From: Greg KH <gregkh@linuxfoundation.org>
To: David Cohen <david.a.cohen@linux.intel.com>
Cc: stern@rowland.harvard.edu, sarah.a.sharp@linux.intel.com,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
jianqian <jianqiang.tang@intel.com>
Subject: Re: [RFC/PATCH] usb/xhci: avoid kernel panic on xhci_suspend()
Date: Tue, 7 Jan 2014 17:45:50 -0800 [thread overview]
Message-ID: <20140108014550.GA7823@kroah.com> (raw)
In-Reply-To: <1389145466-8302-1-git-send-email-david.a.cohen@linux.intel.com>
On Tue, Jan 07, 2014 at 05:44:26PM -0800, David Cohen wrote:
> From: jianqian <jianqiang.tang@intel.com>
>
> There is a possible kernel panic faced on xhci_suspend().
> Due to kernel modified the hub autosupend_delay to 0s, after usb1 root
> hub finishes initialization, it will trigger runtime_suspend and then
> it will trigger xhci runtime suspend. But at that time, if
> xhci->shared_hcd is still doing initialization, it is possible to face
> null pointer kernel panic in xhci_suspend() function.
>
> This patch checks if xhci->shared_hcd is null to avoid panic.
That sounds like this is a race that should be fixed properly, not just
papered over, right?
thanks,
greg k-h
next prev parent reply other threads:[~2014-01-08 1:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-08 1:44 [RFC/PATCH] usb/xhci: avoid kernel panic on xhci_suspend() David Cohen
2014-01-08 1:45 ` Greg KH [this message]
2014-01-08 15:48 ` Alan Stern
2014-01-08 19:53 ` David Cohen
2014-02-21 13:29 ` Mathias Nyman
2014-01-08 1:46 ` Greg KH
2014-01-08 3:49 ` Tang, Jianqiang
2014-01-08 4:16 ` Greg KH
2014-01-08 5:45 ` David Cohen
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