Commit 67059d65 authored Jun 11, 2019 by Miroslav Benes Committed by Petr Mladek Jun 20, 2019

Revert "livepatch: Remove reliable stacktrace check in klp_try_switch_task()"



This reverts commit 1d98a69e. Commit
31adf230 ("livepatch: Convert error about unsupported reliable
stacktrace into a warning") weakened the enforcement for architectures
to have reliable stack traces support. The system only warns now about
it.

It only makes sense to reintroduce the compile time checking in
klp_try_switch_task() again and bail out early.

Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>

parent 380178ef

kernel/livepatch/transition.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -305,6 +305,13 @@ static bool klp_try_switch_task(struct task_struct *task)
		if (task->patch_state == klp_target_state)
		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