From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 16 May 2018 07:49:09 +0200 From: Greg KH To: "Shuah Khan (Samsung OSG)" Cc: valentina.manea.m@gmail.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] usbip: usbip_host: fix bad unlock balance during stub_probe() Message-ID: <20180516054909.GB29964@kroah.com> References: <20180515235723.30845-1-shuah@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180515235723.30845-1-shuah@kernel.org> User-Agent: Mutt/1.9.5 (2018-04-13) X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Tue, May 15, 2018 at 05:57:23PM -0600, Shuah Khan (Samsung OSG) wrote: > stub_probe() calls put_busid_priv() in an error path when device isn't > found in the busid_table. Fix it by making put_busid_priv() safe to be > called with null struct bus_id_priv pointer. > > This problem happens when "usbip bind" is run without loading usbip_host > driver and then running modprobe. The first failed bind attempt unbinds > the device from the original driver and when usbip_host is modprobed, > stub_probe() runs and doesn't find the device in its busid table and calls > put_busid_priv(0 with null bus_id_priv pointer. > > usbip-host 3-10.2: 3-10.2 is not in match_busid table... skip! > > [ 367.359679] ===================================== > [ 367.359681] WARNING: bad unlock balance detected! > [ 367.359683] 4.17.0-rc4+ #5 Not tainted > [ 367.359685] ------------------------------------- > [ 367.359688] modprobe/2768 is trying to release lock ( > [ 367.359689] > ================================================================== > [ 367.359696] BUG: KASAN: null-ptr-deref in > print_unlock_imbalance_bug+0x99/0x110 > [ 367.359699] Read of size 8 at addr 0000000000000058 by task > modprobe/2768 Minor nit, no need to line-wrap this. > [ 367.359705] CPU: 4 PID: 2768 Comm: modprobe Not tainted 4.17.0-rc4+ #5 > > Fixes: 22076557b07c ("usbip: usbip_host: fix NULL-ptr deref and > use-after-free errors") in usb-linus Nor this, and the extra blank line isn't needed here either. I'll fix it up by hand when I queue this up later today, thanks. greg k-h