================================================================== BUG: KASAN: slab-use-after-free in force_devcd_write+0x312/0x340 drivers/bluetooth/hci_vhci.c:327 Read of size 8 at addr ffff8880278a4000 by task syz.0.616/8003 CPU: 0 UID: 0 PID: 8003 Comm: syz.0.616 Not tainted 6.15.0-syzkaller-g7d4e49a77d99 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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+0xcd/0x680 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 force_devcd_write+0x312/0x340 drivers/bluetooth/hci_vhci.c:327 full_proxy_write+0x13c/0x200 fs/debugfs/file.c:398 vfs_write+0x2a0/0x1150 fs/read_write.c:684 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd58c18d169 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:00007fd58cff5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fd58c3a5fa0 RCX: 00007fd58c18d169 RDX: 000000000000000e RSI: 0000000000000000 RDI: 0000000000000002 RBP: 00007fd58c20e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fd58c3a5fa0 R15: 00007fff0dea1de8 Allocated by task 6482: 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] vhci_open+0x4c/0x430 drivers/bluetooth/hci_vhci.c:635 misc_open+0x35d/0x420 drivers/char/misc.c:179 chrdev_open+0x234/0x6a0 fs/char_dev.c:414 do_dentry_open+0x741/0x1c10 fs/open.c:964 vfs_open+0x82/0x3f0 fs/open.c:1094 do_open fs/namei.c:3887 [inline] path_openat+0x1de4/0x2cb0 fs/namei.c:4046 do_filp_open+0x20b/0x470 fs/namei.c:4073 do_sys_openat2+0x11b/0x1d0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6482: 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+0x2b4/0x4d0 mm/slub.c:4841 vhci_release+0xbb/0xf0 drivers/bluetooth/hci_vhci.c:671 __fput+0x3ff/0xb70 fs/file_table.c:465 task_work_run+0x150/0x240 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x864/0x2bd0 kernel/exit.c:955 do_group_exit+0xd3/0x2a0 kernel/exit.c:1104 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:111 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x3f6/0x490 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880278a4000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 0 bytes inside of freed 1024-byte region [ffff8880278a4000, ffff8880278a4400) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x278a0 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 ffff88801b441dc0 ffffea000070be00 dead000000000002 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b441dc0 ffffea000070be00 dead000000000002 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea00009e2801 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 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 12, tgid 12 (kworker/u8:0), ts 9953408624, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704 prep_new_page mm/page_alloc.c:1712 [inline] get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959 alloc_slab_page mm/slub.c:2452 [inline] allocate_slab mm/slub.c:2618 [inline] new_slab+0x94/0x330 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] blk_alloc_flush_queue+0x11e/0x2d0 block/blk-flush.c:490 blk_mq_alloc_hctx block/blk-mq.c:4037 [inline] blk_mq_alloc_and_init_hctx+0xc70/0x11c0 block/blk-mq.c:4500 __blk_mq_realloc_hw_ctxs+0x495/0x610 block/blk-mq.c:4531 blk_mq_realloc_hw_ctxs block/blk-mq.c:4558 [inline] blk_mq_init_allocated_queue+0x3af/0x1240 block/blk-mq.c:4590 blk_mq_alloc_queue+0x1be/0x290 block/blk-mq.c:4400 scsi_alloc_sdev+0x88f/0xd80 drivers/scsi/scsi_scan.c:339 scsi_probe_and_add_lun+0x76b/0xd80 drivers/scsi/scsi_scan.c:1210 __scsi_scan_target+0x1e8/0x580 drivers/scsi/scsi_scan.c:1775 scsi_scan_channel drivers/scsi/scsi_scan.c:1863 [inline] scsi_scan_channel+0x149/0x1e0 drivers/scsi/scsi_scan.c:1839 page_owner free stack trace missing Memory state around the buggy address: ffff8880278a3f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880278a3f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880278a4000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880278a4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880278a4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================