This is a note to let you know that I've just added the patch titled sched/features: Fix !CONFIG_JUMP_LABEL case to the 5.8-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sched-features-fix-config_jump_label-case.patch and it can be found in the queue-5.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 2097f0c5c41dc1987a232889ae686b509d5dcd4c Author: Juri Lelli <juri.lelli@xxxxxxxxxx> Date: Tue Oct 13 07:31:14 2020 +0200 sched/features: Fix !CONFIG_JUMP_LABEL case [ Upstream commit a73f863af4ce9730795eab7097fb2102e6854365 ] Commit: 765cc3a4b224e ("sched/core: Optimize sched_feat() for !CONFIG_SCHED_DEBUG builds") made sched features static for !CONFIG_SCHED_DEBUG configurations, but overlooked the CONFIG_SCHED_DEBUG=y and !CONFIG_JUMP_LABEL cases. For the latter echoing changes to /sys/kernel/debug/sched_features has the nasty effect of effectively changing what sched_features reports, but without actually changing the scheduler behaviour (since different translation units get different sysctl_sched_features). Fix CONFIG_SCHED_DEBUG=y and !CONFIG_JUMP_LABEL configurations by properly restructuring ifdefs. Fixes: 765cc3a4b224e ("sched/core: Optimize sched_feat() for !CONFIG_SCHED_DEBUG builds") Co-developed-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> Signed-off-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> Signed-off-by: Juri Lelli <juri.lelli@xxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Acked-by: Patrick Bellasi <patrick.bellasi@xxxxxxxxxx> Reviewed-by: Valentin Schneider <valentin.schneider@xxxxxxx> Link: https://lore.kernel.org/r/20201013053114.160628-1-juri.lelli@xxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f788cd61df212..1c68621743ac2 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -39,7 +39,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(sched_overutilized_tp); DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); -#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_JUMP_LABEL) +#ifdef CONFIG_SCHED_DEBUG /* * Debugging: various feature bits * diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index c82857e2e288a..0b1485ac19c4e 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1600,7 +1600,7 @@ enum { #undef SCHED_FEAT -#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_JUMP_LABEL) +#ifdef CONFIG_SCHED_DEBUG /* * To support run-time toggling of sched features, all the translation units @@ -1608,6 +1608,7 @@ enum { */ extern const_debug unsigned int sysctl_sched_features; +#ifdef CONFIG_JUMP_LABEL #define SCHED_FEAT(name, enabled) \ static __always_inline bool static_branch_##name(struct static_key *key) \ { \ @@ -1620,7 +1621,13 @@ static __always_inline bool static_branch_##name(struct static_key *key) \ extern struct static_key sched_feat_keys[__SCHED_FEAT_NR]; #define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x])) -#else /* !(SCHED_DEBUG && CONFIG_JUMP_LABEL) */ +#else /* !CONFIG_JUMP_LABEL */ + +#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x)) + +#endif /* CONFIG_JUMP_LABEL */ + +#else /* !SCHED_DEBUG */ /* * Each translation unit has its own copy of sysctl_sched_features to allow @@ -1636,7 +1643,7 @@ static const_debug __maybe_unused unsigned int sysctl_sched_features = #define sched_feat(x) !!(sysctl_sched_features & (1UL << __SCHED_FEAT_##x)) -#endif /* SCHED_DEBUG && CONFIG_JUMP_LABEL */ +#endif /* SCHED_DEBUG */ extern struct static_key_false sched_numa_balancing; extern struct static_key_false sched_schedstats;