================================================================== BUG: KASAN: slab-use-after-free in force_devcd_write+0x312/0x340 drivers/bluetooth/hci_vhci.c:327 Read of size 8 at addr ffff88802838f000 by task syz.2.2659/19063 CPU: 0 UID: 0 PID: 19063 Comm: syz.2.2659 Tainted: G U 6.17.0-rc1-syzkaller-00038-g0cc53520e68b #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 force_devcd_write+0x312/0x340 drivers/bluetooth/hci_vhci.c:327 full_proxy_write+0x12e/0x1a0 fs/debugfs/file.c:388 vfs_write+0x29d/0x11d0 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: 0033:0x7f6384f8ebe9 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:00007f6385e50038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f63851b5fa0 RCX: 00007f6384f8ebe9 RDX: 000000000000000e RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f6385011e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f63851b6038 R14: 00007f63851b5fa0 R15: 00007ffdfa142078 Allocated by task 18898: 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:388 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4365 [inline] __kvmalloc_node_noprof+0x27b/0x620 mm/slub.c:5052 kvmalloc_array_node_noprof include/linux/slab.h:1065 [inline] io_alloc_cache_init+0x33/0x170 io_uring/alloc_cache.c:25 io_ring_ctx_alloc io_uring/io_uring.c:337 [inline] io_uring_create io_uring/io_uring.c:3743 [inline] io_uring_setup+0x63b/0x2080 io_uring/io_uring.c:3890 __do_sys_io_uring_setup io_uring/io_uring.c:3924 [inline] __se_sys_io_uring_setup io_uring/io_uring.c:3915 [inline] __x64_sys_io_uring_setup+0xc2/0x170 io_uring/io_uring.c:3915 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 18135: 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:243 [inline] __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4680 [inline] kfree+0x2b4/0x4d0 mm/slub.c:4879 io_alloc_cache_free+0x1eb/0x2e0 io_uring/alloc_cache.c:16 io_free_alloc_caches+0x55/0x80 io_uring/io_uring.c:292 io_ring_ctx_free io_uring/io_uring.c:2794 [inline] io_ring_exit_work+0x7d8/0x10a0 io_uring/io_uring.c:3031 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff88802838f000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 0 bytes inside of freed 1024-byte region [ffff88802838f000, ffff88802838f400) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28388 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 ffff88801b841dc0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b841dc0 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0000a0e201 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 260, tgid 260 (kworker/u8:5), ts 16903036263, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148 alloc_slab_page mm/slub.c:2489 [inline] allocate_slab mm/slub.c:2655 [inline] new_slab+0x94/0x330 mm/slub.c:2709 ___slab_alloc+0xcf2/0x1740 mm/slub.c:3891 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3981 __slab_alloc_node mm/slub.c:4056 [inline] slab_alloc_node mm/slub.c:4217 [inline] __do_kmalloc_node mm/slub.c:4364 [inline] __kmalloc_node_noprof+0x2ed/0x500 mm/slub.c:4371 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:4041 [inline] blk_mq_alloc_and_init_hctx+0xc70/0x11c0 block/blk-mq.c:4504 __blk_mq_realloc_hw_ctxs+0x495/0x610 block/blk-mq.c:4535 blk_mq_realloc_hw_ctxs block/blk-mq.c:4562 [inline] blk_mq_init_allocated_queue+0x3af/0x1240 block/blk-mq.c:4594 blk_mq_alloc_queue+0x1bb/0x280 block/blk-mq.c:4404 scsi_alloc_sdev+0x888/0xd70 drivers/scsi/scsi_scan.c:339 scsi_probe_and_add_lun+0x76b/0xd80 drivers/scsi/scsi_scan.c:1211 __scsi_scan_target+0x1e8/0x580 drivers/scsi/scsi_scan.c:1776 scsi_scan_channel drivers/scsi/scsi_scan.c:1864 [inline] scsi_scan_channel+0x149/0x1e0 drivers/scsi/scsi_scan.c:1840 page_owner free stack trace missing Memory state around the buggy address: ffff88802838ef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802838ef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802838f000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802838f080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802838f100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================