syzbot

 sign-in | mailing list | source | docs | 🏰
🐞 Open [1330]
≡ Subsystems
🐞 Fixed [7140]
🐞 Invalid [18880]
⬇ Missing Backports [220]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
Total Repo Heatmap Subsystems Heatmap
✨ AI
💬 Send us feedback

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

Status: closed as invalid on 2025/07/02 15:51
Subsystems: kernel
[Documentation on labels]
First crash: 370d, last: 370d
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in netdev_register_kobject (2) kernel prio:high actionable 19 2 12d 3d23h 0/29 upstream: reported on 2026/06/01 15:08
upstream general protection fault in netdev_register_kobject kernel 8 C done 512 974d 1009d 0/29 closed as dup on 2023/08/31 14:15
linux-4.19 general protection fault in netdev_register_kobject 2 1 1623d 1623d 0/1 auto-closed as invalid on 2022/04/23 17:30

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in kobject_get+0x115/0x120 lib/kobject.c:639
Read of size 1 at addr ffff888061638c24 by task syz.1.1131/10263

CPU: 1 UID: 0 PID: 10263 Comm: syz.1.1131 Not tainted 6.15.0-syzkaller-07774-g90b83efa6701 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xd2/0x2b0 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 kobject_get+0x115/0x120 lib/kobject.c:639
 get_device drivers/base/core.c:3788 [inline]
 device_add+0x22d/0xb50 drivers/base/core.c:3615
 netdev_register_kobject+0x156/0x2f0 net/core/net-sysfs.c:2336
 register_netdevice+0x126c/0x1ae0 net/core/dev.c:11104
 register_netdev+0x40/0x60 net/core/dev.c:11220
 bnep_add_connection+0x6bf/0xbf0 net/bluetooth/bnep/core.c:624
 do_bnep_sock_ioctl+0x40e/0x640 net/bluetooth/bnep/sock.c:83
 sock_do_ioctl+0xd9/0x300 net/socket.c:1190
 sock_ioctl+0x576/0x790 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc61f98e969
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:00007fc620808038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc61fbb5fa0 RCX: 00007fc61f98e969
RDX: 00002000000000c0 RSI: 00000000400442c8 RDI: 000000000000000b
RBP: 00007fc61fa10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fc61fbb5fa0 R15: 00007ffd21011618
 </TASK>

Allocated by task 5150:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4358
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 __hci_conn_add+0x233/0x1b30 net/bluetooth/hci_conn.c:939
 hci_conn_request_evt+0x53e/0xb60 net/bluetooth/hci_event.c:3316
 hci_event_func net/bluetooth/hci_event.c:7511 [inline]
 hci_event_packet+0x7e3/0x1200 net/bluetooth/hci_event.c:7565
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4036
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 9959:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2380 [inline]
 slab_free mm/slub.c:4642 [inline]
 kfree+0x18e/0x440 mm/slub.c:4841
 device_release+0x9c/0x1c0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x22b/0x480 lib/kobject.c:737
 hci_conn_cleanup net/bluetooth/hci_conn.c:175 [inline]
 hci_conn_del+0x8ff/0xcb0 net/bluetooth/hci_conn.c:1173
 hci_conn_hash_flush+0x191/0x230 net/bluetooth/hci_conn.c:2544
 hci_dev_close_sync+0xaef/0x1330 net/bluetooth/hci_sync.c:5225
 hci_dev_do_close net/bluetooth/hci_core.c:483 [inline]
 hci_unregister_dev+0x206/0x500 net/bluetooth/hci_core.c:2678
 vhci_release+0x80/0xd0 drivers/bluetooth/hci_vhci.c:665
 __fput+0x44c/0xa70 fs/file_table.c:465
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8d1/0x2550 kernel/exit.c:959
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1108
 __do_sys_exit_group kernel/exit.c:1119 [inline]
 __se_sys_exit_group kernel/exit.c:1117 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1117
 x64_sys_call+0x21ba/0x21c0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548
 insert_work+0x3d/0x330 kernel/workqueue.c:2183
 __queue_work+0xcfc/0xfe0 kernel/workqueue.c:2341
 queue_delayed_work_on+0x18b/0x280 kernel/workqueue.c:2561
 l2cap_chan_del+0x285/0x5e0 net/bluetooth/l2cap_core.c:671
 l2cap_conn_del+0x388/0x680 net/bluetooth/l2cap_core.c:1787
 hci_disconn_cfm include/net/bluetooth/hci_core.h:2065 [inline]
 hci_conn_hash_flush+0x10a/0x230 net/bluetooth/hci_conn.c:2543
 hci_dev_close_sync+0xaef/0x1330 net/bluetooth/hci_sync.c:5225
 hci_dev_do_close net/bluetooth/hci_core.c:483 [inline]
 hci_unregister_dev+0x206/0x500 net/bluetooth/hci_core.c:2678
 vhci_release+0x80/0xd0 drivers/bluetooth/hci_vhci.c:665
 __fput+0x44c/0xa70 fs/file_table.c:465
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8d1/0x2550 kernel/exit.c:959
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1108
 __do_sys_exit_group kernel/exit.c:1119 [inline]
 __se_sys_exit_group kernel/exit.c:1117 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1117
 x64_sys_call+0x21ba/0x21c0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888061638000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 3108 bytes inside of
 freed 8192-byte region [ffff888061638000, ffff88806163a000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x61638
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 ffff88801a442280 ffffea000093e400 dead000000000006
raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801a442280 ffffea000093e400 dead000000000006
head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001858e01 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6368, tgid 6356 (syz.0.118), ts 109874263258, free_ts 109794933525
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1710
 prep_new_page mm/page_alloc.c:1718 [inline]
 get_page_from_freelist+0x21e0/0x22c0 mm/page_alloc.c:3680
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4970
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2618
 new_slab mm/slub.c:2672 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3858
 __slab_alloc mm/slub.c:3948 [inline]
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0x296/0x3d0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 mr_table_alloc+0x65/0x250 net/ipv4/ipmr_base.c:41
 ip6mr_new_table net/ipv6/ip6mr.c:401 [inline]
 ip6mr_rules_init net/ipv6/ip6mr.c:249 [inline]
 ip6mr_net_init+0x21a/0x390 net/ipv6/ip6mr.c:1334
 ops_init+0x35c/0x5c0 net/core/net_namespace.c:138
 setup_net+0x219/0x4b0 net/core/net_namespace.c:442
 copy_net_ns+0x32e/0x590 net/core/net_namespace.c:574
 create_new_namespaces+0x3f3/0x720 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x11c/0x170 kernel/nsproxy.c:218
 ksys_unshare+0x4c8/0x8c0 kernel/fork.c:3390
 __do_sys_unshare kernel/fork.c:3461 [inline]
 __se_sys_unshare kernel/fork.c:3459 [inline]
 __x64_sys_unshare+0x38/0x50 kernel/fork.c:3459
page last free pid 6360 tgid 6357 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1254 [inline]
 __free_frozen_pages+0xc6e/0xe50 mm/page_alloc.c:2717
 discard_slab mm/slub.c:2716 [inline]
 __put_partials+0x161/0x1c0 mm/slub.c:3185
 put_cpu_partial+0x17c/0x250 mm/slub.c:3260
 __slab_free+0x2f7/0x400 mm/slub.c:4512
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4147 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0 mm/slub.c:4248
 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:660
 alloc_skb include/linux/skbuff.h:1336 [inline]
 alloc_skb_with_frags+0xca/0x890 net/core/skbuff.c:6668
 sock_alloc_send_pskb+0x857/0x990 net/core/sock.c:2999
 sock_alloc_send_skb include/net/sock.h:1847 [inline]
 __ip_append_data+0x2cd3/0x40f0 net/ipv4/ip_output.c:1120
 ip_make_skb+0x1de/0x3f0 net/ipv4/ip_output.c:1568
 udp_sendmsg+0x191e/0x2300 net/ipv4/udp.c:1480
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x19c/0x270 net/socket.c:727
 ____sys_sendmsg+0x52d/0x830 net/socket.c:2566

Memory state around the buggy address:
 ffff888061638b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888061638b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888061638c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff888061638c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888061638d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/30 18:44 net-next 90b83efa6701 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce KASAN: slab-use-after-free Read in netdev_register_kobject
* Struck through repros no longer work on HEAD.