linux-kernel - [PATCH] livepatch: Remove reliable stacktrace check in klp_try_switch

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Date:   Thu, 12 Jul 2018 13:35:06 +0530
From:   Kamalesh Babulal <kamalesh@...ux.vnet.ibm.com>
To:     Miroslav Benes <mbenes@...e.cz>,
        Josh Poimboeuf <jpoimboe@...hat.com>
Cc:     Kamalesh Babulal <kamalesh@...ux.vnet.ibm.com>,
        Jiri Kosina <jkosina@...e.cz>, live-patching@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [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 <kamalesh@...ux.vnet.ibm.com>
---
 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