Commit 514d5c55 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Andrew Morton
Browse files

lib/stacktrace: drop impossible WARN_ON for depot_init_pool 

depot_init_pool has two call sites:

1. In depot_alloc_stack with a potentially NULL prealloc.
2. In __stack_depot_save with a non-NULL prealloc.

At the same time depot_init_pool can only return false when prealloc is
NULL.

As the second call site makes sure that prealloc is not NULL, the WARN_ON
there can never trigger. Thus, drop the WARN_ON and also move the prealloc
check from depot_init_pool to its first call site.

Also change the return type of depot_init_pool to void as it now always
returns true.

Link: https://lkml.kernel.org/r/ce149f9bdcbc80a92549b54da67eafb27f846b7b.1676063693.git.andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: default avatarAlexander Potapenko <glider@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent cb788e84

lib/stackdepot.c

+5 −7
Original line number Diff line number Diff line
@@ -218,16 +218,14 @@ int stack_depot_init(void) 
}

EXPORT_SYMBOL_GPL(stack_depot_init);



static bool depot_init_pool(void **prealloc)

static void depot_init_pool(void **prealloc)

{

	if (!*prealloc)

		return false;

	/*

	 * This smp_load_acquire() pairs with smp_store_release() to

	 * |next_pool_inited| below and in depot_alloc_stack().

	 */

	if (smp_load_acquire(&next_pool_inited))

		return true;

		return;

	if (stack_pools[pool_index] == NULL) {

		stack_pools[pool_index] = *prealloc;

		*prealloc = NULL;
@@ -243,7 +241,6 @@ static bool depot_init_pool(void **prealloc) 
		 */

		smp_store_release(&next_pool_inited, 1);

	}

	return true;

}



/* Allocation of a new stack in raw storage */
@@ -270,6 +267,7 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) 
		if (pool_index + 1 < DEPOT_MAX_POOLS)

			smp_store_release(&next_pool_inited, 0);

	}

	if (*prealloc)

		depot_init_pool(prealloc);

	if (stack_pools[pool_index] == NULL)

		return NULL;
@@ -435,7 +433,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, 
		 * We didn't need to store this stack trace, but let's keep

		 * the preallocated memory for the future.

		 */

		WARN_ON(!depot_init_pool(&prealloc));

		depot_init_pool(&prealloc);

	}



	raw_spin_unlock_irqrestore(&pool_lock, flags);