On Wed, Jun 19, 2019 at 12:00:46PM +0000, Rantala, Tommi T. (Nokia - FI/Espoo) wrote: > From: Arnaldo Carvalho de Melo <[email protected]> > > commit 4a2233b194c77ae1ea8304cb7c00b551de4313f0 upstream. > > A recent fix for 'perf trace' introduced a bug where > machine__exit(trace->host) could be called while trace->host was still > NULL, so make this more robust by guarding against NULL, just like > free() does. > > The problem happens, for instance, when !root users try to run 'perf > trace': > > [acme@jouet linux]$ trace > 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' > > perf: Segmentation fault > Obtained 7 stack frames. > [0x4f1b2e] > /lib64/libc.so.6(+0x3671f) [0x7f43a1dd971f] > [0x4f3fec] > [0x47468b] > [0x42a2db] > /lib64/libc.so.6(__libc_start_main+0xe9) [0x7f43a1dc3509] > [0x42a6c9] > Segmentation fault (core dumped) > [acme@jouet linux]$ > > Cc: Adrian Hunter <[email protected]> > Cc: Alexander Shishkin <[email protected]> > Cc: Andrei Vagin <[email protected]> > Cc: David Ahern <[email protected]> > Cc: Jiri Olsa <[email protected]> > Cc: Namhyung Kim <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Vasily Averin <[email protected]> > Cc: Wang Nan <[email protected]> > Fixes: 33974a414ce2 ("perf trace: Call machine__exit() at exit") > Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> > Signed-off-by: Tommi Rantala <[email protected]> > --- > tools/perf/util/machine.c | 3 +++ > 1 file changed, 3 insertions(+)
Now applied, thanks. greg k-h
