On Mon, Sep 21, 2015 at 10:30:51AM -0400, Stephen Chandler Paul wrote: > 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: > > > [<ffffffff8163f449>] ? input_event+0x59/0x80 > > > [<ffffffffa0509234>] ? uinput_write+0x154/0x460 [uinput] > > > [<ffffffffa00e704d>] ? port_fops_read+0xfd/0x1f0 [virtio_console] > > > [<ffffffff81261627>] ? __vfs_write+0x37/0x100 > > > [<ffffffff81261ff9>] ? vfs_write+0xa9/0x1a0 > > > [<ffffffff81283386>] ? __fget_light+0x66/0x90 > > > [<ffffffff81262cf8>] ? SyS_write+0x58/0xd0 > > > [<ffffffff81833c72>] ? 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: [<ffffffff8163f142>] > > > 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. Thanks Lyude! -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
