linux_dsm_epyc7002/arch/x86/kernel
Suresh Siddha 870568b390 x86, fpu: fix CONFIG_PREEMPT=y corruption of application's FPU stack
Jürgen Mell reported an FPU state corruption bug under CONFIG_PREEMPT,
and bisected it to commit v2.6.19-1363-gacc2076, "i386: add sleazy FPU
optimization".

Add tsk_used_math() checks to prevent calling math_state_restore()
which can sleep in the case of !tsk_used_math(). This prevents
making a blocking call in __switch_to().

Apparently "fpu_counter > 5" check is not enough, as in some signal handling
and fork/exec scenarios, fpu_counter > 5 and !tsk_used_math() is possible.

It's a side effect though. This is the failing scenario:

process 'A' in save_i387_ia32() just after clear_used_math()

Got an interrupt and pre-empted out.

At the next context switch to process 'A' again, kernel tries to restore
the math state proactively and sees a fpu_counter > 0 and !tsk_used_math()

This results in init_fpu() during the __switch_to()'s math_state_restore()

And resulting in fpu corruption which will be saved/restored
(save_i387_fxsave and restore_i387_fxsave) during the remaining
part of the signal handling after the context switch.

Bisected-by: Jürgen Mell <j.mell@t-online.de>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Jürgen Mell <j.mell@t-online.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
2008-06-04 16:21:24 +02:00
..
acpi x86: fix APIC warning on 32bit v2 2008-06-04 13:11:46 +02:00
cpu [CPUFREQ] Crusoe: longrun cpufreq module reports false min freq 2008-05-19 18:17:28 -04:00
.gitignore
alternative.c x86: harden kernel code patching 2008-04-25 19:54:07 +02:00
aperture_64.c x86: clean up aperture_64.c 2008-04-17 17:41:19 +02:00
apic_32.c x86: cleanup div_sc() usage 2008-04-26 17:35:47 +02:00
apic_64.c x86: don't read maxlvt before checking if APIC is mapped 2008-05-23 14:08:06 +02:00
apm_32.c Merge branches 'release', 'acpica', 'bugzilla-10224', 'bugzilla-9772', 'bugzilla-9916', 'ec', 'eeepc', 'idle', 'misc', 'pm-legacy', 'sysfs-links-2.6.26', 'thermal', 'thinkpad' and 'video' into release 2008-04-30 13:58:00 -04:00
asm-offsets_32.c x86: use kbuild.h 2008-04-29 08:06:29 -07:00
asm-offsets_64.c x86: use kbuild.h 2008-04-29 08:06:29 -07:00
asm-offsets.c
audit_64.c
bootflag.c x86: coding style cleanup for kernel/bootflag.c 2008-01-30 13:32:31 +01:00
bugs_64.c x86: don't use large pages to map the first 2/4MB of memory 2008-04-17 17:41:30 +02:00
cpuid.c PM: Remove destroy_suspended_device() 2008-04-19 19:10:28 -07:00
crash_dump_32.c
crash_dump_64.c
crash.c x86: allow machine_crash_shutdown to be replaced 2008-04-27 12:00:29 +03:00
doublefault_32.c x86: unify tss_struct 2008-01-30 13:31:31 +01:00
ds.c x86: debug Store - call kfree if only we really need it 2008-04-17 17:41:34 +02:00
e820_32.c x86: rename find_max_pfn() to propagate_e820_map() 2008-04-19 19:19:55 +02:00
e820_64.c bootprotocol: cleanup 2008-04-29 13:45:24 +02:00
early_printk.c x86: coding style fixes to x86/kernel/early_printk.c 2008-04-17 17:40:51 +02:00
early-quirks.c x86: fix section mismatch warning in early-quirks.c 2008-01-30 13:33:37 +01:00
efi_32.c x86: sparse error in efi_32.c 2008-02-19 16:18:28 +01:00
efi_64.c x86: EFI_PAGE_SHIFT fix 2008-04-19 19:19:54 +02:00
efi_stub_32.S
efi_stub_64.S x86: EFI runtime service support 2008-01-30 13:31:19 +01:00
efi.c x86: EFI_PAGE_SHIFT fix 2008-04-19 19:19:54 +02:00
entry_32.S xen: fold xen_sysexit into xen_iret 2008-04-24 23:57:33 +02:00
entry_64.S x86: ptrace vs -ENOSYS 2008-04-17 17:41:13 +02:00
genapic_64.c fix: x86: support for new UV apic 2008-04-30 23:15:34 +02:00
genapic_flat_64.c x86: use cpumask_of_cpu() 2008-04-17 17:41:36 +02:00
genx2apic_uv_x.c x86: UV startup of slave cpus 2008-04-19 19:19:58 +02:00
geode_32.c x86: GEODE: cache results from geode_has_vsa2() and uninline 2008-05-08 15:43:50 +02:00
head32.c x86: introduce kernel/head32.c 2008-04-17 17:40:49 +02:00
head64.c x86, boot: add linked list of struct setup_data 2008-04-26 21:34:42 +02:00
head_32.S x86: fix early-BUG message 2008-04-30 23:15:34 +02:00
head_64.S x86: move suspend wakeup code to C 2008-04-17 17:41:37 +02:00
hpet.c hpet: fix 2008-04-30 23:15:34 +02:00
i386_ksyms_32.c Generic semaphore implementation 2008-04-17 10:42:34 -04:00
i387.c x86: fix broken math-emu with lazy allocation of fpu area 2008-06-04 13:11:46 +02:00
i8237.c Driver core: change sysdev classes to use dynamic kobject names 2008-01-24 20:40:40 -08:00
i8253.c x86: cleanup div_sc() usage 2008-04-26 17:35:47 +02:00
i8259_32.c x86: i8259A: remove redundant irq_descinitialization 2008-02-19 16:18:34 +01:00
i8259_64.c x86: provide a native_init_IRQ function on 64-bit 2008-01-30 13:33:19 +01:00
init_task.c [PATCH] take init_files to fs/file.c 2008-05-16 17:22:20 -04:00
io_apic_32.c x86: Fix 32-bit MSI-X allocation leakage 2008-04-28 10:49:17 -07:00
io_apic_64.c x86: section mismatch fixes, #3 2008-04-26 17:35:48 +02:00
io_delay.c x86: add dmi quirk for io_delay 2008-03-26 22:23:40 +01:00
ioport.c x86: refactor ioport unification 2008-01-30 13:33:10 +01:00
ipi.c x86: create ipi.c 2008-04-17 17:40:56 +02:00
irq_32.c proper __do_softirq() prototype 2008-04-29 08:06:02 -07:00
irq_64.c x86: rename the struct pt_regs members for 32/64-bit consistency 2008-01-30 13:30:56 +01:00
k8.c
kdebugfs.c x86, boot: export linked list of struct setup_data via debugfs 2008-04-26 21:34:42 +02:00
kgdb.c x86: KGDB build fix 2008-04-19 19:19:54 +02:00
kprobes.c x86: replace most VM86 flags with flags from processor-flags.h 2008-04-17 17:41:33 +02:00
kvm.c x86: KVM guest: hypercall batching 2008-04-27 12:00:28 +03:00
kvmclock.c namespacecheck: automated fixes 2008-05-23 14:08:06 +02:00
ldt.c x86: cleanup - eliminate numbers in LDT allocation code 2008-02-04 16:48:03 +01:00
machine_kexec_32.c vmcoreinfo: fix the configuration dependencies 2008-02-07 08:42:25 -08:00
machine_kexec_64.c vmcoreinfo: add the symbol "phys_base" 2008-04-02 15:28:19 -07:00
Makefile pcspkr: fix dependancies 2008-05-07 12:42:03 +02:00
mca_32.c x86: coding style fixes to arch/x86/kernel/mca_32.c 2008-04-17 17:40:49 +02:00
mfgpt_32.c x86: geode: MSR cleanup 2008-04-28 08:58:35 -07:00
microcode.c x86: use new set_cpus_allowed_ptr function 2008-04-19 19:44:58 +02:00
mmconf-fam10h_64.c x86: add pci=check_enable_amd_mmconf and dmi check 2008-04-26 23:41:04 +02:00
module_32.c
module_64.c
mpparse.c x86: es7000 build fix 2008-05-04 20:04:45 +02:00
msr.c PM: Remove destroy_suspended_device() 2008-04-19 19:10:28 -07:00
nmi_32.c ftrace: add notrace annotations for NMI routines 2008-04-19 19:19:55 +02:00
nmi_64.c ftrace: add notrace annotations for NMI routines 2008-04-19 19:19:55 +02:00
numaq_32.c x86: convert TSC disabling to generic cpuid disable bitmap 2008-01-30 13:33:20 +01:00
olpc.c x86: olpc: add One Laptop Per Child architecture support 2008-04-29 08:06:07 -07:00
paravirt_patch_32.c x86: move patching code to arch-specific file. 2008-01-30 13:32:10 +01:00
paravirt_patch_64.c x86: add stringify header 2008-01-30 13:33:19 +01:00
paravirt.c x86: add pud_alloc for 4-level pagetables 2008-04-24 23:57:31 +02:00
pci-calgary_64.c x86: remove duplicate get_bios_ebda() from rio.h 2008-04-26 17:35:47 +02:00
pci-dma.c x86/pci: fix broken ISA DMA 2008-05-12 21:27:50 +02:00
pci-gart_64.c suspend-vs-iommu: prevent suspend if we could not resume 2008-06-04 13:11:47 +02:00
pci-nommu.c x86: unify pci-nommu 2008-04-19 19:19:57 +02:00
pci-swiotlb_64.c x86: dma-ops on highmem fix 2008-04-19 19:19:56 +02:00
pcspeaker.c
pmtimer_64.c x86: move pmtmr related declarations 2008-01-30 13:30:18 +01:00
process_32.c x86, fpu: fix CONFIG_PREEMPT=y corruption of application's FPU stack 2008-06-04 16:21:24 +02:00
process_64.c x86, fpu: fix CONFIG_PREEMPT=y corruption of application's FPU stack 2008-06-04 16:21:24 +02:00
process.c x86: disable mwait for AMD family 10H/11H CPUs 2008-05-17 22:57:20 +02:00
ptrace.c x86: user_regset_view table fix for ia32 on 64-bit 2008-05-13 19:40:20 +02:00
quirks.c x86: hpet clock enable quirk on nVidia nForce 430 2008-03-21 17:06:15 +01:00
reboot_fixups_32.c x86: add the RDC machine specific reboot fixup 2008-01-30 13:33:36 +01:00
reboot.c x86: remove dell reboot dmi quirk board name match 2008-05-04 20:04:45 +02:00
relocate_kernel_32.S x86: relocate_kernel - use predefined macroses for page attributes 2008-04-17 17:41:29 +02:00
relocate_kernel_64.S x86: relocate_kernel - use predefined macroses for page attributes 2008-04-17 17:41:29 +02:00
rtc.c x86: fix cmos read and write to not use inb_p and outb_p 2008-04-17 17:40:47 +02:00
scx200_32.c x86: fix sparse warning in kernel/scx200_32.c 2008-01-31 22:05:45 +01:00
setup64.c x86: fix exec mappings comments 2008-04-19 19:19:55 +02:00
setup_32.c x86: restrict keyboard io ports reservation to make ipmi driver work 2008-05-10 19:31:45 +02:00
setup_64.c x86: early_init_centaur(): use set_cpu_cap() 2008-05-13 19:37:38 +02:00
setup.c x86: [VOYAGER] fix duplicate phys_cpu_present_map symbol 2008-05-12 21:27:51 +02:00
sigframe.h x86: move struct definitions to unifed sigframe.h 2008-04-17 17:40:46 +02:00
signal_32.c signals: x86 TS_RESTORE_SIGMASK 2008-04-30 08:29:37 -07:00
signal_64.c signals: x86 TS_RESTORE_SIGMASK 2008-04-30 08:29:37 -07:00
smp.c x86: fix app crashes after SMP resume 2008-05-13 19:36:12 +02:00
smpboot.c x86: disable preemption in native_smp_prepare_cpus 2008-06-04 13:11:46 +02:00
smpcommon_32.c x86: create smpcommon.c 2008-04-17 17:40:55 +02:00
smpcommon.c x86: create smpcommon.c 2008-04-17 17:40:55 +02:00
srat_32.c x86: replace remaining __FUNCTION__ occurances 2008-04-17 17:40:57 +02:00
stacktrace.c x86: don't save unreliable stack trace entries 2008-02-26 12:55:58 +01:00
step.c x86: prevent unconditional writes to DebugCtl MSR 2008-04-17 17:40:58 +02:00
summit_32.c x86: use get_bios_ebda() 2008-04-26 17:35:47 +02:00
sys_i386_32.c unified (weak) sys_pipe implementation 2008-05-03 13:50:33 -07:00
sys_x86_64.c unified (weak) sys_pipe implementation 2008-05-03 13:50:33 -07:00
syscall_64.c x86: coding style fixes to arch/x86/kernel/syscall_64.c 2008-04-17 17:40:48 +02:00
syscall_table_32.S timerfd: wire the new timerfd API to the x86 family 2008-02-05 09:44:07 -08:00
tce_64.c
test_nx.c x86: Explicitly include required header files. 2008-04-17 17:41:15 +02:00
test_rodata.c x86: include proper prototypes for rodata_test 2008-02-14 23:30:20 +01:00
time_32.c proper extern for late_time_init 2008-04-29 08:06:03 -07:00
time_64.c time: fix typo in comments 2008-02-08 09:22:29 -08:00
tlb_32.c x86: create tlb files 2008-04-17 17:40:56 +02:00
tlb_64.c x86: use cpumask function for present, possible, and online cpus 2008-04-26 17:35:47 +02:00
tls.c asmlinkage_protect replaces prevent_tail_call 2008-04-10 17:28:26 -07:00
tls.h x86: x86 user_regset TLS 2008-01-30 13:31:52 +01:00
topology.c x86: fix section mismatch warning in topology.c:arch_register_cpu 2008-02-19 16:18:30 +01:00
trampoline_32.S x86: trampoline_32.S - switch to .cpuinit.data 2008-04-26 17:35:47 +02:00
trampoline_64.S x86: move suspend wakeup code to C 2008-04-17 17:41:37 +02:00
trampoline.c x86: standalone trampoline code 2008-04-17 17:41:37 +02:00
traps_32.c i386: fix signal type for iret exception 2008-04-26 17:35:46 +02:00
traps_64.c x86, fpu: lazy allocation of FPU area - v5 2008-04-19 19:19:55 +02:00
tsc_32.c x86: disable TSC for sched_clock() when calibration failed 2008-05-23 14:08:06 +02:00
tsc_64.c x86: fix setup of cyc2ns in tsc_64.c 2008-05-23 14:08:06 +02:00
tsc_sync.c x86: add warning to check_tsc_warp() 2008-01-30 13:33:24 +01:00
verify_cpu_64.S
vm86_32.c x86: replace most VM86 flags with flags from processor-flags.h 2008-04-17 17:41:33 +02:00
vmi_32.c x86: unify KERNEL_PGD_PTRS 2008-04-24 23:57:31 +02:00
vmiclock_32.c x86: isolate PIC/PIT in/out calls 2008-01-30 13:33:14 +01:00
vmlinux_32.lds.S x86: use ELF section to list CPU vendor specific code 2008-04-17 17:40:47 +02:00
vmlinux_64.lds.S x86_64 vDSO: use initdata 2008-04-28 13:49:35 -07:00
vmlinux.lds.S
vsmp_64.c x86: fix warning in "x86: clean up vSMP detection" 2008-04-29 13:45:24 +02:00
vsyscall_64.c "make namespacecheck" fixes 2008-04-24 23:15:44 +02:00
x8664_ksyms_64.c x86: fix csum_partial() export 2008-05-13 19:38:47 +02:00