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

.gitignore update for x86 arch

2007-10-17 21:19:04 +02:00

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

i386: move kernel

2007-10-11 11:17:01 +02:00

audit_64.c

x86_64: move kernel

2007-10-11 11:17:24 +02:00

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

kmap leak fix for x86_32 kdump

2007-10-19 11:53:33 -07:00

crash_dump_64.c

Delete filenames in comments.

2007-10-13 10:01:23 -07:00

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

i386: move kernel

2007-10-11 11:17:01 +02:00

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

x86_64: move kernel

2007-10-11 11:17:24 +02:00

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

i386: move kernel

2007-10-11 11:17:01 +02:00

module_64.c

x86_64: move kernel

2007-10-11 11:17:24 +02:00

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

i386: move kernel

2007-10-11 11:17:01 +02:00

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

x86: Create clflush() inline, remove hardcoded wbinvd

2007-10-17 20:16:12 +02:00

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

x86_64: move kernel

2007-10-11 11:17:24 +02:00

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

i386: move kernel

2007-10-11 11:17:01 +02:00

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