================================================================== BUG: KASAN: slab-use-after-free in force_devcd_write+0x31f/0x350 drivers/bluetooth/hci_vhci.c:327 Read of size 8 at addr ffff888034b36800 by task syz.4.1420/10888 CPU: 1 UID: 0 PID: 10888 Comm: syz.4.1420 Not tainted 6.13.0-rc3-syzkaller-00289-g48f506ad0b68 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 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:378 [inline] print_report+0xc3/0x620 mm/kasan/report.c:489 kasan_report+0xd9/0x110 mm/kasan/report.c:602 force_devcd_write+0x31f/0x350 drivers/bluetooth/hci_vhci.c:327 full_proxy_write+0xfb/0x1b0 fs/debugfs/file.c:356 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: 0033:0x7faffb385d29 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:00007faffc1da038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007faffb575fa0 RCX: 00007faffb385d29 RDX: 000000000000000e RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007faffb401aa8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007faffb575fa0 R15: 00007ffd673e1e38 Allocated by task 5832: 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:165 chrdev_open+0x237/0x6a0 fs/char_dev.c:414 do_dentry_open+0xf59/0x1ea0 fs/open.c:945 vfs_open+0x82/0x3f0 fs/open.c:1075 do_open fs/namei.c:3828 [inline] path_openat+0x1e6a/0x2d60 fs/namei.c:3987 do_filp_open+0x20c/0x470 fs/namei.c:4014 do_sys_openat2+0x17a/0x1e0 fs/open.c:1402 do_sys_open fs/open.c:1417 [inline] __do_sys_openat fs/open.c:1433 [inline] __se_sys_openat fs/open.c:1428 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1428 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 10572: 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:582 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:4613 [inline] kfree+0x14f/0x4b0 mm/slub.c:4761 vhci_release+0xbb/0xf0 drivers/bluetooth/hci_vhci.c:670 __fput+0x3f8/0xb60 fs/file_table.c:450 task_work_run+0x14e/0x250 kernel/task_work.c:239 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0xad8/0x2d70 kernel/exit.c:938 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087 get_signal+0x2576/0x2610 kernel/signal.c:3017 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] irqentry_exit_to_user_mode+0x13f/0x280 kernel/entry/common.c:231 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 The buggy address belongs to the object at ffff888034b36800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 0 bytes inside of freed 1024-byte region [ffff888034b36800, ffff888034b36c00) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34b30 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 ffff88801ac41dc0 ffffea0001f6f000 dead000000000002 raw: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000 head: 00fff00000000040 ffff88801ac41dc0 ffffea0001f6f000 dead000000000002 head: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000 head: 00fff00000000003 ffffea0000d2cc01 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 1, tgid 1 (swapper/0), ts 32644005686, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1558 prep_new_page mm/page_alloc.c:1566 [inline] get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3476 __alloc_pages_noprof+0x223/0x25b0 mm/page_alloc.c:4753 alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2269 alloc_slab_page mm/slub.c:2423 [inline] allocate_slab mm/slub.c:2589 [inline] new_slab+0x2c9/0x410 mm/slub.c:2642 ___slab_alloc+0xce2/0x1650 mm/slub.c:3830 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3920 __slab_alloc_node mm/slub.c:3995 [inline] slab_alloc_node mm/slub.c:4156 [inline] __do_kmalloc_node mm/slub.c:4297 [inline] __kmalloc_noprof+0x2de/0x4f0 mm/slub.c:4310 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] __alloc_workqueue+0xd4c/0x1810 kernel/workqueue.c:5669 alloc_workqueue+0xd3/0x200 kernel/workqueue.c:5772 udp_tunnel_nic_init_module+0x21/0x110 net/ipv4/udp_tunnel_nic.c:933 do_one_initcall+0x128/0x630 init/main.c:1266 do_initcall_level init/main.c:1328 [inline] do_initcalls init/main.c:1344 [inline] do_basic_setup init/main.c:1363 [inline] kernel_init_freeable+0x58f/0x8b0 init/main.c:1577 kernel_init+0x1c/0x2b0 init/main.c:1466 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 page_owner free stack trace missing Memory state around the buggy address: ffff888034b36700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888034b36780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888034b36800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888034b36880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888034b36900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================