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KASAN: use-after-free Read in ax25_find_cb (2)

Status: upstream: reported on 2026/03/10 09:17
Reported-by: syzbot+d8ca3167427da255d585@syzkaller.appspotmail.com
First crash: 6d16h, last: 5d00h
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 KASAN: use-after-free Read in ax25_find_cb 19 3 206d 237d 0/3 auto-obsoleted due to no activity on 2025/11/30 02:07
linux-6.1 KASAN: use-after-free Read in ax25_find_cb origin:upstream 19 syz error 1 127d 127d 0/3 upstream: reported syz repro on 2025/11/09 13:50
upstream KASAN: slab-use-after-free Read in ax25_find_cb hams 19 C error 11 1d15h 144d 0/29 upstream: reported C repro on 2025/10/23 12:13
linux-6.6 KASAN: slab-use-after-free Read in ax25_find_cb origin:upstream 19 C error 1 64d 98d 0/2 upstream: reported C repro on 2025/12/08 04:33

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in ax25_find_cb+0x175/0x3a0 net/ax25/af_ax25.c:232
Read of size 8 at addr ffff888024906708 by task syz.0.175/4922

CPU: 1 PID: 4922 Comm: syz.0.175 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 ax25_find_cb+0x175/0x3a0 net/ax25/af_ax25.c:232
 rose_link_up net/rose/rose_link.c:129 [inline]
 rose_transmit_link+0x169/0x730 net/rose/rose_link.c:271
 rose_write_internal+0x680/0x1e90 net/rose/rose_subr.c:198
 rose_release+0x22a/0x4e0 net/rose/af_rose.c:670
 __sock_release net/socket.c:651 [inline]
 sock_close+0xd5/0x240 net/socket.c:1345
 __fput+0x234/0x930 fs/file_table.c:311
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 get_signal+0x1222/0x12c0 kernel/signal.c:2672
 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc7d69aa799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc7d4c04028 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffe00 RBX: 00007fc7d6c23fa0 RCX: 00007fc7d69aa799
RDX: 000000000000001c RSI: 0000200000000240 RDI: 0000000000000008
RBP: 00007fc7d6a40c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc7d6c24038 R14: 00007fc7d6c23fa0 R15: 00007fff1a471da8
 </TASK>

Allocated by task 4619:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:607 [inline]
 kzalloc include/linux/slab.h:738 [inline]
 ax25_dev_device_up+0x50/0x580 net/ax25/ax25_dev.c:55
 ax25_device_event+0x483/0x4f0 net/ax25/af_ax25.c:139
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
 call_netdevice_notifiers_extack net/core/dev.c:2074 [inline]
 call_netdevice_notifiers net/core/dev.c:2088 [inline]
 __dev_notify_flags+0x194/0x300 net/core/dev.c:8917
 dev_change_flags+0xe3/0x1a0 net/core/dev.c:8955
 dev_ifsioc+0x130/0xd50 net/core/dev_ioctl.c:324
 dev_ioctl+0x545/0xe30 net/core/dev_ioctl.c:572
 sock_do_ioctl+0x245/0x320 net/socket.c:1161
 sock_ioctl+0x4d2/0x710 net/socket.c:1266
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 4921:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kfree+0xef/0x2a0 mm/slub.c:4564
 ax25_dev_put include/net/ax25.h:302 [inline]
 ax25_release+0x661/0x870 net/ax25/af_ax25.c:1062
 __sock_release net/socket.c:651 [inline]
 sock_close+0xd5/0x240 net/socket.c:1345
 __fput+0x234/0x930 fs/file_table.c:311
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Last potentially related work creation:
 kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
 insert_work+0x54/0x3d0 kernel/workqueue.c:1366
 __queue_work+0x9c5/0xd50 kernel/workqueue.c:1532
 queue_work_on+0x124/0x1f0 kernel/workqueue.c:1559
 queue_work include/linux/workqueue.h:512 [inline]
 netdevice_queue_work drivers/infiniband/core/roce_gid_mgmt.c:659 [inline]
 netdevice_event+0x803/0x900 drivers/infiniband/core/roce_gid_mgmt.c:802
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
 call_netdevice_notifiers_extack net/core/dev.c:2074 [inline]
 call_netdevice_notifiers net/core/dev.c:2088 [inline]
 register_netdevice+0x12a6/0x1710 net/core/dev.c:10454
 veth_newlink+0x6bc/0xe30 drivers/net/veth.c:1683
 __rtnl_newlink net/core/rtnetlink.c:3526 [inline]
 rtnl_newlink+0x1359/0x1a50 net/core/rtnetlink.c:3574
 rtnetlink_rcv_msg+0x844/0xf30 net/core/rtnetlink.c:5684
 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2507
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 __sys_sendto+0x46d/0x620 net/socket.c:2072
 __do_sys_sendto net/socket.c:2084 [inline]
 __se_sys_sendto net/socket.c:2080 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2080
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff888024906700
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 8 bytes inside of
 192-byte region [ffff888024906700, ffff8880249067c0)
The buggy address belongs to the page:
page:ffffea0000924180 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24906
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 dead000000000100 dead000000000122 ffff888016c41a00
raw: 0000000000000000 0000000000100010 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 0x12c00(GFP_NOIO|__GFP_NOWARN|__GFP_NORETRY), pid 1107, ts 8276146320, free_ts 8086388553
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 alloc_slab_page mm/slub.c:1780 [inline]
 allocate_slab mm/slub.c:1917 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1980
 ___slab_alloc+0x80a/0xdd0 mm/slub.c:3013
 __slab_alloc mm/slub.c:3100 [inline]
 slab_alloc_node mm/slub.c:3191 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 __kmalloc+0x1cd/0x330 mm/slub.c:4408
 kmalloc include/linux/slab.h:612 [inline]
 usb_alloc_urb+0x3f/0x140 drivers/usb/core/urb.c:74
 usb_internal_control_msg drivers/usb/core/message.c:95 [inline]
 usb_control_msg+0x115/0x3e0 drivers/usb/core/message.c:153
 get_port_status drivers/usb/core/hub.c:596 [inline]
 hub_ext_port_status+0x103/0x6d0 drivers/usb/core/hub.c:613
 hub_port_status drivers/usb/core/hub.c:635 [inline]
 hub_activate+0x6e9/0x1a30 drivers/usb/core/hub.c:1146
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
 __vunmap+0x8b9/0xa50 mm/vmalloc.c:2628
 free_work+0x56/0x80 mm/vmalloc.c:95
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
 ffff888024906600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888024906680: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888024906700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888024906780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888024906800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (41):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/12 01:11 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 01:10 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 01:10 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 01:09 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 01:09 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 01:08 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 01:05 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 01:04 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 01:04 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 01:03 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 01:02 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 01:00 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 01:00 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 00:59 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 00:58 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 00:56 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 00:51 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/12 00:50 linux-5.15.y 91d48252ad4b 2d88ab01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/11 11:59 linux-5.15.y 91d48252ad4b 86914af9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/11 10:52 linux-5.15.y 91d48252ad4b 86914af9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/11 10:51 linux-5.15.y 91d48252ad4b 86914af9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 22:32 linux-5.15.y 91d48252ad4b 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 22:32 linux-5.15.y 91d48252ad4b 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 22:27 linux-5.15.y 91d48252ad4b 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 22:27 linux-5.15.y 91d48252ad4b 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 22:23 linux-5.15.y 91d48252ad4b 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 22:23 linux-5.15.y 91d48252ad4b 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 22:21 linux-5.15.y 91d48252ad4b 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 22:14 linux-5.15.y 91d48252ad4b 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 22:14 linux-5.15.y 91d48252ad4b 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 22:12 linux-5.15.y 91d48252ad4b 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 21:44 linux-5.15.y 91d48252ad4b 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 21:44 linux-5.15.y 91d48252ad4b 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 09:25 linux-5.15.y 91d48252ad4b 6972f302 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 09:25 linux-5.15.y 91d48252ad4b 6972f302 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 09:24 linux-5.15.y 91d48252ad4b 6972f302 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 09:22 linux-5.15.y 91d48252ad4b 6972f302 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 09:22 linux-5.15.y 91d48252ad4b 6972f302 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 09:22 linux-5.15.y 91d48252ad4b 6972f302 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 09:17 linux-5.15.y 91d48252ad4b 6972f302 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
2026/03/10 09:17 linux-5.15.y 91d48252ad4b 6972f302 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ax25_find_cb
* Struck through repros no longer work on HEAD.