From: Paul E. McKenney Date: Thu, 17 Mar 2022 18:05:09 +0000 (-0700) Subject: rcu: Make the TASKS_RCU Kconfig option be selected X-Git-Tag: v5.19-rc1~252^2~1^7~10 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=835f14ed53076384f0e1dad2fddb4881315f124f;p=thirdparty%2Fkernel%2Flinux.git rcu: Make the TASKS_RCU Kconfig option be selected Currently, any kernel built with CONFIG_PREEMPTION=y also gets CONFIG_TASKS_RCU=y, which is not helpful to people trying to build preemptible kernels of minimal size. Because CONFIG_TASKS_RCU=y is needed only in kernels doing tracing of one form or another, this commit moves from TASKS_RCU deciding when it should be enabled to the tracing Kconfig options explicitly selecting it. This allows building preemptible kernels without TASKS_RCU, if desired. This commit also updates the SRCU-N and TREE09 rcutorture scenarios in order to avoid Kconfig errors that would otherwise result from CONFIG_TASKS_RCU being selected without its CONFIG_RCU_EXPERT dependency being met. [ paulmck: Apply BPF_SYSCALL feedback from Andrii Nakryiko. ] Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Zhouyi Zhou Cc: Andrii Nakryiko Cc: Alexei Starovoitov Cc: Steven Rostedt Cc: Mathieu Desnoyers Acked-by: Masami Hiramatsu Signed-off-by: Paul E. McKenney --- diff --git a/arch/Kconfig b/arch/Kconfig index 29b0167c088b8..1bf29ce754af1 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -35,6 +35,7 @@ config KPROBES depends on MODULES depends on HAVE_KPROBES select KALLSYMS + select TASKS_RCU if PREEMPTION help Kprobes allows you to trap at almost any kernel address and execute a callback function. register_kprobe() establishes diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig index d56ee177d5f8f..2dfe1079f7727 100644 --- a/kernel/bpf/Kconfig +++ b/kernel/bpf/Kconfig @@ -27,6 +27,7 @@ config BPF_SYSCALL bool "Enable bpf() system call" select BPF select IRQ_WORK + select TASKS_RCU if PREEMPTION select TASKS_TRACE_RCU select BINARY_PRINTF select NET_SOCK_MSG if NET diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig index f559870fbf8b3..4f665ae0cf55d 100644 --- a/kernel/rcu/Kconfig +++ b/kernel/rcu/Kconfig @@ -78,7 +78,8 @@ config TASKS_RCU_GENERIC task-based RCU implementations. Not for manual selection. config TASKS_RCU - def_bool PREEMPTION + def_bool 0 + select IRQ_WORK help This option enables a task-based RCU implementation that uses only voluntary context switch (not preemption!), idle, and diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 2c43e327a619f..bf5da6c4e9992 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -144,6 +144,7 @@ config TRACING select BINARY_PRINTF select EVENT_TRACING select TRACE_CLOCK + select TASKS_RCU if PREEMPTION config GENERIC_TRACER bool diff --git a/tools/testing/selftests/rcutorture/configs/rcu/SRCU-N b/tools/testing/selftests/rcutorture/configs/rcu/SRCU-N index 2da8b49589a03..07f5e0a70ae70 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/SRCU-N +++ b/tools/testing/selftests/rcutorture/configs/rcu/SRCU-N @@ -6,3 +6,5 @@ CONFIG_PREEMPT_NONE=y CONFIG_PREEMPT_VOLUNTARY=n CONFIG_PREEMPT=n #CHECK#CONFIG_RCU_EXPERT=n +CONFIG_KPROBES=n +CONFIG_FTRACE=n diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE09 b/tools/testing/selftests/rcutorture/configs/rcu/TREE09 index 8523a7515cbf8..fc45645bb5f42 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE09 +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE09 @@ -13,3 +13,5 @@ CONFIG_DEBUG_LOCK_ALLOC=n CONFIG_RCU_BOOST=n CONFIG_DEBUG_OBJECTS_RCU_HEAD=n #CHECK#CONFIG_RCU_EXPERT=n +CONFIG_KPROBES=n +CONFIG_FTRACE=n