Created attachment 313488 [details] full dmesg for 2.6.27-0.215.rc1.git4.fc10.x86_64 showing the crash in question Description of problem: Attempts to start X server with 2.6.27-rc1 kernels invariably end up with kernels trying a NULL pointer dereference followed by a blank screen. The last rawhide kernel with a working X is 2.6.27-0.186.rc0.git15. Later kernels boot without any issues to level3 (console). Only an attempt to start X kills video although a machine is still accessible over the net. Version-Release number of selected component (if applicable): kernel-2.6.27-0.215.rc1.git4.fc10.x86_64 and earlier "rc1" How reproducible: always Additional information: With 2.6.27-0.211.rc1.git3.fc10.x86_64 there was also: [drm] Detected VRAM RAM=65536K, accessible=65536K, BAR=65536K [drm] Can't use agp base @0xe0000000lx, won't fit 2.6.27-0.215.rc1.git4.fc10.x86_64 gives only [drm] Initialized drm 1.1.0 20060810 pci 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16 [drm] Initialized radeon 1.29.0 20080528 on minor 0 [drm] Setting GART location based on new memory map so this appears to be ok but later in dmesg output one can see BUG kmalloc-32 (Tainted: G D ): Padding overwritten. 0xffff880015ac1fd8-0xffff880015ac1fff and similar although these may be results of messed up stack.
While with older "rc1" kernels an attempt to start X server was killing it and video doing the same after booting kernel-2.6.27-0.226.rc1.git5.fc10.i686 either locks up a machine completely without any traces in logs or reboots it. With a remote login active before X is tried the following shows up on a remote screen before my machine dies: Message from syslogd@dyna0 at Aug 5 19:22:56 ... kernel:Oops: 0002 [1] SMP DEBUG_PAGEALLOC Message from syslogd@dyna0 at Aug 5 19:22:56 ... kernel:Code: e8 48 fd ff ff 31 db eb 3f 48 c1 e8 20 83 ca 0c 25 ff 00 00 00 c1 e0 04 09 c2 eb 0f 48 c1 e8 20 c1 ea 08 c1 e0 18 09 c2 83 ca 0c <41> 89 54 9d 00 48 ff c3 48 3b 5d d0 0f 82 0d ff ff ff 0f 09 66 Message from syslogd@dyna0 at Aug 5 19:22:56 ... kernel:CR2: 0000000000000000 Message from syslogd@dyna0 at Aug 5 19:22:56 ... kernel:general protection fault: 0000 [2] SMP DEBUG_PAGEALLOC Message from syslogd@dyna0 at Aug 5 19:22:56 ... kernel:Code: 02 00 00 49 8d 94 24 c0 02 00 00 48 8b 03 eb 1e 4c 39 6b 10 75 12 48 89 df e8 fe ff e5 e0 48 89 df e8 8b c1 db e0 eb 0b 48 89 c3 <48> 8b 00 48 39 d3 75 dd 4c 89 f7 e8 2d e7 ff e0 5b 41 5c 41 5d Message from syslogd@dyna0 at Aug 5 19:23:03 ... kernel:Oops: 0000 [3] SMP DEBUG_PAGEALLOC Message from syslogd@dyna0 at Aug 5 19:23:03 ... kernel:Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 48 85 c0 74 0c 48 39 da 74 07 90 ff 88 98 00 00 00 <49> 8b 3e e8 4e a6 de e0 48 8b 43 40 31 d2 48 c7 40 68 00 00 00 Message from syslogd@dyna0 at Aug 5 19:23:03 ... kernel:CR2: 0000000000000000
kernel 2.6.27-0.237.rc2.fc10.x86_64 allows me to start X again. This takes a looong time, and a lots of screen blinking, regardless if this is 'startx' from a console or a login from gdm, but eventually it gets there. I did not try enough times yet to be sure that this is reliable but so far so good. A difference between "rc1" and "rc2"?