Created attachment 433780 [details]
File: backtrace

Adding Ben and Dave since this looks display driver related.

I've seen this with the -44.el6 kernel (with the patch to add support for single CRTC devices), but also with a -52.el6:

WARNING: at mm/highmem.c:444 debug_kmap_atomic+0x137/0x1b0() (Tainted: G   M    W )
Hardware name: 808625U
Modules linked in: fuse nfs lockd fscache nfs_acl auth_rpcgss autofs4 sunrpc p4_clockmod ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT nf_conntrack_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables ipv6 dm_mirror dm_region_hash dm_log uinput ppdev parport_pc parport e1000 sg snd_intel8x0 snd_ac97_codec ac97_bus snd_seq snd_seq_device snd_pcm snd_timer snd soundcore snd_page_alloc i2c_i801 iTCO_wdt iTCO_vendor_support ext4 mbcache jbd2 sr_mod cdrom sd_mod crc_t10dif ata_generic pata_acpi ata_piix i915 drm_kms_helper drm i2c_algo_bit i2c_core video output dm_mod [last unloaded: microcode]
Pid: 0, comm: swapper Tainted: G   M    W  2.6.32-52.el6.i686 #1
Call Trace:
 [<c044fd87>] ? warn_slowpath_common+0x77/0xb0
 [<c04f2757>] ? debug_kmap_atomic+0x137/0x1b0
 [<c044fdd3>] ? warn_slowpath_null+0x13/0x20
 [<c04f2757>] ? debug_kmap_atomic+0x137/0x1b0
 [<c043677a>] ? kmap_atomic_prot+0x8a/0x150
 [<c043685c>] ? kmap_atomic+0x1c/0x30
 [<f802afcb>] ? i915_error_object_create+0xfb/0x1e0 [i915]
 [<f802b8d7>] ? i915_handle_error+0x827/0xa80 [i915]
 [<c0479edd>] ? do_gettimeofday+0xd/0x30
 [<f802be65>] ? i915_driver_irq_handler+0x205/0x400 [i915]
 [<c0425363>] ? lapic_next_event+0x13/0x20
 [<c047e01c>] ? clockevents_program_event+0x8c/0x120
 [<c04ad885>] ? handle_IRQ_event+0x45/0x140
 [<c04af98f>] ? handle_fasteoi_irq+0x5f/0xd0
 [<c040c192>] ? handle_irq+0x32/0x60
 [<c040b7c7>] ? do_IRQ+0x47/0xc0
 [<c0474b70>] ? hrtimer_start+0x20/0x30
 [<c040a0f0>] ? common_interrupt+0x30/0x38
 [<c04112dd>] ? mwait_idle+0x4d/0x90
 [<c0408884>] ? cpu_idle+0x94/0xd0
 [<c08090cb>] ? start_secondary+0x20f/0x254
---[ end trace dbc1b4e94e5920a3 ]---

This issue has been proposed when we are only considering blocker
issues in the current Red Hat Enterprise Linux release.

** If you would still like this issue considered for the current
release, ask your support representative to file as a blocker on
your behalf. Otherwise ask that it be considered for the next
Red Hat Enterprise Linux release. **

Is this the 865 machine?

Intel have nearly given up on supporting X on those from what I can see upstream, they seem to have a lot of issues and I'm not sure how well we can support acceleration on them going forward, I suppose I could turn it off for EL6.

Yes, it's the 865 machine. I can provide access to it if it helps...

FWIW, the relevant lspci info:

00:02.0 VGA compatible controller: Intel Corporation 82865G Integrated Graphics Controller (rev 02) (prog-if 00 [VGA controller])
	Subsystem: IBM Device 02d2
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
	Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx+
	Latency: 0
	Interrupt: pin A routed to IRQ 16
	Region 0: Memory at f0000000 (32-bit, prefetchable) [size=128M]
	Region 1: Memory at e8000000 (32-bit, non-prefetchable) [size=512K]
	Region 2: I/O ports at 1800 [size=8]
	Expansion ROM at <unassigned> [disabled]
	Capabilities: <access denied>
	Kernel driver in use: i915
	Kernel modules: i915

Thank you for your bug report. This issue was evaluated for inclusion
in the current release of Red Hat Enterprise Linux. Unfortunately, we
are unable to address this request in the current release. Because we
are in the final stage of Red Hat Enterprise Linux 6 development, only
significant, release-blocking issues involving serious regressions and
data corruption can be considered.

If you believe this issue meets the release blocking criteria as
defined and communicated to you by your Red Hat Support representative,
please ask your representative to file this issue as a blocker for the
current release. Otherwise, ask that it be evaluated for inclusion in
the next minor release of Red Hat Enterprise Linux.

Created attachment 452051 [details]
sosreport of another affected system

I'm seeing a very similar backtrace with RC-4 on one of my test systems; it is captured in this sosreport's var/log/messages .

Created attachment 481715 [details]
File: backtrace

I'm not saying we can't support Intel 8xx but there would want to be a major need for us to investigate and fixes issues on this hardware, which is close to 7-8 years old.

Could it be that we just need this patch? The problem seems to be that the kmap slot is wrong:

commit 788885ae7a298dec73ba999c2fc5d46d42072ddf
Author: Andrew Morton <akpm>
Date:   Tue May 11 14:07:05 2010 -0700

    drivers/gpu/drm/i915/i915_irq.c:i915_error_object_create(): use correct kmap-atomic slot
    
    i915_error_object_create() is called from the timer interrupt and hence
    can corrupt the KM_USER0 slot.  Use KM_IRQ0 instead.
    
    Reported-by: Jaswinder Singh Rajput <jaswinderlinux>
    Tested-by: Jaswinder Singh Rajput <jaswinderlinux>
    Acked-by: Chris Wilson <chris.uk>
    Cc: Dave Airlie <airlied>
    Signed-off-by: Andrew Morton <akpm>
    Signed-off-by: Linus Torvalds <torvalds>

that should be in kernel > 117 and will be in 6.1

Excellent. I'll plan to test out the newer kernel tomorrow when I'll be near the machine.

So far, so good...

I upgraded my machine to -118 today and I no longer see these warnings. Usually I'd get them within an hour or so of normal desktop usage. I'm going to go ahead and close this as a duplicate of the bug under which that patch was committed.

*** This bug has been marked as a duplicate of bug 667565 ***