kernel.git/arch/x86/kernel, branch linux-4.12.y

x86/switch_to/64: Rewrite FS/GS switching yet again to fix AMD CPUs

2017-09-20T06:22:11Z

commit e137a4d8f4dd2e277e355495b6b2cb241a8693c3 upstream. Switching FS and GS is a mess, and the current code is still subtly wrong: it assumes that "Loading a nonzero value into FS sets the index and base", which is false on AMD CPUs if the value being loaded is 1, 2, or 3. (The current code came from commit 3e2b68d752c9 ("x86/asm, sched/x86: Rewrite the FS and GS context switch code"), which made it better but didn't fully fix it.) Rewrite it to be much simpler and more obviously correct. This should fix it fully on AMD CPUs and shouldn't adversely affect performance. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Chang Seok Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86/fsgsbase/64: Fully initialize FS and GS state in start_thread_common

2017-09-20T06:22:11Z

commit 767d035d838f4fd6b5a5bbd7a3f6d293b7f65a49 upstream. execve used to leak FSBASE and GSBASE on AMD CPUs. Fix it. The security impact of this bug is small but not quite zero -- it could weaken ASLR when a privileged task execs a less privileged program, but only if program changed bitness across the exec, or the child binary was highly unusual or actively malicious. A child program that was compromised after the exec would not have access to the leaked base. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Chang Seok Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

KVM: async_pf: make rcu irq exit if not triggered from idle task

2017-08-11T15:33:52Z

commit 337c017ccdf2653d0040099433fc1a2b1beb5926 upstream. WARNING: CPU: 5 PID: 1242 at kernel/rcu/tree_plugin.h:323 rcu_note_context_switch+0x207/0x6b0 CPU: 5 PID: 1242 Comm: unity-settings- Not tainted 4.13.0-rc2+ #1 RIP: 0010:rcu_note_context_switch+0x207/0x6b0 Call Trace: __schedule+0xda/0xba0 ? kvm_async_pf_task_wait+0x1b2/0x270 schedule+0x40/0x90 kvm_async_pf_task_wait+0x1cc/0x270 ? prepare_to_swait+0x22/0x70 do_async_page_fault+0x77/0xb0 ? do_async_page_fault+0x77/0xb0 async_page_fault+0x28/0x30 RIP: 0010:__d_lookup_rcu+0x90/0x1e0 I encounter this when trying to stress the async page fault in L1 guest w/ L2 guests running. Commit 9b132fbe5419 (Add rcu user eqs exception hooks for async page fault) adds rcu_irq_enter/exit() to kvm_async_pf_task_wait() to exit cpu idle eqs when needed, to protect the code that needs use rcu. However, we need to call the pair even if the function calls schedule(), as seen from the above backtrace. This patch fixes it by informing the RCU subsystem exit/enter the irq towards/away from idle for both n.halted and !n.halted. Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Paul E. McKenney Signed-off-by: Wanpeng Li Reviewed-by: Paolo Bonzini Signed-off-by: Radim Krčmář Signed-off-by: Greg Kroah-Hartman

x86/ioapic: Pass the correct data to unmask_ioapic_irq()

2017-07-27T22:10:18Z

commit e708e35ba6d89ff785b225cd07dcccab04fa954a upstream. One of the rarely executed code pathes in check_timer() calls unmask_ioapic_irq() passing irq_get_chip_data(0) as argument. That's wrong as unmask_ioapic_irq() expects a pointer to the irq data of interrupt 0. irq_get_chip_data(0) returns NULL, so the following dereference in unmask_ioapic_irq() causes a kernel panic. The issue went unnoticed in the first place because irq_get_chip_data() returns a void pointer so the compiler cannot do a type check on the argument. The code path was added for machines with broken configuration, but it seems that those machines are either not running current kernels or simply do not longer exist. Hand in irq_get_irq_data(0) as argument which provides the correct data. [ tglx: Rewrote changelog ] Fixes: 4467715a44cc ("x86/irq: Move irq_cfg.irq_2_pin into io_apic.c") Signed-off-by: Seunghun Han Signed-off-by: Thomas Gleixner Link: http://lkml.kernel.org/r/1500369644-45767-1-git-send-email-kkamagui@gmail.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86/acpi: Prevent out of bound access caused by broken ACPI tables

2017-07-27T22:10:18Z

commit dad5ab0db8deac535d03e3fe3d8f2892173fa6a4 upstream. The bus_irq argument of mp_override_legacy_irq() is used as the index into the isa_irq_to_gsi[] array. The bus_irq argument originates from ACPI_MADT_TYPE_IO_APIC and ACPI_MADT_TYPE_INTERRUPT items in the ACPI tables, but is nowhere sanity checked. That allows broken or malicious ACPI tables to overwrite memory, which might cause malfunction, panic or arbitrary code execution. Add a sanity check and emit a warning when that triggers. [ tglx: Added warning and rewrote changelog ] Signed-off-by: Seunghun Han Signed-off-by: Thomas Gleixner Cc: security@kernel.org Cc: "Rafael J. Wysocki" Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86/mm/pat: Don't report PAT on CPUs that don't support it

2017-07-15T11:09:05Z

commit 99c13b8c8896d7bcb92753bf0c63a8de4326e78d upstream. The pat_enabled() logic is broken on CPUs which do not support PAT and where the initialization code fails to call pat_init(). Due to that the enabled flag stays true and pat_enabled() returns true wrongfully. As a consequence the mappings, e.g. for Xorg, are set up with the wrong caching mode and the required MTRR setups are omitted. To cure this the following changes are required: 1) Make pat_enabled() return true only if PAT initialization was invoked and successful. 2) Invoke init_cache_modes() unconditionally in setup_arch() and remove the extra callsites in pat_disable() and the pat disabled code path in pat_init(). Also rename __pat_enabled to pat_disabled to reflect the real purpose of this variable. Fixes: 9cd25aac1f44 ("x86/mm/pat: Emulate PAT when it is disabled") Signed-off-by: Mikulas Patocka Signed-off-by: Thomas Gleixner Cc: Bernhard Held Cc: Denys Vlasenko Cc: Peter Zijlstra Cc: Brian Gerst Cc: "Luis R. Rodriguez" Cc: Borislav Petkov Cc: Andy Lutomirski Cc: Josh Poimboeuf Cc: Andrew Morton Cc: Linus Torvalds Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1707041749300.3456@file01.intranet.prod.int.rdu2.redhat.com Signed-off-by: Greg Kroah-Hartman

Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2017-07-01T16:10:17Z

Pull x86 fixes from Thomas Gleixner: "Fixlets for x86: - Prevent kexec crash when KASLR is enabled, which was caused by an address calculation bug - Restore the freeing of PUDs on memory hot remove - Correct a negated pointer check in the intel uncore performance monitoring driver - Plug a memory leak in an error exit path in the RDT code" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/intel_rdt: Fix memory leak on mount failure x86/boot/KASLR: Fix kexec crash due to 'virt_addr' calculation bug x86/boot/KASLR: Add checking for the offset of kernel virtual address randomization perf/x86/intel/uncore: Fix wrong box pointer check x86/mm/hotplug: Fix BUG_ON() after hot-remove by not freeing PUD

x86/intel_rdt: Fix memory leak on mount failure

2017-06-30T19:20:00Z

If mount fails, the kn_info directory is not freed causing memory leak. Add the missing error handling path. Fixes: 4e978d06dedb ("x86/intel_rdt: Add "info" files to resctrl file system") Signed-off-by: Vikas Shivappa Signed-off-by: Thomas Gleixner Cc: ravi.v.shankar@intel.com Cc: tony.luck@intel.com Cc: fenghua.yu@intel.com Cc: peterz@infradead.org Cc: vikas.shivappa@intel.com Cc: andi.kleen@intel.com Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1498503368-20173-3-git-send-email-vikas.shivappa@linux.intel.com

Merge tag 'iommu-fixes-v4.12-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu

2017-06-30T17:37:48Z

Pull IOMMU fixes from Joerg Roedel: "Two fixes: - A fix for AMD IOMMU interrupt remapping code when IRQs are forwarded directly to KVM guests - Fixed check in the recently merged code to allow tboot with Intel VT-d disabled" * tag 'iommu-fixes-v4.12-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: iommu/amd: Fix interrupt remapping when disable guest_mode iommu/vt-d: Correctly disable Intel IOMMU force on

arch: remove unused macro/function thread_saved_pc()

2017-06-28T23:13:57Z

The only user of thread_saved_pc() in non-arch-specific code was removed in commit 8243d5597793 ("sched/core: Remove pointless printout in sched_show_task()"). Remove the implementations as well. Some architectures use thread_saved_pc() in their arch-specific code. Leave their thread_saved_pc() intact. Signed-off-by: Tobias Klauser Acked-by: Geert Uytterhoeven Cc: Ingo Molnar Signed-off-by: Linus Torvalds