From: Petr Mladek Date: Wed, 24 Apr 2019 08:55:48 +0000 (+0200) Subject: livepatch: Convert error about unsupported reliable stacktrace into a warning X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=31adf2308f33dcae59009019675224be0978bc70;p=openwrt%2Fstaging%2Fblogic.git livepatch: Convert error about unsupported reliable stacktrace into a warning The commit d0807da78e11d46f ("livepatch: Remove immediate feature") caused that any livepatch was refused when reliable stacktraces were not supported on the given architecture. The limitation is too strong. User space processes are safely migrated even when entering or leaving the kernel. Kthreads transition would need to get forced. But it is safe when: + The livepatch does not change the semantic of the code. + Callbacks do not depend on a safely finished transition. Suggested-by: Josh Poimboeuf Acked-by: Josh Poimboeuf Acked-by: Miroslav Benes Reviewed-by: Kamalesh Babulal Signed-off-by: Petr Mladek --- diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index eb0ee10a1981..14f33ab6c583 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -1003,11 +1003,10 @@ int klp_enable_patch(struct klp_patch *patch) return -ENODEV; if (!klp_have_reliable_stack()) { - pr_err("This architecture doesn't have support for the livepatch consistency model.\n"); - return -EOPNOTSUPP; + pr_warn("This architecture doesn't have support for the livepatch consistency model.\n"); + pr_warn("The livepatch transition may never complete.\n"); } - mutex_lock(&klp_mutex); ret = klp_init_patch_early(patch);