linux/arch/x86/kernel
Brian Geffon bae7fc6f0d x86/fpu: Correct pkru/xstate inconsistency
When eagerly switching PKRU in switch_fpu_finish() it checks that
current is not a kernel thread as kernel threads will never use PKRU.
It's possible that this_cpu_read_stable() on current_task
(ie. get_current()) is returning an old cached value. To resolve this
reference next_p directly rather than relying on current.

As written it's possible when switching from a kernel thread to a
userspace thread to observe a cached PF_KTHREAD flag and never restore
the PKRU. And as a result this issue only occurs when switching
from a kernel thread to a userspace thread, switching from a non kernel
thread works perfectly fine because all that is considered in that
situation are the flags from some other non kernel task and the next fpu
is passed in to switch_fpu_finish().

This behavior only exists between 5.2 and 5.13 when it was fixed by a
rewrite decoupling PKRU from xstate, in:
  commit 954436989c ("x86/fpu: Remove PKRU handling from switch_fpu_finish()")

Unfortunately backporting the fix from 5.13 is probably not realistic as
it's part of a 60+ patch series which rewrites most of the PKRU handling.

Fixes: 0cecca9d03 ("x86/fpu: Eager switch PKRU state")
Signed-off-by: Brian Geffon <bgeffon@google.com>
Signed-off-by: Willis Kung <williskung@google.com>
Tested-by: Willis Kung <williskung@google.com>
Cc: <stable@vger.kernel.org> # v5.4.x
Cc: <stable@vger.kernel.org> # v5.10.x
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-02 11:42:47 +01:00
..
acpi ACPI: tables: x86: Reserve memory occupied by ACPI tables 2021-04-07 15:00:08 +02:00
apic x86/ioapic: Force affinity setup before startup 2021-08-18 08:59:15 +02:00
cpu x86/cpu: Add Xeon Icelake-D to list of CPUs that support PPIN 2022-02-05 12:37:55 +01:00
fpu x86/fpu: Limit xstate copy size in xstateregs_set() 2021-07-20 16:05:52 +02:00
kprobes x86/kprobes: Fix to check non boostable prefixes correctly 2021-05-14 09:50:24 +02:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
alternative.c A couple of x86 fixes which missed rc1 due to my stupidity: 2020-10-27 14:39:29 -07:00
amd_gart_64.c dma-mapping: split <linux/dma-mapping.h> 2020-10-06 07:07:03 +02:00
amd_nb.c x86/amd_nb: Add AMD family 17h model 60h PCI IDs 2020-05-22 18:24:40 +02:00
apb_timer.c x86/apb_timer: Drop unused TSC calibration 2020-05-27 13:05:59 +02:00
aperture_64.c
apm_32.c
asm-offsets_32.c x86 entry code updates: 2020-03-30 19:14:28 -07:00
asm-offsets_64.c x86/pv: Switch SWAPGS to ALTERNATIVE 2021-12-08 09:03:27 +01:00
asm-offsets.c x86: remove address space overrides using set_fs() 2020-09-08 22:21:36 -04:00
audit_64.c x86/audit: Fix a -Wmissing-prototypes warning for ia32_classify_syscall() 2020-05-19 18:03:07 +02:00
bootflag.c
cc_platform.c x86/sev: Add an x86 version of cc_platform_has() 2021-11-18 14:04:32 +01:00
check.c
cpuid.c
crash_core_32.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
crash_core_64.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
crash_dump_32.c
crash_dump_64.c fs/core/vmcore: Move sev_active() reference to x86 arch code 2019-08-09 22:52:10 +10:00
crash.c x86/crash: Fix crash_setup_memmap_entries() out-of-bounds access 2021-04-28 13:40:02 +02:00
devicetree.c x86_ioapic_Consolidate_IOAPIC_allocation 2020-09-16 16:52:32 +02:00
doublefault_32.c x86/entry: Convert double fault exception to IDTENTRY_DF 2020-06-11 15:15:03 +02:00
dumpstack_32.c x86/32: Remove CONFIG_DOUBLEFAULT 2020-04-14 14:24:05 +02:00
dumpstack_64.c x86/dumpstack/64: Add noinstr version of get_stack_info() 2020-09-09 11:33:19 +02:00
dumpstack.c x86/dumpstack: Do not try to access user space code of other tasks 2020-11-18 12:56:29 +01:00
e820.c PM: hibernate: x86: Use crc32 instead of md5 for hibernation e820 integrity check 2021-05-14 09:50:21 +02:00
early_printk.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
early-quirks.c x86/gpu: Reserve stolen memory for first integrated Intel GPU 2022-01-27 10:53:41 +01:00
ebda.c
eisa.c
espfix_64.c mm: introduce include/linux/pgtable.h 2020-06-09 09:39:13 -07:00
ftrace_32.S x86: Change {JMP,CALL}_NOSPEC argument 2020-04-30 20:14:34 +02:00
ftrace_64.S x86/ftrace: Do not jump to direct code in created trampolines 2020-06-29 11:42:48 -04:00
ftrace.c x86/ftrace: Do not jump to direct code in created trampolines 2020-06-29 11:42:48 -04:00
head_32.S x86/xen: remove 32-bit Xen PV guest support 2020-08-11 08:26:48 +02:00
head_64.S x86/head/64: Check SEV encryption before switching to kernel page-table 2020-10-29 18:09:59 +01:00
head32.c
head64.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
hpet.c x86/hpet: Use another crystalball to evaluate HPET usability 2021-10-13 10:04:30 +02:00
hw_breakpoint.c x86/debug: Prevent data breakpoints on cpu_dr7 2021-02-10 09:29:22 +01:00
i8237.c
i8253.c
i8259.c x86/i8259: Use printk_deferred() to prevent deadlock 2020-07-29 16:27:16 +02:00
idt.c This feature enhances the current guest memory encryption support 2020-10-14 10:21:34 -07:00
ima_arch.c EFI updates for v5.7: 2020-02-26 15:21:22 +01:00
io_delay.c
ioport.c x86/ioperm: Prevent a memory leak when fork fails 2020-05-28 21:36:20 +02:00
irq_32.c x86/irq: Rework handle_irq() for 64-bit 2020-06-11 15:15:12 +02:00
irq_64.c x86/irq: Make run_on_irqstack_cond() typesafe 2020-09-22 22:13:34 +02:00
irq_work.c x86/entry: Convert various system vectors 2020-06-11 15:15:14 +02:00
irq.c x86/irq: Ensure PI wakeup handler is unregistered before module unload 2021-11-18 14:03:41 +01:00
irqflags.S x86/asm: Change all ENTRY+ENDPROC to SYM_FUNC_* 2019-10-18 11:58:33 +02:00
irqinit.c x86/headers: Remove APIC headers from <asm/smp.h> 2020-08-06 16:13:09 +02:00
itmt.c sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
jailhouse.c locking/seqlock, headers: Untangle the spaghetti monster 2020-08-06 16:13:13 +02:00
jump_label.c x86/jump_label: Move 'inline' keyword placement 2020-03-27 11:05:41 +01:00
kdebugfs.c x86/boot: Introduce setup_indirect 2019-11-12 16:21:15 +01:00
kexec-bzimage64.c x86/kexec: Use up-to-dated screen_info copy to fill boot params 2020-10-14 17:05:03 +02:00
kgdb.c x86/debug: Change thread.debugreg6 to thread.virtual_dr6 2020-09-04 15:12:58 +02:00
ksysfs.c x86/boot: Introduce setup_indirect 2019-11-12 16:21:15 +01:00
kvm.c x86/kvm: Disable all PV features on crash 2021-06-10 13:39:29 +02:00
kvmclock.c x86/kvmclock: Move this_cpu_pvti into kvmclock.h 2021-10-06 15:55:48 +02:00
ldt.c x86/ldt: use "pr_info_once()" instead of open-coding it badly 2020-07-05 12:50:20 -07:00
machine_kexec_32.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
machine_kexec_64.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
Makefile x86/sev: Add an x86 version of cc_platform_has() 2021-11-18 14:04:32 +01:00
mmconf-fam10h_64.c
module.c x86/build: Treat R_386_PLT32 relocation as R_386_PC32 2021-03-07 12:34:04 +01:00
mpparse.c Surgery of the MSI interrupt handling to prepare the support of upcoming 2020-10-12 11:40:41 -07:00
msr.c x86/MSR: Filter MSR writes through X86_IOC_WRMSR_REGS ioctl too 2021-03-04 11:37:26 +01:00
nmi_selftest.c
nmi.c KVM/VMX: Invoke NMI non-IST entry instead of IST entry 2021-05-19 10:12:51 +02:00
paravirt_patch.c x86/pv: Switch SWAPGS to ALTERNATIVE 2021-12-08 09:03:27 +01:00
paravirt-spinlocks.c
paravirt.c x86/pv: Switch SWAPGS to ALTERNATIVE 2021-12-08 09:03:27 +01:00
pci-dma.c dma-mapping: move dma-debug.h to kernel/dma/ 2020-10-06 07:07:05 +02:00
pci-iommu_table.c
pci-swiotlb.c dma-mapping: fix filename references 2019-09-03 08:36:30 +02:00
pcspeaker.c
perf_regs.c perf/arch: Remove perf_sample_data::regs_user_copy 2020-11-09 18:12:34 +01:00
platform-quirks.c
pmem.c
probe_roms.c maccess: make get_kernel_nofault() check for minimal type compatibility 2020-06-18 12:10:37 -07:00
process_32.c x86/fpu: Correct pkru/xstate inconsistency 2022-03-02 11:42:47 +01:00
process_64.c x86/fpu: Correct pkru/xstate inconsistency 2022-03-02 11:42:47 +01:00
process.c x86/iopl: Fake iopl(3) CLI/STI usage 2021-11-21 13:46:36 +01:00
process.h x86: Use the correct SPDX License Identifier in headers 2019-10-01 20:31:35 +02:00
ptrace.c x86/debug: Change thread.debugreg6 to thread.virtual_dr6 2020-09-04 15:12:58 +02:00
pvclock.c x86/vdso: Use generic VDSO clock mode storage 2020-02-17 14:40:23 +01:00
quirks.c x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}() 2020-10-06 11:18:04 +02:00
reboot_fixups_32.c
reboot.c x86/mm: Flush global TLB when switching to trampoline page-table 2022-01-27 10:54:14 +01:00
relocate_kernel_32.S x86/asm: Annotate relocate_kernel_{32,64}.c 2019-10-18 09:53:19 +02:00
relocate_kernel_64.S x86/kexec: Make relocate_kernel_64.S objtool clean 2020-03-25 18:28:28 +01:00
resource.c
rtc.c
setup_percpu.c x86/mm: remove vmalloc faulting 2020-06-02 10:59:12 -07:00
setup.c ACPI: x86: Call acpi_boot_table_init() after acpi_table_upgrade() 2021-04-21 13:00:51 +02:00
sev_verify_cbit.S x86/boot/compressed/64: Check SEV encryption in 64-bit boot-path 2020-10-29 18:06:52 +01:00
sev-es-shared.c x86/sev: Return an error on a returned non-zero SW_EXITINFO1[31:0] 2021-10-13 10:04:30 +02:00
sev-es.c x86/sev: Fix SEV-ES INS/OUTS instructions for word, dword, and qword 2021-12-08 09:03:27 +01:00
signal_compat.c arm64: mte: Add specific SIGSEGV codes 2020-09-04 12:46:06 +01:00
signal.c x86/signal: Detect and prevent an alternate signal stack overflow 2021-07-20 16:05:50 +02:00
smp.c x86/entry: Convert reschedule interrupt to IDTENTRY_SYSVEC_SIMPLE 2020-06-11 15:15:16 +02:00
smpboot.c sched/core: Initialize the idle task with preemption disabled 2021-07-14 16:55:50 +02:00
stacktrace.c stacktrace: Remove reliable argument from arch_stack_walk() callback 2020-09-18 14:24:16 +01:00
static_call.c static_call: Allow early init 2020-09-01 09:58:06 +02:00
step.c
sys_ia32.c x86: switch to kernel_clone() 2020-08-20 13:12:58 +02:00
sys_x86_64.c x86: Remove unneeded includes 2020-03-21 16:03:25 +01:00
sysfb_efi.c x86/sysfb_efi: Add quirks for some devices with swapped width and height 2019-07-22 10:47:11 +02:00
sysfb_simplefb.c x86/sysfb: Fix check for bad VRAM size 2020-01-20 10:57:53 +01:00
sysfb.c
tboot.c mm/gup: prevent gup_fast from racing with COW during fork 2020-12-30 11:53:54 +01:00
time.c A set of fixes and updates for x86: 2020-06-11 15:54:31 -07:00
tls.c x86: switch to ->regset_get() 2020-07-27 14:31:07 -04:00
tls.h x86: switch to ->regset_get() 2020-07-27 14:31:07 -04:00
topology.c x86/headers: Remove APIC headers from <asm/smp.h> 2020-08-06 16:13:09 +02:00
trace_clock.c
tracepoint.c x86/entry: Convert reschedule interrupt to IDTENTRY_SYSVEC_SIMPLE 2020-06-11 15:15:16 +02:00
traps.c x86/iopl: Fake iopl(3) CLI/STI usage 2021-11-21 13:46:36 +01:00
tsc_msr.c Misc fixes and small updates all around the place: 2020-08-15 10:38:03 -07:00
tsc_sync.c x86/tsc: Add a timer to make sure TSC_adjust is always checked 2021-12-08 09:03:28 +01:00
tsc.c clocksource: Reduce clocksource-skew threshold 2022-01-27 10:54:05 +01:00
umip.c x86/umip: Factor out instruction decoding 2020-09-07 19:45:24 +02:00
unwind_frame.c fork-v5.9 2020-08-04 14:47:45 -07:00
unwind_guess.c
unwind_orc.c x86/unwind/orc: Disable KASAN checking in the ORC unwinder, part 2 2021-03-17 17:06:35 +01:00
uprobes.c x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes 2020-12-06 09:58:13 +01:00
verify_cpu.S x86/asm: Annotate local pseudo-functions 2019-10-18 10:04:04 +02:00
vm86_32.c mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
vmlinux.lds.S This tree introduces static_call(), which is the idea of static_branch() 2020-10-12 13:58:15 -07:00
vsmp_64.c
x86_init.c x86/irq: Cleanup the arch_*_msi_irqs() leftovers 2020-09-16 16:52:38 +02:00