Patchwork [16/35] percpu: fix percpu accessors to potentially !cpu_possible() cpus

login
register
mail settings
Submitter Mike Travis
Date Oct. 20, 2008, 5:03 p.m.
Message ID <20081020170321.816821000@polaris-admin.engr.sgi.com>
Download mbox | patch
Permalink /patch/5090/
State Not Applicable, archived
Headers show

Comments

Mike Travis - Oct. 20, 2008, 5:03 p.m.
Percpu areas are only allocated for possible cpus.  In general, you
shouldn't access random cpu's percpu areas: you're corrupting memory.

From: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
---
 arch/m32r/kernel/smpboot.c          |    2 +-
 arch/x86/mach-voyager/voyager_smp.c |    2 +-
 drivers/pnp/pnpbios/bioscalls.c     |    2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

Patch

--- test-compile.orig/arch/m32r/kernel/smpboot.c
+++ test-compile/arch/m32r/kernel/smpboot.c
@@ -598,7 +598,7 @@  int setup_profiling_timer(unsigned int m
 	 * accounting. At that time they also adjust their APIC timers
 	 * accordingly.
 	 */
-	for (i = 0; i < NR_CPUS; ++i)
+	for_each_possible_cpu(i)
 		per_cpu(prof_multiplier, i) = multiplier;
 
 	return 0;
--- test-compile.orig/arch/x86/mach-voyager/voyager_smp.c
+++ test-compile/arch/x86/mach-voyager/voyager_smp.c
@@ -1223,7 +1223,7 @@  int setup_profiling_timer(unsigned int m
 	 * new values until the next timer interrupt in which they do process
 	 * accounting.
 	 */
-	for (i = 0; i < NR_CPUS; ++i)
+	for_each_possible_cpu(i)
 		per_cpu(prof_multiplier, i) = multiplier;
 
 	return 0;
--- test-compile.orig/drivers/pnp/pnpbios/bioscalls.c
+++ test-compile/drivers/pnp/pnpbios/bioscalls.c
@@ -481,7 +481,7 @@  void pnpbios_calls_init(union pnp_bios_i
 
 	set_base(bad_bios_desc, __va((unsigned long)0x40 << 4));
 	_set_limit((char *)&bad_bios_desc, 4095 - (0x40 << 4));
-	for (i = 0; i < NR_CPUS; i++) {
+	for_each_possible_cpu(i) {
 		struct desc_struct *gdt = get_cpu_gdt_table(i);
 		if (!gdt)
 			continue;