From: Krister Johansen <[email protected]> The perf top command needs to unshare its fs from the helper threads in order to successfully setns(2) during its symbol lookup. It also needs to impelement a force flag to ignore ownership of perf-<pid>.map files.
Signed-off-by: Krister Johansen <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Brendan Gregg <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas-Mich Richter <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> --- tools/perf/Documentation/perf-top.txt | 4 ++++ tools/perf/builtin-top.c | 15 +++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/tools/perf/Documentation/perf-top.txt b/tools/perf/Documentation/perf-top.txt index e71d63843f45..d864ea6fd367 100644 --- a/tools/perf/Documentation/perf-top.txt +++ b/tools/perf/Documentation/perf-top.txt @@ -237,6 +237,10 @@ Default is to monitor all CPUS. --hierarchy:: Enable hierarchy output. +--force:: + Don't do ownership validation. + + INTERACTIVE PROMPTING KEYS -------------------------- diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index e5a8f249077f..ee954bde7e3e 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -587,6 +587,13 @@ static void *display_thread_tui(void *arg) .refresh = top->delay_secs, }; + /* In order to read symbols from other namespaces perf to needs to call + * setns(2). This isn't permitted if the struct_fs has multiple users. + * unshare(2) the fs so that we may continue to setns into namespaces + * that we're observing. + */ + unshare(CLONE_FS); + perf_top__sort_new_samples(top); /* @@ -628,6 +635,13 @@ static void *display_thread(void *arg) struct perf_top *top = arg; int delay_msecs, c; + /* In order to read symbols from other namespaces perf to needs to call + * setns(2). This isn't permitted if the struct_fs has multiple users. + * unshare(2) the fs so that we may continue to setns into namespaces + * that we're observing. + */ + unshare(CLONE_FS); + display_setup_sig(); pthread__unblock_sigwinch(); repeat: @@ -1206,6 +1220,7 @@ int cmd_top(int argc, const char **argv) "Show raw trace event output (do not use print fmt or plugins)"), OPT_BOOLEAN(0, "hierarchy", &symbol_conf.report_hierarchy, "Show entries in a hierarchy"), + OPT_BOOLEAN(0, "force", &symbol_conf.force, "don't complain, do it"), OPT_END() }; const char * const top_usage[] = { -- 2.9.4
