mem=nopentium PANIC: early exception 08 rip 246:10

I should also mention that the machine boots and generally works great without "mem=nopentium" (I wanted to experiment with that option with respect to a suspend/resume problem.

This panic still occurs in Maverick and Natty amd64 kernels...

still occurs: maverick 2.6.35-26-generic #46
still occurs: natty 2.6.38-1-generic #28

Here's the fix:

1. "mem=nopentium" is actually only supported on x86_32. On all other platforms, "mem=nopentium" is not recognized at all, and gets handled the same as "mem=blahblah" or any junk string: as if "mem=0" (zero) was specified. So on amd64 ...

2. Specifying "mem=0" (or any junk string, as above) surprisingly is not detected as being a nutty idea... the kernel dutifully configures itself with *zero* bytes of memory (!), resulting in the panic.

The attached patches correct the problem (I'll send them upstream).

I suspect that we can get away with just the second patch if any backporting is on going. I assume we will avoid seeing this as mem=0 if we have that fix and avoid the issue. The first patch is still under discussions. As this is not very likely to be seen I suspect we can wait until this hits mainline before pulling it in. Thanks Kamal for the patches.

Both of the patches have now been applied to [tip:x86/mm]:
http://git.kernel.org/tip/77eed821accf5dd962b1f13bed0680e217e49112
http://git.kernel.org/tip/9a6d44b9adb777ca9549e88cd55bd8f2673c52a2

I do agree that there is no rush to pull these into Ubuntu; I will advise after they land in mainline.

[Unmarking patches as solutions to bug. As per previous two comments, these should not be included but rather the upstream git commits be cherrypicked in.]

Both "x86: Fix panic when handling "mem={invalid}" param" and "x86: Emit "mem=nopentium ignored" warning when not supported" were part of 2.6.38.1 and have landed in natty by now.

Accepted linux into maverick-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

I have tested this in maverick-proposed (2.6.35-29.51) and confirm that the issue is now fixed in Maverick.

Accepted linux into maverick-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

Accepted linux into lucid-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

I confirm this is fixed in lucid-proposed (2.6.32-32.62).

This bug was fixed in the package linux - 2.6.32-32.62

---------------
linux (2.6.32-32.62) lucid-proposed; urgency=low

  [ Brad Figg ]

  * Release Tracking Bug
    - LP: #767370

  [ Stefan Bader ]

  * (config) Disable CONFIG_NET_NS
    - LP: #720095

  [ Upstream Kernel Changes ]

  * Revert "drm/radeon/kms: Fix retrying ttm_bo_init() after it failed
    once."
    - LP: #736234
  * Revert "drm/radeon: fall back to GTT if bo creation/validation in VRAM
    fails."
    - LP: #736234
  * x86: pvclock: Move scale_delta into common header
  * KVM: x86: Fix a possible backwards warp of kvmclock
  * KVM: x86: Fix kvmclock bug
  * cpuset: add a missing unlock in cpuset_write_resmask()
    - LP: #736234
  * keyboard: integer underflow bug
    - LP: #736234
  * RxRPC: Fix v1 keys
    - LP: #736234
  * ixgbe: fix for 82599 erratum on Header Splitting
    - LP: #736234
  * mm: fix possible cause of a page_mapped BUG
    - LP: #736234
  * powerpc/kdump: CPUs assume the context of the oopsing CPU
    - LP: #736234
  * powerpc/kdump: Use chip->shutdown to disable IRQs
    - LP: #736234
  * powerpc: Use more accurate limit for first segment memory allocations
    - LP: #736234
  * powerpc/pseries: Add hcall to read 4 ptes at a time in real mode
    - LP: #736234
  * powerpc/kexec: Speedup kexec hash PTE tear down
    - LP: #736234
  * powerpc/crashdump: Do not fail on NULL pointer dereferencing
    - LP: #736234
  * powerpc/kexec: Fix orphaned offline CPUs across kexec
    - LP: #736234
  * netfilter: nf_log: avoid oops in (un)bind with invalid nfproto values
    - LP: #736234
  * nfsd: wrong index used in inner loop
    - LP: #736234
  * r8169: use RxFIFO overflow workaround for 8168c chipset.
    - LP: #736234
  * Staging: comedi: jr3_pci: Don't ioremap too much space. Check result.
    - LP: #736234
  * net: don't allow CAP_NET_ADMIN to load non-netdev kernel modules,
    CVE-2011-1019
    - LP: #736234
    - CVE-2011-1019
  * ip6ip6: autoload ip6 tunnel
    - LP: #736234
  * Linux 2.6.32.33
    - LP: #736234
  * drm/radeon: fall back to GTT if bo creation/validation in VRAM fails.
    - LP: #652934, #736234
  * drm/radeon/kms: Fix retrying ttm_bo_init() after it failed once.
    - LP: #652934, #736234
  * drm: fix unsigned vs signed comparison issue in modeset ctl ioctl,
    CVE-2011-1013
    - LP: #736234
    - CVE-2011-1013
  * Linux 2.6.32.33+drm33.15
    - LP: #736234
  * econet: Fix crash in aun_incoming(). CVE-2010-4342
    - LP: #736394
    - CVE-2010-4342
  * igb: only use vlan_gro_receive if vlans are registered, CVE-2010-4263
    - LP: #737024
    - CVE-2010-4263
  * irda: prevent integer underflow in IRLMP_ENUMDEVICES, CVE-2010-4529
    - LP: #737823
    - CVE-2010-4529
  * hwmon/f71882fg: Set platform drvdata to NULL later
    - LP: #742056
  * mtd: add "platform:" prefix for platform modalias
    - LP: #742056
  * libata: no special completion processing for EH commands
    - LP: #742056
  * MIPS: MTX-1: Make au1000_eth probe all PHY addresses
    - LP: #742056
  * x86/mm: Handle mm_fault_error() in kernel space
    - LP: #742056
  * ftrace: Fix memory leak with function graph and cpu hotplug
    - LP: #742056
  * x86: Fix panic when ...

This bug was fixed in the package linux - 2.6.35-30.54

---------------
linux (2.6.35-30.54) maverick-proposed; urgency=low

  [ Brad Figg ]

  * Release Tracking Bug
    - LP: #794114

  [ Upstream Kernel Changes ]

  * Revert "xhci: Fix full speed bInterval encoding."
  * Revert "USB: xhci - also free streams when resetting devices"
  * Revert "USB: xhci - fix math in xhci_get_endpoint_interval()"
  * Revert "USB: xhci - fix unsafe macro definitions"

linux (2.6.35-30.53) maverick-proposed; urgency=low

  [ Upstream Kernel Changes ]

  * xhci: Fix full speed bInterval encoding.
    - LP: #792959

linux (2.6.35-30.52) maverick-proposed; urgency=low

  [ Herton R. Krzesinski ]

  * Release Tracking Bug
    - LP: #790653

  [ Stefan Bader ]

  * Include nls_iso8859-1 for virtual images
    - LP: #732046

  [ Thomas Schlichter ]

  * SAUCE: vesafb: mtrr module parameter is uint, not bool
    - LP: #778043

  [ Tim Gardner ]

  * [Config] Add cachefiles.ko to virtual flavour
    - LP: #770430

  [ Upstream Kernel Changes ]

  * Revert "intel_idle: PCI quirk to prevent Lenovo Ideapad s10-3 boot
    hang"
    - LP: #772560
  * Revert "TPM: Long default timeout fix"
    - LP: #772560
  * Revert "tpm_tis: Use timeouts returned from TPM"
    - LP: #772560
  * Revert "xen: set max_pfn_mapped to the last pfn mapped"
  * CAN: Use inode instead of kernel address for /proc file, CVE-2010-4565
    - LP: #765007
    - CVE-2010-4565
  * xfs: prevent leaking uninitialized stack memory in FSGEOMETRY_V1,
    CVE-2011-0711
    - LP: #767740
    - CVE-2011-0711
  * Treat writes as new when holes span across page boundaries,
    CVE-2011-0463
    - LP: #770483
    - CVE-2011-0463
  * fs/partitions/ldm.c: fix oops caused by corrupted partition table,
    CVE-2011-1017
    - LP: #771382
    - CVE-2011-1017
  * qla2xxx: Make the FC port capability mutual exclusive.
    - LP: #772560
  * staging: usbip: bugfixes related to kthread conversion
    - LP: #772560
  * staging: usbip: bugfix add number of packets for isochronous frames
    - LP: #772560
  * staging: usbip: bugfix for isochronous packets and optimization
    - LP: #772560
  * staging: hv: Fix GARP not sent after Quick Migration
    - LP: #772560
  * staging: hv: use sync_bitops when interacting with the hypervisor
    - LP: #772560
  * irda: validate peer name and attribute lengths
    - LP: #772560
  * irda: prevent heap corruption on invalid nickname
    - LP: #772560
  * nilfs2: fix data loss in mmap page write for hole blocks
    - LP: #772560
  * ASoC: Explicitly say registerless widgets have no register
    - LP: #772560
  * ALSA: ens1371: fix Creative Ectiva support
    - LP: #772560
  * ROSE: prevent heap corruption with bad facilities
    - LP: #772560
  * Btrfs: Fix uninitialized root flags for subvolumes
    - LP: #772560
  * x86, mtrr, pat: Fix one cpu getting out of sync during resume
    - LP: #772560
  * UBIFS: do not read flash unnecessarily
    - LP: #772560
  * UBIFS: fix oops on error path in read_pnode
    - LP: #772560
  * UBIFS: fix debugging failure in dbg_check_space_info
    - LP: #772560
  * quota: Don't write quota info in dquot_commit()
    - LP: #772560
  * mm: avoid wrapping vm_...