================================================================== BUG: KASAN: slab-use-after-free in hci_chan_del+0x3b/0x1b0 net/bluetooth/hci_conn.c:2853 Read of size 8 at addr ffff888026f93218 by task syz.5.1675/12064 CPU: 1 UID: 0 PID: 12064 Comm: syz.5.1675 Not tainted 6.14.0-rc1-next-20250207-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x169/0x550 mm/kasan/report.c:489 kasan_report+0x143/0x180 mm/kasan/report.c:602 hci_chan_del+0x3b/0x1b0 net/bluetooth/hci_conn.c:2853 l2cap_conn_free net/bluetooth/l2cap_core.c:1816 [inline] kref_put include/linux/kref.h:65 [inline] l2cap_conn_put+0x70/0xe0 net/bluetooth/l2cap_core.c:1830 l2cap_sock_shutdown+0xa8a/0x1020 net/bluetooth/l2cap_sock.c:1377 l2cap_sock_release+0x79/0x1d0 net/bluetooth/l2cap_sock.c:1416 __sock_release net/socket.c:647 [inline] sock_close+0xbc/0x240 net/socket.c:1398 __fput+0x3e9/0x9f0 fs/file_table.c:464 task_work_run+0x24f/0x310 kernel/task_work.c:227 get_signal+0x15f7/0x1750 kernel/signal.c:2809 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe76ef8cde9 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:00007fe76fe88038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: fffffffffffffffc RBX: 00007fe76f1a5fa0 RCX: 00007fe76ef8cde9 RDX: 000000000000000e RSI: 0000200000000080 RDI: 0000000000000004 RBP: 00007fe76f00e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fe76f1a5fa0 R15: 00007ffc39eecc78 Allocated by task 12064: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4339 kmalloc_noprof include/linux/slab.h:902 [inline] kzalloc_noprof include/linux/slab.h:1038 [inline] hci_chan_create+0xc8/0x310 net/bluetooth/hci_conn.c:2838 l2cap_conn_add+0x69/0x8e0 net/bluetooth/l2cap_core.c:6864 l2cap_chan_connect+0x623/0xeb0 net/bluetooth/l2cap_core.c:7059 l2cap_sock_connect+0x5c9/0x800 net/bluetooth/l2cap_sock.c:256 __sys_connect_file net/socket.c:2045 [inline] __sys_connect+0x288/0x2d0 net/socket.c:2064 __do_sys_connect net/socket.c:2070 [inline] __se_sys_connect net/socket.c:2067 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:2067 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5836: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2367 [inline] slab_free mm/slub.c:4623 [inline] kfree+0x196/0x430 mm/slub.c:4816 hci_chan_list_flush net/bluetooth/hci_conn.c:2878 [inline] hci_conn_cleanup net/bluetooth/hci_conn.c:149 [inline] hci_conn_del+0x4b5/0xc40 net/bluetooth/hci_conn.c:1164 hci_conn_failed+0x319/0x400 net/bluetooth/hci_conn.c:1267 hci_abort_conn_sync+0x56c/0x11f0 net/bluetooth/hci_sync.c:5588 hci_cmd_sync_work+0x22b/0x400 net/bluetooth/hci_sync.c:332 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317 worker_thread+0x870/0xd30 kernel/workqueue.c:3398 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 The buggy address belongs to the object at ffff888026f93200 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 24 bytes inside of freed 128-byte region [ffff888026f93200, ffff888026f93280) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26f93 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801ac41a00 ffffea000184fd80 dead000000000002 raw: 0000000000000000 0000000000100010 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 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 5957, tgid 5957 (syz.4.16), ts 101532936605, free_ts 101531888991 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1629 prep_new_page mm/page_alloc.c:1637 [inline] get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3555 __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4817 alloc_slab_page mm/slub.c:2439 [inline] allocate_slab+0x66/0x3a0 mm/slub.c:2601 new_slab mm/slub.c:2654 [inline] ___slab_alloc+0xc27/0x14a0 mm/slub.c:3840 __slab_alloc+0x58/0xa0 mm/slub.c:3930 __slab_alloc_node mm/slub.c:4005 [inline] slab_alloc_node mm/slub.c:4166 [inline] __do_kmalloc_node mm/slub.c:4307 [inline] __kmalloc_node_noprof+0x2ee/0x4d0 mm/slub.c:4314 kmalloc_array_node_noprof include/linux/slab.h:1019 [inline] alloc_slab_obj_exts+0x3a/0xa0 mm/slub.c:1965 __memcg_slab_post_alloc_hook+0x319/0x7e0 mm/memcontrol.c:3016 memcg_slab_post_alloc_hook mm/slub.c:2166 [inline] slab_post_alloc_hook mm/slub.c:4139 [inline] slab_alloc_node mm/slub.c:4178 [inline] kmem_cache_alloc_noprof+0x287/0x380 mm/slub.c:4185 anon_vma_alloc mm/rmap.c:94 [inline] __anon_vma_prepare+0x117/0x4a0 mm/rmap.c:202 __vmf_anon_prepare mm/memory.c:3432 [inline] vmf_anon_prepare mm/internal.h:372 [inline] do_anonymous_page mm/memory.c:4922 [inline] do_pte_missing mm/memory.c:4090 [inline] handle_pte_fault mm/memory.c:5936 [inline] __handle_mm_fault+0x617e/0x70f0 mm/memory.c:6079 handle_mm_fault+0x3e5/0x8d0 mm/memory.c:6248 do_user_addr_fault arch/x86/mm/fault.c:1337 [inline] handle_page_fault arch/x86/mm/fault.c:1480 [inline] exc_page_fault+0x459/0x8b0 arch/x86/mm/fault.c:1538 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 page last free pid 5959 tgid 5957 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1205 [inline] free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2738 rcu_do_batch kernel/rcu/tree.c:2546 [inline] rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2802 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561 __do_softirq kernel/softirq.c:595 [inline] invoke_softirq kernel/softirq.c:435 [inline] __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x57/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 Memory state around the buggy address: ffff888026f93100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888026f93180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888026f93200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888026f93280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888026f93300: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc 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