smp: Warn on function calls from softirq context

It's clearly documented that smp function calls cannot be invoked from
softirq handling context. Unfortunately nothing enforces that or emits a

A single function call can be invoked from softirq context only via

The only legit context is task context, so add a warning to that effect.

Reported-by: luferry <>
Signed-off-by: Peter Zijlstra <>
Signed-off-by: Thomas Gleixner <>
1 file changed