linux/arch
Oleg Nesterov 7575637ab2 x86, fpu: Fix math_state_restore() race with kernel_fpu_begin()
math_state_restore() can race with kernel_fpu_begin() if irq comes
right after __thread_fpu_begin(), __save_init_fpu() will overwrite
fpu->state we are going to restore.

Add 2 simple helpers, kernel_fpu_disable() and kernel_fpu_enable()
which simply set/clear in_kernel_fpu, and change math_state_restore()
to exclude kernel_fpu_begin() in between.

Alternatively we could use local_irq_save/restore, but probably these
new helpers can have more users.

Perhaps they should disable/enable preemption themselves, in this case
we can remove preempt_disable() in __restore_xstate_sig().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: matt.fleming@intel.com
Cc: bp@suse.de
Cc: pbonzini@redhat.com
Cc: luto@amacapital.net
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Link: http://lkml.kernel.org/r/20150115192028.GD27332@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-01-20 13:53:07 +01:00
..
alpha arch: Cleanup read_barrier_depends() and comments 2014-12-11 21:15:05 -05:00
arc Minor updates for ARC for 3.19 2014-12-18 16:26:41 -08:00
arm kernel: Provide READ_ONCE and ASSIGN_ONCE 2014-12-20 16:48:59 -08:00
arm64 kernel: Provide READ_ONCE and ASSIGN_ONCE 2014-12-20 16:48:59 -08:00
avr32 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-12-11 14:27:06 -08:00
blackfin TTY/Serial driver patches for 3.19-rc1 2014-12-14 15:23:32 -08:00
c6x net, lib: kill arch_fast_hash library bits 2014-12-10 15:17:46 -05:00
cris CRISv32: Remove last remnants of ETRAX_SPI_MMC_BOARD 2014-12-20 00:06:13 +01:00
frv Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-12-11 14:27:06 -08:00
hexagon Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rkuo/linux-hexagon-kernel 2014-12-19 17:57:51 -08:00
ia64 __get_cpu_var removed from rest of tree, drop reference from comments in arch/ia64 2014-12-19 17:07:27 -08:00
m32r Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-12-11 14:27:06 -08:00
m68k Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-12-11 14:27:06 -08:00
metag arch: Add lightweight memory barriers dma_rmb() and dma_wmb() 2014-12-11 21:15:06 -05:00
microblaze Microblaze patches for 3.19-rc1 2014-12-17 09:54:05 -08:00
mips kernel: Provide READ_ONCE and ASSIGN_ONCE 2014-12-20 16:48:59 -08:00
mn10300 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-12-11 14:27:06 -08:00
nios2 nios2/uaccess: fix sparse errors 2014-12-17 13:53:41 +08:00
openrisc net, lib: kill arch_fast_hash library bits 2014-12-10 15:17:46 -05:00
parisc parisc: percpu: update comments referring to __get_cpu_var 2014-12-13 12:42:53 -08:00
powerpc CONFIG_PM_RUNTIME elimination for 3.19-rc1 2014-12-20 13:37:44 -08:00
s390 kernel: Provide READ_ONCE and ASSIGN_ONCE 2014-12-20 16:48:59 -08:00
score net, lib: kill arch_fast_hash library bits 2014-12-10 15:17:46 -05:00
sh PM: Eliminate CONFIG_PM_RUNTIME 2014-12-19 22:55:06 +01:00
sparc sparc32: destroy_context() and switch_mm() needs to disable interrupts. 2014-12-18 12:47:54 -05:00
tile Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile 2014-12-16 13:54:16 -08:00
um TTY/Serial driver patches for 3.19-rc1 2014-12-14 15:23:32 -08:00
unicore32 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-12-11 14:27:06 -08:00
x86 x86, fpu: Fix math_state_restore() race with kernel_fpu_begin() 2015-01-20 13:53:07 +01:00
xtensa Xtensa fixes for 3.19: 2014-12-16 14:08:53 -08:00
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