Messages in this thread Patch in this message | | | Date | Fri, 25 Apr 2008 08:44:06 +0200 | From | Ingo Molnar <> | Subject | Re: [REGRESSION] x86: support for new UV apic |
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* Priit Laes <plaes@plaes.org> wrote:
> Hey, > > I am getting two following warnings (probable one per each CPU core) > using the latest Linus's git: > > WARNING: at arch/x86/kernel/genapic_64.c:86 read_apic_id+0x30/0x62() > Modules linked in: > Pid: 1, comm: swapper Not tainted 2.6.25-03563-gf7288b1 #20
thanks - could you check the patch below, does it fix the warnings?
Ingo
---------------> Subject: x86: disable preemption in native_smp_prepare_cpus From: Ingo Molnar <mingo@elte.hu> Date: Fri Apr 18 11:07:10 CEST 2008
Priit Laes reported the following warning:
Call Trace: [<ffffffff8022f1e1>] warn_on_slowpath+0x51/0x63 [<ffffffff80282e48>] sys_ioctl+0x2d/0x5d [<ffffffff805185ff>] _spin_lock+0xe/0x24 [<ffffffff80227459>] task_rq_lock+0x3d/0x73 [<ffffffff805133c3>] set_cpu_sibling_map+0x336/0x350 [<ffffffff8021c1b8>] read_apic_id+0x30/0x62 [<ffffffff806d921d>] verify_local_APIC+0x90/0x138 [<ffffffff806d84b5>] native_smp_prepare_cpus+0x1f9/0x305 [<ffffffff806ce7b1>] kernel_init+0x59/0x2d9 [<ffffffff80518a26>] _spin_unlock_irq+0x11/0x2b [<ffffffff8020bf48>] child_rip+0xa/0x12 [<ffffffff806ce758>] kernel_init+0x0/0x2d9 [<ffffffff8020bf3e>] child_rip+0x0/0x12
fix this by generally disabling preemption in native_smp_prepare_cpus().
Reported-and-bisected-by: Priit Laes <plaes@plaes.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- arch/x86/kernel/smpboot.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
Index: linux-x86.q/arch/x86/kernel/smpboot.c =================================================================== --- linux-x86.q.orig/arch/x86/kernel/smpboot.c +++ linux-x86.q/arch/x86/kernel/smpboot.c @@ -1181,6 +1181,7 @@ static void __init smp_cpu_index_default */ 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; @@ -1197,7 +1198,7 @@ void __init native_smp_prepare_cpus(unsi if (smp_sanity_check(max_cpus) < 0) { printk(KERN_INFO "SMP disabled\n"); disable_smp(); - return; + goto out; } preempt_disable(); @@ -1237,6 +1238,8 @@ void __init native_smp_prepare_cpus(unsi printk(KERN_INFO "CPU%d: ", 0); print_cpu_info(&cpu_data(0)); setup_boot_clock(); +out: + preempt_enable(); } /* * Early setup to make printk work.
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