KASAN: slab-use-after-free Read in skb_queue_purge

Title	Replies (including bot)	Last reply
[syzbot] [bluetooth?] KASAN: slab-use-after-free Read in skb_queue_purge_reason (3)	0 (1)	2025/06/16 09:57

Kernel	Title	Repro	Cause bisect	Count	Last	Reported	Patched	Status
upstream	KASAN: slab-use-after-free Read in skb_queue_purge_reason bluetooth			1	553d	549d	0/29	auto-obsoleted due to no activity on 2024/03/26 16:32
linux-6.6	KASAN: slab-use-after-free Read in skb_queue_purge_reason			1	11d	11d	0/2	upstream: reported on 2025/06/21 08:51
upstream	KASAN: slab-use-after-free Read in skb_queue_purge_reason (2) bluetooth	C	done	132	27d	411d	28/29	fixed on 2025/06/10 16:19

==================================================================
BUG: KASAN: slab-use-after-free in skb_queue_empty_lockless include/linux/skbuff.h:1891 [inline]
BUG: KASAN: slab-use-after-free in skb_queue_purge_reason+0x381/0x420 net/core/skbuff.c:3937
Read of size 8 at addr ffff888012feb858 by task syz.2.1008/10041

CPU: 0 UID: 0 PID: 10041 Comm: syz.2.1008 Not tainted 6.16.0-rc2-syzkaller-00318-g739a6c93cc75 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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:408 [inline]
 print_report+0xcd/0x680 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 skb_queue_empty_lockless include/linux/skbuff.h:1891 [inline]
 skb_queue_purge_reason+0x381/0x420 net/core/skbuff.c:3937
 vhci_flush+0x40/0x50 drivers/bluetooth/hci_vhci.c:65
 hci_dev_do_reset net/bluetooth/hci_core.c:552 [inline]
 hci_dev_reset+0x231/0x530 net/bluetooth/hci_core.c:592
 hci_sock_ioctl+0x493/0x7d0 net/bluetooth/hci_sock.c:1140
 sock_do_ioctl+0x118/0x280 net/socket.c:1190
 sock_ioctl+0x227/0x6b0 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f19c058e929
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:00007f19c1485038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f19c07b5fa0 RCX: 00007f19c058e929
RDX: 0000000000000000 RSI: 00000000400448cb RDI: 0000000000000004
RBP: 00007f19c0610b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f19c07b5fa0 R15: 00007ffcecab7fb8
 </TASK>

Allocated by task 9692:
 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
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 vhci_open+0x4c/0x430 drivers/bluetooth/hci_vhci.c:635
 misc_open+0x35d/0x420 drivers/char/misc.c:161
 chrdev_open+0x234/0x6a0 fs/char_dev.c:414
 do_dentry_open+0x744/0x1c10 fs/open.c:964
 vfs_open+0x82/0x3f0 fs/open.c:1094
 do_open fs/namei.c:3896 [inline]
 path_openat+0x1de4/0x2cb0 fs/namei.c:4055
 do_filp_open+0x20b/0x470 fs/namei.c:4082
 do_sys_openat2+0x11b/0x1d0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x174/0x210 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 9692:
 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:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x2b4/0x4d0 mm/slub.c:4842
 vhci_release+0xbb/0xf0 drivers/bluetooth/hci_vhci.c:671
 __fput+0x402/0xb70 fs/file_table.c:465
 task_work_run+0x150/0x240 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x864/0x2bd0 kernel/exit.c:955
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1104
 get_signal+0x2673/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:111
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888012feb800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 88 bytes inside of
 freed 1024-byte region [ffff888012feb800, ffff888012febc00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12fe8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b841dc0 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b841dc0 0000000000000000 dead000000000001
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea00004bfa01 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 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 6526, tgid 6526 (kworker/u8:22), ts 202959187400, free_ts 196809252929
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab mm/slub.c:2619 [inline]
 new_slab+0x23b/0x330 mm/slub.c:2673
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3859
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3949
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_noprof+0x2f2/0x510 mm/slub.c:4340
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 ieee802_11_parse_elems_full+0x1d7/0x3780 net/mac80211/parse.c:1013
 ieee802_11_parse_elems_crc net/mac80211/ieee80211_i.h:2414 [inline]
 ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2421 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1569 [inline]
 ieee80211_ibss_rx_queued_mgmt+0xc69/0x2fd0 net/mac80211/ibss.c:1600
 ieee80211_iface_process_skb net/mac80211/iface.c:1668 [inline]
 ieee80211_iface_work+0xbf4/0x1020 net/mac80211/iface.c:1722
 cfg80211_wiphy_work+0x3df/0x550 net/wireless/core.c:435
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
page last free pid 5843 tgid 5843 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706
 discard_slab mm/slub.c:2717 [inline]
 __put_partials+0x16d/0x1c0 mm/slub.c:3186
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4204
 getname_flags.part.0+0x4c/0x550 fs/namei.c:146
 getname_flags+0x93/0xf0 include/linux/audit.h:322
 user_path_at+0x24/0x60 fs/namei.c:3135
 ksys_umount fs/namespace.c:2147 [inline]
 __do_sys_umount fs/namespace.c:2155 [inline]
 __se_sys_umount fs/namespace.c:2153 [inline]
 __x64_sys_umount+0x10a/0x1a0 fs/namespace.c:2153
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888012feb700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888012feb780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888012feb800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff888012feb880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888012feb900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Bluetooth: hci0: Opcode 0x0c03 failed: -4

Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Assets (help?)	Manager	Title
2025/06/22 19:22	upstream	739a6c93cc75	d6cdfb8a	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci-upstream-kasan-badwrites-root	KASAN: slab-use-after-free Read in skb_queue_purge_reason
2025/06/19 13:22	upstream	fb4d33ab452e	ed3e87f7	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci-upstream-kasan-gce-selinux-root	KASAN: slab-use-after-free Read in skb_queue_purge_reason
2025/06/24 12:08	net-next	a6a4db166c65	e2f27c35	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci-upstream-net-kasan-gce	KASAN: slab-use-after-free Read in skb_queue_purge_reason
2025/06/13 18:53	net-next	08207f42d3ff	98683f8f	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci-upstream-net-kasan-gce	KASAN: slab-use-after-free Read in skb_queue_purge_reason
2025/06/12 15:20	git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci	19272b37aa4f	98683f8f	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci-upstream-gce-arm64	KASAN: slab-use-after-free Read in skb_queue_purge_reason