syzbot

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BUG: KASAN: slab-use-after-free in msft_opcode_get+0x6d/0x80 drivers/bluetooth/hci_vhci.c:222
Read of size 2 at addr ffff888028b6ba32 by task syz.3.1861/15496

CPU: 0 UID: 0 PID: 15496 Comm: syz.3.1861 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __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
 msft_opcode_get+0x6d/0x80 drivers/bluetooth/hci_vhci.c:222
 simple_attr_read+0x168/0x370 fs/libfs.c:1348
 debugfs_attr_read+0x76/0xa0 fs/debugfs/file.c:523
 full_proxy_read+0x12e/0x1a0 fs/debugfs/file.c:378
 vfs_read+0x1e1/0xcf0 fs/read_write.c:570
 ksys_read+0x12a/0x250 fs/read_write.c:715
 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: 0033:0x7fab0a18ebe9
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:00007fab0afa3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fab0a3b5fa0 RCX: 00007fab0a18ebe9
RDX: 000000000000ffff RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007fab0a211e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fab0a3b6038 R14: 00007fab0a3b5fa0 R15: 00007fff1e59dc58
 </TASK>

Allocated by task 15425:
 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]
 __kmalloc_noprof+0x223/0x510 mm/slub.c:4377
 kmalloc_noprof include/linux/slab.h:909 [inline]
 load_elf_phdrs+0x102/0x210 fs/binfmt_elf.c:525
 load_elf_binary+0x151b/0x4fe0 fs/binfmt_elf.c:954
 search_binary_handler fs/exec.c:1670 [inline]
 exec_binprm fs/exec.c:1702 [inline]
 bprm_execve fs/exec.c:1754 [inline]
 bprm_execve+0x8be/0x1640 fs/exec.c:1730
 kernel_execve+0x2ef/0x3b0 fs/exec.c:1920
 call_usermodehelper_exec_async+0x255/0x4c0 kernel/umh.c:109
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 15425:
 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
 load_elf_binary+0x1e26/0x4fe0 fs/binfmt_elf.c:1262
 search_binary_handler fs/exec.c:1670 [inline]
 exec_binprm fs/exec.c:1702 [inline]
 bprm_execve fs/exec.c:1754 [inline]
 bprm_execve+0x8be/0x1640 fs/exec.c:1730
 kernel_execve+0x2ef/0x3b0 fs/exec.c:1920
 call_usermodehelper_exec_async+0x255/0x4c0 kernel/umh.c:109
 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 ffff888028b6b800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 562 bytes inside of
 freed 1024-byte region [ffff888028b6b800, ffff888028b6bc00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28b68
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 ffffea0000a2da01 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 145, tgid 145 (kworker/u8:5), ts 17226773271, 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]
 __kmalloc_cache_node_noprof+0x100/0x420 mm/slub.c:4404
 kmalloc_node_noprof include/linux/slab.h:928 [inline]
 blk_mq_alloc_hctx block/blk-mq.c:4001 [inline]
 blk_mq_alloc_and_init_hctx+0x639/0x11c0 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
 scsi_scan_host_selected+0x302/0x400 drivers/scsi/scsi_scan.c:1893
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888028b6b900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888028b6b980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888028b6ba00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888028b6ba80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888028b6bb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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