Bug#645785: [nouveau] unable to handle kernel NULL pointer dereference

[Jonathan Nieder <jrnieder@gmail.com>]

tags 645785 + unreproducible
quit

Giuseppe Sacco wrote:
>> Giuseppe Sacco wrote:

>>> I just got this trace while using new gnome shell and playing a video on
>>> youtube on a browser:
[...]
>>> BUG: unable to handle kernel NULL pointer dereference at 00000001
[...]
> today I tried to reproduce it but the system did not crash.

Thanks; marking accordingly.

What chipset do you use?  Please attach /var/log/Xorg.0.log and dmesg
output from just after booting.

The invalid pointer dereference is in nouveau_fence_update(),
dereferencing "chan" to compute chan->dev.  chan is 0x1 (weird ---
shouldn't a struct nouveau_channel be word-aligned?) and was obtained
by dereferencing sync_obj (== fence).

Call trace and interpretation of stack, for the curious:

  nouveau_fence_update(0x1)
	sequence: <uninitialized>
	%ebx: 0xc7fda2e0
	%esi: 0xf6d00ed0
	%edi: 0xf6d00ed0
	%ebp: 0x00000001
 __nouveau_fence_signalled(0xc7fda2e0, 0x0)
	%ebx: 0x000f4240
 __nouveau_fence_wait(0xc7fda2e0, 0x0, 1, 0)
	intr: ?
	timeout: 0x00800c3a
	sync_obj: 0xc7fda2e0
	sync_arg: 0x0
	sleep_time (64 bits): <uninitialized>
	%ebx: 0xf4000000
	%esi: 0x00000004
	%edi: 0xf6ebb800
	%ebp: 0xc61b4d60
 nouveau_fence_sync(0xc7fda2e0, 0xf6ebb800)
	<stack as far as we have includes some locals from here>