Re: [ 06/23] [Suspend2] Disable usermode helper invocations when the freezer is on.

From: Rafael J. Wysocki
Date: Mon Jan 30 2006 - 17:02:57 EST


Hi,

On Thursday 26 January 2006 04:45, Nigel Cunningham wrote:
>
> Disable usermode helper invocations when the freezer is on. This avoids
> deadlocks due to hotplug events occuring while processes are frozen.
>
> Signed-off-by: Nigel Cunningham <nigel@xxxxxxxxxxxx>
>
> kernel/kmod.c | 4 ++++
> 1 files changed, 4 insertions(+), 0 deletions(-)
>
> diff --git a/kernel/kmod.c b/kernel/kmod.c
> index 51a8920..12afa2c 100644
> --- a/kernel/kmod.c
> +++ b/kernel/kmod.c
> @@ -36,6 +36,7 @@
> #include <linux/mount.h>
> #include <linux/kernel.h>
> #include <linux/init.h>
> +#include <linux/freezer.h>
> #include <asm/uaccess.h>
>
> extern int max_threads;
> @@ -249,6 +250,9 @@ int call_usermodehelper_keys(char *path,
> if (!khelper_wq)
> return -EBUSY;
>
> + if (freezer_is_on())
> + return 0;
> +
> if (path[0] == '\0')
> return 0;
>

Disabling the usermode helper while freeze_processes() is executed seems to be
a good idea to me, but I think it should be done with a mutex or something
like that.

Greetings,
Rafael
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