| Message ID | 1452520124-2073-43-git-send-email-wangnan0@huawei.com |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | David Miller |
| Headers | show |
Hello. On 01/11/2016 04:48 PM, Wang Nan wrote: > When record__mmap_read() require data more than the size of ring > buffer, drop those data to avoid access invalid memory. > > This can happen when reading from overwritable ring buffer, which > should be avoided. However, check this for robustness. > > Signed-off-by: Wang Nan <wangnan0@huawei.com> > Signed-off-by: He Kuang <hekuang@huawei.com> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > Cc: Jiri Olsa <jolsa@kernel.org> > 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/builtin-record.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index b65b41f..3f58426 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -37,6 +37,7 @@ > #include <unistd.h> > #include <sched.h> > #include <sys/mman.h> > +#include <asm/bug.h> > > > struct record { > @@ -94,6 +95,13 @@ static int record__mmap_read(struct record *rec, int idx) > rec->samples++; > > size = head - old; > + if (size > (unsigned long)(md->mask) + 1) { > + WARN_ONCE(1, "WARNING: failed to keep up with mmap data. (warn only once)\n"); WARNING is already printed by WARN*(), no? [...] MBR, Sergei
Em Mon, Jan 11, 2016 at 05:21:44PM +0300, Sergei Shtylyov escreveu: > On 01/11/2016 04:48 PM, Wang Nan wrote: > > size = head - old; > >+ if (size > (unsigned long)(md->mask) + 1) { > >+ WARN_ONCE(1, "WARNING: failed to keep up with mmap data. (warn only once)\n"); > > WARNING is already printed by WARN*(), no? No, at least not in tools/include/asm/bug.h, perhaps include/asm/bug.h has this now and tools/ drifted? Checking now... - Arnaldo
Em Mon, Jan 11, 2016 at 01:00:07PM -0200, Arnaldo Carvalho de Melo escreveu: > Em Mon, Jan 11, 2016 at 05:21:44PM +0300, Sergei Shtylyov escreveu: > > On 01/11/2016 04:48 PM, Wang Nan wrote: > > > size = head - old; > > >+ if (size > (unsigned long)(md->mask) + 1) { > > >+ WARN_ONCE(1, "WARNING: failed to keep up with mmap data. (warn only once)\n"); > > > > WARNING is already printed by WARN*(), no? > > No, at least not in tools/include/asm/bug.h, perhaps include/asm/bug.h > has this now and tools/ drifted? Checking now... Indeed, need to bring it closer together again... - Arnaldo
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index b65b41f..3f58426 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -37,6 +37,7 @@ #include <unistd.h> #include <sched.h> #include <sys/mman.h> +#include <asm/bug.h> struct record { @@ -94,6 +95,13 @@ static int record__mmap_read(struct record *rec, int idx) rec->samples++; size = head - old; + if (size > (unsigned long)(md->mask) + 1) { + WARN_ONCE(1, "WARNING: failed to keep up with mmap data. (warn only once)\n"); + + md->prev = head; + perf_evlist__mmap_consume(rec->evlist, idx); + return 0; + } if ((old & md->mask) + size != (head & md->mask)) { buf = &data[old & md->mask];