Re: [PATCH 1/1] usb: dwc3: core: fix kernel panic when do reboot

[Felipe Balbi <balbi@kernel.org>]

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Peter Chen <peter.chen@kernel.org> writes:

> On 21-06-10 08:36:57, Greg Kroah-Hartman wrote:
>> On Thu, Jun 10, 2021 at 10:00:47AM +0800, Peter Chen wrote:
>> > On 21-06-09 11:42:53, Greg Kroah-Hartman wrote:
>> > > On Wed, Jun 09, 2021 at 11:01:07AM +0200, Greg Kroah-Hartman wrote:
>> > > > On Tue, Jun 08, 2021 at 09:50:01AM -0700, Jack Pham wrote:
>> > > > > Hi Peter,
>> > > > > 
>> > > > > On Tue, Jun 08, 2021 at 06:56:56PM +0800, Peter Chen wrote:
>> > > > > > When do system reboot, it calls dwc3_shutdown and the whole debugfs
>> > > > > > for dwc3 has removed first, when the gadget tries to do deinit, and
>> > > > > > remove debugfs for its endpoints, it meets NULL pointer dereference
>> > > > > > issue when call debugfs_lookup. Fix it by removing the whole dwc3
>> > > > > > debugfs later than dwc3_drd_exit.
>> > > > > 
>> > > > > Ouch, thanks for catching this! I think in your previous reply[1] you
>> > > > > did warn about the debugfs_remove_recursive() getting called twice, but
>> > > > > it seems here the issue is due to the debugfs_lookup() getting called on
>> > > > > a stale dwc->root pointer after it was already removed.
>> > > > 
>> > > > We can also fix this by getting rid of that "root" pointer as it's
>> > > > useless (we can look it up if we need it.)  I'll send a patch later to
>> > > > do that, as it's a good idea to do anyway, and is independant of this
>> > > > fix.
>> > > 
>> > > Now sent:
>> > > 	https://lore.kernel.org/r/20210609093924.3293230-1-gregkh@linuxfoundation.org
>> > 
>> > Hi Felipe,
>> > 
>> > With Greg above patch, this issue is fixed indirectly. I don't think my patch is
>> > needed, do you think so?
>> 
>> Which patch is "your patch" here?
>> 
>
> The patch in this thread.

This one, Greg:
https://lore.kernel.org/r/20210609093924.3293230-1-gregkh@linuxfoundation.org

Now that we have that, I don't think $subject is required.

-- 
balbi

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