syzbot

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BUG: KASAN: slab-use-after-free in ax25_find_cb+0x179/0x3a0 net/ax25/af_ax25.c:236
Read of size 8 at addr ffff888079f73810 by task syz.1.1039/7077

CPU: 0 UID: 0 PID: 7077 Comm: syz.1.1039 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 ax25_find_cb+0x179/0x3a0 net/ax25/af_ax25.c:236
 rose_link_up net/rose/rose_link.c:129 [inline]
 rose_transmit_link+0x16d/0x740 net/rose/rose_link.c:271
 rose_write_internal+0x11dc/0x1ac0 net/rose/rose_subr.c:198
 rose_release+0x2be/0x590 net/rose/af_rose.c:671
 __sock_release+0xb9/0x250 net/socket.c:666
 sock_close+0x1c/0x30 net/socket.c:1470
 __fput+0x44c/0xa70 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x694/0x22f0 kernel/exit.c:971
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f390d58f749
Code: Unable to access opcode bytes at 0x7f390d58f71f.
RSP: 002b:00007ffd7442bb88 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffe00 RBX: 00007f390d7e5fa0 RCX: 00007f390d58f749
RDX: 0000000000000040 RSI: 0000200000000100 RDI: 0000000000000009
RBP: 00007f390d613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f390d7e5fa0 R14: 00007f390d7e5fa0 R15: 0000000000000003
 </TASK>

Allocated by task 7202:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5796
 kmalloc_noprof include/linux/slab.h:958 [inline]
 kzalloc_noprof include/linux/slab.h:1200 [inline]
 ax25_dev_device_up+0x54/0x600 net/ax25/ax25_dev.c:57
 ax25_device_event+0x124/0x630 net/ax25/af_ax25.c:143
 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
 call_netdevice_notifiers net/core/dev.c:2282 [inline]
 __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1
 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9804
 dev_change_flags+0x130/0x260 net/core/dev_api.c:68
 dev_ioctl+0x7b4/0x1150 net/core/dev_ioctl.c:842
 sock_do_ioctl+0x22c/0x300 net/socket.c:1283
 sock_ioctl+0x576/0x790 net/socket.c:1390
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 50:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2556 [inline]
 slab_free_freelist_hook mm/slub.c:2585 [inline]
 slab_free_bulk mm/slub.c:6723 [inline]
 kmem_cache_free_bulk+0x3fb/0xdb0 mm/slub.c:7410
 kfree_bulk include/linux/slab.h:831 [inline]
 kvfree_rcu_bulk+0xe5/0x1b0 mm/slab_common.c:1523
 kfree_rcu_work+0xed/0x170 mm/slab_common.c:1601
 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
 process_scheduled_works kernel/workqueue.c:3362 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
 kthread+0x389/0x480 kernel/kthread.c:467
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 kvfree_call_rcu+0x106/0x440 mm/slab_common.c:1994
 ax25_device_event+0x57e/0x630 net/ax25/af_ax25.c:148
 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
 call_netdevice_notifiers net/core/dev.c:2282 [inline]
 __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1
 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9804
 dev_change_flags+0x130/0x260 net/core/dev_api.c:68
 dev_ioctl+0x7b4/0x1150 net/core/dev_ioctl.c:842
 sock_do_ioctl+0x22c/0x300 net/socket.c:1283
 sock_ioctl+0x576/0x790 net/socket.c:1390
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888079f73800
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 16 bytes inside of
 freed 256-byte region [ffff888079f73800, ffff888079f73900)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x79f72
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813fe26b40 ffffea000097ae00 dead000000000003
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813fe26b40 ffffea000097ae00 dead000000000003
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea0001e7dc81 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
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 5841, tgid 5841 (syz-executor), ts 89714267007, free_ts 89709003884
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x23d/0x2a0 mm/page_alloc.c:1887
 prep_new_page mm/page_alloc.c:1895 [inline]
 get_page_from_freelist+0x23a5/0x2440 mm/page_alloc.c:3948
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5257
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3091 [inline]
 allocate_slab+0x86/0x3b0 mm/slub.c:3264
 new_slab mm/slub.c:3318 [inline]
 ___slab_alloc+0xdb6/0x17b0 mm/slub.c:4672
 __slab_alloc+0x65/0x100 mm/slub.c:4795
 __slab_alloc_node mm/slub.c:4871 [inline]
 slab_alloc_node mm/slub.c:5271 [inline]
 __do_kmalloc_node mm/slub.c:5676 [inline]
 __kmalloc_noprof+0x47d/0x800 mm/slub.c:5689
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1200 [inline]
 fib_create_info+0x171d/0x31f0 net/ipv4/fib_semantics.c:1402
 fib_table_insert+0xca/0x1b80 net/ipv4/fib_trie.c:1212
 fib_magic+0x2c4/0x390 net/ipv4/fib_frontend.c:1134
 fib_add_ifaddr+0x3fb/0x5f0 net/ipv4/fib_frontend.c:1178
 fib_netdev_event+0x382/0x490 net/ipv4/fib_frontend.c:1516
 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
 call_netdevice_notifiers net/core/dev.c:2282 [inline]
 __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1
 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9804
page last free pid 5841 tgid 5841 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1436 [inline]
 __free_frozen_pages+0xb99/0xd10 mm/page_alloc.c:2976
 __slab_free+0x2ce/0x320 mm/slub.c:6024
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4969 [inline]
 slab_alloc_node mm/slub.c:5283 [inline]
 __kmalloc_cache_noprof+0x37c/0x700 mm/slub.c:5791
 kmalloc_noprof include/linux/slab.h:958 [inline]
 netdevice_queue_work drivers/infiniband/core/roce_gid_mgmt.c:687 [inline]
 netdevice_event+0x3f2/0x8e0 drivers/infiniband/core/roce_gid_mgmt.c:849
 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
 call_netdevice_notifiers net/core/dev.c:2282 [inline]
 __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1
 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9804
 do_setlink+0xc55/0x41c0 net/core/rtnetlink.c:3158
 rtnl_changelink net/core/rtnetlink.c:3776 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3935 [inline]
 rtnl_newlink+0x161c/0x1c90 net/core/rtnetlink.c:4072
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894

Memory state around the buggy address:
 ffff888079f73700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888079f73780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888079f73800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888079f73880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888079f73900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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