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

Status: upstream: reported on 2025/06/27 22:34
Reported-by: syzbot+c564c1880084746719de@syzkaller.appspotmail.com
First crash: 7d23h, last: 7d23h
▶ ▼ Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in __ethtool_get_link_ksettings net syz done 8878 19m 470d 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 7 284d 417d 0/3 auto-obsoleted due to no activity on 2025/01/02 21:40
upstream KASAN: use-after-free Read in __ethtool_get_link_ksettings net 2 1184d 1221d 0/29 auto-closed as invalid on 2022/07/07 00:01
upstream general protection fault in __ethtool_get_link_ksettings net C error unreliable 298 1452d 1611d 0/29 closed as invalid on 2021/10/06 01:39
upstream KASAN: use-after-free Read in __ethtool_get_link_ksettings (2) net 1 1078d 1073d 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 ffff88807844c210 by task kworker/0:1/9

CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.6.95-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: infiniband ib_cache_event_task
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/0x230 mm/kasan/report.c:475
 kasan_report+0x117/0x150 mm/kasan/report.c:588
 __ethtool_get_link_ksettings+0x6e/0x180 net/ethtool/ioctl.c:438
 ib_get_eth_speed+0x15b/0x7a0 drivers/infiniband/core/verbs.c:1984
 rxe_query_port+0x74/0x260 drivers/infiniband/sw/rxe/rxe_verbs.c:55
 __ib_query_port drivers/infiniband/core/device.c:2076 [inline]
 ib_query_port+0x167/0x820 drivers/infiniband/core/device.c:2108
 ib_cache_update+0x1aa/0xaa0 drivers/infiniband/core/cache.c:1494
 ib_cache_event_task+0xd8/0x1c0 drivers/infiniband/core/cache.c:1568
 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
 </TASK>

Allocated by task 22312:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383
 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:10817
 rtnl_create_link+0x30e/0xd00 net/core/rtnetlink.c:3381
 rtnl_newlink_create net/core/rtnetlink.c:3507 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3737 [inline]
 rtnl_newlink+0x13ee/0x2020 net/core/rtnetlink.c:3750
 rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6475
 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2537
 netlink_unicast_kernel net/netlink/af_netlink.c:1323 [inline]
 netlink_unicast+0x750/0x8c0 net/netlink/af_netlink.c:1349
 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x46a/0x620 net/socket.c:2201
 __do_sys_sendto net/socket.c:2213 [inline]
 __se_sys_sendto net/socket.c:2209 [inline]
 __x64_sys_sendto+0xde/0xf0 net/socket.c:2209
 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

Freed by task 26593:
 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:1806 [inline]
 slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1832
 slab_free mm/slub.c:3816 [inline]
 __kmem_cache_free+0xba/0x1f0 mm/slub.c:3829
 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+0x221/0x470 lib/kobject.c:737
 netdev_run_todo+0xc93/0xd90 net/core/dev.c:10589
 default_device_exit_batch+0x9d0/0xa60 net/core/dev.c:11609
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x77f/0xb90 net/core/net_namespace.c:652
 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 ffff88807844c000
 which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 528 bytes inside of
 freed 4096-byte region [ffff88807844c000, ffff88807844d000)

The buggy address belongs to the physical page:
page:ffffea0001e11200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78448
head:ffffea0001e11200 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88805f262fc1
anon flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff88801784f500 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000040004 00000001ffffffff ffff88805f262fc1
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 22139, tgid 22139 (udevadm), ts 866287119975, free_ts 866280305707
 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:1876
 allocate_slab mm/slub.c:2023 [inline]
 new_slab+0x87/0x2e0 mm/slub.c:2076
 ___slab_alloc+0xc6d/0x12f0 mm/slub.c:3230
 __slab_alloc mm/slub.c:3329 [inline]
 __slab_alloc_node mm/slub.c:3382 [inline]
 slab_alloc_node mm/slub.c:3475 [inline]
 __kmem_cache_alloc_node+0x1a2/0x260 mm/slub.c:3524
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc_node+0xa4/0x230 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]
 seq_buf_alloc fs/seq_file.c:38 [inline]
 seq_read_iter+0x1fa/0xd50 fs/seq_file.c:210
 call_read_iter include/linux/fs.h:2012 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x431/0x920 fs/read_write.c:470
 ksys_read+0x147/0x250 fs/read_write.c:613
 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:2122 [inline]
 __unfreeze_partials+0x1cf/0x210 mm/slub.c:2662
 put_cpu_partial+0x17c/0x250 mm/slub.c:2738
 __slab_free+0x31d/0x410 mm/slub.c:3686
 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:3485 [inline]
 __kmem_cache_alloc_node+0x13e/0x260 mm/slub.c:3524
 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 kernfs_iop_get_link+0x66/0x660 fs/kernfs/symlink.c:135
 vfs_readlink+0x164/0x350 fs/namei.c:5121
 do_readlinkat+0x23f/0x480 fs/stat.c:506
 __do_sys_readlink fs/stat.c:527 [inline]
 __se_sys_readlink fs/stat.c:524 [inline]
 __x64_sys_readlink+0x7f/0x90 fs/stat.c:524
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81

Memory state around the buggy address:
 ffff88807844c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807844c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807844c200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88807844c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807844c300: 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
2025/06/27 22:33 linux-6.6.y 3f5b4c104b7d fc9d8ee5 .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.