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authorMiroslav Benes <mbenes@suse.cz>2019-06-11 16:13:19 +0200
committerPetr Mladek <pmladek@suse.com>2019-06-20 16:08:41 +0200
commit67059d65f7da537c41513fc52e78eff096092b8c (patch)
treedfad02a0ea99db7a64df350cf8a1d803fc66a423 /kernel/livepatch
parent380178ef7fde58f2040788a1bab972ce4867ac58 (diff)
Revert "livepatch: Remove reliable stacktrace check in klp_try_switch_task()"
This reverts commit 1d98a69e5cef3aeb68bcefab0e67e342d6bb4dad. Commit 31adf2308f33 ("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>
Diffstat (limited to 'kernel/livepatch')
-rw-r--r--kernel/livepatch/transition.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index 0a3889c4f617..cb85dae09ce5 100644
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -306,6 +306,13 @@ 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.