From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Chandler Paul Subject: Re: [PATCH] Input: Use for_each_set_bit where appropriate Date: Mon, 21 Sep 2015 10:30:51 -0400 Message-ID: <1442845851.5133.0.camel@redhat.com> References: <1436378929-65748-1-git-send-email-aksgarg1989@gmail.com> <1442520167.3355.13.camel@redhat.com> <20150919182622.GF7081@dtor-ws> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:37986 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752372AbbIUOaw (ORCPT ); Mon, 21 Sep 2015 10:30:52 -0400 In-Reply-To: <20150919182622.GF7081@dtor-ws> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Dmitry Torokhov Cc: aksgarg1989@gmail.com, "linux-input@vger.kernel.org" On Sat, 2015-09-19 at 11:26 -0700, Dmitry Torokhov wrote: > On Thu, Sep 17, 2015 at 04:02:47PM -0400, Stephen Chandler Paul > wrote: > > Hi! The currently upstream version of this patch actually breaks > > uinput, and causes the kernel to panic when attempting to run it > > under > > qemu using spice. Here's a backtrace from kdb: > > > > Stack traceback for pid 656 > > 0xffff8800babed480 656 1 1 2 R > > 0xffff8800babefa80 *spice-vdagentd > > ffff88013747bd58 0000000000000018 ffff88013747bd80 > > ffff8800b7977000 > > 0000000000000003 0000000000000001 0000000000000001 > > ffff8800b7977240 > > ffff88013747bdc0 ffffffff8163f449 0000000000000286 > > 0000000000000018 > > Call Trace: > > [] ? input_event+0x59/0x80 > > [] ? uinput_write+0x154/0x460 [uinput] > > [] ? port_fops_read+0xfd/0x1f0 [virtio_console] > > [] ? __vfs_write+0x37/0x100 > > [] ? vfs_write+0xa9/0x1a0 > > [] ? __fget_light+0x66/0x90 > > [] ? SyS_write+0x58/0xd0 > > [] ? entry_SYSCALL_64_fastpath+0x12/0x76 > > > > And the relevant messages from dmesg: > > > > <1>[ 15.064330] BUG: unable to handle kernel NULL pointer > > dereference at 0000000000000024 > > <1>[ 15.064336] IP: [] > > input_handle_event+0x232/0x4e0 > > <4>[ 15.064343] PGD 0 > > <4>[ 15.064345] Oops: 0000 [#1] SMP > > > > The steps for reproducing this are pretty simple: setup a Fedora 22 > > VM, > > build the latest kernel and install it with make install, and try > > to > > boot the machine and use it over spice with qemu. After moving the > > cursor it'll run into a NULL dereference and panic. > > > > I've tested reverting this commit, and that fixes the NULL > > dereference > > completely. I'm willing to git send-email you the revert if wish. > > *sigh* Sorry about that, the 2nd chunk of the change was completely > bogus. > > Does the patch below fixes this for you? Yep! Applied it to my local tree, and the virtual machine appears to have no issues now. Cheers, Lyude > > Thanks. >