================================================================== BUG: KASAN: slab-use-after-free in force_devcd_write+0x317/0x330 drivers/bluetooth/hci_vhci.c:327 Read of size 8 at addr ffff8880279fe800 by task syz.2.777/9801 CPU: 0 UID: 0 PID: 9801 Comm: syz.2.777 Tainted: G U 6.14.0-syzkaller #0 Tainted: [U]=USER 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: 0033:0x7f53ecd8d169 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:00007f53eabd5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f53ecfa6080 RCX: 00007f53ecd8d169 RDX: 000000000000000e RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f53ece0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f53ecfa6080 R15: 00007ffe394ae418 Allocated by task 9670: 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:4294 [inline] __kmalloc_node_noprof+0x21f/0x510 mm/slub.c:4300 __kvmalloc_node_noprof+0xad/0x1a0 mm/util.c:665 kvmalloc_array_node_noprof include/linux/slab.h:1063 [inline] io_alloc_cache_init+0x33/0x170 io_uring/alloc_cache.c:25 io_ring_ctx_alloc io_uring/io_uring.c:319 [inline] io_uring_create io_uring/io_uring.c:3619 [inline] io_uring_setup+0x5a7/0x2200 io_uring/io_uring.c:3793 __do_sys_io_uring_setup io_uring/io_uring.c:3820 [inline] __se_sys_io_uring_setup io_uring/io_uring.c:3814 [inline] __x64_sys_io_uring_setup+0x98/0x140 io_uring/io_uring.c:3814 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 6902: 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 kvfree+0x47/0x50 mm/util.c:708 io_alloc_cache_free+0x1eb/0x2e0 io_uring/alloc_cache.c:16 io_ring_ctx_free io_uring/io_uring.c:2708 [inline] io_ring_exit_work+0x774/0xf70 io_uring/io_uring.c:2941 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 The buggy address belongs to the object at ffff8880279fe800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 0 bytes inside of freed 1024-byte region [ffff8880279fe800, ffff8880279fec00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x279f8 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 ffffea0001ea3800 dead000000000002 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b041dc0 ffffea0001ea3800 dead000000000002 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea00009e7e01 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 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 66, tgid 66 (kworker/u8:4), ts 14704146013, free_ts 0 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_slab_page mm/slub.c:2425 [inline] allocate_slab mm/slub.c:2587 [inline] new_slab+0x94/0x330 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_noprof+0x2f0/0x510 mm/slub.c:4300 kmalloc_node_noprof include/linux/slab.h:928 [inline] blk_alloc_flush_queue+0x108/0x2b0 block/blk-flush.c:490 blk_mq_alloc_hctx block/blk-mq.c:3985 [inline] blk_mq_alloc_and_init_hctx+0xc6c/0x11b0 block/blk-mq.c:4448 blk_mq_realloc_hw_ctxs+0x8e0/0xbe0 block/blk-mq.c:4481 blk_mq_init_allocated_queue+0x39e/0x11f0 block/blk-mq.c:4535 blk_mq_alloc_queue+0x1c3/0x290 block/blk-mq.c:4348 scsi_alloc_sdev+0x890/0xd80 drivers/scsi/scsi_scan.c:338 scsi_probe_and_add_lun+0x789/0xda0 drivers/scsi/scsi_scan.c:1209 __scsi_scan_target+0x1ea/0x580 drivers/scsi/scsi_scan.c:1774 scsi_scan_channel drivers/scsi/scsi_scan.c:1862 [inline] scsi_scan_channel+0x149/0x1e0 drivers/scsi/scsi_scan.c:1838 page_owner free stack trace missing Memory state around the buggy address: ffff8880279fe700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880279fe780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880279fe800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880279fe880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880279fe900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================