From 84ffae55af79d7b8834fd0c08d0d1ebf2c77f91e Mon Sep 17 00:00:00 2001
From: Anton Blanchard <anton@samba.org>
Date: Thu, 7 Apr 2011 21:44:21 +0000
Subject: [PATCH] powerpc: Fix oops if scan_dispatch_log is called too early
We currently enable interrupts before the dispatch log for the boot
cpu is setup. If a timer interrupt comes in early enough we oops in
scan_dispatch_log:
Unable to handle kernel paging request for data at address 0x00000010
...
.scan_dispatch_log+0xb0/0x170
.account_system_vtime+0xa0/0x220
.irq_enter+0x88/0xc0
.do_IRQ+0x48/0x230
The patch below adds a check to scan_dispatch_log to ensure the
dispatch log has been allocated.
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
arch/powerpc/kernel/time.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 375480c56eb9..f33acfd872ad 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -229,6 +229,9 @@ static u64 scan_dispatch_log(u64 stop_tb)
u64 stolen = 0;
u64 dtb;
+ if (!dtl)
+ return 0;
+
if (i == vpa->dtl_idx)
return 0;
while (i < vpa->dtl_idx) {
--
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