* [patch kexec] Fix test for loaded kernel
@ 2008-09-12 19:08 Geoff Levand
2008-09-12 19:33 ` Geoff Levand
0 siblings, 1 reply; 4+ messages in thread
From: Geoff Levand @ 2008-09-12 19:08 UTC (permalink / raw)
To: Simon Horman; +Cc: kexec, Cell Broadband Engine OSS Development
Fix these reboot errors with NFS mounted root filesystems:
nfs: server 192.168.1.1 not responding, still trying
The main kexec code that uses kexec_loaded() expects a non-zero
return to mean a kexec kernel has been loaded for execution.
Here is the current check:
if ((result == 0) && (do_shutdown || do_exec) && !kexec_loaded())
die
In cases where the currently running kernel does not have kexec enabled,
or in cases where the distro init scripts (YDL, maybe others) have unmounted
the sys filesystem prior to running kexec, the open of
"/sys/kernel/kexec_loaded" will fail. This result should be returned as
(0), meaning NOT LOADED. The current kexec_loaded() code returns (-1),
meaning LOADED.
With the current code, kexec will continue on. The next steps are to
shutdown the network, then call sys_kexec. The shutdown of the network
will succeed, but the call to sys_kexec will fail. In this case, control
will pass back to the init scripts, but the network will be down.
Systems with NFS mounted root filesystem cannot work in this state.
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
---
kexec/kexec.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -805,7 +805,7 @@ static int kexec_loaded(void)
fp = fopen("/sys/kernel/kexec_loaded", "r");
if (fp == NULL)
- return -1;
+ return 0;
fscanf(fp, "%d", &ret);
fclose(fp);
return ret;
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [patch kexec] Fix test for loaded kernel
2008-09-12 19:08 [patch kexec] Fix test for loaded kernel Geoff Levand
@ 2008-09-12 19:33 ` Geoff Levand
2008-09-15 6:18 ` Mohan Kumar M
0 siblings, 1 reply; 4+ messages in thread
From: Geoff Levand @ 2008-09-12 19:33 UTC (permalink / raw)
To: Simon Horman; +Cc: kexec, Cell Broadband Engine OSS Development
Hi Simon,
Sorry, this does not work correctly. Please ignore.
Geoff Levand wrote:
> Fix these reboot errors with NFS mounted root filesystems:
>
> nfs: server 192.168.1.1 not responding, still trying
>
> The main kexec code that uses kexec_loaded() expects a non-zero
> return to mean a kexec kernel has been loaded for execution.
> Here is the current check:
>
> if ((result == 0) && (do_shutdown || do_exec) && !kexec_loaded())
> die
>
> In cases where the currently running kernel does not have kexec enabled,
> or in cases where the distro init scripts (YDL, maybe others) have unmounted
> the sys filesystem prior to running kexec, the open of
> "/sys/kernel/kexec_loaded" will fail. This result should be returned as
> (0), meaning NOT LOADED. The current kexec_loaded() code returns (-1),
> meaning LOADED.
Unfortunately, in the case where a kernel has been loaded, but the init
scripts unmount sys_fs, my change will not allow the kexec to continue.
The only way to fix the NFS problem is to change the init scripts to
pass the -x option to kexec.
-Geoff
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [patch kexec] Fix test for loaded kernel
2008-09-12 19:33 ` Geoff Levand
@ 2008-09-15 6:18 ` Mohan Kumar M
2008-09-15 7:03 ` Simon Horman
0 siblings, 1 reply; 4+ messages in thread
From: Mohan Kumar M @ 2008-09-15 6:18 UTC (permalink / raw)
To: Geoff Levand; +Cc: Simon Horman, kexec, Cell Broadband Engine OSS Development
Hi Geoff,
>
> The only way to fix the NFS problem is to change the init scripts to
> pass the -x option to kexec.
Can we simply call ifup (that function does not exist now) to bring up
the network interface while returning from main() in kexec.c? This will
be executed only if kexec'ing a kernel fails.
Regards,
Mohan.
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [patch kexec] Fix test for loaded kernel
2008-09-15 6:18 ` Mohan Kumar M
@ 2008-09-15 7:03 ` Simon Horman
0 siblings, 0 replies; 4+ messages in thread
From: Simon Horman @ 2008-09-15 7:03 UTC (permalink / raw)
To: Mohan Kumar M; +Cc: kexec, Cell Broadband Engine OSS Development, Geoff Levand
On Mon, Sep 15, 2008 at 11:48:56AM +0530, Mohan Kumar M wrote:
> Hi Geoff,
>
>>
>> The only way to fix the NFS problem is to change the init scripts to
>> pass the -x option to kexec.
>
> Can we simply call ifup (that function does not exist now) to bring up
> the network interface while returning from main() in kexec.c? This will
> be executed only if kexec'ing a kernel fails.
Good greif, that ifdown() stuff seems horrible. I wonder what the
motivation for it is/was.
--
Simon Horman
VA Linux Systems Japan K.K., Sydney, Australia Satellite Office
H: www.vergenet.net/~horms/ W: www.valinux.co.jp/en
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2008-09-12 19:08 [patch kexec] Fix test for loaded kernel Geoff Levand
2008-09-12 19:33 ` Geoff Levand
2008-09-15 6:18 ` Mohan Kumar M
2008-09-15 7:03 ` Simon Horman
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