From: Oleg Nesterov <oleg@redhat.com>
To: Al Viro <viro@ZenIV.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Suresh Siddha <sbsiddha@gmail.com>
Cc: Bean Anderson <bean@azulsystems.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] x86, fpu: __restore_xstate_sig()->math_state_restore() needs preempt_disable()
Date: Mon, 25 Aug 2014 20:08:06 +0200 [thread overview]
Message-ID: <20140825180806.GA22193@redhat.com> (raw)
In-Reply-To: <20140822171142.GA14812@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
---
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 453343c..c52eb9c 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:[~2014-08-25 18:10 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-22 17:11 [PATCH 0/1] x86, fpu: shift drop_init_fpu() from save_xstate_sig() to handle_signal() Oleg Nesterov
2014-08-22 17:12 ` [PATCH 1/1] " Oleg Nesterov
2014-08-24 19:47 ` [PATCH 0/5] x86, fpu: make use_eager_fpu() more eager Oleg Nesterov
2014-08-24 19:47 ` [PATCH 1/5] x86, fpu: change sanitize_restored_xstate() and convert_to_fxsr() to accept thread_xstate Oleg Nesterov
2014-08-24 19:47 ` [PATCH 2/5] x86, fpu: don't drop_fpu() in __restore_xstate_sig() if use_eager_fpu() Oleg Nesterov
2014-08-24 20:05 ` Linus Torvalds
2014-08-25 14:26 ` Oleg Nesterov
2014-08-25 14:41 ` Oleg Nesterov
2014-08-25 16:27 ` Linus Torvalds
2014-08-25 17:09 ` Oleg Nesterov
2014-08-25 17:26 ` Linus Torvalds
2014-08-25 17:39 ` Oleg Nesterov
2014-08-27 17:02 ` Oleg Nesterov
2014-08-24 19:47 ` [PATCH 3/5] x86, fpu: don't drop_fpu() in exit_thread() " Oleg Nesterov
2014-08-24 19:47 ` [PATCH 4/5] x86, fpu: shift init_fpu() from eager_fpu_init() to eager_fpu_init_bp() Oleg Nesterov
2014-08-24 19:47 ` [PATCH 5/5] x86, fpu: sanitize the usage of use_eager_fpu() in switch_fpu_prepare() Oleg Nesterov
2014-08-25 18:08 ` Oleg Nesterov [this message]
2014-09-02 5:01 ` [PATCH] x86, fpu: __restore_xstate_sig()->math_state_restore() needs preempt_disable() Suresh Siddha
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