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| author | Oleg Nesterov <oleg@redhat.com> | 2015-02-06 15:02:00 -0500 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2015-02-19 11:15:03 +0100 |
| commit | 08a744c6bfded3d5fa66f94263f81773226113d1 (patch) | |
| tree | a32ef7c2c947b7331eeb52480948ce41e6fa8431 /arch | |
| parent | 1a2a7f4ec8e3a7ac582dac4d01fcc7e8acd3bb30 (diff) | |
| download | lwn-08a744c6bfded3d5fa66f94263f81773226113d1.tar.gz lwn-08a744c6bfded3d5fa66f94263f81773226113d1.zip | |
x86/fpu: Change math_error() to use unlazy_fpu(), kill (now) unused save_init_fpu()
math_error() calls save_init_fpu() after conditional_sti(), this means
that the caller can be preempted. If !use_eager_fpu() we can hit the
WARN_ON_ONCE(!__thread_has_fpu(tsk)) and/or save the wrong FPU state.
Change math_error() to use unlazy_fpu() and kill save_init_fpu().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1423252925-14451-4-git-send-email-riel@redhat.com
Signed-off-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/fpu-internal.h | 18 | ||||
| -rw-r--r-- | arch/x86/kernel/traps.c | 2 |
2 files changed, 1 insertions, 19 deletions
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index e97622f57722..02f2e0817918 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -518,24 +518,6 @@ static inline void __save_fpu(struct task_struct *tsk) } /* - * These disable preemption on their own and are safe - */ -static inline void save_init_fpu(struct task_struct *tsk) -{ - WARN_ON_ONCE(!__thread_has_fpu(tsk)); - - if (use_eager_fpu()) { - __save_fpu(tsk); - return; - } - - preempt_disable(); - __save_init_fpu(tsk); - __thread_fpu_end(tsk); - preempt_enable(); -} - -/* * i387 state interaction */ static inline unsigned short get_fpu_cwd(struct task_struct *tsk) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 88900e288021..9d889f74e806 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -663,7 +663,7 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr) /* * Save the info for the exception handler and clear the error. */ - save_init_fpu(task); + unlazy_fpu(task); task->thread.trap_nr = trapnr; task->thread.error_code = error_code; info.si_signo = SIGFPE; |