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2009-04-01rtc: add platform driver for EFIdann frazier
Munge Stephane Eranian's efirtc.c code into an rtc platform driver [akpm@linux-foundation.org: use is_leap_year()] Signed-off-by: dann frazier <dannf@hp.com> Cc: Alessandro Zummo <alessandro.zummo@towertech.it> Cc: stephane eranian <eranian@googlemail.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01proc tty: switch ia64 simserial to ->proc_fopsAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-30Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-cpumaskLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-cpumask: oprofile: Thou shalt not call __exit functions from __init functions cpumask: remove the now-obsoleted pcibus_to_cpumask(): generic cpumask: remove cpumask_t from core cpumask: convert rcutorture.c cpumask: use new cpumask_ functions in core code. cpumask: remove references to struct irqaction's mask field. cpumask: use mm_cpumask() wrapper: kernel/fork.c cpumask: use set_cpu_active in init/main.c cpumask: remove node_to_first_cpu cpumask: fix seq_bitmap_*() functions. cpumask: remove dangerous CPU_MASK_ALL_PTR, &CPU_MASK_ALL
2009-03-30Merge branch 'proc-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc * 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc: Revert "proc: revert /proc/uptime to ->read_proc hook" proc 2/2: remove struct proc_dir_entry::owner proc 1/2: do PDE usecounting even for ->read_proc, ->write_proc proc: fix sparse warnings in pagemap_read() proc: move fs/proc/inode-alloc.txt comment into a source file
2009-03-31proc 2/2: remove struct proc_dir_entry::ownerAlexey Dobriyan
Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy as correctly noted at bug #12454. Someone can lookup entry with NULL ->owner, thus not pinning enything, and release it later resulting in module refcount underflow. We can keep ->owner and supply it at registration time like ->proc_fops and ->data. But this leaves ->owner as easy-manipulative field (just one C assignment) and somebody will forget to unpin previous/pin current module when switching ->owner. ->proc_fops is declared as "const" which should give some thoughts. ->read_proc/->write_proc were just fixed to not require ->owner for protection. rmmod'ed directories will be empty and return "." and ".." -- no harm. And directories with tricky enough readdir and lookup shouldn't be modular. We definitely don't want such modular code. Removing ->owner will also make PDE smaller. So, let's nuke it. Kudos to Jeff Layton for reminding about this, let's say, oversight. http://bugzilla.kernel.org/show_bug.cgi?id=12454 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-03-30cpumask: remove node_to_first_cpuRusty Russell
Everyone defines it, and only one person uses it (arch/mips/sgi-ip27/ip27-nmi.c). So just open code it there. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: linux-mips@linux-mips.org
2009-03-28Merge branch 'linus' into core/iommuIngo Molnar
Conflicts: arch/x86/Kconfig
2009-03-28Merge branch 'percpu-cpumask-x86-for-linus-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'percpu-cpumask-x86-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (682 commits) percpu: fix spurious alignment WARN in legacy SMP percpu allocator percpu: generalize embedding first chunk setup helper percpu: more flexibility for @dyn_size of pcpu_setup_first_chunk() percpu: make x86 addr <-> pcpu ptr conversion macros generic linker script: define __per_cpu_load on all SMP capable archs x86: UV: remove uv_flush_tlb_others() WARN_ON percpu: finer grained locking to break deadlock and allow atomic free percpu: move fully free chunk reclamation into a work percpu: move chunk area map extension out of area allocation percpu: replace pcpu_realloc() with pcpu_mem_alloc() and pcpu_mem_free() x86, percpu: setup reserved percpu area for x86_64 percpu, module: implement reserved allocation and use it for module percpu variables percpu: add an indirection ptr for chunk page map access x86: make embedding percpu allocator return excessive free space percpu: use negative for auto for pcpu_setup_first_chunk() arguments percpu: improve first chunk initial area map handling percpu: cosmetic renames in pcpu_setup_first_chunk() percpu: clean up percpu constants x86: un-__init fill_pud/pmd/pte x86: remove vestigial fix_ioremap prototypes ... Manually merge conflicts in arch/ia64/kernel/irq_ia64.c
2009-03-28Merge branch 'release' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6 * 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6: [IA64] Fix kstat_this_cpu build breakage
2009-03-28Merge branch 'linus' into percpu-cpumask-x86-for-linus-2Ingo Molnar
Conflicts: arch/sparc/kernel/time_64.c drivers/gpu/drm/drm_proc.c Manual merge to resolve build warning due to phys_addr_t type change on x86: drivers/gpu/drm/drm_info.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-27Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (37 commits) fs: avoid I_NEW inodes Merge code for single and multiple-instance mounts Remove get_init_pts_sb() Move common mknod_ptmx() calls into caller Parse mount options just once and copy them to super block Unroll essentials of do_remount_sb() into devpts vfs: simple_set_mnt() should return void fs: move bdev code out of buffer.c constify dentry_operations: rest constify dentry_operations: configfs constify dentry_operations: sysfs constify dentry_operations: JFS constify dentry_operations: OCFS2 constify dentry_operations: GFS2 constify dentry_operations: FAT constify dentry_operations: FUSE constify dentry_operations: procfs constify dentry_operations: ecryptfs constify dentry_operations: CIFS constify dentry_operations: AFS ...
2009-03-27constify dentry_operations: restAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-27generic compat_sys_ustatChristoph Hellwig
Due to a different size of ino_t ustat needs a compat handler, but currently only x86 and mips provide one. Add a generic compat_sys_ustat and switch all architectures over to it. Instead of doing various user copy hacks compat_sys_ustat just reimplements sys_ustat as it's trivial. This was suggested by Arnd Bergmann. Found by Eric Sandeen when running xfstests/017 on ppc64, which causes stack smashing warnings on RHEL/Fedora due to the too large amount of data writen by the syscall. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-27[IA64] Fix kstat_this_cpu build breakageJes Sorensen
arch/ia64/kernel/irq_ia64.c: In function 'ia64_handle_irq': arch/ia64/kernel/irq_ia64.c:498: error: 'struct kernel_stat' has no member named 'irqs' arch/ia64/kernel/irq_ia64.c:500: error: 'struct kernel_stat' has no member named 'irqs' arch/ia64/kernel/irq_ia64.c: In function 'ia64_process_pending_intr': arch/ia64/kernel/irq_ia64.c:556: error: 'struct kernel_stat' has no member named 'irqs' arch/ia64/kernel/irq_ia64.c:558: error: 'struct kernel_stat' has no member named 'irqs' Fix build breakage due to recent kstat_this_cpu changes in: d7e51e66899f95dabc89b4d4c6674a6e50fa37fc sparseirq: make some func to be used with genirq Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
2009-03-27Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2Ingo Molnar
Conflicts: arch/parisc/kernel/irq.c arch/x86/include/asm/fixmap_64.h arch/x86/include/asm/setup.h kernel/irq/handle.c Semantic merge: arch/x86/include/asm/fixmap.h Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-26Merge branch 'header-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'header-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (50 commits) x86: headers cleanup - setup.h emu101k1.h: fix duplicate include of <linux/types.h> compiler-gcc4: conditionalize #error on __KERNEL__ remove __KERNEL_STRICT_NAMES make netfilter use strict integer types make drm headers use strict integer types make MTD headers use strict integer types make most exported headers use strict integer types make exported headers use strict posix types unconditionally include asm/types.h from linux/types.h make linux/types.h as assembly safe Neither asm/types.h nor linux/types.h is required for arch/ia64/include/asm/fpu.h headers_check fix cleanup: linux/reiserfs_fs.h headers_check fix cleanup: linux/nubus.h headers_check fix cleanup: linux/coda_psdev.h headers_check fix: x86, setup.h headers_check fix: x86, prctl.h headers_check fix: linux/reinserfs_fs.h headers_check fix: linux/socket.h headers_check fix: linux/nubus.h ... Manually fix trivial conflicts in: include/linux/netfilter/xt_limit.h include/linux/netfilter/xt_statistic.h
2009-03-26Merge branch 'irq-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (32 commits) x86: disable __do_IRQ support sparseirq, powerpc/cell: fix unused variable warning in interrupt.c genirq: deprecate obsolete typedefs and defines genirq: deprecate __do_IRQ genirq: add doc to struct irqaction genirq: use kzalloc instead of explicit zero initialization genirq: make irqreturn_t an enum genirq: remove redundant if condition genirq: remove unused hw_irq_controller typedef irq: export remove_irq() and setup_irq() symbols irq: match remove_irq() args with setup_irq() irq: add remove_irq() for freeing of setup_irq() irqs genirq: assert that irq handlers are indeed running in hardirq context irq: name 'p' variables a bit better irq: further clean up the free_irq() code flow irq: refactor and clean up the free_irq() code flow irq: clean up manage.c irq: use GFP_KERNEL for action allocation in request_irq() kernel/irq: fix sparse warning: make symbol static irq: optimize init_kstat_irqs/init_copy_kstat_irqs ...
2009-03-26Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1750 commits) ixgbe: Allow Priority Flow Control settings to survive a device reset net: core: remove unneeded include in net/core/utils.c. e1000e: update version number e1000e: fix close interrupt race e1000e: fix loss of multicast packets e1000e: commonize tx cleanup routine to match e1000 & igb netfilter: fix nf_logger name in ebt_ulog. netfilter: fix warning in ebt_ulog init function. netfilter: fix warning about invalid const usage e1000: fix close race with interrupt e1000: cleanup clean_tx_irq routine so that it completely cleans ring e1000: fix tx hang detect logic and address dma mapping issues bridge: bad error handling when adding invalid ether address bonding: select current active slave when enslaving device for mode tlb and alb gianfar: reallocate skb when headroom is not enough for fcb Bump release date to 25Mar2009 and version to 0.22 r6040: Fix second PHY address qeth: fix wait_event_timeout handling qeth: check for completion of a running recovery qeth: unregister MAC addresses during recovery. ... Manually fixed up conflicts in: drivers/infiniband/hw/cxgb3/cxio_hal.h drivers/infiniband/hw/nes/nes_nic.c
2009-03-26Merge branch 'master' of /home/davem/src/GIT/linux-2.6/David S. Miller
Conflicts: drivers/net/wimax/i2400m/usb-notif.c
2009-03-26Merge commit 'v2.6.29' into core/header-fixesIngo Molnar
2009-03-24KVM: ia64: Fix the build errors due to lack of macros related to MSI.Xiantao Zhang
Include the newly introduced msidef.h to solve the build issues. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24ia64: Move the macro definitions related to MSI to one header file.Xiantao Zhang
For kvm's MSI support, it needs these macros defined in ia64_msi.c, and to avoid duplicate them, move them to one header file and share with kvm. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Acked-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: Report IRQ injection status to userspace.Gleb Natapov
IRQ injection status is either -1 (if there was no CPU found that should except the interrupt because IRQ was masked or ioapic was misconfigured or ...) or >= 0 in that case the number indicates to how many CPUs interrupt was injected. If the value is 0 it means that the interrupt was coalesced and probably should be reinjected. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: ia64: dynamic nr online cpusJes Sorensen
Account for number of online cpus and use that in loops iterating over the list of vpus instead of scanning the full array unconditionally. This patch is a building block to facilitate allowing to bump up the size of MAX_VCPUS significantly. Signed-off-by: Jes Sorensen <jes@sgi.com> Acked-by : Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: ia64: Implement some pal calls needed for windows 2008Xiantao Zhang
For windows 2008, it needs more pal calls to implement for booting. In addition, also changes the name of set_{sal, pal}_call_result to get_{sal,pal}_call_result for readability. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: ia64: Add the support for translating PAL Call's pointer argsXiantao Zhang
Add the support to translate PAL Call's pointer args. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: ia64: vTLB change for enabling windows 2008 bootXiantao Zhang
Simply the logic of hash vTLB, and export kvm_gpa_to_mpa. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: Userspace controlled irq routingAvi Kivity
Currently KVM has a static routing from GSI numbers to interrupts (namely, 0-15 are mapped 1:1 to both PIC and IOAPIC, and 16:23 are mapped 1:1 to the IOAPIC). This is insufficient for several reasons: - HPET requires non 1:1 mapping for the timer interrupt - MSIs need a new method to assign interrupt numbers and dispatch them - ACPI APIC mode needs to be able to reassign the PCI LINK interrupts to the ioapics This patch implements an interrupt routing table (as a linked list, but this can be easily changed) and a userspace interface to replace the table. The routing table is initialized according to the current hardwired mapping. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: ia64: expose registers in struct kvm_regsJes Sorensen
Provide register layout for struct kvm_regs exposed to userland. Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: Add CONFIG_HAVE_KVM_IRQCHIPAvi Kivity
Two KVM archs support irqchips and two don't. Add a Kconfig item to make selecting between the two models easier. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: ia64: Code cleanupXiantao Zhang
Remove some unnecessary blank lines to accord with Kernel's coding style. Also remove vcpu_get_itir_on_fault due to no reference to it. Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: Remove old kvm_guest_debug structsJan Kiszka
Remove the remaining arch fragments of the old guest debug interface that now break non-x86 builds. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: ia64: stack get/restore patchJes Sorensen
Implement KVM_IA64_VCPU_[GS]ET_STACK ioctl calls. This is required for live migrations. Patch is based on previous implementation that was part of old GET/SET_REGS ioctl calls. Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: New guest debug interfaceJan Kiszka
This rips out the support for KVM_DEBUG_GUEST and introduces a new IOCTL instead: KVM_SET_GUEST_DEBUG. The IOCTL payload consists of a generic part, controlling the "main switch" and the single-step feature. The arch specific part adds an x86 interface for intercepting both types of debug exceptions separately and re-injecting them when the host was not interested. Moveover, the foundation for guest debugging via debug registers is layed. To signal breakpoint events properly back to userland, an arch-specific data block is now returned along KVM_EXIT_DEBUG. For x86, the arch block contains the PC, the debug exception, and relevant debug registers to tell debug events properly apart. The availability of this new interface is signaled by KVM_CAP_SET_GUEST_DEBUG. Empty stubs for not yet supported archs are provided. Note that both SVM and VTX are supported, but only the latter was tested yet. Based on the experience with all those VTX corner case, I would be fairly surprised if SVM will work out of the box. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-18Merge branch 'linus' into core/iommuIngo Molnar
2009-03-16Merge branches 'irq/genirq' and 'linus' into irq/coreIngo Molnar
2009-03-10linker script: define __per_cpu_load on all SMP capable archsTejun Heo
Impact: __per_cpu_load available on all SMP capable archs Percpu now requires three symbols to be defined - __per_cpu_load, __per_cpu_start and __per_cpu_end. There were three archs which didn't have it. Update them as follows. * powerpc: can use generic PERCPU() macro. Compile tested for powerpc32, compile/boot tested for powerpc64. * ia64: can use generic PERCPU_VADDR() macro. __phys_per_cpu_start is identical to __per_cpu_load. Compile tested and symbol table looks identical after the change except for the additional __per_cpu_load. * arm: added explicit __per_cpu_load definition. Currently uses unified .init output section so can't use the generic macro. Dunno whether the unified .init ouput section is required by arch peculiarity so I left it alone. Please break it up and use PERCPU() if possible. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Pat Gefre <pfg@sgi.com> Cc: Russell King <rmk@arm.linux.org.uk>
2009-03-06[IA64] fix PCI DMA flag propagation on SN (Altix) with PICsJeremy Higdon
We recently discovered a problem with passing of DMA attributes on SN systems with the older PIC chips. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Jeremy Higdon <jeremy@sgi.com> Cc: <habeck@sgi.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
2009-03-05Merge branch 'linus' into core/iommuIngo Molnar
2009-03-01Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/wireless/iwlwifi/iwl-tx.c net/8021q/vlan_core.c net/core/dev.c
2009-03-01Merge branch 'x86/urgent' into x86/patIngo Molnar
2009-02-25[IA64] Don't go beyond iosapic_intr_info's arraysizeRoel Kluin
vi arch/ia64/kernel/iosapic.c +142 static struct iosapic_intr_info { ... } iosapic_intr_info[NR_IRQS]; But at line 510 we have: for (i = 0; i <= NR_IRQS; i++) { s/<=/</ Signed-off-by: Roel Kluin <roel.kluin@gmail.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
2009-02-25[IA64] Do not go beyond ARRAY_SIZE of unw.hashRoel Kluin
static struct { ... :114 unsigned short hash[UNW_HASH_SIZE]; ... :2152 for (index = 0; index <= UNW_HASH_SIZE; ++index) { This is a bug, isn't it? s/<=/</ Signed-off-by: Roel Kluin <roel.kluin@gmail.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
2009-02-25[IA64] enable setting DMAR on by defaultKyle McMartin
The previous commit which introduced the DMAR_DEFAULT_ON setting in drivers/pci/dmar.c neglected to add the ability for ia64 to enable the IOMMU by default. Rectify that mistake, doh! Signed-off-by: Kyle McMartin <kyle@redhat.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
2009-02-24Merge branch 'master' of /home/davem/src/GIT/linux-2.6/David S. Miller
2009-02-22Merge branch 'linus' into x86/apicIngo Molnar
Conflicts: arch/x86/mach-default/setup.c Semantic conflict resolution: arch/x86/kernel/setup.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-19[IA64] xen_domu build fixTony Luck
arch/ia64/xen/xen_pv_ops.c:156: error: xen_init_ops causes a section type conflict arch/ia64/xen/xen_pv_ops.c:340: error: xen_iosapic_ops causes a section type conflict Signed-off-by: Tony Luck <tony.luck@intel.com>
2009-02-19[IA64] fixes configs and add default config for ia64 xen domUIsaku Yamahata
This patch fixes xen related Kconfigs and add default config file for ia64 xen domU. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Tony Luck <aegl@agluck-desktop.(none)>
2009-02-19[IA64] Remove redundant cpu_clear() in __cpu_disable pathAlex Chiang
The second call to cpu_clear() is redundant, as we've already removed the CPU from cpu_online_map before calling migrate_platform_irqs(). Signed-off-by: Alex Chiang <achiang@hp.com> Signed-off-by: Tony Luck <aegl@agluck-desktop.(none)>
2009-02-19[IA64] Revert "prevent ia64 from invoking irq handlers on offline CPUs"Alex Chiang
This reverts commit e7b140365b86aaf94374214c6f4e6decbee2eb0a. Commit e7b14036 removes the targetted disabled CPU from the cpu_online_map after calls to migrate_platform_irqs and fixup_irqs. Paul McKenney states that the reasoning behind the patch was to prevent irq handlers from running on CPUs marked offline because: RCU happily ignores CPUs that don't have their bits set in cpu_online_map, so if there are RCU read-side critical sections in the irq handlers being run, RCU will ignore them. If the other CPUs were running, they might sequence through the RCU state machine, which could result in data structures being yanked out from under those irq handlers, which in turn could result in oopses or worse. Unfortunately, both ia64 functions above look at cpu_online_map to find a new CPU to migrate interrupts onto. This means we can potentially migrate an interrupt off ourself back to... ourself. Uh oh. This causes an oops when we finally try to process pending interrupts on the CPU we want to disable. The oops results from calling __do_IRQ with a NULL pt_regs: Unable to handle kernel NULL pointer dereference (address 0000000000000040) Call Trace: [<a000000100016930>] show_stack+0x50/0xa0 sp=e0000009c922fa00 bsp=e0000009c92214d0 [<a0000001000171a0>] show_regs+0x820/0x860 sp=e0000009c922fbd0 bsp=e0000009c9221478 [<a00000010003c700>] die+0x1a0/0x2e0 sp=e0000009c922fbd0 bsp=e0000009c9221438 [<a0000001006e92f0>] ia64_do_page_fault+0x950/0xa80 sp=e0000009c922fbd0 bsp=e0000009c92213d8 [<a00000010000c7a0>] ia64_native_leave_kernel+0x0/0x270 sp=e0000009c922fc60 bsp=e0000009c92213d8 [<a0000001000ecdb0>] profile_tick+0xd0/0x1c0 sp=e0000009c922fe30 bsp=e0000009c9221398 [<a00000010003bb90>] timer_interrupt+0x170/0x3e0 sp=e0000009c922fe30 bsp=e0000009c9221330 [<a00000010013a800>] handle_IRQ_event+0x80/0x120 sp=e0000009c922fe30 bsp=e0000009c92212f8 [<a00000010013aa00>] __do_IRQ+0x160/0x4a0 sp=e0000009c922fe30 bsp=e0000009c9221290 [<a000000100012290>] ia64_process_pending_intr+0x2b0/0x360 sp=e0000009c922fe30 bsp=e0000009c9221208 [<a0000001000112d0>] fixup_irqs+0xf0/0x2a0 sp=e0000009c922fe30 bsp=e0000009c92211a8 [<a00000010005bd80>] __cpu_disable+0x140/0x240 sp=e0000009c922fe30 bsp=e0000009c9221168 [<a0000001006c5870>] take_cpu_down+0x50/0xa0 sp=e0000009c922fe30 bsp=e0000009c9221148 [<a000000100122610>] stop_cpu+0xd0/0x200 sp=e0000009c922fe30 bsp=e0000009c92210f0 [<a0000001000e0440>] kthread+0xc0/0x140 sp=e0000009c922fe30 bsp=e0000009c92210c8 [<a000000100014ab0>] kernel_thread_helper+0xd0/0x100 sp=e0000009c922fe30 bsp=e0000009c92210a0 [<a00000010000a4c0>] start_kernel_thread+0x20/0x40 sp=e0000009c922fe30 bsp=e0000009c92210a0 I don't like this revert because it is fragile. ia64 is getting lucky because we seem to only ever process timer interrupts in this path, but if we ever race with an IPI here, we definitely use RCU and have the potential of hitting an oops that Paul describes above. Patching ia64's timer_interrupt() to check for NULL pt_regs is insufficient though, as we still hit the above oops. As a short term solution, I do think that this revert is the right answer. The revert hold up under repeated testing (24+ hour test runs) with this setup: - 8-way rx6600 - randomly toggling CPU online/offline state every 2 seconds - running CPU exercisers, memory hog, disk exercisers, and network stressors - average system load around ~160 In the long term, we really need to figure out why we set pt_regs = NULL in ia64_process_pending_intr(). If it turns out that it is unnecessary to do so, then we could safely re-introduce e7b14036 (along with some other logic to be smarter about migrating interrupts). One final note: x86 also removes the disabled CPU from cpu_online_map and then re-enables interrupts for 1ms, presumably to handle any pending interrupts: arch/x86/kernel/irq_32.c (and irq_64.c): cpu_disable_common: [remove cpu from cpu_online_map] fixup_irqs(): for_each_irq: [break CPU affinities] local_irq_enable(); mdelay(1); local_irq_disable(); So they are doing implicitly what ia64 is doing explicitly. Signed-off-by: Alex Chiang <achiang@hp.com> Signed-off-by: Tony Luck <aegl@agluck-desktop.(none)>