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Suresh Siddha d75f1b391f x86, xsave: remove thread_has_fpu() bug check in __sanitize_i387_state() 
Code paths like fork(), exit() and signal handling flush the fpu
state explicitly to the structures in memory.

BUG_ON() in __sanitize_i387_state() is checking that the fpu state
is not live any more. But for preempt kernels, task can be scheduled
out and in at any place and the preload_fpu logic during context switch
can make the fpu registers live again.

For example, consider a 64-bit Task which uses fpu frequently and as such
you will find its fpu_counter mostly non-zero. During its time slice, kernel
used fpu by doing kernel_fpu_begin/kernel_fpu_end(). After this, in the same
scheduling slice, task-A got a signal to handle. Then during the signal
setup path we got preempted when we are just before the sanitize_i387_state()
in arch/x86/kernel/xsave.c:save_i387_xstate(). And when we come back we
will have the fpu registers live that can hit the bug_on.

Similarly during core dump, other threads can context-switch in and out
(because of spurious wakeups while waiting for the coredump to finish in
 kernel/exit.c:exit_mm()) and the main thread dumping core can run into this
bug when it finds some other thread with its fpu registers live on some other cpu.

So remove the paranoid check for now, even though it caught a bug in the
multi-threaded core dump case (fixed in the previous patch).

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1336692811-30576-3-git-send-email-suresh.b.siddha@intel.com
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
 		2012-05-16 15:17:17 -07:00
..
acpi x86, acpi: Call acpi_enter_sleep_state via an asmlinkage C function from assembler 2012-04-23 13:29:18 -07:00
apic x86/apic: Use x2apic physical mode based on FADT setting 2012-04-25 12:47:08 +02:00
cpu x86/amd: Re-enable CPU topology extensions in case BIOS has disabled it 2012-04-27 16:43:09 +02:00
.gitignore
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Makefile x86/kprobes: Split out optprobe related code to kprobes-opt.c 2012-03-06 09:49:49 +01:00
alternative.c x86: Call stop_machine_text_poke() on all CPUs 2011-11-14 13:05:15 +01:00
amd_gart_64.c X86 & IA64: adapt for dma_map_ops changes 2012-03-28 16:36:31 +02:00
amd_nb.c Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
apb_timer.c Merge branch 'timers-clocksource-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-07-23 10:34:47 -07:00
aperture_64.c memblock, x86: Replace memblock_x86_reserve/free_range() with generic ones 2011-07-14 11:47:53 -07:00
apm_32.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
asm-offsets.c x86, efi: EFI boot stub support 2011-12-12 14:26:10 -08:00
asm-offsets_32.c x86: Generate system call tables and unistd_*.h from tables 2011-11-17 13:35:37 -08:00
asm-offsets_64.c x32: If configured, add x32 system calls to system call tables 2012-02-20 12:52:06 -08:00
audit_64.c
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bootflag.c
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check.c memblock, x86: Replace memblock_x86_reserve/free_range() with generic ones 2011-07-14 11:47:53 -07:00
cpuid.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
crash.c x86, nmi: Wire up NMI handlers to new routines 2011-10-10 06:56:57 +02:00
crash_dump_32.c x86: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:15 +08:00
crash_dump_64.c crash_dump: export is_kdump_kernel to modules, consolidate elfcorehdr_addr, setup_elfcorehdr and saved_max_pfn 2011-03-23 19:47:19 -07:00
devicetree.c irq_domain/x86: Convert x86 (embedded) to use common irq_domain 2012-02-23 14:37:47 -07:00
doublefault_32.c
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dumpstack.c Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:21:35 -07:00
dumpstack_32.c x86/32: Print control and debug registers for kerenel context 2012-03-08 10:57:35 +01:00
dumpstack_64.c Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus', 'sched-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-02-02 11:11:13 -08:00
e820.c Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2012-01-18 15:51:48 -08:00
early-quirks.c x86, quirk: Fix SB600 revision check 2011-03-16 14:03:32 +01:00
early_printk.c Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-01-11 19:13:40 -08:00
entry_32.S x86-32: Fix endless loop when processing signals for kernel tasks 2012-03-22 13:50:25 -07:00
entry_64.S Merge branch 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:12:23 -07:00
ftrace.c x86/ftrace: Fix compiler warning in ftrace.c 2011-05-25 19:56:26 -04:00
head.c memblock, x86: Replace memblock_x86_reserve/free_range() with generic ones 2011-07-14 11:47:53 -07:00
head32.c memblock: Kill memblock_init() 2011-12-08 10:22:07 -08:00
head64.c memblock: Kill memblock_init() 2011-12-08 10:22:07 -08:00
head_32.S Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-03-15 20:01:36 -07:00
head_64.S x86: Keep current stack in NMI breakpoints 2011-12-21 15:38:55 -05:00
hpet.c Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core 2012-01-07 12:03:30 -08:00
hw_breakpoint.c x86: Use this_cpu_ops to optimize code 2010-12-30 12:20:28 +01:00
i386_ksyms_32.c
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i387.c i387: ptrace breaks the lazy-fpu-restore logic 2012-04-16 16:23:59 -07:00
i8237.c x86: Use syscore_ops instead of sysdev classes and sysdevs 2011-03-23 22:15:54 +01:00
i8253.c x86: Use common i8253 clockevent 2011-07-01 10:37:14 +02:00
i8259.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
init_task.c
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io_delay.c
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ioport.c x86: Use bitmap library functions 2011-02-17 14:59:22 +01:00
irq.c x86: Preserve lazy irq disable semantics in fixup_irqs() 2012-03-29 15:28:47 +02:00
irq_32.c x86-32/irq: Don't switch to irq stack for a user-mode irq 2012-02-20 09:30:18 +01:00
irq_64.c x86: Add stack top margin for stack overflow checking 2011-12-07 09:27:11 +01:00
irq_work.c
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irqinit.c Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:21:35 -07:00
jump_label.c jump_label, x86: Fix section mismatch 2011-12-06 20:41:02 +01:00
kdebugfs.c simple_open: automatically convert to simple_open() 2012-04-05 15:25:50 -07:00
kgdb.c KGDB/KDB regression fixes 2012-04-04 17:26:08 -07:00
kprobes-common.h x86/kprobes: Split out optprobe related code to kprobes-opt.c 2012-03-06 09:49:49 +01:00
kprobes-opt.c x86/kprobes: Split out optprobe related code to kprobes-opt.c 2012-03-06 09:49:49 +01:00
kprobes.c x86/kprobes: Split out optprobe related code to kprobes-opt.c 2012-03-06 09:49:49 +01:00
kvm.c KVM: Do not take reference to mm during async #PF 2012-05-06 15:00:02 +03:00
kvmclock.c x86: kvmclock: abstract save/restore sched_clock_state 2012-03-20 12:37:45 +02:00
ldt.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
machine_kexec_32.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
machine_kexec_64.c
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mca_32.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
microcode_amd.c x86, microcode: Ensure that module is only loaded on supported AMD CPUs 2012-04-13 11:51:05 +02:00
microcode_core.c x86, microcode: Ensure that module is only loaded on supported AMD CPUs 2012-04-13 11:51:05 +02:00
microcode_intel.c x86, intel: Output microcode revision in /proc/cpuinfo 2011-10-14 13:16:35 +02:00
mmconf-fam10h_64.c x86-64: Fix and clean up AMD Fam10 MMCONF enabling 2010-11-18 13:41:35 +01:00
module.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
mpparse.c Merge branch 'memblock-kill-early_node_map' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/memblock 2011-12-20 12:14:26 +01:00
msr.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
nmi.c x86: Allow NMIs to hit breakpoints in i386 2011-12-21 15:38:55 -05:00
nmi_selftest.c x86: Properly _init-annotate NMI selftest code 2012-02-27 08:43:37 +01:00
paravirt-spinlocks.c
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paravirt.c Disintegrate and delete asm/system.h 2012-03-28 15:58:21 -07:00
paravirt_patch_32.c
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paravirt_patch_64.c
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pci-calgary_64.c Merge branch 'for-linus' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping 2012-04-04 17:13:43 -07:00
pci-dma.c Merge branch 'for-linus' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping 2012-04-04 17:13:43 -07:00
pci-iommu_table.c arch/x86/kernel/pci-iommu_table.c: Convert sprintf_symbol to %pS 2011-05-10 10:21:35 +02:00
pci-nommu.c X86 & IA64: adapt for dma_map_ops changes 2012-03-28 16:36:31 +02:00
pci-swiotlb.c X86 & IA64: adapt for dma_map_ops changes 2012-03-28 16:36:31 +02:00
pcspeaker.c
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probe_roms.c x86: Include probe_roms.h in probe_roms.c 2012-03-08 10:57:35 +01:00
process.c fork: move the real prepare_to_copy() users to arch_dup_task_struct() 2012-05-16 15:16:26 -07:00
process_32.c fork: move the real prepare_to_copy() users to arch_dup_task_struct() 2012-05-16 15:16:26 -07:00
process_64.c fork: move the real prepare_to_copy() users to arch_dup_task_struct() 2012-05-16 15:16:26 -07:00
ptrace.c Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:21:35 -07:00
pvclock.c x86/pvclock: Zero last_value on resume 2010-11-28 09:33:20 +01:00
quirks.c x86, amd: Fix up numa_node information for AMD CPU family 15h model 0-0fh northbridge functions 2011-12-05 18:13:11 +01:00
reboot.c x86/reboot: Remove VersaLogic Menlow reboot quirk 2012-01-30 10:52:33 +01:00
reboot_32.S x86, reboot: Fix relocations in reboot_32.S 2011-05-02 14:44:46 -07:00
reboot_fixups_32.c x86: Ce4100: Add reboot_fixup() for CE4100 2010-11-12 00:45:41 +01:00
relocate_kernel_32.S kexec, x86: Fix incorrect jump back address if not preserving context 2011-07-21 11:19:28 +02:00
relocate_kernel_64.S kexec, x86: Fix incorrect jump back address if not preserving context 2011-07-21 11:19:28 +02:00
resource.c x86: avoid high BIOS area when allocating address space 2010-12-17 10:01:30 -08:00
rtc.c x86/rtc, mrst: Don't register a platform RTC device for for Intel MID platforms 2011-12-05 17:09:21 +01:00
setup.c Merge branch 'akpm' (Andrew's patch-bomb) 2012-03-28 17:19:28 -07:00
setup_percpu.c percpu, x86: don't use PMD_SIZE as embedded atom_size on 32bit 2012-05-08 09:42:18 -07:00
signal.c Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:21:35 -07:00
smp.c x86, reboot: Fix typo in nmi reboot path 2012-01-07 12:19:37 +01:00
smpboot.c Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2012-03-30 16:45:39 -07:00
stacktrace.c x86: Swap save_stack_trace_regs parameters 2011-06-14 22:48:51 -04:00
step.c x86-64: Add user_64bit_mode paravirt op 2011-08-04 16:13:49 -07:00
sys_i386_32.c
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sys_x86_64.c Merge branch 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:12:23 -07:00
syscall_32.c x86, syscall: Re-fix typo in comment 2011-11-18 16:25:07 -08:00
syscall_64.c x32: If configured, add x32 system calls to system call tables 2012-02-20 12:52:06 -08:00
tboot.c tboot: Add return values for tboot_sleep 2012-03-13 14:06:55 -04:00
tce_64.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
test_nx.c x86: Eliminate various 'set but not used' warnings 2011-05-21 19:10:33 +02:00
test_rodata.c
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time.c x86/time: Eliminate unused irq0_irqs counter 2012-02-27 08:46:25 +01:00
tls.c Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 14:28:26 -07:00
tls.h
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topology.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
trampoline.c memblock, x86: Replace memblock_x86_reserve/free_range() with generic ones 2011-07-14 11:47:53 -07:00
trampoline_32.S x86, trampoline: Common infrastructure for low memory trampolines 2011-02-17 21:02:43 -08:00
trampoline_64.S x86-64, trampoline: Remove unused variable 2011-02-18 15:50:36 -08:00
traps.c Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:21:35 -07:00
tsc.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 14:16:48 -07:00
tsc_sync.c x86/tsc: Reduce the TSC sync check time for core-siblings 2012-02-22 11:49:40 +01:00
verify_cpu.S x86: Fix common misspellings 2011-03-18 10:39:30 +01:00
vm86_32.c Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:21:35 -07:00
vmlinux.lds.S x86-64: Rework vsyscall emulation and add vsyscall= parameter 2011-08-10 19:26:46 -05:00
vsmp_64.c
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vsyscall_64.c x86: vsyscall: Use NULL instead 0 for a pointer argument 2012-04-06 11:49:59 +02:00
vsyscall_emu_64.S x86-64: Rework vsyscall emulation and add vsyscall= parameter 2011-08-10 19:26:46 -05:00
vsyscall_trace.h x86-64: Add vsyscall:emulate_vsyscall trace event 2011-08-04 16:13:53 -07:00
x86_init.c x86/platform: Remove incorrect error message in x86_default_fixup_cpu_id() 2012-04-16 20:43:43 +02:00
x8664_ksyms_64.c x86-64, mem: Convert memmove() to assembly file and fix return value bug 2011-01-25 16:58:39 -08:00
xsave.c x86, xsave: remove thread_has_fpu() bug check in __sanitize_i387_state() 2012-05-16 15:17:17 -07:00