Re: [dpdk-dev] [PATCH] mem: fix deadlock on secondary allocation

[Thomas Monjalon <thomas@monjalon.net>]

29/01/2021 16:29, Anatoly Burakov:
> Previous fix used `rte_malloc_heap_socket_is_external()` to check if the
> heap was an external heap. However, that API is thread-safe, and when
> we're inside the allocation process, we're already write-locked, so
> calling `rte_malloc_heap_socket_is_external()` will result in a
> deadlock followed by a timeout.
> 
> Fix it by replacing the API call with a check against maximum number of
> NUMA nodes, because external heaps always have higher socket ID's.

Is there some unit tests for such thing?

> 
> Fixes: 7ac31e82bc8f ("mem: improve parameter checking on memory hotplug")
> 
> Reported-by: Jim Harris <james.r.harris@intel.com>
> 

No need of blank line here.

> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> ---
>  lib/librte_eal/common/malloc_mp.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_eal/common/malloc_mp.c b/lib/librte_eal/common/malloc_mp.c
> index 0b19d4d5fb..b1f7f7824b 100644
> --- a/lib/librte_eal/common/malloc_mp.c
> +++ b/lib/librte_eal/common/malloc_mp.c
> -	/* for allocations, we must only use internal heaps */
> -	if (rte_malloc_heap_socket_is_external(heap->socket_id)) {
> +	/*
> +	 * for allocations, we must only use internal heaps, but since the
> +	 * rte_malloc_heap_socket_is_external() is thread-safe and we're already
> +	 * read-locked, we'll have to take advantage of the fac that internal

fac -> fact?

> +	 * socket ID's are always lower than RTE_MAX_NUMA_NODES.
> +	 */
> +	if (heap->socket_id >= RTE_MAX_NUMA_NODES) {