Re: [PATCH] livepatch: Remove reliable stacktrace check in klp_try_switch_task()
On Thu, 12 Jul 2018, Kamalesh Babulal wrote:
> Support for immediate flag was removed by commit d0807da78e11
> ("livepatch: Remove immediate feature"). We bail out during
> patch registration for architectures, those don't support
> reliable stack trace. Remove the check in klp_try_switch_task(),
> as its not required.
>
> Signed-off-by: Kamalesh Babulal
Applied, thanks.
--
Jiri Kosina
SUSE Labs
Re: [PATCH] livepatch: Remove reliable stacktrace check in klp_try_switch_task()
On Thu, Jul 12, 2018 at 01:35:06PM +0530, Kamalesh Babulal wrote:
> Support for immediate flag was removed by commit d0807da78e11
> ("livepatch: Remove immediate feature"). We bail out during
> patch registration for architectures, those don't support
> reliable stack trace. Remove the check in klp_try_switch_task(),
> as its not required.
>
> Signed-off-by: Kamalesh Babulal
Acked-by: Josh Poimboeuf
> ---
> kernel/livepatch/transition.c | 7 ---
> 1 file changed, 7 deletions(-)
>
> diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
> index 7c6631e693bc..5bc349805e03 100644
> --- a/kernel/livepatch/transition.c
> +++ b/kernel/livepatch/transition.c
> @@ -310,13 +310,6 @@ static bool klp_try_switch_task(struct task_struct *task)
> return true;
>
> /*
> - * For arches which don't have reliable stack traces, we have to rely
> - * on other methods (e.g., switching tasks at kernel exit).
> - */
> - if (!klp_have_reliable_stack())
> - return false;
> -
> - /*
>* Now try to check the stack for any to-be-patched or to-be-unpatched
>* functions. If all goes well, switch the task to the target patch
>* state.
> --
> 2.7.4
>
--
Josh
Re: [PATCH] livepatch: Remove reliable stacktrace check in klp_try_switch_task()
On Sun, Jul 15, 2018 at 01:05:56PM +0530, Kamalesh Babulal wrote: > On Saturday 14 July 2018 12:07 AM, Josh Poimboeuf wrote: > > > We bail out during patch registration for architectures, those don't > > > support reliable stack trace. > > > > Does anybody know if that change was intentional? I thought the plan > > was to allow non-consistency-model arches to still use livepatch, and > > that they'd just have to 'force' patches to completion instead. That > > seems a little more forgiving. > > > > The initial proposal was to allow 'force' feature on architectures > without HAVE_RELIABLE_STACKTRACE support and use pr_notice() to warn > user about the non-availability of consistency model. It was argued > against, as it will encourage people to use it as an alternative instead > of adding HAVE_RELIABLE_STACKTRACE support to the kernel. Ok, looking through the archives, I found it: https://lkml.kernel.org/r/20171221151428.rt4dlizxb5nqh...@pathway.suse.cz I'm not sure I agree with that conclusion, but nobody has complained about it, so it's probably fine... -- Josh
Re: [PATCH] livepatch: Remove reliable stacktrace check in klp_try_switch_task()
On Saturday 14 July 2018 12:07 AM, Josh Poimboeuf wrote: We bail out during patch registration for architectures, those don't support reliable stack trace. Does anybody know if that change was intentional? I thought the plan was to allow non-consistency-model arches to still use livepatch, and that they'd just have to 'force' patches to completion instead. That seems a little more forgiving. The initial proposal was to allow 'force' feature on architectures without HAVE_RELIABLE_STACKTRACE support and use pr_notice() to warn user about the non-availability of consistency model. It was argued against, as it will encourage people to use it as an alternative instead of adding HAVE_RELIABLE_STACKTRACE support to the kernel. -- cheers, Kamalesh.
Re: [PATCH] livepatch: Remove reliable stacktrace check in klp_try_switch_task()
> We bail out during patch registration for architectures, those don't > support reliable stack trace. Does anybody know if that change was intentional? I thought the plan was to allow non-consistency-model arches to still use livepatch, and that they'd just have to 'force' patches to completion instead. That seems a little more forgiving. -- Josh
Re: [PATCH] livepatch: Remove reliable stacktrace check in klp_try_switch_task()
On Thu, 12 Jul 2018, Kamalesh Babulal wrote:
> Support for immediate flag was removed by commit d0807da78e11
> ("livepatch: Remove immediate feature"). We bail out during
> patch registration for architectures, those don't support
> reliable stack trace. Remove the check in klp_try_switch_task(),
> as its not required.
>
> Signed-off-by: Kamalesh Babulal
Acked-by: Miroslav Benes
M
Re: [PATCH] livepatch: Remove reliable stacktrace check in klp_try_switch_task()
On Thu 2018-07-12 13:35:06, Kamalesh Babulal wrote:
> Support for immediate flag was removed by commit d0807da78e11
> ("livepatch: Remove immediate feature"). We bail out during
> patch registration for architectures, those don't support
> reliable stack trace. Remove the check in klp_try_switch_task(),
> as its not required.
>
> Signed-off-by: Kamalesh Babulal
Good catch!
Reviewed-by: Petr Mladek
Best Regards,
Petr
[PATCH] livepatch: Remove reliable stacktrace check in klp_try_switch_task()
Support for immediate flag was removed by commit d0807da78e11
("livepatch: Remove immediate feature"). We bail out during
patch registration for architectures, those don't support
reliable stack trace. Remove the check in klp_try_switch_task(),
as its not required.
Signed-off-by: Kamalesh Babulal
---
kernel/livepatch/transition.c | 7 ---
1 file changed, 7 deletions(-)
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index 7c6631e693bc..5bc349805e03 100644
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -310,13 +310,6 @@ static bool klp_try_switch_task(struct task_struct *task)
return true;
/*
-* For arches which don't have reliable stack traces, we have to rely
-* on other methods (e.g., switching tasks at kernel exit).
-*/
- if (!klp_have_reliable_stack())
- return false;
-
- /*
* Now try to check the stack for any to-be-patched or to-be-unpatched
* functions. If all goes well, switch the task to the target patch
* state.
--
2.7.4
