path: root/kernel
diff options
authorPaul E. McKenney <>2020-02-05 06:34:09 -0800
committerThomas Gleixner <>2020-02-07 15:34:12 +0100
commit1e474b28e78897d0d170fab3b28ba683149cb9ea (patch)
treeb96998f3ca19bfda3d6ff614367363e7516cbba7 /kernel
parent25a3a15417cf4311f812f5a2b18c5fc2809f66d7 (diff)
smp/up: Make smp_call_function_single() match SMP semantics
In CONFIG_SMP=y kernels, smp_call_function_single() returns -ENXIO when invoked for a non-existent CPU. In contrast, in CONFIG_SMP=n kernels, a splat is emitted and smp_call_function_single() otherwise silently ignores its "cpu" argument, instead pretending that the caller intended to have something happen on CPU 0. Given that there is now code that expects smp_call_function_single() to return an error if a bad CPU was specified, this difference in semantics needs to be addressed. Bring the semantics of the CONFIG_SMP=n version of smp_call_function_single() into alignment with its CONFIG_SMP=y counterpart. Signed-off-by: Paul E. McKenney <> Signed-off-by: Thomas Gleixner <> Link:
Diffstat (limited to 'kernel')
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/up.c b/kernel/up.c
index 53144d056252..c6f323dcd45b 100644
--- a/kernel/up.c
+++ b/kernel/up.c
@@ -14,7 +14,8 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
unsigned long flags;
- WARN_ON(cpu != 0);
+ if (cpu != 0)
+ return -ENXIO;