Subject: [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in mgmt_remove_adv_monitor_sync

From: syzbot <[email-masked]>
Date: Wed, 24 Jul 2024 01:59:20 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    d7e78951a8b8 Merge tag 'net-6.11-rc0' of git://git.kernel...
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=126a9fc3980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8d1cf7c29e32ce12
dashboard link: https://syzkaller.appspot.com/bug?extid=479aff51bb361ef5aa18
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3c208b51873e/disk-d7e78951.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/adec146cf41c/vmlinux-d7e78951.xz
kernel image: https://storage.googleapis.com/syzbot-assets/52f09b8f7356/bzImage-d7e78951.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

==================================================================
BUG: KASAN: slab-use-after-free in mgmt_remove_adv_monitor_sync+0x3a/0xd0 net/bluetooth/mgmt.c:5444
Read of size 8 at addr ffff88802aac0f18 by task kworker/u9:0/54

CPU: 0 PID: 54 Comm: kworker/u9:0 Not tainted 6.10.0-syzkaller-09703-gd7e78951a8b8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 mgmt_remove_adv_monitor_sync+0x3a/0xd0 net/bluetooth/mgmt.c:5444
 hci_cmd_sync_work+0x22b/0x400 net/bluetooth/hci_sync.c:328
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd40 kernel/workqueue.c:3390
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 7112:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __kmalloc_cache_noprof+0x19c/0x2c0 mm/slub.c:4180
 kmalloc_noprof include/linux/slab.h:681 [inline]
 kzalloc_noprof include/linux/slab.h:807 [inline]
 mgmt_pending_new+0x65/0x250 net/bluetooth/mgmt_util.c:269
 mgmt_pending_add+0x36/0x120 net/bluetooth/mgmt_util.c:296
 remove_adv_monitor+0x102/0x1b0 net/bluetooth/mgmt.c:5469
 hci_mgmt_cmd+0xc47/0x11d0 net/bluetooth/hci_sock.c:1712
 hci_sock_sendmsg+0x7b8/0x11c0 net/bluetooth/hci_sock.c:1832
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 sock_write_iter+0x2dd/0x400 net/socket.c:1160
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa72/0xc90 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 7179:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
 poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2235 [inline]
 slab_free mm/slub.c:4464 [inline]
 kfree+0x149/0x360 mm/slub.c:4585
 mgmt_pending_foreach+0xd1/0x130 net/bluetooth/mgmt_util.c:259
 __mgmt_power_off+0x187/0x420 net/bluetooth/mgmt.c:9458
 hci_dev_close_sync+0x665/0x11a0 net/bluetooth/hci_sync.c:5118
 hci_dev_do_close net/bluetooth/hci_core.c:490 [inline]
 hci_dev_close+0x112/0x210 net/bluetooth/hci_core.c:515
 sock_do_ioctl+0x158/0x460 net/socket.c:1222
 sock_ioctl+0x629/0x8e0 net/socket.c:1341
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802aac0f00
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 24 bytes inside of
 freed 96-byte region [ffff88802aac0f00, ffff88802aac0f60)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88802aac0b80 pfn:0x2aac0
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffefff(slab)
raw: 00fff00000000200 ffff888015041280 ffffea00007c85d0 ffffea0001a17590
raw: ffff88802aac0b80 000000000020000a 00000001ffffefff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x352800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL|__GFP_THISNODE), pid 5330, tgid 5329 (syz.3.37), ts 87033405855, free_ts 86894920419
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1473
 prep_new_page mm/page_alloc.c:1481 [inline]
 get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3425
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4683
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 alloc_slab_page+0x5f/0x120 mm/slub.c:2304
 allocate_slab+0x5a/0x2f0 mm/slub.c:2467
 new_slab mm/slub.c:2520 [inline]
 ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3706
 __slab_alloc+0x58/0xa0 mm/slub.c:3796
 __slab_alloc_node mm/slub.c:3849 [inline]
 slab_alloc_node mm/slub.c:4016 [inline]
 __do_kmalloc_node mm/slub.c:4148 [inline]
 __kmalloc_node_noprof+0x286/0x440 mm/slub.c:4155
 kmalloc_array_node_noprof include/linux/slab.h:788 [inline]
 alloc_slab_obj_exts mm/slub.c:1959 [inline]
 account_slab mm/slub.c:2430 [inline]
 allocate_slab+0xb6/0x2f0 mm/slub.c:2485
 new_slab mm/slub.c:2520 [inline]
 ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3706
 __slab_alloc+0x58/0xa0 mm/slub.c:3796
 __slab_alloc_node mm/slub.c:3849 [inline]
 slab_alloc_node mm/slub.c:4016 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x2a0 mm/slub.c:4035
 sk_prot_alloc+0x58/0x210 net/core/sock.c:2090
 sk_alloc+0x38/0x370 net/core/sock.c:2149
 inet_create+0x652/0xe70 net/ipv4/af_inet.c:326
 __sock_create+0x490/0x920 net/socket.c:1571
page last free pid 5318 tgid 5318 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1093 [inline]
 free_unref_folios+0xf23/0x19e0 mm/page_alloc.c:2637
 folios_put_refs+0x93a/0xa60 mm/swap.c:1024
 free_pages_and_swap_cache+0x5c8/0x690 mm/swap_state.c:332
 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:366 [inline]
 tlb_flush_mmu+0x3a3/0x680 mm/mmu_gather.c:373
 tlb_finish_mmu+0xd4/0x200 mm/mmu_gather.c:465
 exit_mmap+0x44f/0xc80 mm/mmap.c:3354
 __mmput+0x115/0x390 kernel/fork.c:1343
 exit_mm+0x220/0x310 kernel/exit.c:566
 do_exit+0x9b2/0x27f0 kernel/exit.c:864
 do_group_exit+0x207/0x2c0 kernel/exit.c:1026
 __do_sys_exit_group kernel/exit.c:1037 [inline]
 __se_sys_exit_group kernel/exit.c:1035 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1035
 x64_sys_call+0x26c3/0x26d0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88802aac0e00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff88802aac0e80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
>ffff88802aac0f00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                            ^
 ffff88802aac0f80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff88802aac1000: 04 fc fc fc 04 fc fc fc 04 fc fc fc 04 fc fc fc
==================================================================

---
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