[moderation] [kernel?] KASAN: slab-use-after-free Read in disable_device

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 5e6de6a2b522 Add linux-next specific files for 20260811
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12ef52c6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=dd154b7aa6fe745e
dashboard link: https://syzkaller.appspot.com/bug?extid=67ba68af98e5ed48755b
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
CC: [da...@kernel.org drive...@lists.linux.dev gre...@linuxfoundation.org linux-...@vger.kernel.org raf...@kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/78d1a91d7316/disk-5e6de6a2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a85543278af6/vmlinux-5e6de6a2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c66856080afa/bzImage-5e6de6a2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+67ba68...@syzkaller.appspotmail.com

smc: removing ib device syz0
smbdirect: ib_dev[syz0] removed
==================================================================
BUG: KASAN: slab-use-after-
BUG: KASAN: slab-use-after-free in kobject_uevent_net_broadcast+0x12c/0x560 lib/kobject_uevent.c:415
Read of size 8 at addr ffff88807719dd90 by task syz.3.2890/12793

CPU: 0 UID: 0 PID: 12793 Comm: syz.3.2890 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description+0x55/0x1e0 mm/kasan/report.c:378
print_report+0x58/0x70 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
kobject_uevent_net_broadcast+0x12c/0x560 lib/kobject_uevent.c:415
kobject_uevent_env+0x566/0x9e0 lib/kobject_uevent.c:611
device_del+0x74d/0x8f0 drivers/base/core.c:3983
remove_one_compat_dev drivers/infiniband/core/device.c:1036 [inline]
remove_compat_devs drivers/infiniband/core/device.c:1047 [inline]
disable_device+0x248/0x330 drivers/infiniband/core/device.c:1339
__ib_unregister_device+0x2c9/0x400 drivers/infiniband/core/device.c:1571
ib_unregister_device_and_put+0xb8/0xf0 drivers/infiniband/core/device.c:1636
nldev_dellink+0x39c/0x430 drivers/infiniband/core/nldev.c:1902
rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:-1 [inline]
rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
rdma_nl_rcv+0x6ef/0xa40 drivers/infiniband/core/netlink.c:259
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
__sock_sendmsg net/socket.c:815 [inline]
____sys_sendmsg+0x54e/0x850 net/socket.c:2709
___sys_sendmsg+0x2a5/0x360 net/socket.c:2763
__sys_sendmsg net/socket.c:2795 [inline]
__do_sys_sendmsg net/socket.c:2800 [inline]
__se_sys_sendmsg net/socket.c:2798 [inline]
__x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2798
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fad7359e0d9
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:00007fad744e8028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fad73825fa0 RCX: 00007fad7359e0d9
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000003
RBP: 00007fad73635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fad73826038 R14: 00007fad73825fa0 R15: 00007fff44643058
</TASK>

Allocated by task 12759:
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+0x321/0x600 mm/slub.c:5563
_kmalloc_noprof include/linux/slab.h:991 [inline]
_kzalloc_noprof include/linux/slab.h:1312 [inline]
uevent_net_init+0xdb/0x2d0 lib/kobject_uevent.c:782
ops_init+0x35d/0x5d0 net/core/net_namespace.c:137
setup_net+0x118/0x350 net/core/net_namespace.c:450
copy_net_ns+0x4f9/0x720 net/core/net_namespace.c:583
create_new_namespaces+0x3f0/0x6b0 kernel/nsproxy.c:132
copy_namespaces+0x432/0x4b0 kernel/nsproxy.c:195
copy_process+0x1ec0/0x43e0 kernel/fork.c:2310
kernel_clone+0x2d7/0x940 kernel/fork.c:2766
__do_sys_clone kernel/fork.c:2908 [inline]
__se_sys_clone kernel/fork.c:2892 [inline]
__x64_sys_clone+0x1b6/0x230 kernel/fork.c:2892
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 12759:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 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:2748 [inline]
slab_free mm/slub.c:6499 [inline]
kfree+0x1c5/0x650 mm/slub.c:6792
ops_exit_list net/core/net_namespace.c:200 [inline]
ops_undo_list+0x43d/0x8d0 net/core/net_namespace.c:253
setup_net+0x2f6/0x350 net/core/net_namespace.c:466
copy_net_ns+0x4f9/0x720 net/core/net_namespace.c:583
create_new_namespaces+0x3f0/0x6b0 kernel/nsproxy.c:132
copy_namespaces+0x432/0x4b0 kernel/nsproxy.c:195
copy_process+0x1ec0/0x43e0 kernel/fork.c:2310
kernel_clone+0x2d7/0x940 kernel/fork.c:2766
__do_sys_clone kernel/fork.c:2908 [inline]
__se_sys_clone kernel/fork.c:2892 [inline]
__x64_sys_clone+0x1b6/0x230 kernel/fork.c:2892
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807719dd80
which belongs to the cache kmalloc-32 of size 32
The buggy address is located 16 bytes inside of
freed 32-byte region [ffff88807719dd80, ffff88807719dda0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807719de00 pfn:0x7719d
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88801b005780 ffffea0001ddee90 ffffea0001d3c010
raw: ffff88807719de00 0000000000400032 00000000f5000000 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 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5763, tgid 5763 (modprobe), ts 88225820550
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab+0x7d/0x620 mm/slub.c:3462
new_slab mm/slub.c:3513 [inline]
refill_objects+0x2d5/0x350 mm/slub.c:7410
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
__kmalloc_cache_noprof+0x39b/0x600 mm/slub.c:5559
_kmalloc_noprof include/linux/slab.h:991 [inline]
slab_free_hook mm/slub.c:2700 [inline]
slab_free mm/slub.c:6499 [inline]
kmem_cache_free+0x156/0x650 mm/slub.c:6626
anon_vma_free mm/rmap.c:137 [inline]
__put_anon_vma+0x12b/0x2d0 mm/rmap.c:2970
put_anon_vma mm/internal.h:293 [inline]
unlink_anon_vmas+0x544/0x720 mm/rmap.c:536
free_pgtables+0x836/0xb70 mm/memory.c:414
exit_mmap+0x4aa/0x9f0 mm/mmap.c:1327
__mmput+0x118/0x420 kernel/fork.c:1193
exit_mm+0x221/0x2d0 kernel/exit.c:614
do_exit+0x6cd/0x2360 kernel/exit.c:996
do_group_exit+0x22d/0x2f0 kernel/exit.c:1151
page last free pid 5633 tgid 5633 ts 88208835587 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
__free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962
rcu_do_batch kernel/rcu/tree.c:2650 [inline]
rcu_core+0x926/0x1260 kernel/rcu/tree.c:2919
handle_softirqs+0x226/0x860 kernel/softirq.c:645
do_softirq+0x77/0xd0 kernel/softirq.c:546
__local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473
local_bh_enable include/linux/bottom_half.h:33 [inline]
__alloc_skb+0x1b1/0x7a0 net/core/skbuff.c:699
alloc_skb include/linux/skbuff.h:1384 [inline]
nlmsg_new include/net/netlink.h:1055 [inline]
inet6_ifa_notify net/ipv6/addrconf.c:5646 [inline]
__ipv6_ifa_notify+0x1d0/0xc60 net/ipv6/addrconf.c:6306
ipv6_ifa_notify net/ipv6/addrconf.c:6358 [inline]
inet6_addr_add+0x6b4/0xb50 net/ipv6/addrconf.c:3085
inet6_rtm_newaddr+0x9fc/0xe00 net/ipv6/addrconf.c:5094
rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7132
netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
__sock_sendmsg net/socket.c:815 [inline]
__sys_sendto+0x408/0x5a0 net/socket.c:2277
__do_sys_sendto net/socket.c:2284 [inline]
__se_sys_sendto net/socket.c:2280 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2280

Memory state around the buggy address:
ffff88807719dc80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
ffff88807719dd00: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff88807719dd80: fa fb fb fb fc fc fc fc 00 00 00 fc fc fc fc fc
^
ffff88807719de00: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
ffff88807719de80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================


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