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 Signed-off-by: Rusty Russell Signed-off-by: Mike Travis --- 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(-) --- 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; -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/