The patch below introduces a pci_ioremap() function that should make it easier for driver authors to do the right thing for the simple, common case. There's also 18 patches that introduce users of this; to reduce lkml noise I've only stuck them in a git tree at git://git.kernel.org/pub/scm/linux/kernel/git/arjan/linux-2.6-pci_ioremap.git (http://git.kernel.org/?p=linux/kernel/git/arjan/linux-2.6-pci_ioremap.git;a=summary) From fef1dd836bc7dc07962a0ae4019af9efd373c76f Mon Sep 17 00:00:00 ...

Hello, I have an Asus N4L-VM DH. This is an Intel Core Solo platform with ICH7-M, it includes the Intel TCO watchdog. When I start the board and kill watchdog, the Intel watchdog reboots the computer. If I have suspended (S3) the machine at least once before killing watchdog, then the board just sits there, no reboot occurs. I have tested this with softdog, and softdog does not fail to reboot the computer post suspend/wake-up. I have compiled the iTCO_wdt module into the kernel, same results ...

The 'parent mmc0 should not be sleeping' message is a known problem with MMC. Thanks, Rafael --

My HP 2510p has an SD card slot and a few days ago I bought one to be able to add support for SD cards in the Debian Installer. Whilst playing with it, I found the following messages in my logs during suspend. At the time the card was inserted, but nothing on it was mounted. There also seems to be a problem while resuming, especially: mmc mmc0:8879: parent mmc0 should not be sleeping More context at the bottom of the mail. From lspci -vvv: 02:06.2 SD Host controller: Ricoh Co Ltd R5C822 ...

Hi Ingo, Here is the fixlets branch, including bitfields API. I think it would be very nice if you could make this a *separate* branch in -tip, say kmemcheck-fixlets or so, as it may touch any part of the kernel and doesn't carry the acks of those maintainers. With these patches, you should be able to include kmemcheck in auto-testing again. At least it works for me :-) You may also kill tip/kmemcheck-dma, which has been integrated already. The following changes since commit ...

I have been involved in numerous discussions with a variety of folks, including Bruce Perens regarding the new policy governing kernel drivers created for specific hardware/features and the Linux Foundations position on proprietary hardware drives. I have attempted to contact the FSF and discuss this with them and they have refused to respond to letters or return telephone calls to discuss this topic (I do not believe this is the result of malice on their part or some conspiracy -- I think its ...

Rik, I do not distribute anything outside of the US, and nothing I offer as downloads is binary without sources. My website at wolfmountaingroup.org is open source only, and I feel I am doing my part to the OSS empire in putting out a kernel debugger and a bunch of other stuff for free. Ad for countries with anally retentive laws about binary drivers, it sounds like places no one wants to pay for stuff anyway so I doubt any of my business associates have any interest in distributing in ...

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Yes, but this compilation warning is pointing to a real problem. We've told the compiler that the pci_dev is const (ie we won't modify it), but pci_dev_put() is most assuredly going to modify and potentially can even free the struct pci_dev. In looking at this, I found another bug in the pci_find_device() rewrite. pci_get_subsys() will put the reference to 'from' (if non-NULL), but the reference was already put by pci_find_device(), so I suspect the reference count ends up going zero very ...

On Sun, 28 Sep 2008 17:47:59 +0200 No, it's not the job of dma_map_sg. Before dma_map_sg, physical continuous page frames in a scatter list are supposed be coalesced. For example, the block layer creates a scatter list in which physical With some of IOMMUs, dma_map_sg might coalesce virtual and physical continuous page frames. If 2.6.24 doesn't do for you, 2.6.27 doesn't too. --

From: Mohammed Gamal <m.gamal005@gmail.com> Add call near absolute instruction. Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com> Signed-off-by: Avi Kivity <avi@qumranet.com> --- arch/x86/kvm/x86_emulate.c | 11 ++++++++++- 1 files changed, 10 insertions(+), 1 deletions(-) diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c index 3ac2f14..0630d21 100644 --- a/arch/x86/kvm/x86_emulate.c +++ b/arch/x86/kvm/x86_emulate.c @@ -286,7 +286,8 @@ static u16 group_table[] = ...

Here is the third and last batch of the KVM updates for the 2.6.28 merge window. Linux 2.6.28 KVM will introduce support for pci device assignment and will improve overall emulation accuracy. Amit Shah (1): KVM: Device Assignment: Free device structures if IRQ allocation fails Avi Kivity (3): KVM: Add statistics for guest irq injections KVM: x86 emulator: fix jmp r/m64 instruction MAINTAINERS: Update Avi Kivity's email address Ben-Ami Yassour (1): KVM: Device Assignment ...

From: Marcelo Tosatti <mtosatti@redhat.com> Convert gfn_to_pfn to use get_user_pages_fast, which can do lockless pagetable lookups on x86. Kernel compilation on 4-way guest is 3.7% faster on VMX. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com> --- arch/powerpc/kvm/44x_tlb.c | 2 -- arch/x86/kvm/mmu.c | 23 +++++++++-------------- arch/x86/kvm/paging_tmpl.h | 8 +------- arch/x86/kvm/vmx.c | 4 ---- ...

Signed-off-by: Avi Kivity <avi@redhat.com> --- MAINTAINERS | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index 232ff4a..6f1f241 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2411,7 +2411,7 @@ S: Supported KERNEL VIRTUAL MACHINE (KVM) P: Avi Kivity -M: avi@qumranet.com +M: avi@redhat.com L: kvm@vger.kernel.org W: http://kvm.qumranet.com S: Supported -- 1.6.0.1 --

From: Kay, Allen M <allen.m.kay@intel.com> This patch extends the VT-d driver to support KVM [Ben: fixed memory pinning] Signed-off-by: Kay, Allen M <allen.m.kay@intel.com> Signed-off-by: Weidong Han <weidong.han@intel.com> Signed-off-by: Ben-Ami Yassour <benami@il.ibm.com> Signed-off-by: Amit Shah <amit.shah@qumranet.com> Acked-by: Mark Gross <mgross@linux.intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com> --- drivers/pci/dmar.c | 4 +- ...

From: Avi Kivity <avi@qumranet.com> jmp r/m64 doesn't require the rex.w prefix to indicate the operand size is 64 bits. Set the Stack attribute (even though it doesn't involve the stack, really) to indicate this. Signed-off-by: Avi Kivity <avi@qumranet.com> --- arch/x86/kvm/x86_emulate.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c index 0630d21..0c120c4 100644 --- a/arch/x86/kvm/x86_emulate.c +++ ...

From: Amit Shah <amit.shah@redhat.com> When an IRQ allocation fails, we free up the device structures and disable the device so that we can unregister the device in the userspace and not expose it to the guest at all. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com> --- arch/x86/kvm/x86.c | 86 +++++++++++++++++++++++++++------------------------- 1 files changed, 45 insertions(+), 41 deletions(-) diff --git a/arch/x86/kvm/x86.c ...

From: Jan Kiszka <jan.kiszka@siemens.com> Commit 1c0f4f5011829dac96347b5f84ba37c2252e1e08 left a useless access of VM_ENTRY_INTR_INFO_FIELD in vmx_intr_assist behind. Clean this up. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@qumranet.com> --- arch/x86/kvm/vmx.c | 3 --- 1 files changed, 0 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index e7e8c86..f8e615f 100644 --- a/arch/x86/kvm/vmx.c +++ ...

From: Sheng Yang <sheng.yang@intel.com> Signed-off-by: Sheng Yang <sheng.yang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com> --- arch/x86/kvm/vmx.c | 18 +++++++++--------- arch/x86/kvm/vmx.h | 4 ++-- 2 files changed, 11 insertions(+), 11 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index f8e615f..046a91b 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -1041,9 +1041,9 @@ static __init int vmx_disabled_by_bios(void) u64 msr; ...

From: Mohammed Gamal <m.gamal005@gmail.com> This adds the std and cld instructions to the emulator. Encountered while running the BIOS with invalid guest state emulation enabled. Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com> Signed-off-by: Avi Kivity <avi@qumranet.com> --- arch/x86/kvm/x86_emulate.c | 10 +++++++++- 1 files changed, 9 insertions(+), 1 deletions(-) diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c index 66e0bd6..944f1f4 100644 --- ...

From: Xiantao Zhang <xiantao.zhang@intel.com> Two ioctl arch functions are added to set vcpu's smp state. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com> --- arch/ia64/kvm/kvm-ia64.c | 37 +++++++++++++++++++++++++++++++++++-- 1 files changed, 35 insertions(+), 2 deletions(-) diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c index cd0d1a7..7ad759e 100644 --- a/arch/ia64/kvm/kvm-ia64.c +++ b/arch/ia64/kvm/kvm-ia64.c @@ ...

From: Avi Kivity <avi@qumranet.com> These can help show whether a guest is making progress or not. Signed-off-by: Avi Kivity <avi@qumranet.com> --- arch/x86/kvm/svm.c | 1 + arch/x86/kvm/vmx.c | 1 + arch/x86/kvm/x86.c | 1 + include/asm-x86/kvm_host.h | 1 + 4 files changed, 4 insertions(+), 0 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 6022888..9b54550 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1519,6 ...

From: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net> For instruction 'and al,imm' we use DstAcc instead of doing the emulation directly into the instruction's opcode. Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net> Signed-off-by: Avi Kivity <avi@qumranet.com> --- arch/x86/kvm/x86_emulate.c | 21 ++------------------- 1 files changed, 2 insertions(+), 19 deletions(-) diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c index 2b43208..ea05117 ...

Hello, Ah yes, the lower bit magic. Thanks! Sorry for the noise. Regards, -- Leon --

This is against tip/iommu. = From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Subject: [PATCH] AMD IOMMU: use iommu_device_max_index AMD IOMMU can use iommu_device_max_index() instead of the homegrown function. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> --- arch/x86/kernel/amd_iommu.c | 10 +++------- 1 files changed, 3 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c index 2028810..34e4d11 100644 --- ...

From: vincen.zswan mcuos.com@gmail.com Dear sir, I have add the Nuvoton ARM series IC W90P910 Platform support to LINUX ARM tree and make a patch named patch-2.6.27-rc7-git5-w90p910.patch. As the file size 177kb,so you can get the patch file from link: http://www.mcuos.com/attachment.php?aid=583 If the patch file is not accepted by Linux, please give some advice , I need to modify it better.thanks! Only add the mach-w90x900 directory to /linux/arch/arm and modify Makefile and ...

I am not a member of this list (I read occasionally via the public archives) or an experienced kernel hacker but I do have a few semi-informed thoughts on the 8256x NVM corruption issue. Take with salt as necessary: According to Intel's datasheet, these interfaces expose *writable* PCI ID registers at NVM words 0x0A-0x0E[1]. Fill the NVM with FFs and the interface will probably respond with vendor ID : device ID FFFF:FFFF during bus enumeration. The potential for these devices to ...

Вітаємо, Владимир Кирилов! Найбільш цікаві події на Коннекті за останній час: Нова версія Коннекту повна нововведень та сюрпризів. По-перше, це функція "Супер Жжот", яка дозволяє яскравіше виражати свою симпатію і підвищувати рейтинг користувачу. По-друге, Коннект.Гроші – бали, які дозволяють використовувати розширені можливості Коннекту. По-третє, це бонусна система, яка дає можливість активним користувачам отримувати Коннект. Гроші і навіть реальні гроші! Нове вiдео: фокус (попробуй ...

Here is my current understanding of the MTRR problems. Please correct any mistakes. There are two broad reasons (use cases) for Linux to change MTRRs (1) to clean up after bad BIOSes. (1a) Some BIOSes don't make all the MTRRs the same on all processors. This is just wrong and the kernel fixes this. (1b) Some BIOSes, for some memory configurations, fail to specify that certain bits of RAM should be cached. The current fix is to not use that RAM, so the MTRRs are not actually changed, ...

--

PCIE extended capability unit is of 4-byte, so the least 2 bits of the most significant 12 bits should be masked off to zero when accessing the extended capability list. Signed-off-by: Harry Ciao<qingtao.cao@windriver.com> --- drivers/pci/pcie/aer/aerdrv_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/pci/pcie/aer/aerdrv_core.c +++ b/drivers/pci/pcie/aer/aerdrv_core.c @@ -52,7 +52,7 @@ if (PCI_EXT_CAP_ID(reg32) == PCI_EXT_CAP_ID_ERR) break; ...

v2: should check with half of range0 size instead of chunk_size So don't have silly big hole. in hpa's case we could auto detect instead of adding mtrr_chunk_size in command line Ingo, please consider to squash this one to previous one | commit 2313c2793d290a8cc37c428f8622c53f3fe1d6dc | Author: Yinghai Lu <yhlu.kernel@gmail.com> | Date: Sat Sep 27 00:30:08 2008 -0700 | | x86: mtrr_cleanup optimization, v2 Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> --- ...

Gabriel, can you check tip/mater too? http://people.redhat.com/mingo/tip.git/readme.txt from reg00: base=0xd0000000 (3328MB), size= 256MB: uncachable, count=1 reg01: base=0xe0000000 (3584MB), size= 512MB: uncachable, count=1 reg02: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1 reg03: base=0x100000000 (4096MB), size= 512MB: write-back, count=1 reg04: base=0x120000000 (4608MB), size= 128MB: write-back, count=1 reg05: base=0x128000000 (4736MB), size= 64MB: write-back, ...

It's looks close, but it seems to be missing some symbols. Below is an excerpt of some of the some of the error messages that come up when trying to link vmlinux.o to another object file. It looks like all the binary layout related symbols are missing, and jiffies also. How/when are these symbols normally linked into the final kernel image? Daniel ... /usr/src/linux/vmlinux.o: In function `sched_clock': /usr/src/linux/kernel/sched.c:80: undefined reference to ...

Is there an object file generated by the kernel build process just before vmlinuz and arch/x86/boot/bzImage are created that contains all the requisite kernel symbols to complete compilation? I understand that such an object file wouldn't make a lot of sense to keep around, because at the point at which such a file were able to be generated the compilation process could just be completed instead. If it's not available is there some easy way to generate it? I am trying to test some kernel code ...

What do you mean by "copy on write", precisely? Do you mean at the file level, directory level, or the filesystem level? We don't have any plans to implement "copy on write" in ext4, although you can create a copy-on-write snapshot at the block device level using LVM/devicemapper. For many things (database backups, etc.) this is quite suitable. So why don't you tell us what you are trying to do, and we can suggest to you ways that you might be able to do it. - Ted --

Thanks Alan, that was it. I recompiled without the pnp serial support and I could finally see the messages. Any chance it will get fixed soon? I had a look to the archives and could only find only a couple of bug reports since a few years, so I guess that's not enough pressure for anyone to care :-( I'll file a bugzilla bug report if there is none and a debian bug too, that might help :-) For the short story about my not booting kernels: my issue is related to a lilo issue in ...

Which defeats the whole purpose of the exercise, we want to provide a single mechanism - including locking - that is usable to all. Otherwise everybody gets to do the hard part themselves, which will undoubtedly result in many broken/suboptimal locking schemes. --

Gents it is great to see this happen one snippet more and you will be able to set the interface into AP mode from userspace hostapd and friends. diff --git a/drivers/net/wireless/ath5k/base.c b/drivers/net/wireless/ath5k/base.c index e09ed2c..69aad6e 100644 --- a/drivers/net/wireless/ath5k/base.c +++ b/drivers/net/wireless/ath5k/base.c @@ -488,6 +488,7 @@ ath5k_pci_probe(struct pci_dev *pdev, hw->wiphy->interface_modes = BIT(NL80211_IFTYPE_STATION) | + ...

No. I think I saw a passing reference from Tim Deegan to it, but I Can the tsc be emulated without a performance hit, or does it trap into the hypervisor? J --

Luis, A huge vote of thanks and congratulations are due to Atheros for taking the step of releasing the HAL. There will be many in the open source community celebrating this move. Much Kudos is due to Atheros for taking this step. The ath5k community is going to benefit hugely from being able to optimise the driver based on a more accurate knowledge of the workings of the HAL. Patches like https://lists.ath5k.org/pipermail/ath5k-devel/2008-September/001311.html will improve the ...

Did you forget something? thanks, greg k-h --

It's just a "don't do that" in my opinion, and it doesn't seem to have caused much trouble for sysadmins down the years. It's good to have a loop driver that can make regular files look like block devices, and it's good to have that working on tmpfs; and I'm glad that trying to swapon a tmpfs file directly just happens to fail because tmpfs doesn't support bmap(). But I don't think it's worth adding in some "valid for swap" call to block devices, and saying no when loop or when loop over ...

On Sun, 28 Sep 2008 20:12:59 +0300 Whoops, sret was left in a bad state. Here's a new one. --- diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6ada059..16b8a22 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2605,7 +2605,6 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, sret = trace_seq_to_user(&iter->seq, ubuf, cnt); if (sret != -EBUSY) return sret; - sret = 0; trace_seq_reset(&iter->seq); ...

On Fri, 26 Sep 2008 17:25:21 +0200 Frederic, this looks good to me, except the very last hunk. I might have chosen names like TRACE_PRINT_{RETRY,DONE,DEFAULT_FORMAT}, but it's your call. I'm not sure which one is more self-explanatory Shouldn't the return type be bool? If it's not, reading this function makes me wonder about the conversion It would be shorter to write if (ret != TRACE_TYPE_UNHANDLED) and then one could even Do these actually need checking? I don't think the default ...

Ok, you were definitely under memory pressure, and yes, it looks like the exact same bug on ppc64 - access to a pointer that is two poointers offset I actually like my second patch better - it looks simpler, and it means that the rules for filesystems using d_compare() are a bit clearer: at least we'll only pass them dentries to look at that haven't gone through d_drop (and we do hold dentry->d_lock that serializes all of that). So here it is again (I sent it out just minutes ago, ...

What about pure memory pressure? We're holding only the RCU read-side lock when looking up dentries, and if there is any memory pressure, the dentries may be unhashed and the inodes removed in parallel. Yes, yes, we end up not actually _releasing_ the dentry, since it's all RCU, but it will set D_UNHASHED and be scheduled for releasing later under RCU. And d_compare() is called before we have done any validation that the name is still active, including checking whether it even got ...

Looks good to me, nicer than the first, and would have prevented my oops today (if I'm interpreting it correctly: certainly I do have I agree that would be insane. There's no end to the weird things a filesystem _could_ do in its d_compare, but it is supposed to be about comparison, and every filesystem I can see in the tree treats Hugh --

The real underlying bug, whatever it is. If this sucker ever becomes negative, we have a big problem. Where _could_ that happen? Remember, we do not allow ->rmdir() and ->unlink() to succeed there. So d_delete() callers in namei.c are out of question. We also never do d_add() with NULL inode in there. We _might_ be doing a bogus d_rehash() on a negative /prooc/sys/<something> dentry that had never been hashed to start with somewhere in generic code, but... I don't see where that could ...

And it is a sign of my admiration for your intellect that I asked you for it. (Does that help?) Rusty. --

On Sat, 27 Sep 2008 20:18:55 +0200 If you use iommu=force boot option, GART always tries to use the IOMMU. --

Hi Mark, do you see my 2 patches for xattr? http://oss.oracle.com/pipermail/ocfs2-devel/2008-September/002839.html this is pretty straightforward and I think it can be committed with it. http://oss.oracle.com/pipermail/ocfs2-devel/2008-September/002839.html this is the new support for empty bucket. Regards, Tao --

Sure, here it is. Honour "quiet" boot parameter in early_printk() calls Signed-off-by: Diego Calleja <diegocg@gmail.com> --- arch/x86/kernel/head64.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) Index: 2.6/arch/x86/kernel/head64.c =================================================================== --- 2.6.orig/arch/x86/kernel/head64.c 2008-09-27 22:54:41.000000000 +0200 +++ 2.6/arch/x86/kernel/head64.c 2008-09-27 23:14:02.000000000 +0200 @@ -108,11 +108,13 ...

Without a vsyscall the cache probably doesn't make too much sense because once you're in the kernel reading the real CPU number is really cheap. I agree with you that the cache should be enabled on all vDSO implementations (that is what my original code did) Also the TSCP version could probably go. I'm still not sure why you say no redzone is that expensive? Do you have numbers? I know it's a few instructions, but it shouldn't Yes, unfortunately glibc didn't chose the same interface ...

I have something in mind what I discussed with Amit at the last KVM forum. The idea was not ready at the event but meanwhile it has matured a bit. I think we should try to build a paravirtualized IOMMU for KVM guests. It should work this way: We reserve a configurable amount of contiguous guest physical memory and map it dma contiguous using some kind of hardware IOMMU. This is possible with all hardare IOMMUs we have in the field by now, also Calgary and GART. The guest does ...

On Mon, 22 Sep 2008 20:21:12 +0200 We already handle the latter. This patchset is more flexible but seems to incur more overheads. This feature will be used for only paravirtualized device passthrough? If so, I feel that there is more simpler (and specific) solutions for it. --

Hi, I'll try an answer since you've had no other replies. You probably need to set up rsyslogd to log all kernel messages. For me, changing the /etc/rsyslog.conf like this does the trick (but beware of my linewrapping client): --- rsyslog.conf.orig 2008-09-28 14:10:20.000000000 +0200 +++ rsyslog.conf.new 2008-09-28 14:10:12.000000000 +0200 @@ -36,7 +36,7 @@ # Log anything (except mail) of level info or higher. # Don't log private authentication ...

> Any thing I can do to help to identify the problem? Best is probably to file a bug report in bugzilla.kernel.org. These sort of things take a bit of pinning down and are often BIOS problems. --

I added might_sleep() to the start of down_timeout() but it neither printed anything to dmesg nor changed the latency issue... Strangely stalling only seems to turn up in linux-tip kernels with very little debugging options set within them. I have a linux-tip that has lots of extra debugging options set and this problem doesn't show up... I've also asked about this on the ACPI mailing list and had a huge amount of help from finding a good point for a cond_resched - ...

Right, I think that's a much better patch. The really Right Thing[TM] to do is probably to pre-clear the buffer and then look for the 0xaa55 signature at offset 510; it is required for sector 0 to be a valid MBR-format partition table and hence for the MBR *signature* to be valid. I'll write that up tomorrow (I'm travelling today), or you can send me a patch. -hpa --