From 72141795d4edd17f88da192447395a48444afa10 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Thu, 19 Apr 2018 20:56:26 -0400 Subject: [PATCH] return chunks split off by memalign using __bin_chunk instead of free this change serves multiple purposes: 1. it ensures that static linking of memalign-family functions will pull in the system malloc implementation, thereby causing link errors if an attempt is made to link the system memalign functions with a replacement malloc (incomplete allocator replacement). 2. it eliminates calls to free that are unpaired with allocations, which are confusing when setting breakpoints or tracing execution. as a bonus, making __bin_chunk external may discourage aggressive and unnecessary inlining of it. --- src/internal/malloc_impl.h | 3 +++ src/malloc/malloc.c | 10 ++++------ src/malloc/memalign.c | 2 +- 3 files changed, 8 insertions(+), 7 deletions(-) diff --git a/src/internal/malloc_impl.h b/src/internal/malloc_impl.h index 1ea0407c..4c4a4b46 100644 --- a/src/internal/malloc_impl.h +++ b/src/internal/malloc_impl.h @@ -36,4 +36,7 @@ struct bin { #define IS_MMAPPED(c) !((c)->csize & (C_INUSE)) +__attribute__((__visibility__("hidden"))) +void __bin_chunk(struct chunk *); + #endif diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c index c8bc9227..239ab9c6 100644 --- a/src/malloc/malloc.c +++ b/src/malloc/malloc.c @@ -263,8 +263,6 @@ static int pretrim(struct chunk *self, size_t n, int i, int j) return 1; } -static void bin_chunk(struct chunk *); - static void trim(struct chunk *self, size_t n) { size_t n1 = CHUNK_SIZE(self); @@ -280,7 +278,7 @@ static void trim(struct chunk *self, size_t n) next->psize = n1-n | C_INUSE; self->csize = n | C_INUSE; - bin_chunk(split); + __bin_chunk(split); } void *malloc(size_t n) @@ -436,7 +434,7 @@ copy_free_ret: return new; } -static void bin_chunk(struct chunk *self) +void __bin_chunk(struct chunk *self) { struct chunk *next = NEXT_CHUNK(self); size_t final_size, new_size, size; @@ -524,7 +522,7 @@ void free(void *p) if (IS_MMAPPED(self)) unmap_chunk(self); else - bin_chunk(self); + __bin_chunk(self); } void __malloc_donate(char *start, char *end) @@ -543,5 +541,5 @@ void __malloc_donate(char *start, char *end) struct chunk *c = MEM_TO_CHUNK(start), *n = MEM_TO_CHUNK(end); c->psize = n->csize = C_INUSE; c->csize = n->psize = C_INUSE | (end-start); - bin_chunk(c); + __bin_chunk(c); } diff --git a/src/malloc/memalign.c b/src/malloc/memalign.c index 9c420229..7246a99b 100644 --- a/src/malloc/memalign.c +++ b/src/malloc/memalign.c @@ -48,7 +48,7 @@ void *__memalign(size_t align, size_t len) n->psize = c->csize = C_INUSE | (new-mem); n->csize = t->psize -= new-mem; - free(mem); + __bin_chunk(c); return new; } -- 2.25.1