From: Serhat Kumral <serhatkumral1@gmail.com>
To: leon@kernel.org
Cc: jgg@ziepe.ca, parav@nvidia.com, linux-rdma@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] RDMA/core: Fix use-after-free when netns exit races compat dev removal
Date: Thu, 3 Sep 2026 12:46:25 +0300 [thread overview]
Message-ID: <20260903094625.18465-1-serhatkumral1@gmail.com> (raw)
In-Reply-To: <20260902075653.GS24140@unreal>
> Please don't trim kernel panic logs. Please post the full output,
> including the steps required to reproduce the issue.
sure,
-----------------------------------------------------------------------------
i=1
while [ "$i" -le 200 ]; do
dev="rxed$i"
unshare -n /bin/sh -c "
ip link add ${dev} type dummy || exit 1
ip link set ${dev} up || exit 1
ip addr add 198.51.100.1/24 dev ${dev} || exit 1
rdma link add rxe${i} type rxe netdev ${dev} || exit 1
sleep 0.2
ip link set ${dev} netns 1 || exit 1
" || echo "iteration $i failed"
sleep 0.05
ip link del "$dev" 2>/dev/null
i=$((i + 1))
done
-----------------------------------------------------------------------------
Run in a qemu guest with -enable-kvm.
-----------------------------------------------------------------------------
[ 50.325096] ==================================================================
[ 50.325099] BUG: KASAN: slab-use-after-free in kobject_uevent_env+0xb6f/0xc80
[ 50.325118] Read of size 8 at addr ffff8881084d0250 by task kworker/u32:1/62
[ 50.325120]
[ 50.325123] CPU: 3 UID: 0 PID: 62 Comm: kworker/u32:1 Not tainted 7.3.0-rc1 #1 PREEMPT(lazy)
[ 50.325126] Hardware name: QEMU Ubuntu 26.04 PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1ubuntu1 04/01/2014
[ 50.325128] Workqueue: ib-unreg-wq ib_unregister_work
[ 50.325133] Call Trace:
[ 50.325134] <TASK>
[ 50.325135] dump_stack_lvl+0x5d/0x80
[ 50.325140] print_report+0x153/0x4b1
[ 50.325143] ? kobject_uevent_env+0xb6f/0xc80
[ 50.325145] ? __virt_addr_valid+0x221/0x4c0
[ 50.325148] ? kobject_uevent_env+0xb6f/0xc80
[ 50.325150] kasan_report+0xe4/0x1a0
[ 50.325153] ? kobject_uevent_env+0xb6f/0xc80
[ 50.325155] ? __pfx_device_namespace+0x10/0x10
[ 50.325159] kobject_uevent_env+0xb6f/0xc80
[ 50.325161] device_del+0x737/0xc10
[ 50.325164] ? __pfx_device_del+0x10/0x10
[ 50.325166] ? __kobject_del+0xcb/0x310
[ 50.325168] disable_device+0x1ad/0x230
[ 50.325169] ? __pfx_disable_device+0x10/0x10
[ 50.325172] __ib_unregister_device+0x229/0x3f0
[ 50.325174] ? process_one_work+0x790/0x1630
[ 50.325177] ib_unregister_work+0x14/0x30
[ 50.325178] process_one_work+0x8e1/0x1630
[ 50.325181] ? __pfx_process_one_work+0x10/0x10
[ 50.325183] ? lock_acquire+0x18c/0x300
[ 50.325186] ? lock_is_held_type+0x87/0xf0
[ 50.325189] worker_thread+0x4af/0xd20
[ 50.325192] ? __pfx_worker_thread+0x10/0x10
[ 50.325193] kthread+0x2ce/0x3a0
[ 50.325195] ? _raw_spin_unlock_irq+0x23/0x40
[ 50.325199] ? __pfx_kthread+0x10/0x10
[ 50.325200] ret_from_fork+0x520/0x770
[ 50.325203] ? __pfx_ret_from_fork+0x10/0x10
[ 50.325205] ? __switch_to+0x58a/0xf60
[ 50.325207] ? __pfx_kthread+0x10/0x10
[ 50.325209] ret_from_fork_asm+0x1a/0x30
[ 50.325212] </TASK>
[ 50.325213]
[ 50.325213] Allocated by task 1409:
[ 50.325215] kasan_save_stack+0x30/0x50
[ 50.325217] kasan_save_track+0x14/0x30
[ 50.325218] __kasan_kmalloc+0x7f/0x90
[ 50.325221] __kmalloc_cache_noprof+0x223/0x510
[ 50.325224] uevent_net_init+0xcf/0x2f0
[ 50.325225] ops_init+0x185/0x560
[ 50.325228] setup_net+0xf7/0x320
[ 50.325229] copy_net_ns+0x225/0x400
[ 50.325231] create_new_namespaces+0x358/0x9e0
[ 50.325234] unshare_nsproxy_namespaces+0x9c/0x140
[ 50.325239] ksys_unshare+0x4dd/0x770
[ 50.325241] __x64_sys_unshare+0x2f/0x50
[ 50.325243] do_syscall_64+0x106/0x5f0
[ 50.325245] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 50.325248]
[ 50.325249] Freed by task 12:
[ 50.325250] kasan_save_stack+0x30/0x50
[ 50.325251] kasan_save_track+0x14/0x30
[ 50.325252] kasan_save_free_info+0x3b/0x70
[ 50.325254] __kasan_slab_free+0x47/0x70
[ 50.325256] kfree+0x1b3/0x550
[ 50.325257] ops_undo_list+0x273/0x8c0
[ 50.325259] cleanup_net+0x3b3/0x720
[ 50.325261] process_one_work+0x8e1/0x1630
[ 50.325262] worker_thread+0x4af/0xd20
[ 50.325264] kthread+0x2ce/0x3a0
[ 50.325265] ret_from_fork+0x520/0x770
[ 50.325267] ret_from_fork_asm+0x1a/0x30
[ 50.325269]
[ 50.325269] The buggy address belongs to the object at ffff8881084d0240
[ 50.325269] which belongs to the cache kmalloc-32 of size 32
[ 50.325271] The buggy address is located 16 bytes inside of
[ 50.325271] freed 32-byte region [ffff8881084d0240, ffff8881084d0260)
[ 50.325273]
[ 50.325273] The buggy address belongs to the physical page:
[ 50.325275] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8881084d0c80 pfn:0x1084d0
[ 50.325277] flags: 0x200000000000200(workingset|node=0|zone=2)
[ 50.325279] page_type: f5(slab)
[ 50.325282] raw: 0200000000000200 ffff888100042780 ffffea000427e690 ffffea0004039fd0
[ 50.325284] raw: ffff8881084d0c80 000000000040002a 00000000f5000000 0000000000000000
[ 50.325285] page dumped because: kasan: bad access detected
[ 50.325286]
[ 50.325286] Memory state around the buggy address:
[ 50.325287] ffff8881084d0100: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
[ 50.325288] ffff8881084d0180: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
[ 50.325289] >ffff8881084d0200: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
[ 50.325290] ^
[ 50.325291] ffff8881084d0280: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
[ 50.325292] ffff8881084d0300: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
[ 50.325293] ==================================================================
prev parent reply other threads:[~2026-09-03 9:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-18 8:09 Serhat Kumral
2026-09-02 7:56 ` Leon Romanovsky
2026-09-03 9:46 ` Serhat Kumral [this message]
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