78c32f4cb1
Comparing pointers with reference count checking is tricky to avoid a SEGV. Add a convenience macro to simplify and use. Signed-off-by: Ian Rogers <irogers@google.com> Cc: K Prateek Nayak <kprateek.nayak@amd.com> Cc: Ravi Bangoria <ravi.bangoria@amd.com> Cc: Sandipan Das <sandipan.das@amd.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: German Gomez <german.gomez@arm.com> Cc: James Clark <james.clark@arm.com> Cc: Nick Terrell <terrelln@fb.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Changbin Du <changbin.du@huawei.com> Cc: liuwenyu <liuwenyu7@huawei.com> Cc: Yang Jihong <yangjihong1@huawei.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Leo Yan <leo.yan@linaro.org> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com> Cc: Yanteng Si <siyanteng@loongson.cn> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Link: https://lore.kernel.org/r/20231024222353.3024098-5-irogers@google.com Signed-off-by: Namhyung Kim <namhyung@kernel.org>
113 lines
3.4 KiB
C
113 lines
3.4 KiB
C
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
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#ifndef __LIBPERF_INTERNAL_RC_CHECK_H
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#define __LIBPERF_INTERNAL_RC_CHECK_H
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#include <stdlib.h>
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#include <linux/zalloc.h>
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/*
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* Enable reference count checking implicitly with leak checking, which is
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* integrated into address sanitizer.
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*/
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#if defined(__SANITIZE_ADDRESS__) || defined(LEAK_SANITIZER) || defined(ADDRESS_SANITIZER)
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#define REFCNT_CHECKING 1
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#elif defined(__has_feature)
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#if __has_feature(address_sanitizer) || __has_feature(leak_sanitizer)
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#define REFCNT_CHECKING 1
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#endif
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#endif
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/*
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* Shared reference count checking macros.
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*
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* Reference count checking is an approach to sanitizing the use of reference
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* counted structs. It leverages address and leak sanitizers to make sure gets
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* are paired with a put. Reference count checking adds a malloc-ed layer of
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* indirection on a get, and frees it on a put. A missed put will be reported as
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* a memory leak. A double put will be reported as a double free. Accessing
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* after a put will cause a use-after-free and/or a segfault.
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*/
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#ifndef REFCNT_CHECKING
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/* Replaces "struct foo" so that the pointer may be interposed. */
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#define DECLARE_RC_STRUCT(struct_name) \
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struct struct_name
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/* Declare a reference counted struct variable. */
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#define RC_STRUCT(struct_name) struct struct_name
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/*
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* Interpose the indirection. Result will hold the indirection and object is the
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* reference counted struct.
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*/
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#define ADD_RC_CHK(result, object) (result = object, object)
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/* Strip the indirection layer. */
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#define RC_CHK_ACCESS(object) object
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/* Frees the object and the indirection layer. */
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#define RC_CHK_FREE(object) free(object)
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/* A get operation adding the indirection layer. */
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#define RC_CHK_GET(result, object) ADD_RC_CHK(result, object)
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/* A put operation removing the indirection layer. */
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#define RC_CHK_PUT(object) {}
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/* Pointer equality when the indirection may or may not be there. */
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#define RC_CHK_EQUAL(object1, object2) (object1 == object2)
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#else
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/* Replaces "struct foo" so that the pointer may be interposed. */
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#define DECLARE_RC_STRUCT(struct_name) \
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struct original_##struct_name; \
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struct struct_name { \
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struct original_##struct_name *orig; \
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}; \
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struct original_##struct_name
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/* Declare a reference counted struct variable. */
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#define RC_STRUCT(struct_name) struct original_##struct_name
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/*
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* Interpose the indirection. Result will hold the indirection and object is the
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* reference counted struct.
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*/
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#define ADD_RC_CHK(result, object) \
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( \
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object ? (result = malloc(sizeof(*result)), \
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result ? (result->orig = object, result) \
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: (result = NULL, NULL)) \
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: (result = NULL, NULL) \
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)
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/* Strip the indirection layer. */
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#define RC_CHK_ACCESS(object) object->orig
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/* Frees the object and the indirection layer. */
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#define RC_CHK_FREE(object) \
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do { \
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zfree(&object->orig); \
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free(object); \
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} while(0)
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/* A get operation adding the indirection layer. */
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#define RC_CHK_GET(result, object) ADD_RC_CHK(result, (object ? object->orig : NULL))
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/* A put operation removing the indirection layer. */
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#define RC_CHK_PUT(object) \
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do { \
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if (object) { \
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object->orig = NULL; \
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free(object); \
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} \
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} while(0)
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/* Pointer equality when the indirection may or may not be there. */
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#define RC_CHK_EQUAL(object1, object2) (object1 == object2 || \
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(object1 && object2 && object1->orig == object2->orig))
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#endif
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#endif /* __LIBPERF_INTERNAL_RC_CHECK_H */
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