Messages in this thread | | | From | Raphaël Beamonte <> | Date | Sat, 19 Sep 2015 11:26:20 -0400 | Subject | Re: [PATCH] tools lib api fs: Store tracing mountpoint for better error message |
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2015-09-19 10:47 GMT-04:00 Jiri Olsa <jolsa@kernel.org>: > Storing the actual tracing path mountpoint to display correct > error message hint ('Hint:' line). The error hint rediscovers > mountpoints, but it could be different from what we actually > used in tracing path. > > Before we'd display debugfs mount even though tracefs was used: > $ perf record -e sched:sched_krava ls > event syntax error: 'sched:sched_krava' > \___ can't access trace events > > Error: No permissions to read /sys/kernel/debug/tracing/events/sched/sched_krava > Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug' > ... > > After this change, correct mountpoint is displayed: > $ perf record -e sched:sched_krava ls > event syntax error: 'sched:sched_krava' > \___ can't access trace events > > Error: No permissions to read /sys/kernel/debug/tracing/events/sched/sched_krava > Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing' > ... > > Link: http://lkml.kernel.org/n/tip-xw7mf64ie0svh6m449vbyh0m@git.kernel.org > Signed-off-by: Jiri Olsa <jolsa@kernel.org> > --- > tools/lib/api/fs/tracing_path.c | 13 +++---------- > 1 file changed, 3 insertions(+), 10 deletions(-) > > diff --git a/tools/lib/api/fs/tracing_path.c b/tools/lib/api/fs/tracing_path.c > index 38aca2dd1946..0406a7d5c891 100644 > --- a/tools/lib/api/fs/tracing_path.c > +++ b/tools/lib/api/fs/tracing_path.c > @@ -12,12 +12,14 @@ > #include "tracing_path.h" > > > +char tracing_mnt[PATH_MAX + 1] = "/sys/kernel/debug"; > char tracing_path[PATH_MAX + 1] = "/sys/kernel/debug/tracing"; > char tracing_events_path[PATH_MAX + 1] = "/sys/kernel/debug/tracing/events"; > > > static void __tracing_path_set(const char *tracing, const char *mountpoint) > { > + snprintf(tracing_mnt, sizeof(tracing_mnt), "%s", mountpoint); > snprintf(tracing_path, sizeof(tracing_path), "%s/%s", > mountpoint, tracing); > snprintf(tracing_events_path, sizeof(tracing_events_path), "%s/%s%s", > @@ -109,19 +111,10 @@ static int strerror_open(int err, char *buf, size_t size, const char *filename) > "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'"); > break; > case EACCES: { > - const char *mountpoint = debugfs__mountpoint(); > - > - if (!access(mountpoint, R_OK) && strncmp(filename, "tracing/", 8) == 0) { > - const char *tracefs_mntpoint = tracefs__mountpoint(); > - > - if (tracefs_mntpoint) > - mountpoint = tracefs__mountpoint(); > - } > - > snprintf(buf, size, > "Error:\tNo permissions to read %s/%s\n" > "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n", > - tracing_events_path, filename, mountpoint); > + tracing_events_path, filename, tracing_mnt); > } > break; > default: > -- > 2.4.3 >
Reviewed-by: Raphaël Beamonte <raphael.beamonte@gmail.com>
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