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From: Mike Travis <travis@sgi.com>
To: Ingo Molnar <mingo@elte.hu>, Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <andi@firstfloor.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	davej@codemonkey.org.uk, David Miller <davem@davemloft.net>,
	Eric Dumazet <dada1@cosmosbay.com>,
	Jack Steiner <steiner@sgi.com>,
	Jeremy Fitzhardinge <jeremy@goop.org>, Jes Sorensen <jes@sgi.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	peterz@infradead.org, Thomas Gleixner <tglx@linutronix.de>,
	Yinghai Lu <yhlu.kernel@gmail.com>,
	IA64 <linux-ia64@vger.kernel.org>,
	PowerPC <linuxppc-dev@ozlabs.org>,
	S390 <linux-s390@vger.kernel.org>,
	SPARC <sparclinux@vger.kernel.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 34/35] cpumask: debug options for cpumasks
Date: Mon, 20 Oct 2008 10:03:53 -0700	[thread overview]
Message-ID: <20081020170324.280990000@polaris-admin.engr.sgi.com> (raw)
In-Reply-To: <20081020170319.539427000@polaris-admin.engr.sgi.com>

[-- Attachment #1: cpumask:check-all-ops-for-limits.patch --]
[-- Type: text/plain, Size: 3034 bytes --]

It's useful to check that no one is accessing > nr_cpumask_bits for
cpumasks.  This also allows you to turn on CONFIG_CPUMASKS_OFFSTACK
even for smaller CONFIG_NR_CPUS.

From: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
---
 include/linux/cpumask.h |   23 +++++++++++++++++------
 lib/Kconfig.debug       |    6 ++++++
 lib/cpumask.c           |    3 +++
 3 files changed, 26 insertions(+), 6 deletions(-)

--- test-compile.orig/include/linux/cpumask.h
+++ test-compile/include/linux/cpumask.h
@@ -217,23 +217,34 @@ extern cpumask_t _unused_cpumask_arg_;
 }
 #endif /* CONFIG_NR_CPUS > BITS_PER_LONG */
 
+/* verify cpu argument to cpumask_* operators */
+static inline unsigned int cpumask_check(unsigned int cpu)
+{
+#ifdef CONFIG_DEBUG_PER_CPU_MAPS
+	/* This breaks at runtime. */
+	BUG_ON(cpu >= nr_cpumask_bits);
+#endif /* CONFIG_DEBUG_PER_CPU_MAPS */
+	return cpu;
+}
+
 /* cpumask_* operators */
 static inline void cpumask_set_cpu(int cpu, volatile struct cpumask *dstp)
 {
-	set_bit(cpu, cpumask_bits(dstp));
+	set_bit(cpumask_check(cpu), cpumask_bits(dstp));
 }
 
 static inline void cpumask_clear_cpu(int cpu, volatile struct cpumask *dstp)
 {
-	clear_bit(cpu, cpumask_bits(dstp));
+	clear_bit(cpumask_check(cpu), cpumask_bits(dstp));
 }
 
 /* No static inline type checking - see Subtlety (1) above. */
-#define cpumask_test_cpu(cpu, cpumask) test_bit((cpu), (cpumask)->bits)
+#define cpumask_test_cpu(cpu, cpumask) \
+	test_bit(cpumask_check(cpu), (cpumask)->bits)
 
 static inline int cpumask_test_and_set_cpu(int cpu, struct cpumask *addr)
 {
-	return test_and_set_bit(cpu, cpumask_bits(addr));
+	return test_and_set_bit(cpumask_check(cpu), cpumask_bits(addr));
 }
 
 static inline void cpumask_setall(struct cpumask *dstp)
@@ -367,8 +378,8 @@ static inline int cpumask_cpuremap(int o
 				   const struct cpumask *oldp,
 				   const struct cpumask *newp)
 {
-	return bitmap_bitremap(oldbit, cpumask_bits(oldp), cpumask_bits(newp),
-							   nr_cpumask_bits);
+	return bitmap_bitremap(cpumask_check(oldbit), cpumask_bits(oldp),
+				cpumask_bits(newp), nr_cpumask_bits);
 }
 
 static inline void cpumask_remap(struct cpumask *dstp,
--- test-compile.orig/lib/Kconfig.debug
+++ test-compile/lib/Kconfig.debug
@@ -766,6 +766,12 @@ config SYSCTL_SYSCALL_CHECK
 	  to properly maintain and use. This enables checks that help
 	  you to keep things correct.
 
+config DEBUG_PER_CPU_MAPS
+	bool "Cpumask debug checks"
+	---help---
+	  Extra debugging for cpumasks.
+	  eg. to make sure accesses to cpumasks are < nr_cpu_ids.
+
 source kernel/trace/Kconfig
 
 config PROVIDE_OHCI1394_DMA_INIT
--- test-compile.orig/lib/cpumask.c
+++ test-compile/lib/cpumask.c
@@ -11,6 +11,9 @@ EXPORT_SYMBOL(cpumask_first);
 
 int cpumask_next(int n, const cpumask_t *srcp)
 {
+	/* -1 is a legal arg here. */
+	if (n != -1)
+		cpumask_check(n);
 	return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n+1);
 }
 EXPORT_SYMBOL(cpumask_next);

-- 

  parent reply	other threads:[~2008-10-20 17:12 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-20 17:03 [PATCH 00/35] cpumask: Replace cpumask_t with struct cpumask Mike Travis
2008-10-20 17:03 ` [PATCH 01/35] x86: clean up speedctep-centrino and reduce cpumask_t usage Mike Travis
2008-10-21  0:09   ` Stephen Rothwell
2008-10-21 12:28     ` Mike Travis
2008-10-20 17:03 ` [PATCH 02/35] cpumask: remove min from first_cpu/next_cpu Mike Travis
2008-10-20 17:03 ` [PATCH 03/35] cpumask: add for_each_cpu_mask_and function Mike Travis
2008-10-20 17:03 ` [PATCH 04/35] x86 smp: modify send_IPI_mask interface to accept cpumask_t pointers Mike Travis
2008-10-20 17:03 ` [PATCH 05/35] sched: Reduce stack size requirements in kernel/sched.c Mike Travis
2008-10-20 17:03 ` [PATCH 06/35] cpumask: introduce struct cpumask Mike Travis
2008-10-20 17:03 ` [PATCH 07/35] cpumask: change cpumask_scnprintf, cpumask_parse_user, cpulist_parse, and cpulist_scnprintf to take pointers Mike Travis
2008-10-20 17:03 ` [PATCH 08/35] cpumask: cpumask_size() Mike Travis
2008-10-20 17:03 ` [PATCH 09/35] cpumask: add cpumask_copy() Mike Travis
2008-10-20 17:03 ` [PATCH 10/35] cpumask: introduce cpumask_var_t for local cpumask vars Mike Travis
2008-10-20 17:03 ` [PATCH 11/35] x86: enable MAXSMP Mike Travis
2008-10-20 17:03 ` [PATCH 12/35] cpumask: make CONFIG_NR_CPUS always valid Mike Travis
2008-10-20 17:03 ` [PATCH 13/35] cpumask: use setup_nr_cpu_ids() instead of direct assignment Mike Travis
2008-10-20 17:03 ` [PATCH 14/35] cpumask: make nr_cpu_ids valid in all configurations Mike Travis
2008-10-20 17:03 ` [PATCH 15/35] cpumask: prepare for iterators to only go to nr_cpu_ids Mike Travis
2008-10-20 17:03 ` [PATCH 16/35] percpu: fix percpu accessors to potentially !cpu_possible() cpus Mike Travis
2008-10-20 17:03 ` [PATCH 17/35] cpumask: make nr_cpu_ids the actual limit on bitmap size Mike Travis
2008-10-20 17:03 ` [PATCH 18/35] cpumask: add nr_cpumask_bits Mike Travis
2008-10-21 12:26   ` Rusty Russell
2008-10-21 13:53     ` Mike Travis
2008-10-20 17:03 ` [PATCH 19/35] cpumask: use cpumask_bits() everywhere Mike Travis
2008-10-20 17:03 ` [PATCH 20/35] cpumask: cpumask_of(): cpumask_of_cpu() which returns a pointer Mike Travis
2008-10-20 17:03 ` [PATCH 21/35] cpumask: for_each_cpu(): for_each_cpu_mask which takes " Mike Travis
2008-10-20 17:03 ` [PATCH 22/35] cpumask: cpumask_first/cpumask_next Mike Travis
2008-10-20 17:03 ` [PATCH 23/35] cpumask: deprecate any_online_cpu() in favour of cpumask_any/cpumask_any_and Mike Travis
2008-10-20 17:03 ` [PATCH 24/35] cpumask: cpumask_any_but() Mike Travis
2008-10-20 17:03 ` [PATCH 25/35] cpumask: Deprecate CPUMASK_ALLOC etc in favor of cpumask_var_t Mike Travis
2008-10-20 17:03 ` [PATCH 26/35] cpumask: get rid of boutique sched.c allocations, use cpumask_var_t Mike Travis
2008-10-20 17:03 ` [PATCH 27/35] cpumask: to_cpumask() Mike Travis
2008-10-20 17:03 ` [PATCH 28/35] cpumask: accessors to manipulate possible/present/online/active maps Mike Travis
2008-10-20 17:03 ` [PATCH 29/35] cpumask: Use accessors code Mike Travis
2008-10-20 17:03 ` [PATCH 30/35] cpumask: CONFIG_BITS_ALL, CONFIG_BITS_NONE and CONFIG_BITS_CPU0 Mike Travis
2008-10-20 17:03 ` [PATCH 31/35] cpumask: switch over to cpu_online/possible/active/present_mask Mike Travis
2008-10-20 17:03 ` [PATCH 32/35] cpumask: cpu_all_mask and cpu_none_mask Mike Travis
2008-10-20 17:03 ` [PATCH 33/35] cpumask: reorder header to minimize separate #ifdefs Mike Travis
2008-10-20 17:03 ` Mike Travis [this message]
2008-10-20 17:03 ` [PATCH 35/35] cpumask: smp_call_function_many() Mike Travis

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