On 24/06/22 09:30, Baoquan He wrote: > On 06/20/22 at 12:15pm, Valentin Schneider wrote: >> @@ -94,14 +94,20 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments, >> /* >> * Because we write directly to the reserved memory region when loading >> * crash kernels we need a mutex here to prevent multiple crash kernels >> - * from attempting to load simultaneously, and to prevent a crash kernel >> - * from loading over the top of a in use crash kernel. >> - * >> - * KISS: always take the mutex. >> + * from attempting to load simultaneously. >> */ >> if (!mutex_trylock(&kexec_mutex)) >> return -EBUSY; > > So kexec_mutex is degenerated to only avoid simultaneous loading, > should we rename to reflect that?, e.g kexec_load_mutex. > It's also serializing crash_get_memory_size() and crash_shrink_memory(); more generally it should still be the preferred serialization mechanism as it's a "proper" lock visible by instrumentation, the atomic variable is a side character for the NMI case.
