From: "Gustavo A. R. Silva" <gustavoars@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH] perf script: Replace zero-length array with flexible-array
Date: Thu, 7 May 2020 14:06:15 -0500 [thread overview]
Message-ID: <20200507190615.GA15677@embeddedor> (raw)
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>
---
arch/x86/events/intel/bts.c | 2 +-
arch/x86/events/intel/uncore.h | 2 +-
include/linux/perf_event.h | 4 ++--
kernel/events/callchain.c | 2 +-
kernel/events/internal.h | 2 +-
tools/perf/bench/sched-messaging.c | 2 +-
tools/perf/builtin-inject.c | 2 +-
tools/perf/builtin-script.c | 2 +-
tools/perf/builtin-timechart.c | 2 +-
tools/perf/util/annotate.h | 4 ++--
tools/perf/util/branch.h | 2 +-
tools/perf/util/cputopo.h | 2 +-
tools/perf/util/dso.h | 4 ++--
tools/perf/util/event.h | 2 +-
tools/perf/util/jitdump.c | 2 +-
tools/perf/util/jitdump.h | 6 +++---
tools/perf/util/ordered-events.h | 2 +-
tools/perf/util/pstack.c | 2 +-
tools/perf/util/symbol.h | 2 +-
tools/perf/util/unwind-libunwind-local.c | 2 +-
20 files changed, 25 insertions(+), 25 deletions(-)
diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c
index 6a3b599ee0fe..731dd8d0dbb1 100644
--- a/arch/x86/events/intel/bts.c
+++ b/arch/x86/events/intel/bts.c
@@ -58,7 +58,7 @@ struct bts_buffer {
local_t head;
unsigned long end;
void **data_pages;
- struct bts_phys buf[0];
+ struct bts_phys buf[];
};
static struct pmu bts_pmu;
diff --git a/arch/x86/events/intel/uncore.h b/arch/x86/events/intel/uncore.h
index 0da4a4605536..b469ddd45515 100644
--- a/arch/x86/events/intel/uncore.h
+++ b/arch/x86/events/intel/uncore.h
@@ -130,7 +130,7 @@ struct intel_uncore_box {
struct list_head list;
struct list_head active_list;
void __iomem *io_addr;
- struct intel_uncore_extra_reg shared_regs[0];
+ struct intel_uncore_extra_reg shared_regs[];
};
/* CFL uncore 8th cbox MSRs */
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 9c3e7619c929..306b07b56cc6 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -61,7 +61,7 @@ struct perf_guest_info_callbacks {
struct perf_callchain_entry {
__u64 nr;
- __u64 ip[0]; /* /proc/sys/kernel/perf_event_max_stack */
+ __u64 ip[]; /* /proc/sys/kernel/perf_event_max_stack */
};
struct perf_callchain_entry_ctx {
@@ -113,7 +113,7 @@ struct perf_raw_record {
struct perf_branch_stack {
__u64 nr;
__u64 hw_idx;
- struct perf_branch_entry entries[0];
+ struct perf_branch_entry entries[];
};
struct task_struct;
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index c2b41a263166..b1991043b7d8 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -16,7 +16,7 @@
struct callchain_cpus_entries {
struct rcu_head rcu_head;
- struct perf_callchain_entry *cpu_entries[0];
+ struct perf_callchain_entry *cpu_entries[];
};
int sysctl_perf_event_max_stack __read_mostly = PERF_MAX_STACK_DEPTH;
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index f16f66b6b655..fcbf5616a441 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -55,7 +55,7 @@ struct perf_buffer {
void *aux_priv;
struct perf_event_mmap_page *user_page;
- void *data_pages[0];
+ void *data_pages[];
};
extern void rb_free(struct perf_buffer *rb);
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 7e124a7b8bfd..8f983877c42d 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 1f57a7ecdf3d..02d64a9c6f64 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -2619,7 +2619,7 @@ 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 9e84fae9b096..0ba568efa939 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/branch.h b/tools/perf/util/branch.h
index 154a05cd03af..748f1d23a5c4 100644
--- a/tools/perf/util/branch.h
+++ b/tools/perf/util/branch.h
@@ -41,7 +41,7 @@ struct branch_entry {
struct branch_stack {
u64 nr;
u64 hw_idx;
- struct branch_entry entries[0];
+ struct branch_entry entries[];
};
/*
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 2db64b79617a..d7ba29ad19ff 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -136,7 +136,7 @@ struct dso_cache {
struct rb_node rb_node;
u64 offset;
u64 size;
- char data[0];
+ char data[];
};
struct auxtrace_cache;
@@ -208,7 +208,7 @@ 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,
next reply other threads:[~2020-05-07 19:01 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 19:06 Gustavo A. R. Silva [this message]
2020-05-08 12:37 ` [PATCH] perf script: Replace zero-length array with flexible-array Peter Zijlstra
2020-05-11 15:48 ` Arnaldo Carvalho de Melo
2020-05-11 17:26 ` Gustavo A. R. Silva
2020-05-11 18:48 ` Arnaldo Melo
2020-05-11 19:05 ` Gustavo A. R. Silva
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200507190615.GA15677@embeddedor \
--to=gustavoars@kernel.org \
--cc=acme@kernel.org \
--cc=alexander.shishkin@linux.intel.com \
--cc=jolsa@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mingo@redhat.com \
--cc=namhyung@kernel.org \
--cc=peterz@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.