From: Wanpeng Li <wanpeng...@hotmail.com>
native_smp_prepare_cpus
-> default_setup_apic_routing
-> enable_IR_x2apic
-> irq_remapping_prepare
-> intel_prepare_irq_remapping
-> intel_setup_irq_remapping
IR table is setup even if "noapic" boot parameter is added.
As a result:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff8d5a5e58>] modify_irte+0x58/0x140
PGD 209638067 PUD 2105f4067 PMD 0
Oops: 0000 [#1] SMP
RIP: 0010:[<ffffffff8d5a5e58>] [<ffffffff8d5a5e58>] modify_irte+0x58/0x140
Call Trace:
intel_ir_set_affinity+0xa3/0xb0
msi_domain_set_affinity+0x21/0x70
? __irq_set_affinity+0x34/0x70
irq_do_set_affinity+0x1d/0x70
irq_set_affinity_locked+0xc2/0x100
__irq_set_affinity+0x47/0x70
write_irq_affinity.isra.7+0xcc/0xf0
irq_affinity_proc_write+0x19/0x20
proc_reg_write+0x3d/0x70
? rcu_sync_lockdep_assert+0x2f/0x60
__vfs_write+0x28/0x120
? percpu_down_read+0x5c/0xa0
? __sb_start_write+0xca/0xe0
? __sb_start_write+0xca/0xe0
vfs_write+0xb5/0x1b0
SyS_write+0x49/0xa0
do_syscall_64+0x81/0x220
entry_SYSCALL64_slow_path+0x25/0x25
RIP [<ffffffff8d5a5e58>] modify_irte+0x58/0x140
RSP <ffff8e9ad01b7c78>
CR2: 0000000000000000
This patch fix it by disabling IOAPIC support if "noapic" is on the kernel
command line.
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: Joerg Roedel <j...@8bytes.org>
Signed-off-by: Wanpeng Li <wanpeng...@hotmail.com>
---
v2 -> v3:
* update changelog
* skip ioapic instead of the whole APIC
v1 -> v2:
* not call any of the apic functions when apic is disabled
arch/x86/kernel/apic/apic.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index cea4fc1..50c95af 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1623,6 +1623,9 @@ void __init enable_IR_x2apic(void)
unsigned long flags;
int ret, ir_stat;
+ if (skip_ioapic_setup)
+ return;
+
ir_stat = irq_remapping_prepare();
if (ir_stat < 0 && !x2apic_supported())
return;
--
1.9.1
