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From: green@linuxhacker.ru
To: Rusty Russell <rusty@rustcorp.com.au>,
	Andrew Morton <akpm@linux-foundation.org>,
	"David S. Miller" <davem@davemloft.net>
Cc: linux-kernel@vger.kernel.org, Oleg Drokin <green@linuxhacker.ru>
Subject: [PATCH 2/2] cpumask: make whole cpumask operations like copy to work with NR_CPUS bits
Date: Thu, 26 Feb 2015 01:19:11 -0500	[thread overview]
Message-ID: <1424931551-11757-3-git-send-email-green@linuxhacker.ru> (raw)
In-Reply-To: <1424931551-11757-1-git-send-email-green@linuxhacker.ru>

From: Oleg Drokin <green@linuxhacker.ru>

When we are doing things like cpumask_copy, and CONFIG_CPUMASK_OFFSTACK
is set, we only copy actual number of bits equal to number of CPUs
we have. But underlying allocations got NR_CPUS = 8192, so
if the cpumask is allocated on the stack or has other prefilled values
there's a lot of garbage left that might become exposed as more CPUs are
added into the system.
The patch converts such whole-mask functions:
cpumask_setall, cpumask_clear, cpumask_copy
to operate on the whole NR_CPUS value.

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
---
 include/linux/cpumask.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index f0599e1..28a8bb3 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -324,21 +324,21 @@ static inline int cpumask_test_and_clear_cpu(int cpu, struct cpumask *cpumask)
 }
 
 /**
- * cpumask_setall - set all cpus (< nr_cpu_ids) in a cpumask
+ * cpumask_setall - set all cpus (< NR_CPUS) in a cpumask
  * @dstp: the cpumask pointer
  */
 static inline void cpumask_setall(struct cpumask *dstp)
 {
-	bitmap_fill(cpumask_bits(dstp), nr_cpumask_bits);
+	bitmap_fill(cpumask_bits(dstp), NR_CPUS);
 }
 
 /**
- * cpumask_clear - clear all cpus (< nr_cpu_ids) in a cpumask
+ * cpumask_clear - clear all cpus (< NR_CPUS) in a cpumask
  * @dstp: the cpumask pointer
  */
 static inline void cpumask_clear(struct cpumask *dstp)
 {
-	bitmap_zero(cpumask_bits(dstp), nr_cpumask_bits);
+	bitmap_zero(cpumask_bits(dstp), NR_CPUS);
 }
 
 /**
@@ -470,7 +470,7 @@ static inline bool cpumask_full(const struct cpumask *srcp)
 
 /**
  * cpumask_weight - Count of bits in *srcp
- * @srcp: the cpumask to count bits (< nr_cpu_ids) in.
+ * @srcp: the cpumask to count bits (< NR_CPUS) in.
  */
 static inline unsigned int cpumask_weight(const struct cpumask *srcp)
 {
@@ -511,7 +511,7 @@ static inline void cpumask_shift_left(struct cpumask *dstp,
 static inline void cpumask_copy(struct cpumask *dstp,
 				const struct cpumask *srcp)
 {
-	bitmap_copy(cpumask_bits(dstp), cpumask_bits(srcp), nr_cpumask_bits);
+	bitmap_copy(cpumask_bits(dstp), cpumask_bits(srcp), NR_CPUS);
 }
 
 /**
-- 
2.1.0


  parent reply	other threads:[~2015-02-26  6:20 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-26  6:19 [PATCH 0/2] incorrect cpumask behavior with CPUMASK_OFFSTACK green
2015-02-26  6:19 ` [PATCH 1/2] cpumask: Properly calculate cpumask values green
2015-02-26  6:19 ` green [this message]
2015-02-27 11:46 ` [PATCH 0/2] incorrect cpumask behavior with CPUMASK_OFFSTACK Rusty Russell
2015-02-27 17:51   ` Oleg Drokin
2015-03-02 11:28     ` Rusty Russell

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