[Linux-kernel-mentees] [PATCH 1/2] events: callchain: Annotate RCU pointer with __rcu

[Joel Fernandes]

On Wed, Jan 29, 2020 at 09:38:12PM +0530, Amol Grover wrote:
> Fixes following instances of sparse error
> error: incompatible types in comparison expression
> (different address spaces)
> kernel/events/callchain.c:66:9: error: incompatible types in comparison
> kernel/events/callchain.c:96:9: error: incompatible types in comparison
> kernel/events/callchain.c:161:19: error: incompatible types in comparison
> 
> This introduces the following warning
> kernel/events/callchain.c:65:17: warning: incorrect type in assignment

Would have been nice if you mentioned the warning is fixed in your second
patch. But I think its ok.

Reviewed-by: Joel Fernandes (Google) <joel at joelfernandes.org>

thanks,

 - Joel

> 
> Signed-off-by: Amol Grover <frextrite at gmail.com>
> ---
>  kernel/events/callchain.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
> index c2b41a263166..f91e1f41d25d 100644
> --- a/kernel/events/callchain.c
> +++ b/kernel/events/callchain.c
> @@ -32,7 +32,7 @@ static inline size_t perf_callchain_entry__sizeof(void)
>  static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
>  static atomic_t nr_callchain_events;
>  static DEFINE_MUTEX(callchain_mutex);
> -static struct callchain_cpus_entries *callchain_cpus_entries;
> +static struct callchain_cpus_entries __rcu *callchain_cpus_entries;
>  
>  
>  __weak void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
> -- 
> 2.24.1
>