From: Shuah Khan <skhan@linuxfoundation.org>
To: Jeffin Philip <jeffinphilip14@gmail.com>
Cc: gregkh@linuxfoundation.org, i@zenithal.me,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
shuah@kernel.org, stable@vger.kernel.org,
syzbot+af76b01c9a0f0ab60fb0@syzkaller.appspotmail.com,
valentina.manea.m@gmail.com,
Shuah Khan <skhan@linuxfoundation.org>
Subject: Re: [PATCH v3 0/2] usbip: usbip_host: remove legacy rebind_store in favor of drivers_probe
Date: Sat, 26 Sep 2026 13:49:21 -0600 [thread overview]
Message-ID: <eeb557fb-7ae5-42f6-8167-83c3828169ef@linuxfoundation.org> (raw)
In-Reply-To: <20260820101800.14650-1-jeffinphilip14@gmail.com>
On 8/20/26 04:18, Jeffin Philip wrote:
> On Tue, 11 Aug 2026 21:35:39 +0530, Jeffin Philip wrote:
>> do_rebind, which sleeps normally gets a mutex lock. However, it does not
>> or should I say, cannot check for null udev between spin lock dropped in
>> rebind_store and entering do_rebind. This is a potential race window
>> already. So, even if we check for null udev under spinlock, we cannot do
>> it outside. Regarding do_rebind, it is called during stub_device_rebind,
>> but that function is called during module exit when all files are removed.
>> So, do_rebind is not designed to work in a concurrent environment in the
>> first place.
>>
>> We have a safer function that can already do what do_rebind does,
>> drivers_probe. So, we use drivers_probe to rebind the device rather than
>> use rebind_store.
>>
>> usbip tool references this function immediately after the device is unbound,
>> which is safe for the tool itself but since we opted for drivers_probe, fix
>> it by using drivers_probe rather than rebind_store after unbinding device
>> which is more safer.
>>
>> Tested and working in both userspace via the tool and manually echoing
>> the busid in the related nodes. rebind node is still left active with a
>> warning to use drivers_probe upon encountering rebind_store.
I want to know your test setup. Can you reproduce this with usbip host and
running bind command from the tool?
Also send me the error messages.
thanks,
-- Shuah
prev parent reply other threads:[~2026-09-26 19:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-11 16:05 Jeffin Philip
2026-08-11 16:05 ` [PATCH v3 1/2] usbip: usbip_host: fix null pointer dereference in rebind_store Jeffin Philip
2026-08-31 10:04 ` Greg KH
2026-08-31 10:25 ` Jeffin Philip
2026-08-11 16:05 ` [PATCH v3 2/2] usbip: tools: replace faulty rebind_store with drivers_probe Jeffin Philip
2026-08-11 22:53 ` [PATCH v3 0/2] usbip: usbip_host: remove legacy rebind_store in favor of drivers_probe Shuah Khan
2026-08-12 2:40 ` Jeffin Philip
2026-08-12 19:31 ` Shuah Khan
2026-08-12 19:42 ` Jeffin Philip
2026-08-20 10:18 ` Jeffin Philip
2026-09-26 19:49 ` Shuah Khan [this message]
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