Patchwork powerpc/kdump: Fix timeout in crash_kexec_wait_realmode

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Submitter Michael Neuling
Date July 5, 2011, 6:40 a.m.
Message ID <29259.1309848010@neuling.org>
Download mbox | patch
Permalink /patch/103203/
State Accepted
Commit 63f21a56f1cc0b800a4c00349c59448f82473d19
Headers show

Comments

Michael Neuling - July 5, 2011, 6:40 a.m.
The existing code it pretty ugly.  How about we clean it up even more
like this?

From: Anton Blanchard <anton@samba.org>

We check for timeout expiry in the outer loop, but we also need to
check it in the inner loop or we can lock up forever waiting for a
CPU to hit real mode.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: <stable@kernel.org>
Anton Blanchard - July 6, 2011, 7:55 a.m.
On Tue, 05 Jul 2011 16:40:10 +1000
Michael Neuling <mikey@neuling.org> wrote:

> The existing code it pretty ugly.  How about we clean it up even more
> like this?

Looks good and it passed my kdump test cases.

Anton
 
> From: Anton Blanchard <anton@samba.org>
> 
> We check for timeout expiry in the outer loop, but we also need to
> check it in the inner loop or we can lock up forever waiting for a
> CPU to hit real mode.
> 
> Signed-off-by: Anton Blanchard <anton@samba.org>
> Signed-off-by: Michael Neuling <mikey@neuling.org>
> Cc: <stable@kernel.org>
> 
> diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
> index 4e6ee94..cc6a9d5 100644
> --- a/arch/powerpc/kernel/crash.c
> +++ b/arch/powerpc/kernel/crash.c
> @@ -242,12 +242,8 @@ static void crash_kexec_wait_realmode(int cpu)
>  
>  		while (paca[i].kexec_state < KEXEC_STATE_REAL_MODE) {
>  			barrier();
> -			if (!cpu_possible(i)) {
> +			if (!cpu_possible(i) || !cpu_online(i) ||
> (msecs <= 0)) break;
> -			}
> -			if (!cpu_online(i)) {
> -				break;
> -			}
>  			msecs--;
>  			mdelay(1);
>  		}
>

Patch

diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
index 4e6ee94..cc6a9d5 100644
--- a/arch/powerpc/kernel/crash.c
+++ b/arch/powerpc/kernel/crash.c
@@ -242,12 +242,8 @@  static void crash_kexec_wait_realmode(int cpu)
 
 		while (paca[i].kexec_state < KEXEC_STATE_REAL_MODE) {
 			barrier();
-			if (!cpu_possible(i)) {
+			if (!cpu_possible(i) || !cpu_online(i) || (msecs <= 0))
 				break;
-			}
-			if (!cpu_online(i)) {
-				break;
-			}
 			msecs--;
 			mdelay(1);
 		}