syzbot

==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: slab-use-after-free in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: slab-use-after-free in refcount_read include/linux/refcount.h:136 [inline]
BUG: KASAN: slab-use-after-free in skb_unref include/linux/skbuff.h:1227 [inline]
BUG: KASAN: slab-use-after-free in __kfree_skb_reason net/core/skbuff.c:1224 [inline]
BUG: KASAN: slab-use-after-free in kfree_skb_reason+0x36/0x210 net/core/skbuff.c:1251
Read of size 4 at addr ffff8880213ccc24 by task syz-executor399/5216

CPU: 3 PID: 5216 Comm: syz-executor399 Not tainted 6.9.0-rc5-syzkaller-00296-g5eb4573ea63d #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 refcount_read include/linux/refcount.h:136 [inline]
 skb_unref include/linux/skbuff.h:1227 [inline]
 __kfree_skb_reason net/core/skbuff.c:1224 [inline]
 kfree_skb_reason+0x36/0x210 net/core/skbuff.c:1251
 kfree_skb include/linux/skbuff.h:1262 [inline]
 __hci_req_sync+0x61d/0x980 net/bluetooth/hci_request.c:184
 hci_req_sync+0x97/0xd0 net/bluetooth/hci_request.c:206
 hci_dev_cmd+0x653/0x9c0 net/bluetooth/hci_core.c:790
 hci_sock_ioctl+0x4f3/0x8e0 net/bluetooth/hci_sock.c:1153
 hci_sock_compat_ioctl net/bluetooth/hci_sock.c:1180 [inline]
 hci_sock_compat_ioctl+0x68/0x80 net/bluetooth/hci_sock.c:1169
 compat_sock_ioctl+0x181/0x7f0 net/socket.c:3521
 __do_compat_sys_ioctl+0x2c3/0x330 fs/ioctl.c:1004
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7e57579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000ffc39564 EFLAGS: 00000292 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000400448dd
RDX: 00000000ffc39638 RSI: 00000000f7f26ff4 RDI: 00000000566193d8
RBP: 00000000ffc397b8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 63:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:312 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:338
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3798 [inline]
 slab_alloc_node mm/slub.c:3845 [inline]
 kmem_cache_alloc+0x136/0x320 mm/slub.c:3852
 skb_clone+0x190/0x3f0 net/core/skbuff.c:2063
 hci_send_cmd_sync net/bluetooth/hci_core.c:4220 [inline]
 hci_cmd_work+0x66a/0x710 net/bluetooth/hci_core.c:4240
 process_one_work+0x902/0x1a30 kernel/workqueue.c:3254
 process_scheduled_works kernel/workqueue.c:3335 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416
 kthread+0x2c1/0x3a0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Freed by task 5227:
 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:579
 poison_slab_object mm/kasan/common.c:240 [inline]
 __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2106 [inline]
 slab_free mm/slub.c:4280 [inline]
 kmem_cache_free+0x12e/0x380 mm/slub.c:4344
 kfree_skbmem+0x10e/0x200 net/core/skbuff.c:1159
 __kfree_skb net/core/skbuff.c:1217 [inline]
 kfree_skb_reason+0x13a/0x210 net/core/skbuff.c:1252
 kfree_skb include/linux/skbuff.h:1262 [inline]
 hci_req_sync_complete+0x16c/0x270 net/bluetooth/hci_request.c:109
 hci_event_packet+0x963/0x1190 net/bluetooth/hci_event.c:7607
 hci_rx_work+0x2c4/0x1610 net/bluetooth/hci_core.c:4171
 process_one_work+0x902/0x1a30 kernel/workqueue.c:3254
 process_scheduled_works kernel/workqueue.c:3335 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416
 kthread+0x2c1/0x3a0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The buggy address belongs to the object at ffff8880213ccb40
 which belongs to the cache skbuff_head_cache of size 240
The buggy address is located 228 bytes inside of
 freed 240-byte region [ffff8880213ccb40, ffff8880213ccc30)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x213cc
head: order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0xfff80000000840(slab|head|node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000840 ffff888015fa8780 ffffea000048ca00 dead000000000003
raw: 0000000000000000 0000000000190019 00000001ffffffff 0000000000000000
head: 00fff80000000840 ffff888015fa8780 ffffea000048ca00 dead000000000003
head: 0000000000000000 0000000000190019 00000001ffffffff 0000000000000000
head: 00fff80000000001 ffffea000084f301 dead000000000122 00000000ffffffff
head: 0000000200000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4703, tgid 343452191 (udevadm), ts 4703, free_ts 21179415539
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1534
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3317
 __alloc_pages+0x22b/0x2460 mm/page_alloc.c:4575
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page mm/slub.c:2175 [inline]
 allocate_slab mm/slub.c:2338 [inline]
 new_slab+0xcc/0x3a0 mm/slub.c:2391
 ___slab_alloc+0x670/0x16d0 mm/slub.c:3525
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3610
 __slab_alloc_node mm/slub.c:3663 [inline]
 slab_alloc_node mm/slub.c:3835 [inline]
 kmem_cache_alloc_node+0x10a/0x340 mm/slub.c:3888
 __alloc_skb+0x2b3/0x380 net/core/skbuff.c:658
 alloc_skb include/linux/skbuff.h:1313 [inline]
 alloc_uevent_skb+0x7d/0x210 lib/kobject_uevent.c:289
 uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline]
 kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
 kobject_uevent_env+0xaf2/0x15f0 lib/kobject_uevent.c:593
 kobject_synth_uevent+0x7de/0x8a0 lib/kobject_uevent.c:207
 uevent_store+0x24/0x80 drivers/base/core.c:2759
 dev_attr_store+0x55/0x80 drivers/base/core.c:2461
 sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x343/0x500 fs/kernfs/file.c:334
 call_write_iter include/linux/fs.h:2110 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x6db/0x1100 fs/read_write.c:590
page last free pid 4690 tgid 4690 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1141 [inline]
 free_unref_page_prepare+0x527/0xb10 mm/page_alloc.c:2347
 free_unref_page+0x33/0x3c0 mm/page_alloc.c:2487
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3798 [inline]
 slab_alloc_node mm/slub.c:3845 [inline]
 kmem_cache_alloc+0x136/0x320 mm/slub.c:3852
 getname_flags.part.0+0x50/0x4f0 fs/namei.c:139
 getname_flags include/linux/audit.h:322 [inline]
 getname fs/namei.c:218 [inline]
 __do_sys_unlink fs/namei.c:4447 [inline]
 __se_sys_unlink fs/namei.c:4445 [inline]
 __x64_sys_unlink+0xb2/0x110 fs/namei.c:4445
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880213ccb00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
 ffff8880213ccb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880213ccc00: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
                               ^
 ffff8880213ccc80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880213ccd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
==================================================================
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	10 06                	adc    %al,(%rsi)
   2:	03 74 b4 01          	add    0x1(%rsp,%rsi,4),%esi
   6:	10 07                	adc    %al,(%rdi)
   8:	03 74 b0 01          	add    0x1(%rax,%rsi,4),%esi
   c:	10 08                	adc    %cl,(%rax)
   e:	03 74 d8 01          	add    0x1(%rax,%rbx,8),%esi
  1e:	00 51 52             	add    %dl,0x52(%rcx)
  21:	55                   	push   %rbp
  22:	89 e5                	mov    %esp,%ebp
  24:	0f 34                	sysenter
  26:	cd 80                	int    $0x80
* 28:	5d                   	pop    %rbp <-- trapping instruction
  29:	5a                   	pop    %rdx
  2a:	59                   	pop    %rcx
  2b:	c3                   	ret
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	90                   	nop
  2f:	90                   	nop
  30:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi
  37:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi