KASAN: slab-use-after-free Read in __ethtool_get_link_ksettings (2)

Status: auto-obsoleted due to no activity on 2026/08/05 06:57
Reported-by: syzbot+2c1df93abe59202d4958@syzkaller.appspotmail.com
First crash: 119d, last: 119d
▶ ▼ Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 KASAN: slab-use-after-free Read in __ethtool_get_link_ksettings 19 1 422d 422d 0/2 auto-obsoleted due to no activity on 2025/10/05 22:34
linux-6.6 KASAN: slab-use-after-free Read in __ethtool_get_link_ksettings (3) 19 1 16h07m 16h06m 0/2 upstream: reported on 2026/08/23 14:50
upstream KASAN: slab-use-after-free Read in __ethtool_get_link_ksettings rdma prio:high 19 syz done 44058 now 884d 0/29 upstream: reported syz repro on 2024/03/22 20:10
linux-6.1 KASAN: use-after-free Read in __ethtool_get_link_ksettings 19 7 698d 831d 0/3 auto-obsoleted due to no activity on 2025/01/02 21:40
linux-6.1 KASAN: use-after-free Read in __ethtool_get_link_ksettings (2) 19 5 25d 188d 0/3 upstream: reported on 2026/02/17 03:21
upstream KASAN: use-after-free Read in __ethtool_get_link_ksettings net 19 2 1599d 1635d 0/29 auto-closed as invalid on 2022/07/07 00:01
upstream general protection fault in __ethtool_get_link_ksettings net 7 syz, C error unreliable 298 1866d 2025d 0/29 closed as invalid on 2021/10/06 01:39
upstream KASAN: use-after-free Read in __ethtool_get_link_ksettings (2) net 19 1 1492d 1487d 0/29 auto-obsoleted due to no activity on 2022/11/20 15:32

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in __ethtool_get_link_ksettings+0x6e/0x180 net/ethtool/ioctl.c:438
Read of size 8 at addr ffff88807376a210 by task kworker/1:0/8483

CPU: 1 PID: 8483 Comm: kworker/1:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: infiniband ib_cache_event_task
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 __ethtool_get_link_ksettings+0x6e/0x180 net/ethtool/ioctl.c:438
 ib_get_eth_speed+0x17d/0x7e0 drivers/infiniband/core/verbs.c:1984
 rxe_query_port+0x8d/0x2d0 drivers/infiniband/sw/rxe/rxe_verbs.c:62
 __ib_query_port drivers/infiniband/core/device.c:2082 [inline]
 ib_query_port+0x167/0x820 drivers/infiniband/core/device.c:2114
 ib_cache_update+0x1ae/0xad0 drivers/infiniband/core/cache.c:1501
 ib_cache_event_task+0xe0/0x1d0 drivers/infiniband/core/cache.c:1575
 process_one_work kernel/workqueue.c:2653 [inline]
 process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811
 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
 </TASK>

Allocated by task 6670:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc_node+0xb4/0x230 mm/slab_common.c:1014
 kmalloc_node include/linux/slab.h:620 [inline]
 kvmalloc_node+0x70/0x180 mm/util.c:617
 kvmalloc include/linux/slab.h:738 [inline]
 kvzalloc include/linux/slab.h:746 [inline]
 alloc_netdev_mqs+0x87/0x1040 net/core/dev.c:10867
 rtnl_create_link+0x30e/0xd00 net/core/rtnetlink.c:3384
 rtnl_newlink_create net/core/rtnetlink.c:3510 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3740 [inline]
 rtnl_newlink+0x1455/0x20a0 net/core/rtnetlink.c:3753
 rtnetlink_rcv_msg+0x869/0xfa0 net/core/rtnetlink.c:6475
 netlink_rcv_skb+0x241/0x4d0 net/netlink/af_netlink.c:2545
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x4a9/0x6b0 net/socket.c:2200
 __do_sys_sendto net/socket.c:2212 [inline]
 __se_sys_sendto net/socket.c:2208 [inline]
 __x64_sys_sendto+0xde/0xf0 net/socket.c:2208
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 145:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 __kmem_cache_free+0xba/0x1e0 mm/slub.c:3843
 device_release+0x96/0x1c0 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+0x221/0x460 lib/kobject.c:737
 netdev_run_todo+0xcb7/0xdc0 net/core/dev.c:10639
 default_device_exit_batch+0x9f3/0xa80 net/core/dev.c:11659
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x795/0xbb0 net/core/net_namespace.c:652
 process_one_work kernel/workqueue.c:2653 [inline]
 process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811
 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 ffff88807376a000
 which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 528 bytes inside of
 freed 4096-byte region [ffff88807376a000, ffff88807376b000)

The buggy address belongs to the physical page:
page:ffffea0001cdda00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x73768
head:ffffea0001cdda00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888077edb001
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888017c4f500 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000040004 00000001ffffffff ffff888077edb001
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 6670, tgid 6670 (syz-executor), ts 300996307530, free_ts 296415525431
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1581
 prep_new_page mm/page_alloc.c:1588 [inline]
 get_page_from_freelist+0x1951/0x19e0 mm/page_alloc.c:3220
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4500
 alloc_slab_page+0x5d/0x160 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2081
 ___slab_alloc+0xc5d/0x12f0 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+0x19e/0x250 mm/slub.c:3534
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc_node_track_caller+0xa2/0x230 mm/slab_common.c:1027
 kmemdup+0x2b/0x70 mm/util.c:131
 kmemdup include/linux/fortify-string.h:779 [inline]
 __addrconf_sysctl_register+0xa6/0x3f0 net/ipv6/addrconf.c:7192
 addrconf_sysctl_register+0x15c/0x1b0 net/ipv6/addrconf.c:7258
 ipv6_add_dev+0xc42/0x11e0 net/ipv6/addrconf.c:451
 addrconf_notify+0x67b/0x1010 net/ipv6/addrconf.c:3640
 notifier_call_chain+0x197/0x380 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:2077 [inline]
 call_netdevice_notifiers net/core/dev.c:2091 [inline]
 register_netdevice+0x16a5/0x1bb0 net/core/dev.c:10351
 virt_wifi_newlink+0x393/0x7c0 drivers/net/wireless/virtual/virt_wifi.c:568
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1181 [inline]
 free_unref_page_prepare+0x7b2/0x8c0 mm/page_alloc.c:2365
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2458
 napi_frag_unref include/linux/skbuff.h:3539 [inline]
 skb_release_data+0x49a/0x800 net/core/skbuff.c:985
 skb_release_all net/core/skbuff.c:1057 [inline]
 __kfree_skb net/core/skbuff.c:1071 [inline]
 skb_attempt_defer_free+0x12f/0x530 net/core/skbuff.c:6846
 tcp_eat_recv_skb net/ipv4/tcp.c:1519 [inline]
 tcp_recvmsg_locked+0x119a/0x2320 net/ipv4/tcp.c:2562
 tcp_recvmsg+0x232/0x860 net/ipv4/tcp.c:2608
 inet_recvmsg+0x140/0x1f0 net/ipv4/af_inet.c:882
 sock_recvmsg_nosec net/socket.c:1046 [inline]
 sock_recvmsg net/socket.c:1068 [inline]
 __sys_recvfrom+0x36a/0x530 net/socket.c:2252
 __do_sys_recvfrom net/socket.c:2270 [inline]
 __se_sys_recvfrom net/socket.c:2266 [inline]
 __x64_sys_recvfrom+0xde/0xf0 net/socket.c:2266
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88807376a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807376a180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807376a200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88807376a280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807376a300: 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
2026/04/27 06:56 linux-6.6.y 9760bf04666d 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in __ethtool_get_link_ksettings
* Struck through repros no longer work on HEAD.