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From: Peter Zijlstra <peterz@infradead.org>
To: Mikulas Patocka <mpatocka@redhat.com>, Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
	Paul Mackerras <paulus@samba.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Vince Weaver <vince@deater.net>,
	"hillf.zj" <hillf.zj@alibaba-inc.com>,
	Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
	linux-kernel@vger.kernel.org
Subject: [PATCH] x86: Fix static_key in load_mm_cr4()
Date: Thu, 9 Jul 2015 19:23:38 +0200	[thread overview]
Message-ID: <20150709172338.GC19282@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.LRH.2.02.1507081253500.1992@file01.intranet.prod.int.rdu2.redhat.com>


Mikulas reported his K6-3 not booting. This is because the static_key
confusion struck and bit Andy, this wants to be static_key_false().

Fixes: a66734297f78 ("perf/x86: Add /sys/devices/cpu/rdpmc=2 to allow rdpmc for all tasks")
Cc: Andy Lutomirski <luto@amacapital.net>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/include/asm/mmu_context.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 5e8daee7c5c9..804a3a6030ca 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -23,7 +23,7 @@ extern struct static_key rdpmc_always_available;
 
 static inline void load_mm_cr4(struct mm_struct *mm)
 {
-	if (static_key_true(&rdpmc_always_available) ||
+	if (static_key_false(&rdpmc_always_available) ||
 	    atomic_read(&mm->context.perf_rdpmc_allowed))
 		cr4_set_bits(X86_CR4_PCE);
 	else

  reply	other threads:[~2015-07-09 17:23 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-08 15:17 Kernel broken on processors without performance counters Mikulas Patocka
2015-07-08 16:07 ` Peter Zijlstra
2015-07-08 16:54   ` Mikulas Patocka
2015-07-09 17:23     ` Peter Zijlstra [this message]
2015-07-09 19:11       ` [PATCH] x86: Fix static_key in load_mm_cr4() Mikulas Patocka
2015-07-10  8:27       ` [tip:perf/urgent] x86, perf: Fix static_key bug " tip-bot for Peter Zijlstra
2015-07-08 17:37   ` Kernel broken on processors without performance counters Andy Lutomirski
2015-07-08 20:04     ` Jason Baron
2015-07-09  0:36       ` Andy Lutomirski
2015-07-10 14:13         ` Peter Zijlstra
2015-07-10 15:29           ` Jason Baron
2015-07-21  8:21           ` Peter Zijlstra
2015-07-21 15:43             ` Thomas Gleixner
2015-07-21 15:49               ` Peter Zijlstra
2015-07-21 15:51                 ` Andy Lutomirski
2015-07-21 16:12                   ` Peter Zijlstra
2015-07-21 16:57                     ` Jason Baron
2015-07-23 14:54                       ` Steven Rostedt
2015-07-21 18:15                     ` Borislav Petkov
2015-07-21 18:50                       ` Jason Baron
2015-07-21 18:54                         ` Andy Lutomirski
2015-07-21 19:00                           ` Valdis.Kletnieks
2015-07-21 19:29                             ` Andy Lutomirski
2015-07-21 23:49                               ` Valdis.Kletnieks
2015-07-22  4:24                         ` Borislav Petkov
2015-07-22 17:06                           ` Jason Baron
2015-07-23 10:42                             ` Peter Zijlstra
2015-07-23 10:53                               ` Borislav Petkov
2015-07-23 14:19                               ` Jason Baron
2015-07-23 14:33                                 ` Peter Zijlstra
2015-07-23 14:49                                   ` Peter Zijlstra
2015-07-23 19:14                                     ` Jason Baron
2015-07-24 10:56                                       ` Peter Zijlstra
2015-07-24 12:36                                         ` Peter Zijlstra
2015-07-24 14:15                                           ` Jason Baron
2015-07-23 14:58                                 ` Peter Zijlstra
2015-07-23 15:34                               ` Steven Rostedt
2015-07-23 17:08                                 ` Peter Zijlstra
2015-07-23 17:18                                   ` Steven Rostedt
2015-07-23 17:33                                   ` Jason Baron
2015-07-23 18:12                                     ` Steven Rostedt
2015-07-23 19:02                                     ` Peter Zijlstra
2015-07-23 17:35                                   ` Andy Lutomirski
2015-07-23 17:54                                   ` Borislav Petkov
2015-07-23 19:02                                     ` Peter Zijlstra
2015-07-24  5:29                                       ` Borislav Petkov
2015-07-24 10:36                                         ` Peter Zijlstra
2015-07-22 20:43                           ` Mikulas Patocka
2015-07-21 15:53                 ` Thomas Gleixner
2015-07-21 15:54                 ` Peter Zijlstra
2015-07-09 17:11       ` Peter Zijlstra
2015-07-09 19:15         ` Jason Baron
2015-07-14  9:35 ` Borislav Petkov
2015-07-14 12:43   ` Mikulas Patocka

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