Messages in this thread Patch in this message | | | Date | Mon, 11 Jan 2016 18:03:27 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH 16/53] perf tools: Fix mmap2 event allocation in synthesize code |
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Em Mon, Jan 11, 2016 at 01:48:07PM +0000, Wang Nan escreveu: > perf_event__synthesize_mmap_events() issues mmap2 events, but the > memory of that event is allocated using: > > mmap_event = malloc(sizeof(mmap_event->mmap) + machine->id_hdr_size); > > If path of mmap source file is long (near PATH_MAX), random crash > would happen. Should use sizeof(mmap_event->mmap2). > > Fix two memory allocations and rename all mmap_event to mmap2_event > to make it clear.
Try not doing two things in the same patch, i.e. do one minimal patch with just the fix, i.e. this part:
- mmap_event = malloc(sizeof(mmap_event->mmap) + > machine->id_hdr_size); + mmap_event = malloc(sizeof(mmap_event->mmap2) + > machine->id_hdr_size);
This way we see the fix straight away, no extra renaming noise.
And the other with the rename, but I wouldn't bother doing that, 'mmap_event' is descriptive enough, and we may end up having a mmap3 event, when we would go on touching all those places again...
We're moving around union perf_event pointers, what we could do would be to, at perf_event allocation time, set the mmap_event->header.type to PERF_RECORD_MMAP2 and when going to use the mmap_event->mmap2 fields, check that what was passed is indeed the type (and size) expected.
- Arnaldo > Signed-off-by: Wang Nan <wangnan0@huawei.com> > Acked-by: Jiri Olsa <jolsa@kernel.org> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > Cc: He Kuang <hekuang@huawei.com> > Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> > Cc: Namhyung Kim <namhyung@kernel.org> > Cc: Zefan Li <lizefan@huawei.com> > Cc: pi3orama@163.com > --- > tools/perf/util/event.c | 28 ++++++++++++++-------------- > 1 file changed, 14 insertions(+), 14 deletions(-) > > diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c > index cd61bb1..cde8228 100644 > --- a/tools/perf/util/event.c > +++ b/tools/perf/util/event.c > @@ -413,7 +413,7 @@ int perf_event__synthesize_modules(struct perf_tool *tool, > } > > static int __event__synthesize_thread(union perf_event *comm_event, > - union perf_event *mmap_event, > + union perf_event *mmap2_event, > union perf_event *fork_event, > pid_t pid, int full, > perf_event__handler_t process, > @@ -436,7 +436,7 @@ static int __event__synthesize_thread(union perf_event *comm_event, > if (tgid == -1) > return -1; > > - return perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid, > + return perf_event__synthesize_mmap_events(tool, mmap2_event, pid, tgid, > process, machine, mmap_data, > proc_map_timeout); > } > @@ -478,7 +478,7 @@ static int __event__synthesize_thread(union perf_event *comm_event, > rc = 0; > if (_pid == pid) { > /* process the parent's maps too */ > - rc = perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid, > + rc = perf_event__synthesize_mmap_events(tool, mmap2_event, pid, tgid, > process, machine, mmap_data, proc_map_timeout); > if (rc) > break; > @@ -496,15 +496,15 @@ int perf_event__synthesize_thread_map(struct perf_tool *tool, > bool mmap_data, > unsigned int proc_map_timeout) > { > - union perf_event *comm_event, *mmap_event, *fork_event; > + union perf_event *comm_event, *mmap2_event, *fork_event; > int err = -1, thread, j; > > comm_event = malloc(sizeof(comm_event->comm) + machine->id_hdr_size); > if (comm_event == NULL) > goto out; > > - mmap_event = malloc(sizeof(mmap_event->mmap) + machine->id_hdr_size); > - if (mmap_event == NULL) > + mmap2_event = malloc(sizeof(mmap2_event->mmap2) + machine->id_hdr_size); > + if (mmap2_event == NULL) > goto out_free_comm; > > fork_event = malloc(sizeof(fork_event->fork) + machine->id_hdr_size); > @@ -513,7 +513,7 @@ int perf_event__synthesize_thread_map(struct perf_tool *tool, > > err = 0; > for (thread = 0; thread < threads->nr; ++thread) { > - if (__event__synthesize_thread(comm_event, mmap_event, > + if (__event__synthesize_thread(comm_event, mmap2_event, > fork_event, > thread_map__pid(threads, thread), 0, > process, tool, machine, > @@ -539,7 +539,7 @@ int perf_event__synthesize_thread_map(struct perf_tool *tool, > > /* if not, generate events for it */ > if (need_leader && > - __event__synthesize_thread(comm_event, mmap_event, > + __event__synthesize_thread(comm_event, mmap2_event, > fork_event, > comm_event->comm.pid, 0, > process, tool, machine, > @@ -551,7 +551,7 @@ int perf_event__synthesize_thread_map(struct perf_tool *tool, > } > free(fork_event); > out_free_mmap: > - free(mmap_event); > + free(mmap2_event); > out_free_comm: > free(comm_event); > out: > @@ -567,7 +567,7 @@ int perf_event__synthesize_threads(struct perf_tool *tool, > DIR *proc; > char proc_path[PATH_MAX]; > struct dirent dirent, *next; > - union perf_event *comm_event, *mmap_event, *fork_event; > + union perf_event *comm_event, *mmap2_event, *fork_event; > int err = -1; > > if (machine__is_default_guest(machine)) > @@ -577,8 +577,8 @@ int perf_event__synthesize_threads(struct perf_tool *tool, > if (comm_event == NULL) > goto out; > > - mmap_event = malloc(sizeof(mmap_event->mmap) + machine->id_hdr_size); > - if (mmap_event == NULL) > + mmap2_event = malloc(sizeof(mmap2_event->mmap2) + machine->id_hdr_size); > + if (mmap2_event == NULL) > goto out_free_comm; > > fork_event = malloc(sizeof(fork_event->fork) + machine->id_hdr_size); > @@ -601,7 +601,7 @@ int perf_event__synthesize_threads(struct perf_tool *tool, > * We may race with exiting thread, so don't stop just because > * one thread couldn't be synthesized. > */ > - __event__synthesize_thread(comm_event, mmap_event, fork_event, pid, > + __event__synthesize_thread(comm_event, mmap2_event, fork_event, pid, > 1, process, tool, machine, mmap_data, > proc_map_timeout); > } > @@ -611,7 +611,7 @@ int perf_event__synthesize_threads(struct perf_tool *tool, > out_free_fork: > free(fork_event); > out_free_mmap: > - free(mmap_event); > + free(mmap2_event); > out_free_comm: > free(comm_event); > out: > -- > 1.8.3.4
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