From deef325086c3897393b8f7d6bccd03405244fe18 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 12 May 2008 15:44:38 +0200 Subject: [PATCH] x86: disable preemption in native_smp_prepare_cpus Priit Laes reported the following warning: Call Trace: [] warn_on_slowpath+0x51/0x63 [] sys_ioctl+0x2d/0x5d [] _spin_lock+0xe/0x24 [] task_rq_lock+0x3d/0x73 [] set_cpu_sibling_map+0x336/0x350 [] read_apic_id+0x30/0x62 [] verify_local_APIC+0x90/0x138 [] native_smp_prepare_cpus+0x1f9/0x305 [] kernel_init+0x59/0x2d9 [] _spin_unlock_irq+0x11/0x2b [] child_rip+0xa/0x12 [] kernel_init+0x0/0x2d9 [] child_rip+0x0/0x12 fix this by generally disabling preemption in native_smp_prepare_cpus(). Reported-and-bisected-by: Priit Laes Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/smpboot.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 38988491c62..56078d61c79 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1190,6 +1190,7 @@ static void __init smp_cpu_index_default(void) */ void __init native_smp_prepare_cpus(unsigned int max_cpus) { + preempt_disable(); nmi_watchdog_default(); smp_cpu_index_default(); current_cpu_data = boot_cpu_data; @@ -1206,7 +1207,7 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) if (smp_sanity_check(max_cpus) < 0) { printk(KERN_INFO "SMP disabled\n"); disable_smp(); - return; + goto out; } preempt_disable(); @@ -1246,6 +1247,8 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) printk(KERN_INFO "CPU%d: ", 0); print_cpu_info(&cpu_data(0)); setup_boot_clock(); +out: + preempt_enable(); } /* * Early setup to make printk work. -- 2.20.1