239 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1714 prep_new_page mm/page_alloc.c:1722 [inline] get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3684 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4966 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2450 [inline] allocate_slab mm/slub.c:2618 [inline] new_slab+0x244/0x340 mm/slub.c:2672 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948 __slab_alloc_node mm/slub.c:4023 [inline] slab_alloc_node mm/slub.c:4184 [inline] __do_kmalloc_node mm/slub.c:4326 [inline] __kmalloc_node_noprof+0x2ed/0x500 mm/slub.c:4333 kmalloc_node_noprof include/linux/slab.h:932 [inline] qdisc_alloc+0xbb/0xc50 net/sched/sch_generic.c:947 qdisc_create_dflt+0x73/0x430 net/sched/sch_generic.c:1009 taprio_init+0x48f/0x910 net/sched/sch_taprio.c:2093 qdisc_create+0x457/0xfa0 net/sched/sch_api.c:1332 __tc_modify_qdisc net/sched/sch_api.c:1757 [inline] tc_modify_qdisc+0x1287/0x2100 net/sched/sch_api.c:1821 rtnetlink_rcv_msg+0x3c6/0xe90 net/core/rtnetlink.c:6964 netlink_rcv_skb+0x16a/0x440 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x53d/0x7f0 net/netlink/af_netlink.c:1339 page last free pid 11465 tgid 11463 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1258 [inline] __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2721 discard_slab mm/slub.c:2716 [inline] __put_partials+0x16d/0x1c0 mm/slub.c:3185 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4147 [inline] slab_alloc_node mm/slub.c:4196 [inline] kmem_cache_alloc_node_noprof+0x1d5/0x3b0 mm/slub.c:4248 __alloc_skb+0x2b2/0x380 net/core/skbuff.c:658 alloc_skb include/linux/skbuff.h:1340 [inline] nlmsg_new include/net/netlink.h:1019 [inline] netlink_ack+0x15d/0xb80 net/netlink/af_netlink.c:2471 netlink_rcv_skb+0x347/0x440 net/netlink/af_netlink.c:2540 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x53d/0x7f0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0xa95/0xc70 net/socket.c:2566 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620 __sys_sendmsg+0x16d/0x220 net/socket.c:2652 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88805afc1a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805afc1a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88805afc1b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88805afc1b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805afc1c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================