From: Oleg Nesterov <oleg@redhat.com>
To: "H. Peter Anvin" <hpa@zytor.com>, Suresh Siddha <sbsiddha@gmail.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
Bean Anderson <bean@azulsystems.com>,
Fenghua Yu <fenghua.yu@intel.com>, Ingo Molnar <mingo@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/7] x86, fpu: __restore_xstate_sig()->math_state_restore() needs preempt_disable()
Date: Tue, 2 Sep 2014 19:57:17 +0200 [thread overview]
Message-ID: <20140902175717.GA21649@redhat.com> (raw)
In-Reply-To: <20140902175654.GA21626@redhat.com>
Add preempt_disable() + preempt_enable() around math_state_restore() in
__restore_xstate_sig(). Otherwise __switch_to() after __thread_fpu_begin()
can overwrite fpu->state we are going to restore.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Suresh Siddha <sbsiddha@gmail.com>
---
arch/x86/kernel/xsave.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index 74b34c2..dd50e26 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -397,8 +397,11 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
set_used_math();
}
- if (use_eager_fpu())
+ if (use_eager_fpu()) {
+ preempt_disable();
math_state_restore();
+ preempt_enable();
+ }
return err;
} else {
--
1.5.5.1
next prev parent reply other threads:[~2014-09-02 17:59 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-02 17:56 [PATCH 0/7] x86, fpu: misc fixes/cleanups, more to come Oleg Nesterov
2014-09-02 17:57 ` [PATCH v2 1/7] x86, fpu: shift drop_init_fpu() from save_xstate_sig() to handle_signal() Oleg Nesterov
2014-09-02 22:18 ` [tip:x86/fpu] " tip-bot for Oleg Nesterov
2014-09-02 17:57 ` Oleg Nesterov [this message]
2014-09-02 22:18 ` [tip:x86/fpu] x86, fpu: __restore_xstate_sig()-> math_state_restore() needs preempt_disable() tip-bot for Oleg Nesterov
2014-09-02 17:57 ` [PATCH v2 3/7] x86, fpu: change __thread_fpu_begin() to use use_eager_fpu() Oleg Nesterov
2014-09-02 22:19 ` [tip:x86/fpu] x86, fpu: Change " tip-bot for Oleg Nesterov
2014-09-02 17:57 ` [PATCH v2 4/7] x86, fpu: copy_process: avoid fpu_alloc/copy if !used_math() Oleg Nesterov
2014-09-02 22:19 ` [tip:x86/fpu] x86, fpu: copy_process: Avoid fpu_alloc/ copy " tip-bot for Oleg Nesterov
2014-09-02 17:57 ` [PATCH v2 5/7] x86, fpu: copy_process: sanitize fpu->last_cpu initialization Oleg Nesterov
2014-09-02 22:19 ` [tip:x86/fpu] x86, fpu: copy_process: Sanitize fpu-> last_cpu initialization tip-bot for Oleg Nesterov
2014-09-02 17:57 ` [PATCH v2 6/7] x86, fpu: shift "fpu_counter = 0" from copy_thread() to arch_dup_task_struct() Oleg Nesterov
2014-09-02 22:19 ` [tip:x86/fpu] x86, fpu: Shift "fpu_counter = 0" from copy_thread( ) " tip-bot for Oleg Nesterov
2014-09-02 17:57 ` [PATCH v2 7/7] x86: copy_thread: don't nullify ->ptrace_bps twice Oleg Nesterov
2014-09-02 22:19 ` [tip:x86/fpu] x86: copy_thread: Don't " tip-bot for Oleg Nesterov
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