tools lib api debugfs: Check for tracefs when reporting errors
authorArnaldo Carvalho de Melo <acme@redhat.com>
Mon, 6 Jul 2015 11:51:41 +0000 (08:51 -0300)
committerArnaldo Carvalho de Melo <acme@redhat.com>
Mon, 6 Jul 2015 15:22:14 +0000 (12:22 -0300)
commitab85785aa13c36440a91a8e9f7616357de411a1f
treee12b993f3ca7ce4df2abf0b077e569cdf91e0988
parent3abebc55d70b6e3247d1f0e34c0bb906e40d2a18
tools lib api debugfs: Check for tracefs when reporting errors

Now that we have two mountpoints, one for debugfs and another, for
tracefs, we end up needing to check permissions for both, so, on
a system with default config we were always asking the user to
check the permission of the debugfs mountpoint, even when it was
already sufficient. Fix it.

E.g.:

  $ trace -e nanosleep usleep 1
  Error: No permissions to read /sys/kernel/debug/tracing/events/raw_syscalls/sys_(enter|exit)
  Hint:  Try 'sudo mount -o remount,mode=755 /sys/kernel/debug'

  $ sudo mount -o remount,mode=755 /sys/kernel/debug
  $ trace -e nanosleep usleep 1
  Error: No permissions to read /sys/kernel/debug/tracing/events/raw_syscalls/sys_(enter|exit)
  Hint:  Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing'

  $ sudo mount -o remount,mode=755 /sys/kernel/debug/tracing
  $ trace -e nanosleep usleep 1
     0.326 ( 0.061 ms): usleep/11961 nanosleep(rqtp: 0x7ffef1081c50) = 0
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/n/tip-0viljeuhc7q84ic8kobsna43@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
tools/lib/api/fs/debugfs.c