aboutsummaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
authorOleg Nesterov <oleg@redhat.com>2015-03-13 09:53:10 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-03-26 15:01:00 +0100
commit16329d3d06836a47ac9bc66867b0bd09dfb76ad9 (patch)
treeabf3f7a8edfec57845fb20bf04cabdbf995552ef /arch
parent1e6d9ee06210b979bca6f4d3a1e1d663e0bc5bcb (diff)
downloadlinux-linaro-stable-16329d3d06836a47ac9bc66867b0bd09dfb76ad9.tar.gz
x86/fpu: Drop_fpu() should not assume that tsk equals current
commit f4c3686386393c120710dd34df2a74183ab805fd upstream. drop_fpu() does clear_used_math() and usually this is correct because tsk == current. However switch_fpu_finish()->restore_fpu_checking() is called before __switch_to() updates the "current_task" variable. If it fails, we will wrongly clear the PF_USED_MATH flag of the previous task. So use clear_stopped_child_used_math() instead. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Pekka Riikonen <priikone@iki.fi> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Suresh Siddha <sbsiddha@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150309171041.GB11388@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/fpu-internal.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index e72b2e41499e..1b2fc5cf1963 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -370,7 +370,7 @@ static inline void drop_fpu(struct task_struct *tsk)
preempt_disable();
tsk->fpu_counter = 0;
__drop_fpu(tsk);
- clear_used_math();
+ clear_stopped_child_used_math(tsk);
preempt_enable();
}