From: syzbot <syzbot+4393dfdddf166f2de2b0@syzkaller.appspotmail.com>
To: dakr@kernel.org, driver-core@lists.linux.dev,
gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
rafael@kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [kernel?] KASAN: slab-use-after-free Read in disable_device
Date: Sun, 13 Sep 2026 08:54:32 -0700 [thread overview]
Message-ID: <6aa6c738.f81106d8.2ab401.0037.GAE@google.com> (raw)
In-Reply-To: <6a8278d8.dbb3a75c.20434b.0041.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 2f0c1cf72f46 Merge tag 's390-7.3-3' of git://git.kernel.or..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=17ccf615580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8c5c3949d762a91f
dashboard link: https://syzkaller.appspot.com/bug?extid=4393dfdddf166f2de2b0
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15fb19f9580000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4393dfdddf166f2de2b0@syzkaller.appspotmail.com
smbdirect: ib_dev[rxe10] removed
======================
==================================================================
BUG: KASAN: slab-use-after-free in kobject_uevent_net_broadcast lib/kobject_uevent.c:415 [inline]
BUG: KASAN: slab-use-after-free in kobject_uevent_env+0x1383/0x18b0 lib/kobject_uevent.c:611
Read of size 8 at addr ffff8880386e9fd0 by task kworker/u33:4/75
CPU: 3 UID: 0 PID: 75 Comm: kworker/u33:4 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: ib-unreg-wq ib_unregister_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
kobject_uevent_net_broadcast lib/kobject_uevent.c:415 [inline]
kobject_uevent_env+0x1383/0x18b0 lib/kobject_uevent.c:611
device_del+0x605/0x9b0 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+0x1ea/0x280 drivers/infiniband/core/device.c:1339
__ib_unregister_device+0x2b4/0x480 drivers/infiniband/core/device.c:1571
ib_unregister_work+0x19/0x30 drivers/infiniband/core/device.c:1683
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
process_scheduled_works kernel/workqueue.c:3479 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Allocated by task 6226:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x2f8/0x6d0 mm/slub.c:5563
_kmalloc_noprof include/linux/slab.h:991 [inline]
_kzalloc_noprof include/linux/slab.h:1312 [inline]
uevent_net_init+0xd3/0x330 lib/kobject_uevent.c:782
ops_init+0x1e2/0x5f0 net/core/net_namespace.c:137
setup_net+0x118/0x3a0 net/core/net_namespace.c:443
copy_net_ns+0x345/0x7a0 net/core/net_namespace.c:582
create_new_namespaces+0x3ea/0xac0 kernel/nsproxy.c:132
unshare_nsproxy_namespaces+0xf2/0x220 kernel/nsproxy.c:234
ksys_unshare+0x4a2/0xa70 kernel/fork.c:3292
__do_sys_unshare kernel/fork.c:3356 [inline]
__se_sys_unshare kernel/fork.c:3354 [inline]
__x64_sys_unshare+0x31/0x40 kernel/fork.c:3354
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 5751:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5f/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:6508 [inline]
kfree+0x22b/0x6d0 mm/slub.c:6801
ops_exit_list net/core/net_namespace.c:200 [inline]
ops_undo_list+0x2ee/0xab0 net/core/net_namespace.c:253
cleanup_net+0x499/0x920 net/core/net_namespace.c:706
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
process_scheduled_works kernel/workqueue.c:3479 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
The buggy address belongs to the object at ffff8880386e9fc0
which belongs to the cache kmalloc-32 of size 32
The buggy address is located 16 bytes inside of
freed 32-byte region [ffff8880386e9fc0, ffff8880386e9fe0)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880386e9980 pfn:0x386e9
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88801c042780 ffffea0000d14c90 ffffea0000dfb110
raw: ffff8880386e9980 000000000040003e 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 4516, tgid 4516 (kworker/u33:10), ts 10789616045
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab mm/slub.c:3462 [inline]
new_slab+0xa9/0x6e0 mm/slub.c:3513
refill_objects+0xe3/0x410 mm/slub.c:7417
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
__kmalloc_cache_noprof+0x4f4/0x6d0 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:6508 [inline]
kmem_cache_free+0x40f/0x6c0 mm/slub.c:6635
__cleanup_sighand kernel/fork.c:1723 [inline]
__cleanup_sighand+0x6a/0xa0 kernel/fork.c:1715
__exit_signal kernel/exit.c:222 [inline]
release_task+0xcb8/0x1b80 kernel/exit.c:272
exit_notify kernel/exit.c:812 [inline]
do_exit+0x13ba/0x2ae0 kernel/exit.c:1023
call_usermodehelper_exec_async+0x35d/0x4b0 kernel/umh.c:120
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing
Memory state around the buggy address:
ffff8880386e9e80: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
ffff8880386e9f00: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff8880386e9f80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
^
ffff8880386ea000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880386ea080: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
prev parent reply other threads:[~2026-09-13 15:54 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-17 2:58 syzbot
2026-09-13 15:54 ` syzbot [this message]
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