From mboxrd@z Thu Jan 1 00:00:00 1970 From: felipe.balbi@linux.intel.com (Felipe Balbi) Date: Mon, 11 Apr 2016 11:24:22 +0300 Subject: [PATCH] usb: core: buffer: avoid NULL pointer dereferrence In-Reply-To: <1460358968.10419.26.camel@mhfsdcap03> References: <1460106483-24793-1-git-send-email-chunfeng.yun@mediatek.com> <20160408140701.GA3547@kroah.com> <1460343705.10419.12.camel@mhfsdcap03> <87shyspwbz.fsf@intel.com> <1460358968.10419.26.camel@mhfsdcap03> Message-ID: <87y48ko8nd.fsf@intel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, chunfeng yun writes: >> > On Fri, 2016-04-08 at 07:07 -0700, Greg Kroah-Hartman wrote: >> >> On Fri, Apr 08, 2016 at 05:08:03PM +0800, Chunfeng Yun wrote: >> >> > NULL pointer dereferrence will happen when class driver >> >> > wants to allocate zero length buffer and pool_max[0] >> >> > can't be used, so skip reserved pool in this case. >> >> >> >> Why would a driver want to allocate a 0 length buffer? What driver does >> >> this? >> > It's misc/usbtest.c >> >> that'll do what you ask it to do with the userspace tool testusb. Are >> you trying to pass a size of 0 ? >> > No, I just ran "testusb -t10" which called test_ctrl_queue(). > In this function, sub-case 8 passed a parameter @len as 0 to > simple_alloc_urb(), and then it tried to allocate a 0-length buffer. odd, I have never seen this problem running testusb with the same arguments. -- balbi -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 818 bytes Desc: not available URL: