From c96c0f94f964eab1b57b7f6081e3538cd611e963 Mon Sep 17 00:00:00 2001
From: Vijay Pai <vpai@google.com>
Date: Wed, 19 Apr 2017 15:39:13 -0700
Subject: [PATCH] Remove DEBUG code that is itself buggy (integer overflow)
---
src/core/lib/support/stack_lockfree.c | 33 ---------------------------
1 file changed, 33 deletions(-)
diff --git a/src/core/lib/support/stack_lockfree.c b/src/core/lib/support/stack_lockfree.c
index 9d7c9e5a38..c481a3e0dc 100644
--- a/src/core/lib/support/stack_lockfree.c
+++ b/src/core/lib/support/stack_lockfree.c
@@ -72,11 +72,6 @@ typedef union lockfree_node {
struct gpr_stack_lockfree {
lockfree_node *entries;
lockfree_node head; /* An atomic entry describing curr head */
-
-#ifndef NDEBUG
- /* Bitmap of pushed entries to check for double-push or pop */
- gpr_atm pushed[(INVALID_ENTRY_INDEX + 1) / (8 * sizeof(gpr_atm))];
-#endif
};
gpr_stack_lockfree *gpr_stack_lockfree_create(size_t entries) {
@@ -91,9 +86,6 @@ gpr_stack_lockfree *gpr_stack_lockfree_create(size_t entries) {
/* Clear out all entries */
memset(stack->entries, 0, entries * sizeof(stack->entries[0]));
memset(&stack->head, 0, sizeof(stack->head));
-#ifndef NDEBUG
- memset(&stack->pushed, 0, sizeof(stack->pushed));
-#endif
GPR_ASSERT(sizeof(stack->entries->atm) == sizeof(stack->entries->contents));
@@ -130,19 +122,6 @@ int gpr_stack_lockfree_push(gpr_stack_lockfree *stack, int entry) {
newhead.contents.aba_ctr = ++curent.contents.aba_ctr;
gpr_atm_no_barrier_store(&stack->entries[entry].atm, curent.atm);
-#ifndef NDEBUG
- /* Check for double push */
- {
- int pushed_index = entry / (int)(8 * sizeof(gpr_atm));
- int pushed_bit = entry % (int)(8 * sizeof(gpr_atm));
- gpr_atm old_val;
-
- old_val = gpr_atm_no_barrier_fetch_add(&stack->pushed[pushed_index],
- ((gpr_atm)1 << pushed_bit));
- GPR_ASSERT((old_val & (((gpr_atm)1) << pushed_bit)) == 0);
- }
-#endif
-
do {
/* Atomically get the existing head value for use */
head.atm = gpr_atm_no_barrier_load(&(stack->head.atm));
@@ -168,18 +147,6 @@ int gpr_stack_lockfree_pop(gpr_stack_lockfree *stack) {
gpr_atm_no_barrier_load(&(stack->entries[head.contents.index].atm));
} while (!gpr_atm_no_barrier_cas(&(stack->head.atm), head.atm, newhead.atm));
-#ifndef NDEBUG
- /* Check for valid pop */
- {
- int pushed_index = head.contents.index / (8 * sizeof(gpr_atm));
- int pushed_bit = head.contents.index % (8 * sizeof(gpr_atm));
- gpr_atm old_val;
-
- old_val = gpr_atm_no_barrier_fetch_add(&stack->pushed[pushed_index],
- -((gpr_atm)1 << pushed_bit));
- GPR_ASSERT((old_val & (((gpr_atm)1) << pushed_bit)) != 0);
- }
-#endif
return head.contents.index;
}
--
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