From 514d5c557b8b590a80f0569af5ae5f4d455ecef2 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:16:00 +0100 Subject: [PATCH] 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: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 7f5f08bb6c3a..d4d988276b91 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -218,16 +218,14 @@ out_unlock: } 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 */ @@ -270,7 +267,8 @@ 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); } - depot_init_pool(prealloc); + 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); -- 2.20.1