================================================================== BUG: KASAN: slab-use-after-free in force_devcd_write+0x312/0x340 drivers/bluetooth/hci_vhci.c:327 Read of size 8 at addr ffff888027f29000 by task syz.3.362/7413 CPU: 1 UID: 0 PID: 7413 Comm: syz.3.362 Tainted: G U 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 PREEMPT(full) Tainted: [U]=USER 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+0xc3/0x670 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+0x13f/0x200 fs/debugfs/file.c:398 vfs_write+0x25f/0x1180 fs/read_write.c:682 ksys_write+0x12a/0x240 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f902bf8e969 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:00007f9029df6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f902c1b5fa0 RCX: 00007f902bf8e969 RDX: 000000000000000e RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f902c010ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f902c1b5fa0 R15: 00007ffc6b607a08 Allocated by task 7366: 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 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4327 [inline] __kvmalloc_node_noprof+0x279/0x600 mm/slub.c:5012 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:334 [inline] io_uring_create io_uring/io_uring.c:3675 [inline] io_uring_setup+0x61d/0x1ff0 io_uring/io_uring.c:3822 __do_sys_io_uring_setup io_uring/io_uring.c:3856 [inline] __se_sys_io_uring_setup io_uring/io_uring.c:3847 [inline] __x64_sys_io_uring_setup+0xc2/0x170 io_uring/io_uring.c:3847 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6477: 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+0x2b6/0x4d0 mm/slub.c:4841 io_alloc_cache_free+0x1eb/0x2e0 io_uring/alloc_cache.c:16 io_free_alloc_caches+0x42/0x80 io_uring/io_uring.c:291 io_ring_ctx_free io_uring/io_uring.c:2728 [inline] io_ring_exit_work+0x7aa/0xf60 io_uring/io_uring.c:2962 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff888027f29000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 0 bytes inside of freed 1024-byte region [ffff888027f29000, ffff888027f29400) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x27f28 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 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b441dc0 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea00009fca01 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 992, tgid 992 (kworker/u8:5), ts 14658303235, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1714 prep_new_page mm/page_alloc.c:1722 [inline] get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3684 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4966 alloc_slab_page mm/slub.c:2452 [inline] allocate_slab mm/slub.c:2618 [inline] new_slab+0x94/0x340 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] __kmalloc_cache_node_noprof+0x100/0x420 mm/slub.c:4366 kmalloc_node_noprof include/linux/slab.h:928 [inline] blk_mq_alloc_hctx block/blk-mq.c:3945 [inline] blk_mq_alloc_and_init_hctx+0x639/0x11c0 block/blk-mq.c:4452 __blk_mq_realloc_hw_ctxs+0x495/0x610 block/blk-mq.c:4483 blk_mq_realloc_hw_ctxs+0x583/0x670 block/blk-mq.c:4516 blk_mq_init_allocated_queue+0x3b1/0x1230 block/blk-mq.c:4549 blk_mq_alloc_queue+0x1c2/0x290 block/blk-mq.c:4352 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: ffff888027f28f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888027f28f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888027f29000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888027f29080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888027f29100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================