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authorGustavo A. R. Silva <gustavoars@kernel.org>2020-05-15 12:29:26 -0500
committerArnaldo Carvalho de Melo <acme@redhat.com>2020-05-28 10:03:27 -0300
commit6549a8c0c3d94500a9a1bb66fc237f7c01c41753 (patch)
tree003129d2a7b9d34ac57d28ca54745dae234c65c9 /tools/perf
parent961224db0470c9be08ef64b14913452a5e865d00 (diff)
downloadlinux-6549a8c0c3d94500a9a1bb66fc237f7c01c41753.tar.bz2
perf tools: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Gustavo A. R. Silva <gustavo@embeddedor.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lore.kernel.org/lkml/20200515172926.GA31976@embeddedor Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
-rw-r--r--tools/perf/bench/sched-messaging.c2
-rw-r--r--tools/perf/builtin-inject.c2
-rw-r--r--tools/perf/builtin-script.c2
-rw-r--r--tools/perf/builtin-timechart.c2
-rw-r--r--tools/perf/util/annotate.h4
-rw-r--r--tools/perf/util/cputopo.h2
-rw-r--r--tools/perf/util/dso.h4
-rw-r--r--tools/perf/util/event.h2
-rw-r--r--tools/perf/util/jitdump.c2
-rw-r--r--tools/perf/util/jitdump.h6
-rw-r--r--tools/perf/util/ordered-events.h2
-rw-r--r--tools/perf/util/pstack.c2
-rw-r--r--tools/perf/util/symbol.h2
-rw-r--r--tools/perf/util/unwind-libunwind-local.c2
14 files changed, 18 insertions, 18 deletions
diff --git a/tools/perf/bench/sched-messaging.c b/tools/perf/bench/sched-messaging.c
index 97e4a4fb3362..71d830d7b923 100644
--- a/tools/perf/bench/sched-messaging.c
+++ b/tools/perf/bench/sched-messaging.c
@@ -40,7 +40,7 @@ struct sender_context {
unsigned int num_fds;
int ready_out;
int wakefd;
- int out_fds[0];
+ int out_fds[];
};
struct receiver_context {
diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index 53932db97a79..4a6de4b03ac0 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -51,7 +51,7 @@ struct perf_inject {
struct event_entry {
struct list_head node;
u32 tid;
- union perf_event event[0];
+ union perf_event event[];
};
static int output_bytes(struct perf_inject *inject, void *buf, size_t sz)
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index ecc8bd4c5e57..4c0837efaceb 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -2449,7 +2449,7 @@ static int __cmd_script(struct perf_script *script)
struct script_spec {
struct list_head node;
struct scripting_ops *ops;
- char spec[0];
+ char spec[];
};
static LIST_HEAD(script_specs);
diff --git a/tools/perf/builtin-timechart.c b/tools/perf/builtin-timechart.c
index c76f84b174c4..4e380e7b5230 100644
--- a/tools/perf/builtin-timechart.c
+++ b/tools/perf/builtin-timechart.c
@@ -128,7 +128,7 @@ struct sample_wrapper {
struct sample_wrapper *next;
u64 timestamp;
- unsigned char data[0];
+ unsigned char data[];
};
#define TYPE_NONE 0
diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
index 2d88069d6428..0a0cd4f32175 100644
--- a/tools/perf/util/annotate.h
+++ b/tools/perf/util/annotate.h
@@ -144,7 +144,7 @@ struct annotation_line {
u32 idx;
int idx_asm;
int data_nr;
- struct annotation_data data[0];
+ struct annotation_data data[];
};
struct disasm_line {
@@ -227,7 +227,7 @@ void symbol__calc_percent(struct symbol *sym, struct evsel *evsel);
struct sym_hist {
u64 nr_samples;
u64 period;
- struct sym_hist_entry addr[0];
+ struct sym_hist_entry addr[];
};
struct cyc_hist {
diff --git a/tools/perf/util/cputopo.h b/tools/perf/util/cputopo.h
index 7bf6b811f715..6201c3790d86 100644
--- a/tools/perf/util/cputopo.h
+++ b/tools/perf/util/cputopo.h
@@ -22,7 +22,7 @@ struct numa_topology_node {
struct numa_topology {
u32 nr;
- struct numa_topology_node nodes[0];
+ struct numa_topology_node nodes[];
};
struct cpu_topology *cpu_topology__new(void);
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 9553a1fd9e8a..e3e9e3b77297 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -137,7 +137,7 @@ struct dso_cache {
struct rb_node rb_node;
u64 offset;
u64 size;
- char data[0];
+ char data[];
};
struct auxtrace_cache;
@@ -209,7 +209,7 @@ struct dso {
struct nsinfo *nsinfo;
struct dso_id id;
refcount_t refcnt;
- char name[0];
+ char name[];
};
/* dso__for_each_symbol - iterate over the symbols of given type
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index b8289f160f07..6ae01c3c2ffa 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -79,7 +79,7 @@ struct sample_read {
struct ip_callchain {
u64 nr;
- u64 ips[0];
+ u64 ips[];
};
struct branch_stack;
diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
index e3ccb0ce1938..32bb05e03fb2 100644
--- a/tools/perf/util/jitdump.c
+++ b/tools/perf/util/jitdump.c
@@ -57,7 +57,7 @@ struct debug_line_info {
unsigned long vma;
unsigned int lineno;
/* The filename format is unspecified, absolute path, relative etc. */
- char const filename[0];
+ char const filename[];
};
struct jit_tool {
diff --git a/tools/perf/util/jitdump.h b/tools/perf/util/jitdump.h
index f2c3823cc81a..ab2842def83d 100644
--- a/tools/perf/util/jitdump.h
+++ b/tools/perf/util/jitdump.h
@@ -93,7 +93,7 @@ struct debug_entry {
uint64_t addr;
int lineno; /* source line number starting at 1 */
int discrim; /* column discriminator, 0 is default */
- const char name[0]; /* null terminated filename, \xff\0 if same as previous entry */
+ const char name[]; /* null terminated filename, \xff\0 if same as previous entry */
};
struct jr_code_debug_info {
@@ -101,7 +101,7 @@ struct jr_code_debug_info {
uint64_t code_addr;
uint64_t nr_entry;
- struct debug_entry entries[0];
+ struct debug_entry entries[];
};
struct jr_code_unwinding_info {
@@ -110,7 +110,7 @@ struct jr_code_unwinding_info {
uint64_t unwinding_size;
uint64_t eh_frame_hdr_size;
uint64_t mapped_size;
- const char unwinding_data[0];
+ const char unwinding_data[];
};
union jr_entry {
diff --git a/tools/perf/util/ordered-events.h b/tools/perf/util/ordered-events.h
index 0920fb0ec6cc..75345946c4b9 100644
--- a/tools/perf/util/ordered-events.h
+++ b/tools/perf/util/ordered-events.h
@@ -29,7 +29,7 @@ typedef int (*ordered_events__deliver_t)(struct ordered_events *oe,
struct ordered_events_buffer {
struct list_head list;
- struct ordered_event event[0];
+ struct ordered_event event[];
};
struct ordered_events {
diff --git a/tools/perf/util/pstack.c b/tools/perf/util/pstack.c
index 80ff41fc45be..a1d1e4ef6257 100644
--- a/tools/perf/util/pstack.c
+++ b/tools/perf/util/pstack.c
@@ -15,7 +15,7 @@
struct pstack {
unsigned short top;
unsigned short max_nr_entries;
- void *entries[0];
+ void *entries[];
};
struct pstack *pstack__new(unsigned short max_nr_entries)
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 93fc43db1be3..ff4f4c47e148 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -55,7 +55,7 @@ struct symbol {
u8 inlined:1;
u8 arch_sym;
bool annotate2;
- char name[0];
+ char name[];
};
void symbol__delete(struct symbol *sym);
diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c
index b4649f5a0c2f..9aededc0bc06 100644
--- a/tools/perf/util/unwind-libunwind-local.c
+++ b/tools/perf/util/unwind-libunwind-local.c
@@ -243,7 +243,7 @@ struct eh_frame_hdr {
* encoded_t fde_addr;
* } binary_search_table[fde_count];
*/
- char data[0];
+ char data[];
} __packed;
static int unwind_spec_ehframe(struct dso *dso, struct machine *machine,