================================================================== BUG: KASAN: slab-use-after-free in force_devcd_write+0x317/0x330 drivers/bluetooth/hci_vhci.c:327 Read of size 8 at addr ffff88807dfa6000 by task syz.0.616/6717 CPU: 0 UID: 0 PID: 6717 Comm: syz.0.616 Not tainted 6.14.0-rc7-syzkaller-00069-g81e4f8d68c66 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 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+0xd9/0x110 mm/kasan/report.c:634 force_devcd_write+0x317/0x330 drivers/bluetooth/hci_vhci.c:327 full_proxy_write+0x13c/0x200 fs/debugfs/file.c:398 vfs_write+0x24c/0x1150 fs/read_write.c:677 ksys_write+0x12b/0x250 fs/read_write.c:731 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7efd1698d169 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:00007fff14c8bd58 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007efd16ba5fa0 RCX: 00007efd1698d169 RDX: 000000000000000e RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007efd16a0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007efd16ba5fa0 R14: 00007efd16ba5fa0 R15: 0000000000000003 Allocated by task 5961: 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:901 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] vhci_open+0x4c/0x430 drivers/bluetooth/hci_vhci.c:634 misc_open+0x35a/0x420 drivers/char/misc.c:179 chrdev_open+0x237/0x6a0 fs/char_dev.c:414 do_dentry_open+0x735/0x1c40 fs/open.c:956 vfs_open+0x82/0x3f0 fs/open.c:1086 do_open fs/namei.c:3830 [inline] path_openat+0x1e88/0x2d80 fs/namei.c:3989 do_filp_open+0x20c/0x470 fs/namei.c:4016 do_sys_openat2+0x17a/0x1e0 fs/open.c:1428 do_sys_open fs/open.c:1443 [inline] __do_sys_openat fs/open.c:1459 [inline] __se_sys_openat fs/open.c:1454 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1454 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5961: 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:2353 [inline] slab_free mm/slub.c:4609 [inline] kfree+0x2c4/0x4d0 mm/slub.c:4757 vhci_release+0xbb/0xf0 drivers/bluetooth/hci_vhci.c:670 __fput+0x3ff/0xb70 fs/file_table.c:464 task_work_run+0x14e/0x250 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xad8/0x2db0 kernel/exit.c:938 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087 get_signal+0x24ed/0x26c0 kernel/signal.c:3036 arch_do_signal_or_restart+0x90/0x7e0 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+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88807dfa6000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 0 bytes inside of freed 1024-byte region [ffff88807dfa6000, ffff88807dfa6400) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7dfa0 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 ffff88801b041dc0 ffffea00009e4800 dead000000000002 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b041dc0 ffffea00009e4800 dead000000000002 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0001f7e801 ffffffffffffffff 0000000000000000 head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000 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 5650, tgid 5650 (dhcpcd), ts 59114035306, free_ts 58816981388 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1551 prep_new_page mm/page_alloc.c:1559 [inline] get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3477 __alloc_frozen_pages_noprof+0x221/0x2470 mm/page_alloc.c:4740 alloc_pages_mpol+0x1fc/0x540 mm/mempolicy.c:2270 alloc_slab_page mm/slub.c:2423 [inline] allocate_slab mm/slub.c:2587 [inline] new_slab+0x23d/0x330 mm/slub.c:2640 ___slab_alloc+0xc5d/0x1720 mm/slub.c:3826 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3916 __slab_alloc_node mm/slub.c:3991 [inline] slab_alloc_node mm/slub.c:4152 [inline] __do_kmalloc_node mm/slub.c:4293 [inline] __kmalloc_node_track_caller_noprof+0x2f1/0x510 mm/slub.c:4313 kmemdup_noprof+0x29/0x60 mm/util.c:136 bpf_migrate_filter net/core/filter.c:1269 [inline] bpf_prepare_filter+0xc4f/0x1100 net/core/filter.c:1355 bpf_prog_create_from_user+0x1e4/0x2d0 net/core/filter.c:1449 seccomp_prepare_filter kernel/seccomp.c:693 [inline] seccomp_prepare_user_filter kernel/seccomp.c:730 [inline] seccomp_set_mode_filter kernel/seccomp.c:1965 [inline] do_seccomp+0x7b6/0x2640 kernel/seccomp.c:2085 prctl_set_seccomp+0x4b/0x70 kernel/seccomp.c:2138 __do_sys_prctl+0xf42/0x2450 kernel/sys.c:2551 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 5503 tgid 5503 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1127 [inline] free_frozen_pages+0x6db/0xfb0 mm/page_alloc.c:2660 __put_partials+0x14c/0x170 mm/slub.c:3153 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:4115 [inline] slab_alloc_node mm/slub.c:4164 [inline] kmem_cache_alloc_node_noprof+0x223/0x3c0 mm/slub.c:4216 __alloc_skb+0x2b1/0x380 net/core/skbuff.c:596 alloc_skb include/linux/skbuff.h:1331 [inline] alloc_skb_with_frags+0xe4/0x850 net/core/skbuff.c:6522 sock_alloc_send_pskb+0x7f1/0x980 net/core/sock.c:2914 unix_dgram_sendmsg+0x45e/0x1880 net/unix/af_unix.c:2017 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:733 [inline] sock_write_iter+0x4fe/0x5b0 net/socket.c:1137 do_iter_readv_writev+0x655/0x950 fs/read_write.c:820 vfs_writev+0x363/0xdd0 fs/read_write.c:1050 do_writev+0x297/0x340 fs/read_write.c:1096 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88807dfa5f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807dfa5f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88807dfa6000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807dfa6080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807dfa6100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================