From: Robert Richter <[email protected]> Persistent event buffers may only be mmapped readonly. Thus, retry mapping it readonly if mmap returns EACCES after trying to mmap writable.
[ namhyung: Don't write to readonly mmap'ed buffers. ] Signed-off-by: Robert Richter <[email protected]> Signed-off-by: Robert Richter <[email protected]> --- tools/perf/builtin-record.c | 11 ++++++++--- tools/perf/builtin-top.c | 8 ++++++-- tools/perf/perf.h | 1 + 3 files changed, 15 insertions(+), 5 deletions(-) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index a41ac415..f3f7483 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -152,8 +152,8 @@ static int perf_record__mmap_read(struct perf_record *rec, } md->prev = old; - perf_mmap__write_tail(md, old); - + if (!rec->opts.mmap_ro) + perf_mmap__write_tail(md, old); out: return rc; } @@ -226,7 +226,12 @@ static int perf_record__open(struct perf_record *rec) goto out; } - if (perf_evlist__mmap(evlist, opts->mmap_pages, false) < 0) { +try_again2: + if (perf_evlist__mmap(evlist, opts->mmap_pages, opts->mmap_ro) < 0) { + if (!opts->mmap_ro && errno == EACCES) { + opts->mmap_ro = true; + goto try_again2; + } if (errno == EPERM) { pr_err("Permission error mapping pages.\n" "Consider increasing " diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index e37521f..bef7b1d 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -894,8 +894,12 @@ static int perf_top__start_counters(struct perf_top *top) goto out_err; } } - - if (perf_evlist__mmap(evlist, opts->mmap_pages, false) < 0) { +try_again2: + if (perf_evlist__mmap(evlist, opts->mmap_pages, opts->mmap_ro) < 0) { + if (!opts->mmap_ro && errno == EACCES) { + opts->mmap_ro = true; + goto try_again2; + } ui__error("Failed to mmap with %d (%s)\n", errno, strerror(errno)); goto out_err; diff --git a/tools/perf/perf.h b/tools/perf/perf.h index cf20187..dca43c72 100644 --- a/tools/perf/perf.h +++ b/tools/perf/perf.h @@ -224,6 +224,7 @@ struct perf_record_opts { bool sample_weight; bool sample_time; bool period; + bool mmap_ro; unsigned int freq; unsigned int mmap_pages; unsigned int user_freq; -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
