From 67963132638e67ad3c5aa16765e6f3f2f3cdd85c Mon Sep 17 00:00:00 2001 From: Maneesh Soni Date: Tue, 14 Mar 2006 15:03:14 +0530 Subject: [PATCH] Plug kdump shutdown race window lapic_shutdown() re-enables interrupts which is un-desirable for panic case, so use local_irq_save() and local_irq_restore() to keep the irqs disabled for kexec on panic case, and close a possible race window while kdump shutdown as shown in this stack trace -- BUG: spinlock lockup on CPU#1, bash/4396, c52781a0 [] _raw_spin_lock+0xb7/0xd2 [] _spin_lock+0x6/0x8 [] scheduler_tick+0xe7/0x328 [] update_process_times+0x51/0x5d [] smp_apic_timer_interrupt+0x4f/0x58 [] lapic_shutdown+0x76/0x7e [] apic_timer_interrupt+0x1c/0x30 [] lapic_shutdown+0x76/0x7e [] machine_crash_shutdown+0x83/0xaa [] crash_kexec+0xc1/0xe3 [] _spin_lock+0x6/0x8 [] crash_kexec+0xad/0xe3 [] __handle_sysrq+0x84/0xfd [] write_sysrq_trigger+0x2c/0x35 [] vfs_write+0xa2/0x13b [] sys_write+0x3b/0x64 [] syscall_call+0x7/0xb Signed-off-by: Maneesh Soni Signed-off-by: Linus Torvalds --- arch/i386/kernel/apic.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c index f39e09ef64ec..776c90989e06 100644 --- a/arch/i386/kernel/apic.c +++ b/arch/i386/kernel/apic.c @@ -570,16 +570,18 @@ void __devinit setup_local_APIC(void) */ void lapic_shutdown(void) { + unsigned long flags; + if (!cpu_has_apic) return; - local_irq_disable(); + local_irq_save(flags); clear_local_APIC(); if (enabled_via_apicbase) disable_local_APIC(); - local_irq_enable(); + local_irq_restore(flags); } #ifdef CONFIG_PM -- cgit v1.2.3