syzbot

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BUG: KASAN: slab-use-after-free in skb_dst_drop include/net/dst.h:281 [inline]
BUG: KASAN: slab-use-after-free in skb_release_head_state+0x3b/0x240 net/core/skbuff.c:1040
Read of size 8 at addr ffff88802d9e2698 by task syz.1.20965/20740

CPU: 1 PID: 20740 Comm: syz.1.20965 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xac/0x220 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 skb_dst_drop include/net/dst.h:281 [inline]
 skb_release_head_state+0x3b/0x240 net/core/skbuff.c:1040
 skb_release_all net/core/skbuff.c:1055 [inline]
 __kfree_skb net/core/skbuff.c:1071 [inline]
 kfree_skb_reason+0xd7/0x170 net/core/skbuff.c:1107
 kfree_skb include/linux/skbuff.h:1232 [inline]
 __hci_req_sync+0x629/0x900 net/bluetooth/hci_request.c:184
 hci_req_sync+0xa2/0xc0 net/bluetooth/hci_request.c:206
 hci_inquiry+0x38e/0x600 net/bluetooth/hci_core.c:394
 sock_do_ioctl+0xd7/0x2f0 net/socket.c:1222
 sock_ioctl+0x623/0x7a0 net/socket.c:1341
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa1a2f8f749
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:00007fa1a3e73038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa1a31e5fa0 RCX: 00007fa1a2f8f749
RDX: 0000200000000140 RSI: 00000000800448f0 RDI: 0000000000000004
RBP: 00007fa1a3013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa1a31e6038 R14: 00007fa1a31e5fa0 R15: 00007ffe20e9b3c8
 </TASK>

Allocated by task 27436:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3495 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3519
 skb_clone+0x1eb/0x370 net/core/skbuff.c:1915
 hci_send_cmd_sync net/bluetooth/hci_core.c:4067 [inline]
 hci_cmd_work+0x283/0x660 net/bluetooth/hci_core.c:4087
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

Freed by task 51:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 kmem_cache_free+0xf8/0x280 mm/slub.c:3852
 kfree_skb include/linux/skbuff.h:1232 [inline]
 hci_send_cmd_sync net/bluetooth/hci_core.c:4066 [inline]
 hci_cmd_work+0x25d/0x660 net/bluetooth/hci_core.c:4087
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

The buggy address belongs to the object at ffff88802d9e2640
 which belongs to the cache skbuff_head_cache of size 240
The buggy address is located 88 bytes inside of
 freed 240-byte region [ffff88802d9e2640, ffff88802d9e2730)

The buggy address belongs to the physical page:
page:ffffea0000b67880 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2d9e2
flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff888143242640 ffffea000105a040 dead000000000004
raw: 0000000000000000 00000000000c000c 00000001ffffffff 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 5800, tgid 5800 (udevd), ts 85993113591, free_ts 83872643342
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
 alloc_slab_page+0x5d/0x170 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2e0 mm/slub.c:2081
 ___slab_alloc+0xc6d/0x1300 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 kmem_cache_alloc_node+0x1ea/0x330 mm/slub.c:3540
 __alloc_skb+0x108/0x2c0 net/core/skbuff.c:643
 alloc_skb include/linux/skbuff.h:1284 [inline]
 alloc_skb_with_frags+0xca/0x7c0 net/core/skbuff.c:6332
 sock_alloc_send_pskb+0x857/0x990 net/core/sock.c:2821
 unix_dgram_sendmsg+0x5a1/0x1720 net/unix/af_unix.c:2001
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 sock_write_iter+0x2bb/0x3f0 net/socket.c:1160
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x43b/0x940 fs/read_write.c:584
 ksys_write+0x147/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429
 discard_slab mm/slub.c:2127 [inline]
 __unfreeze_partials+0x1cf/0x210 mm/slub.c:2667
 put_cpu_partial+0x17c/0x250 mm/slub.c:2743
 __slab_free+0x31d/0x410 mm/slub.c:3700
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x75/0xe0 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3495 [inline]
 __kmem_cache_alloc_node+0x13e/0x260 mm/slub.c:3534
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc+0xa4/0x240 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x1c3/0x3c0 security/tomoyo/file.c:771
 security_file_open+0x62/0xa0 security/security.c:2854
 do_dentry_open+0x380/0x1500 fs/open.c:916
 do_open fs/namei.c:3640 [inline]
 path_openat+0x274b/0x3190 fs/namei.c:3797

Memory state around the buggy address:
 ffff88802d9e2580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
 ffff88802d9e2600: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>ffff88802d9e2680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88802d9e2700: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
 ffff88802d9e2780: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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