xorg-server-1.9
kernel 2.6.32-rc2 with KMS enabled
xf86-video-ati from git master
mesa from git master
Chipset: "ATI Radeon HD 4200" (ChipID = 0x9710)


Since I updated to kernel 2.6.36-rc1 and rc2, I get random X crashes, 2-3 times/day. It happens browsing with Firefox mostly. But it happened also when I was not on the PC: I came back and X had crashed.

Last part of /var/log/Xorg.0.log.old

Backtrace:
[  1472.163] 0: /usr/bin/X (xorg_backtrace+0x28) [0x48fa08]
[  1472.163] 1: /usr/bin/X (0x400000+0x6ae49) [0x46ae49]
[  1472.163] 2: /lib/libpthread.so.0 (0x7f2941338000+0xf150) [0x7f2941347150]
[  1472.163] 3: /usr/lib/libpixman-1.so.0 (0x7f29410d6000+0x52f50) [0x7f2941128f50]
[  1472.163] 4: /usr/lib/libpixman-1.so.0 (0x7f29410d6000+0x53496) [0x7f2941129496]
[  1472.163] 5: /usr/lib/libpixman-1.so.0 (pixman_fill+0x3d) [0x7f294110895d]
[  1472.163] 6: /usr/lib64/xorg/modules/libfb.so (fbFill+0x2cc) [0x7f293dffe3ec]
[  1472.163] 7: /usr/lib64/xorg/modules/libfb.so (fbPolyFillRect+0x1c6) [0x7f293dffe926]
[  1472.163] 8: /usr/bin/X (0x400000+0x14a3b8) [0x54a3b8]
[  1472.163] 9: /usr/bin/X (0x400000+0x14a5b6) [0x54a5b6]
[  1472.163] 10: /usr/bin/X (miWideLine+0x1a8) [0x54c508]
[  1472.163] 11: /usr/lib64/xorg/modules/libexa.so (0x7f293ddd0000+0x133df) [0x7f293dde33df]
[  1472.163] 12: /usr/bin/X (0x400000+0xc1bec) [0x4c1bec]
[  1472.164] 13: /usr/bin/X (0x400000+0x3fec0) [0x43fec0]
[  1472.172] 14: /usr/bin/X (0x400000+0x418f1) [0x4418f1]
[  1472.172] 15: /usr/bin/X (0x400000+0x2478a) [0x42478a]
[  1472.172] 16: /lib/libc.so.6 (__libc_start_main+0xfd) [0x7f29402cabbd]
[  1472.172] 17: /usr/bin/X (0x400000+0x242e9) [0x4242e9]
[  1472.172] Bus error at address 0x7f2935f63354
[  1472.172] 
Fatal server error:
[  1472.172] Caught signal 7 (Bus error). Server aborting
[  1472.172] 
[  1472.172] 
Please consult the The X.Org Foundation support 
         at http://wiki.x.org
 for help. 
[  1472.172] Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[  1472.172] 
[  1472.184] (II) Power Button: Close
[  1472.184] (II) UnloadModule: "evdev"
[  1472.192] (II) Power Button: Close
[  1472.192] (II) UnloadModule: "evdev"
[  1472.209] (II) Microsoft Basic Optical Mouse: Close
[  1472.209] (II) UnloadModule: "evdev"
[  1472.216] (II) AT Translated Set 2 keyboard: Close
[  1472.216] (II) UnloadModule: "evdev"
[  1472.217] (II) AIGLX: Suspending AIGLX clients for VT switch