Christian Kujau wrote:

Hi,

I started some x11 application (here: firefox) through an ssh connection 
on a remote host and it crashed somehow. OK, no biggie, killed the 
application and be done with it. However, I noticed that the load of the 
machine is now constantly at 7. It's an iBook G4, has nothing to do, 
disks, cpu, netwokr is idle and load is usually < 1. Now it's not
slow to work or anyhow sluggish, but only the load is at 7 after the 
application crashed. When I looked into dmesg I saw:

[84983.750977] Unable to handle kernel paging request for data at address 0x4815d000
[84983.751046] Faulting instruction address: 0xc0012090
[84983.751157] Oops: Kernel access of bad area, sig: 11 [#1]
[84983.751178] PREEMPT PowerMac
[84983.751214] Modules linked in: nls_iso8859_15 nls_cp850 vfat fat isofs nls_base zlib_inflate radeon drm snd_powermac snd_pcm snd_timer snd soundcore snd_page_alloc fuse firewire_ohci firewire_core crc_itu_t ide_cd cdrom ssb bcm43xx rng_core ieee80211softmac uninorth_agp ieee80211 ieee80211_crypt agpgart
[84983.751750] NIP: c0012090 LR: c00165fc CTR: 00000080
[84983.751786] REGS: cea65b30 TRAP: 0300   Not tainted  (2.6.24-rc5)
[84983.751805] MSR: 00009032 <EE,ME,IR,DR>  CR: 24822282  XER: 00000000
[84983.751946] DAR: 4815d000, DSISR: 40000000
[84983.751965] TASK = ee372670[9138] 'firefox-bin' THREAD: cea64000
[84983.751984] GPR00: e62b3a00 cea65be0 ee372670 4815d000 00000080 1bc0c181 4815d000 ffffffff
[84983.752148] GPR08: 00010008 e62b3a00 00000000 c045f000 24822288 1002ea3c cea67690 ce954000
[84983.752315] GPR16: c0420000 c03f6400 cea65cac cea65ca8 c0440000 ce974480 c07d7180 ceba2280
[84983.752468] GPR24: e62b3a00 e62b3a50 4815d000 00000574 ceba2280 4815d000 1bc0c181 c07d7180
[84983.752665] NIP [c0012090] __flush_dcache_icache+0x14/0x40
[84983.752716] LR [c00165fc] update_mmu_cache+0x11c/0x120

Better to include the full stack trace in such reports, but here it
is:

 NIP [c0012090] __flush_dcache_icache+0x14/0x40
 LR [c00165fc] update_mmu_cache+0x11c/0x120
 Call Trace:
 [cea65be0] [ce8c1000] 0xce8c1000 (unreliable)
 [cea65c00] [c0075868] handle_mm_fault+0x39c/0x7f8
 [cea65c50] [c0075dec] get_user_pages+0x128/0x398
 [cea65ca0] [c00c5e18] elf_core_dump+0xb64/0xc28
 [cea65d40] [c0091e64] do_coredump+0x754/0x788
 [cea65e50] [c003cb20] get_signal_to_deliver+0x2dc/0x3fc
 [cea65e80] [c000a678] do_signal+0x48/0x28c
 [cea65f40] [c0012cb4] do_user_signal+0x74/0xc4
 --- Exception: c00 at 0xfd36ea4
     LR = 0x10012018
 Instruction dump:
 4d820020 7c8903a6 7c001bac 38630020 4200fff8 7c0004ac 4e800020 60000000
 54630026 38800080 7c8903a6 7c661b78 <7c00186c> 38630020 4200fff8 7c0004ac

So it looks like the kernel oopsed while firefox was dumping core,
yuck.

This is the first time that this happened on this iBook, and it was not 
reproducible so far (well, it happened just a few minutes ago). Is this 
something to worry about? Or should I file this under "well, shit 
happens"?

It's a real bug.  Hopefully someone on the list can help...