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2011-05-23x86, mce, AMD: Fix leaving freed data in a listJulia Lawall
commit d9a5ac9ef306eb5cc874f285185a15c303c50009 upstream. b may be added to a list, but is not removed before being freed in the case of an error. This is done in the corresponding deallocation function, so the code here has been changed to follow that. The sematic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression E,E1,E2; identifier l; @@ *list_add(&E->l,E1); ... when != E1 when != list_del(&E->l) when != list_del_init(&E->l) when != E = E2 *kfree(E);// </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Cc: Borislav Petkov <borislav.petkov@amd.com> Cc: Robert Richter <robert.richter@amd.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Andreas Herrmann <andreas.herrmann3@amd.com> Link: http://lkml.kernel.org/r/1305294731-12127-1-git-send-email-julia@diku.dk Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-23x86, apic: Fix spurious error interrupts triggering on all non-boot APsYouquan Song
commit e503f9e4b092e2349a9477a333543de8f3c7f5d9 upstream. This patch fixes a bug reported by a customer, who found that many unreasonable error interrupts reported on all non-boot CPUs (APs) during the system boot stage. According to Chapter 10 of Intel Software Developer Manual Volume 3A, Local APIC may signal an illegal vector error when an LVT entry is set as an illegal vector value (0~15) under FIXED delivery mode (bits 8-11 is 0), regardless of whether the mask bit is set or an interrupt actually happen. These errors are seen as error interrupts. The initial value of thermal LVT entries on all APs always reads 0x10000 because APs are woken up by BSP issuing INIT-SIPI-SIPI sequence to them and LVT registers are reset to 0s except for the mask bits which are set to 1s when APs receive INIT IPI. When the BIOS takes over the thermal throttling interrupt, the LVT thermal deliver mode should be SMI and it is required from the kernel to keep AP's LVT thermal monitoring register programmed as such as well. This issue happens when BIOS does not take over thermal throttling interrupt, AP's LVT thermal monitor register will be restored to 0x10000 which means vector 0 and fixed deliver mode, so all APs will signal illegal vector error interrupts. This patch check if interrupt delivery mode is not fixed mode before restoring AP's LVT thermal monitor register. Signed-off-by: Youquan Song <youquan.song@intel.com> Acked-by: Suresh Siddha <suresh.b.siddha@intel.com> Acked-by: Yong Wang <yong.y.wang@intel.com> Cc: hpa@linux.intel.com Cc: joe@perches.com Cc: jbaron@redhat.com Cc: trenn@suse.de Cc: kent.liu@intel.com Cc: chaohong.guo@intel.com Link: http://lkml.kernel.org/r/1303402963-17738-1-git-send-email-youquan.song@intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-23x86, AMD: Fix ARAT feature setting againBorislav Petkov
commit 14fb57dccb6e1defe9f89a66f548fcb24c374c1d upstream. Trying to enable the local APIC timer on early K8 revisions uncovers a number of other issues with it, in conjunction with the C1E enter path on AMD. Fixing those causes much more churn and troubles than the benefit of using that timer brings so don't enable it on K8 at all, falling back to the original functionality the kernel had wrt to that. Reported-and-bisected-by: Nick Bowler <nbowler@elliptictech.com> Cc: Boris Ostrovsky <Boris.Ostrovsky@amd.com> Cc: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Greg Kroah-Hartman <greg@kroah.com> Cc: Hans Rosenfeld <hans.rosenfeld@amd.com> Cc: Nick Bowler <nbowler@elliptictech.com> Cc: Joerg-Volker-Peetz <jvpeetz@web.de> Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> Link: http://lkml.kernel.org/r/1305636919-31165-3-git-send-email-bp@amd64.org Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-23Revert "x86, AMD: Fix APIC timer erratum 400 affecting K8 Rev.A-E processors"Borislav Petkov
commit 328935e6348c6a7cb34798a68c326f4b8372e68a upstream. This reverts commit e20a2d205c05cef6b5783df339a7d54adeb50962, as it crashes certain boxes with specific AMD CPU models. Moving the lower endpoint of the Erratum 400 check to accomodate earlier K8 revisions (A-E) opens a can of worms which is simply not worth to fix properly by tweaking the errata checking framework: * missing IntPenging MSR on revisions < CG cause #GP: http://marc.info/?l=linux-kernel&m=130541471818831 * makes earlier revisions use the LAPIC timer instead of the C1E idle routine which switches to HPET, thus not waking up in deeper C-states: http://lkml.org/lkml/2011/4/24/20 Therefore, leave the original boundary starting with K8-revF. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-23x86, hw_breakpoints: Fix racy access to ptrace breakpointsFrederic Weisbecker
commit 87dc669ba25777b67796d7262c569429e58b1ed4 upstream. While the tracer accesses ptrace breakpoints, the child task may concurrently exit due to a SIGKILL and thus release its breakpoints at the same time. We can then dereference some freed pointers. To fix this, hold a reference on the child breakpoints before manipulating them. Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Will Deacon <will.deacon@arm.com> Cc: Prasad <prasad@linux.vnet.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Link: http://lkml.kernel.org/r/1302284067-7860-3-git-send-email-fweisbec@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-09ARM: 6891/1: prevent heap corruption in OABI semtimedopDan Rosenberg
commit 0f22072ab50cac7983f9660d33974b45184da4f9 upstream. When CONFIG_OABI_COMPAT is set, the wrapper for semtimedop does not bound the nsops argument. A sufficiently large value will cause an integer overflow in allocation size, followed by copying too much data into the allocated buffer. Fix this by restricting nsops to SEMOPM. Untested. Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-09x86, AMD: Fix APIC timer erratum 400 affecting K8 Rev.A-E processorsBoris Ostrovsky
commit e20a2d205c05cef6b5783df339a7d54adeb50962 upstream. Older AMD K8 processors (Revisions A-E) are affected by erratum 400 (APIC timer interrupts don't occur in C states greater than C1). This, for example, means that X86_FEATURE_ARAT flag should not be set for these parts. This addresses regression introduced by commit b87cf80af3ba4b4c008b4face3c68d604e1715c6 ("x86, AMD: Set ARAT feature on AMD processors") where the system may become unresponsive until external interrupt (such as keyboard input) occurs. This results, for example, in time not being reported correctly, lack of progress on the system and other lockups. Reported-by: Joerg-Volker Peetz <jvpeetz@web.de> Tested-by: Joerg-Volker Peetz <jvpeetz@web.de> Acked-by: Borislav Petkov <borislav.petkov@amd.com> Signed-off-by: Boris Ostrovsky <Boris.Ostrovsky@amd.com> Link: http://lkml.kernel.org/r/1304113663-6586-1-git-send-email-ostr@amd64.org Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-09m68k/mm: Set all online nodes in N_NORMAL_MEMORYMichael Schmitz
commit 4aac0b4815ba592052758f4b468f253d383dc9d6 upstream. For m68k, N_NORMAL_MEMORY represents all nodes that have present memory since it does not support HIGHMEM. This patch sets the bit at the time node_present_pages has been set by free_area_init_node. At the time the node is brought online, the node state would have to be done unconditionally since information about present memory has not yet been recorded. If N_NORMAL_MEMORY is not accurate, slub may encounter errors since it uses this nodemask to setup per-cache kmem_cache_node data structures. This pach is an alternative to the one proposed by David Rientjes <rientjes@google.com> attempting to set node state immediately when bringing the node online. Signed-off-by: Michael Schmitz <schmitz@debian.org> Tested-by: Thorsten Glaser <tg@debian.org> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-09set memory ranges in N_NORMAL_MEMORY when onlinedDavid Rientjes
commit d9b41e0b54fd7e164daf1e9c539c1070398aa02e upstream. When a DISCONTIGMEM memory range is brought online as a NUMA node, it also needs to have its bet set in N_NORMAL_MEMORY. This is necessary for generic kernel code that utilizes N_NORMAL_MEMORY as a subset of N_ONLINE for memory savings. These types of hacks can hopefully be removed once DISCONTIGMEM is either removed or abstracted away from CONFIG_NUMA. Fixes a panic in the slub code which only initializes structures for N_NORMAL_MEMORY to save memory: Backtrace: [<000000004021c938>] add_partial+0x28/0x98 [<000000004021faa0>] __slab_free+0x1d0/0x1d8 [<000000004021fd04>] kmem_cache_free+0xc4/0x128 [<000000004033bf9c>] ida_get_new_above+0x21c/0x2c0 [<00000000402a8980>] sysfs_new_dirent+0xd0/0x238 [<00000000402a974c>] create_dir+0x5c/0x168 [<00000000402a9ab0>] sysfs_create_dir+0x98/0x128 [<000000004033d6c4>] kobject_add_internal+0x114/0x258 [<000000004033d9ac>] kobject_add_varg+0x7c/0xa0 [<000000004033df20>] kobject_add+0x50/0x90 [<000000004033dfb4>] kobject_create_and_add+0x54/0xc8 [<00000000407862a0>] cgroup_init+0x138/0x1f0 [<000000004077ce50>] start_kernel+0x5a0/0x840 [<000000004011fa3c>] start_parisc+0xa4/0xb8 [<00000000404bb034>] packet_ioctl+0x16c/0x208 [<000000004049ac30>] ip_mroute_setsockopt+0x260/0xf20 Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-09x86, gart: Make sure GART does not map physmem above 1TBJoerg Roedel
commit 665d3e2af83c8fbd149534db8f57d82fa6fa6753 upstream. The GART can only map physical memory below 1TB. Make sure the gart driver in the kernel does not try to map memory above 1TB. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Link: http://lkml.kernel.org/r/1303134346-5805-5-git-send-email-joerg.roedel@amd.com Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-22x86, cpu: Fix regression in AMD errata checking codeHans Rosenfeld
commit 07a7795ca2e6e66d00b184efb46bd0e23d90d3fe upstream. A bug in the family-model-stepping matching code caused the presence of errata to go undetected when OSVW was not used. This causes hangs on some K8 systems because the E400 workaround is not enabled. Signed-off-by: Hans Rosenfeld <hans.rosenfeld@amd.com> LKML-Reference: <1282141190-930137-1-git-send-email-hans.rosenfeld@amd.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-22x86, amd: Disable GartTlbWlkErr when BIOS forgets itJoerg Roedel
commit 5bbc097d890409d8eff4e3f1d26f11a9d6b7c07e upstream. This patch disables GartTlbWlk errors on AMD Fam10h CPUs if the BIOS forgets to do is (or is just too old). Letting these errors enabled can cause a sync-flood on the CPU causing a reboot. The AMD BKDG recommends disabling GART TLB Wlk Error completely. This patch is the fix for https://bugzilla.kernel.org/show_bug.cgi?id=33012 on my machine. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Link: http://lkml.kernel.org/r/20110415131152.GJ18463@8bytes.org Tested-by: Alexandre Demers <alexandre.f.demers@gmail.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-22x86, cpu: Clean up AMD erratum 400 workaroundHans Rosenfeld
commit 9d8888c2a214aece2494a49e699a097c2ba9498b upstream. Remove check_c1e_idle() and use the new AMD errata checking framework instead. Signed-off-by: Hans Rosenfeld <hans.rosenfeld@amd.com> LKML-Reference: <1280336972-865982-2-git-send-email-hans.rosenfeld@amd.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-22x86, cpu: AMD errata checking frameworkHans Rosenfeld
commit d78d671db478eb8b14c78501c0cee1cc7baf6967 upstream. Errata are defined using the AMD_LEGACY_ERRATUM() or AMD_OSVW_ERRATUM() macros. The latter is intended for newer errata that have an OSVW id assigned, which it takes as first argument. Both take a variable number of family-specific model-stepping ranges created by AMD_MODEL_RANGE(). Iff an erratum has an OSVW id, OSVW is available on the CPU, and the OSVW id is known to the hardware, it is used to determine whether an erratum is present. Otherwise, the model-stepping ranges are matched against the current CPU to find out whether the erratum applies. For certain special errata, the code using this framework might have to conduct further checks to make sure an erratum is really (not) present. Signed-off-by: Hans Rosenfeld <hans.rosenfeld@amd.com> LKML-Reference: <1280336972-865982-1-git-send-email-hans.rosenfeld@amd.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-22x86, AMD: Set ARAT feature on AMD processorsBoris Ostrovsky
commit b87cf80af3ba4b4c008b4face3c68d604e1715c6 upstream. Support for Always Running APIC timer (ARAT) was introduced in commit db954b5898dd3ef3ef93f4144158ea8f97deb058. This feature allows us to avoid switching timers from LAPIC to something else (e.g. HPET) and go into timer broadcasts when entering deep C-states. AMD processors don't provide a CPUID bit for that feature but they also keep APIC timers running in deep C-states (except for cases when the processor is affected by erratum 400). Therefore we should set ARAT feature bit on AMD CPUs. Tested-by: Borislav Petkov <borislav.petkov@amd.com> Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com> Acked-by: Mark Langsdorf <mark.langsdorf@amd.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@amd.com> LKML-Reference: <1300205624-4813-1-git-send-email-ostr@amd64.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-22mca.c: Fix cast from integer to pointer warningJeff Mahoney
commit c1d036c4d1cb00b7e8473a2ad0a78f13e13a8183 upstream. ia64_mca_cpu_init has a void *data local variable that is assigned the value from either __get_free_pages() or mca_bootmem(). The problem is that __get_free_pages returns an unsigned long and mca_bootmem, via alloc_bootmem(), returns a void *. format_mca_init_stack takes the void *, and it's also used with __pa(), but that casts it to long anyway. This results in the following build warning: arch/ia64/kernel/mca.c:1898: warning: assignment makes pointer from integer without a cast Cast the return of __get_free_pages to a void * to avoid the warning. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-22tioca: Fix assignment from incompatible pointer warningsJeff Mahoney
commit b4a6b3436531f6c5256e6d60d388c3c28ff1a0e9 upstream. The prototype for sn_pci_provider->{dma_map,dma_map_consistent} expects an unsigned long instead of a u64. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-22x86: Fix a bogus unwind annotation in lib/semaphore_32.SJan Beulich
commit e938c287ea8d977e079f07464ac69923412663ce upstream. 'simple' would have required specifying current frame address and return address location manually, but that's obviously not the case (and not necessary) here. Signed-off-by: Jan Beulich <jbeulich@novell.com> LKML-Reference: <4D6D1082020000780003454C@vpn.id2.novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-14Revert "x86: Cleanup highmap after brk is concluded"Greg Kroah-Hartman
This reverts upstream commit e5f15b45ddf3afa2bbbb10c7ea34fb32b6de0a0e It caused problems in the stable tree and should not have been there. Cc: Yinghai Lu <yinghai@kernel.org> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-14powerpc: Fix default_machine_crash_shutdown #ifdef botchKamalesh Babulal
powerpc: Fix default_machine_crash_shutdown #ifdef botch Commit: c2be05481f6125254c45b78f334d4dd09c701c82 upstream crash_kexec_wait_realmode() is defined only if CONFIG_PPC_STD_MMU_64 and CONFIG_SMP, but is called if CONFIG_PPC_STD_MMU_64 even if !CONFIG_SMP. Fix the conditional compilation around the invocation. Reported-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> cc: Anton Blanchard <anton@samba.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-14powerpc/kexec: Add ifdef CONFIG_PPC_STD_MMU_64 to PPC64 codeKamalesh Babulal
powerpc/kexec: Add ifdef CONFIG_PPC_STD_MMU_64 to PPC64 code This patch introduces PPC64 specific #ifdef bits from the upstream commit: b3df895aebe091b1657a42a8c859bd49fc96646b. Reported-and-tested-by: dann frazier <dannf@dannf.org> Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> cc: Anton Blanchard <anton@samba.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-14x86, mtrr, pat: Fix one cpu getting out of sync during resumeSuresh Siddha
commit 84ac7cdbdd0f04df6b96153f7a79127fd6e45467 upstream. On laptops with core i5/i7, there were reports that after resume graphics workloads were performing poorly on a specific AP, while the other cpu's were ok. This was observed on a 32bit kernel specifically. Debug showed that the PAT init was not happening on that AP during resume and hence it contributing to the poor workload performance on that cpu. On this system, resume flow looked like this: 1. BP starts the resume sequence and we reinit BP's MTRR's/PAT early on using mtrr_bp_restore() 2. Resume sequence brings all AP's online 3. Resume sequence now kicks off the MTRR reinit on all the AP's. 4. For some reason, between point 2 and 3, we moved from BP to one of the AP's. My guess is that printk() during resume sequence is contributing to this. We don't see similar behavior with the 64bit kernel but there is no guarantee that at this point the remaining resume sequence (after AP's bringup) has to happen on BP. 5. set_mtrr() was assuming that we are still on BP and skipped the MTRR/PAT init on that cpu (because of 1 above) 6. But we were on an AP and this led to not reprogramming PAT on this cpu leading to bad performance. Fix this by doing unconditional mtrr_if->set_all() in set_mtrr() during MTRR/PAT init. This might be unnecessary if we are still running on BP. But it is of no harm and will guarantee that after resume, all the cpu's will be in sync with respect to the MTRR/PAT registers. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> LKML-Reference: <1301438292-28370-1-git-send-email-eric@anholt.net> Signed-off-by: Eric Anholt <eric@anholt.net> Tested-by: Keith Packard <keithp@keithp.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-28x86: Cleanup highmap after brk is concludedYinghai Lu
commit e5f15b45ddf3afa2bbbb10c7ea34fb32b6de0a0e upstream. Now cleanup_highmap actually is in two steps: one is early in head64.c and only clears above _end; a second one is in init_memory_mapping() and tries to clean from _brk_end to _end. It should check if those boundaries are PMD_SIZE aligned but currently does not. Also init_memory_mapping() is called several times for numa or memory hotplug, so we really should not handle initial kernel mappings there. This patch moves cleanup_highmap() down after _brk_end is settled so we can do everything in one step. Also we honor max_pfn_mapped in the implementation of cleanup_highmap. Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> LKML-Reference: <alpine.DEB.2.00.1103171739050.3382@kaball-desktop> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-28xen: set max_pfn_mapped to the last pfn mappedStefano Stabellini
commit 14988a4d350ce3b41ecad4f63c4f44c56f5ae34d upstream. Do not set max_pfn_mapped to the end of the initial memory mappings, that also contain pages that don't belong in pfn space (like the mfn list). Set max_pfn_mapped to the last real pfn mapped in the initial memory mappings that is the pfn backing _end. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> LKML-Reference: <alpine.DEB.2.00.1103171739050.3382@kaball-desktop> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-28x86, binutils, xen: Fix another wrong size directiveAlexander van Heukelum
commit 371c394af27ab7d1e58a66bc19d9f1f3ac1f67b4 upstream. The latest binutils (2.21.0.20110302/Ubuntu) breaks the build yet another time, under CONFIG_XEN=y due to a .size directive that refers to a slightly differently named (hence, to the now very strict and unforgiving assembler, non-existent) symbol. [ mingo: This unnecessary build breakage caused by new binutils version 2.21 gets escallated back several kernel releases spanning several years of Linux history, affecting over 130,000 upstream kernel commits (!), on CONFIG_XEN=y 64-bit kernels (i.e. essentially affecting all major Linux distro kernel configs). Git annotate tells us that this slight debug symbol code mismatch bug has been introduced in 2008 in commit 3d75e1b8: 3d75e1b8 (Jeremy Fitzhardinge 2008-07-08 15:06:49 -0700 1231) ENTRY(xen_do_hypervisor_callback) # do_hypervisor_callback(struct *pt_regs) The 'bug' is just a slight assymetry in ENTRY()/END() debug-symbols sequences, with lots of assembly code between the ENTRY() and the END(): ENTRY(xen_do_hypervisor_callback) # do_hypervisor_callback(struct *pt_regs) ... END(do_hypervisor_callback) Human reviewers almost never catch such small mismatches, and binutils never even warned about it either. This new binutils version thus breaks the Xen build on all upstream kernels since v2.6.27, out of the blue. This makes a straightforward Git bisection of all 64-bit Xen-enabled kernels impossible on such binutils, for a bisection window of over hundred thousand historic commits. (!) This is a major fail on the side of binutils and binutils needs to turn this show-stopper build failure into a warning ASAP. ] Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Jan Beulich <jbeulich@novell.com> Cc: H.J. Lu <hjl.tools@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kees Cook <kees.cook@canonical.com> LKML-Reference: <1299877178-26063-1-git-send-email-heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-28powerpc: rtas_flash needs to use rtas_data_bufMilton Miller
commit bd2b64a12bf55bec0d1b949e3dca3f8863409646 upstream. When trying to flash a machine via the update_flash command, Anton received the following error: Restarting system. FLASH: kernel bug...flash list header addr above 4GB The code in question has a comment that the flash list should be in the kernel data and therefore under 4GB: /* NOTE: the "first" block list is a global var with no data * blocks in the kernel data segment. We do this because * we want to ensure this block_list addr is under 4GB. */ Unfortunately the Kconfig option is marked tristate which means the variable may not be in the kernel data and could be above 4GB. Instead of relying on the data segment being below 4GB, use the static data buffer allocated by the kernel for use by rtas. Since we don't use the header struct directly anymore, convert it to a simple pointer. Reported-By: Anton Blanchard <anton@samba.org> Signed-Off-By: Milton Miller <miltonm@bga.com> Tested-By: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-28powerpc/kdump: Fix race in kdump shutdownMichael Neuling
commit 60adec6226bbcf061d4c2d10944fced209d1847d upstream. When we are crashing, the crashing/primary CPU IPIs the secondaries to turn off IRQs, go into real mode and wait in kexec_wait. While this is happening, the primary tears down all the MMU maps. Unfortunately the primary doesn't check to make sure the secondaries have entered real mode before doing this. On PHYP machines, the secondaries can take a long time shutting down the IRQ controller as RTAS calls are need. These RTAS calls need to be serialised which resilts in the secondaries contending in lock_rtas() and hence taking a long time to shut down. We've hit this on large POWER7 machines, where some secondaries are still waiting in lock_rtas(), when the primary tears down the HPTEs. This patch makes sure all secondaries are in real mode before the primary tears down the MMU. It uses the new kexec_state entry in the paca. It times out if the secondaries don't reach real mode after 10sec. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-28fix per-cpu flag problem in the cpu affinity checkersThomas Gleixner
commit 9804c9eaeacfe78651052c5ddff31099f60ef78c upstream. The CHECK_IRQ_PER_CPU is wrong, it should be checking irq_to_desc(irq)->status not just irq. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: James Bottomley <James.Bottomley@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21x86: Flush TLB if PGD entry is changed in i386 PAE modeShaohua Li
commit 4981d01eada5354d81c8929d5b2836829ba3df7b upstream. According to intel CPU manual, every time PGD entry is changed in i386 PAE mode, we need do a full TLB flush. Current code follows this and there is comment for this too in the code. But current code misses the multi-threaded case. A changed page table might be used by several CPUs, every such CPU should flush TLB. Usually this isn't a problem, because we prepopulate all PGD entries at process fork. But when the process does munmap and follows new mmap, this issue will be triggered. When it happens, some CPUs keep doing page faults: http://marc.info/?l=linux-kernel&m=129915020508238&w=2 Reported-by: Yasunori Goto<y-goto@jp.fujitsu.com> Tested-by: Yasunori Goto<y-goto@jp.fujitsu.com> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Shaohua Li<shaohua.li@intel.com> Cc: Mallick Asit K <asit.k.mallick@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm <linux-mm@kvack.org> LKML-Reference: <1300246649.2337.95.camel@sli10-conroe> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21perf, powerpc: Handle events that raise an exception without overflowingAnton Blanchard
commit 0837e3242c73566fc1c0196b4ec61779c25ffc93 upstream. Events on POWER7 can roll back if a speculative event doesn't eventually complete. Unfortunately in some rare cases they will raise a performance monitor exception. We need to catch this to ensure we reset the PMC. In all cases the PMC will be 256 or less cycles from overflow. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20110309143842.6c22845e@kryten> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21IA64: Optimize ticket spinlocks in fsys_rt_sigprocmaskPetr Tesarik
commit 2d2b6901649a62977452be85df53eda2412def24 upstream. Tony's fix (f574c843191728d9407b766a027f779dcd27b272) has a small bug, it incorrectly uses "r3" as a scratch register in the first of the two unlock paths ... it is also inefficient. Optimize the fast path again. Signed-off-by: Petr Tesarik <ptesarik@suse.cz> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21IA64: fix siglockTony Luck
commit f574c843191728d9407b766a027f779dcd27b272 upstream. When ia64 converted to using ticket locks, an inline implementation of trylock/unlock in fsys.S was missed. This was not noticed because in most circumstances it simply resulted in using the slow path because the siglock was apparently not available (under old spinlock rules). Problems occur when the ticket spinlock has value 0x0 (when first initialised, or when it wraps around). At this point the fsys.S code acquires the lock (changing the 0x0 to 0x1. If another process attempts to get the lock at this point, it will change the value from 0x1 to 0x2 (using new ticket lock rules). Then the fsys.S code will free the lock using old spinlock rules by writing 0x0 to it. From here a variety of bad things can happen. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21x86, quirk: Fix SB600 revision checkAndreas Herrmann
commit 1d3e09a304e6c4e004ca06356578b171e8735d3c upstream. Commit 7f74f8f28a2bd9db9404f7d364e2097a0c42cc12 (x86 quirk: Fix polarity for IRQ0 pin2 override on SB800 systems) introduced a regression. It removed some SB600 specific code to determine the revision ID without adapting a corresponding revision ID check for SB600. See this mail thread: http://marc.info/?l=linux-kernel&m=129980296006380&w=2 This patch adapts the corresponding check to cover all SB600 revisions. Tested-by: Wang Lei <f3d27b@gmail.com> Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20110315143137.GD29499@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21x86: Emit "mem=nopentium ignored" warning when not supportedKamal Mostafa
commit 9a6d44b9adb777ca9549e88cd55bd8f2673c52a2 upstream. Emit warning when "mem=nopentium" is specified on any arch other than x86_32 (the only that arch supports it). Signed-off-by: Kamal Mostafa <kamal@canonical.com> BugLink: http://bugs.launchpad.net/bugs/553464 Cc: Yinghai Lu <yinghai@kernel.org> Cc: Len Brown <len.brown@intel.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> LKML-Reference: <1296783486-23033-2-git-send-email-kamal@canonical.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21x86: Fix panic when handling "mem={invalid}" paramKamal Mostafa
commit 77eed821accf5dd962b1f13bed0680e217e49112 upstream. Avoid removing all of memory and panicing when "mem={invalid}" is specified, e.g. mem=blahblah, mem=0, or mem=nopentium (on platforms other than x86_32). Signed-off-by: Kamal Mostafa <kamal@canonical.com> BugLink: http://bugs.launchpad.net/bugs/553464 Cc: Yinghai Lu <yinghai@kernel.org> Cc: Len Brown <len.brown@intel.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> LKML-Reference: <1296783486-23033-1-git-send-email-kamal@canonical.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21x86/mm: Handle mm_fault_error() in kernel spaceAndrey Vagin
commit f86268549f424f83b9eb0963989270e14fbfc3de upstream. mm_fault_error() should not execute oom-killer, if page fault occurs in kernel space. E.g. in copy_from_user()/copy_to_user(). This would happen if we find ourselves in OOM on a copy_to_user(), or a copy_from_user() which faults. Without this patch, the kernels hangs up in copy_from_user(), because OOM killer sends SIG_KILL to current process, but it can't handle a signal while in syscall, then the kernel returns to copy_from_user(), reexcute current command and provokes page_fault again. With this patch the kernel return -EFAULT from copy_from_user(). The code, which checks that page fault occurred in kernel space, has been copied from do_sigbus(). This situation is handled by the same way on powerpc, xtensa, tile, ... Signed-off-by: Andrey Vagin <avagin@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <201103092322.p29NMNPH001682@imap1.linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21MIPS: MTX-1: Make au1000_eth probe all PHY addressesFlorian Fainelli
commit bf3a1eb85967dcbaae42f4fcb53c2392cec32677 upstream. When au1000_eth probes the MII bus for PHY address, if we do not set au1000_eth platform data's phy_search_highest_address, the MII probing logic will exit early and will assume a valid PHY is found at address 0. For MTX-1, the PHY is at address 31, and without this patch, the link detection/speed/duplex would not work correctly. Signed-off-by: Florian Fainelli <florian@openwrt.org> To: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2111/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21powerpc/kexec: Fix orphaned offline CPUs across kexecMatt Evans
Commit: e8e5c2155b0035b6e04f29be67f6444bc914005b upstream When CPU hotplug is used, some CPUs may be offline at the time a kexec is performed. The subsequent kernel may expect these CPUs to be already running, and will declare them stuck. On pseries, there's also a soft-offline (cede) state that CPUs may be in; this can also cause problems as the kexeced kernel may ask RTAS if they're online -- and RTAS would say they are. The CPU will either appear stuck, or will cause a crash as we replace its cede loop beneath it. This patch kicks each present offline CPU awake before the kexec, so that none are forever lost to these assumptions in the subsequent kernel. Now, the behaviour is that all available CPUs that were offlined are now online & usable after the kexec. This mimics the behaviour of a full reboot (on which all CPUs will be restarted). Signed-off-by: Matt Evans <matt@ozlabs.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Kamalesh babulal <kamalesh@linux.vnet.ibm.com> cc: Anton Blanchard <anton@samba.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21powerpc/crashdump: Do not fail on NULL pointer dereferencingMaxim Uvarov
commit 426b6cb478e60352a463a0d1ec75c1c9fab30b13 upstream. Signed-off-by: Maxim Uvarov <muvarov@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Kamalesh babulal <kamalesh@linux.vnet.ibm.com> cc: Anton Blanchard <anton@samba.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21powerpc/kexec: Speedup kexec hash PTE tear downMichael Neuling
commit d504bed676caad29a3dba3d3727298c560628f5c upstream. Currently for kexec the PTE tear down on 1TB segment systems normally requires 3 hcalls for each PTE removal. On a machine with 32GB of memory it can take around a minute to remove all the PTEs. This optimises the path so that we only remove PTEs that are valid. It also uses the read 4 PTEs at once HCALL. For the common case where a PTEs is invalid in a 1TB segment, this turns the 3 HCALLs per PTE down to 1 HCALL per 4 PTEs. This gives an > 10x speedup in kexec times on PHYP, taking a 32GB machine from around 1 minute down to a few seconds. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Kamalesh babulal <kamalesh@linux.vnet.ibm.com> cc: Anton Blanchard <anton@samba.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21powerpc/pseries: Add hcall to read 4 ptes at a time in real modeMichael Neuling
commit f90ece28c1f5b3ec13fe481406857fe92f4bc7d1 upstream. This adds plpar_pte_read_4_raw() which can be used read 4 PTEs from PHYP at a time, while in real mode. It also creates a new hcall9 which can be used in real mode. It's the same as plpar_hcall9 but minus the tracing hcall statistics which may require variables outside the RMO. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Kamalesh babulal <kamalesh@linux.vnet.ibm.com> Cc: Anton Blanchard <anton@samba.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21powerpc/kdump: Use chip->shutdown to disable IRQsAnton Blanchard
commit 5d7a87217de48b234b3c8ff8a73059947d822e07 upstream. I saw this in a kdump kernel: IOMMU table initialized, virtual merging enabled Interrupt 155954 (real) is invalid, disabling it. Interrupt 155953 (real) is invalid, disabling it. ie we took some spurious interrupts. default_machine_crash_shutdown tries to disable all interrupt sources but uses chip->disable which maps to the default action of: static void default_disable(unsigned int irq) { } If we use chip->shutdown, then we actually mask the IRQ: static void default_shutdown(unsigned int irq) { struct irq_desc *desc = irq_to_desc(irq); desc->chip->mask(irq); desc->status |= IRQ_MASKED; } Not sure why we don't implement a ->disable action for xics.c, or why default_disable doesn't mask the interrupt. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Kamalesh babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21powerpc/kdump: CPUs assume the context of the oopsing CPUAnton Blanchard
commit 0644079410065567e3bb31fcb8e6441f2b7685a9 upstream. We wrap the crash_shutdown_handles[] calls with longjmp/setjmp, so if any of them fault we can recover. The problem is we add a hook to the debugger fault handler hook which calls longjmp unconditionally. This first part of kdump is run before we marshall the other CPUs, so there is a very good chance some CPU on the box is going to page fault. And when it does it hits the longjmp code and assumes the context of the oopsing CPU. The machine gets very confused when it has 10 CPUs all with the same stack, all thinking they have the same CPU id. I get even more confused trying to debug it. The patch below adds crash_shutdown_cpu and uses it to specify which cpu is in the protected region. Since it can only be -1 or the oopsing CPU, we don't need to use memory barriers since it is only valid on the local CPU - no other CPU will ever see a value that matches it's local CPU id. Eventually we should switch the order and marshall all CPUs before doing the crash_shutdown_handles[] calls, but that is a bigger fix. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Kamalesh babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21powerpc: Use more accurate limit for first segment memory allocationsAnton Blanchard
commit 095c7965f4dc870ed2b65143b1e2610de653416c upstream. Author: Milton Miller <miltonm@bga.com> On large machines we are running out of room below 256MB. In some cases we only need to ensure the allocation is in the first segment, which may be 256MB or 1TB. Add slb0_limit and use it to specify the upper limit for the irqstack and emergency stacks. On a large ppc64 box, this fixes a panic at boot when the crashkernel= option is specified (previously we would run out of memory below 256MB). Signed-off-by: Milton Miller <miltonm@bga.com> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21x86: Use u32 instead of long to set reset vector back to 0Don Zickus
commit 299c56966a72b9109d47c71a6db52097098703dd upstream. A customer of ours, complained that when setting the reset vector back to 0, it trashed other data and hung their box. They noticed when only 4 bytes were set to 0 instead of 8, everything worked correctly. Mathew pointed out: | | We're supposed to be resetting trampoline_phys_low and | trampoline_phys_high here, which are two 16-bit values. | Writing 64 bits is definitely going to overwrite space | that we're not supposed to be touching. | So limit the area modified to u32. Signed-off-by: Don Zickus <dzickus@redhat.com> Acked-by: Matthew Garrett <mjg@redhat.com> LKML-Reference: <1297139100-424-1-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21x86 quirk: Fix polarity for IRQ0 pin2 override on SB800 systemsAndreas Herrmann
commit 7f74f8f28a2bd9db9404f7d364e2097a0c42cc12 upstream. On some SB800 systems polarity for IOAPIC pin2 is wrongly specified as low active by BIOS. This caused system hangs after resume from S3 when HPET was used in one-shot mode on such systems because a timer interrupt was missed (HPET signal is high active). For more details see: http://marc.info/?l=linux-kernel&m=129623757413868 Tested-by: Manoj Iyer <manoj.iyer@canonical.com> Tested-by: Andre Przywara <andre.przywara@amd.com> Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Borislav Petkov <borislav.petkov@amd.com> LKML-Reference: <20110224145346.GD3658@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21ARM: Ensure predictable endian state on signal handler entryRussell King
commit 53399053eb505cf541b2405bd9d9bca5ecfb96fb upstream. Ensure a predictable endian state when entering signal handlers. This avoids programs which use SETEND to momentarily switch their endian state from having their signal handlers entered with an unpredictable endian state. Acked-by: Dave Martin <dave.martin@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21s390: remove task_show_regsMartin Schwidefsky
commit 261cd298a8c363d7985e3482946edb4bfedacf98 upstream. task_show_regs used to be a debugging aid in the early bringup days of Linux on s390. /proc/<pid>/status is a world readable file, it is not a good idea to show the registers of a process. The only correct fix is to remove task_show_regs. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21x86/pvclock: Zero last_value on resumeJeremy Fitzhardinge
commit e7a3481c0246c8e45e79c629efd63b168e91fcda upstream. If the guest domain has been suspend/resumed or migrated, then the system clock backing the pvclock clocksource may revert to a smaller value (ie, can be non-monotonic across the migration/save-restore). Make sure we zero last_value in that case so that the domain continues to see clock updates. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-21x86, mm: avoid possible bogus tlb entries by clearing prev mm_cpumask after ↵Suresh Siddha
switching mm commit 831d52bc153971b70e64eccfbed2b232394f22f8 upstream. Clearing the cpu in prev's mm_cpumask early will avoid the flush tlb IPI's while the cr3 is still pointing to the prev mm. And this window can lead to the possibility of bogus TLB fills resulting in strange failures. One such problematic scenario is mentioned below. T1. CPU-1 is context switching from mm1 to mm2 context and got a NMI etc between the point of clearing the cpu from the mm_cpumask(mm1) and before reloading the cr3 with the new mm2. T2. CPU-2 is tearing down a specific vma for mm1 and will proceed with flushing the TLB for mm1. It doesn't send the flush TLB to CPU-1 as it doesn't see that cpu listed in the mm_cpumask(mm1). T3. After the TLB flush is complete, CPU-2 goes ahead and frees the page-table pages associated with the removed vma mapping. T4. CPU-2 now allocates those freed page-table pages for something else. T5. As the CR3 and TLB caches for mm1 is still active on CPU-1, CPU-1 can potentially speculate and walk through the page-table caches and can insert new TLB entries. As the page-table pages are already freed and being used on CPU-2, this page walk can potentially insert a bogus global TLB entry depending on the (random) contents of the page that is being used on CPU-2. T6. This bogus TLB entry being global will be active across future CR3 changes and can result in weird memory corruption etc. To avoid this issue, for the prev mm that is handing over the cpu to another mm, clear the cpu from the mm_cpumask(prev) after the cr3 is changed. Marking it for -stable, though we haven't seen any reported failure that can be attributed to this. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>