Commit d66a270b authored Mar 15, 2018 by Mathieu Desnoyers Committed by Steven Rostedt (VMware) Apr 30, 2018

tracepoint: Do not warn on ENOMEM

Tracepoint should only warn when a kernel API user does not respect the
required preconditions (e.g. same tracepoint enabled twice, or called
to remove a tracepoint that does not exist).

Silence warning in out-of-memory conditions, given that the error is
returned to the caller.

This ensures that out-of-memory error-injection testing does not trigger
warnings in tracepoint.c, which were seen by syzbot.

Link: https://lkml.kernel.org/r/001a114465e241a8720567419a72@google.com
Link: https://lkml.kernel.org/r/001a1140e0de15fc910567464190@google.com
Link: http://lkml.kernel.org/r/20180315124424.32319-1-mathieu.desnoyers@efficios.com



CC: Peter Zijlstra <peterz@infradead.org>
CC: Jiri Olsa <jolsa@redhat.com>
CC: Arnaldo Carvalho de Melo <acme@kernel.org>
CC: Alexander Shishkin <alexander.shishkin@linux.intel.com>
CC: Namhyung Kim <namhyung@kernel.org>
CC: stable@vger.kernel.org
Fixes: de7b2973 ("tracepoint: Use struct pointer instead of name hash for reg/unreg tracepoints")
Reported-by:  <syzbot+9c0d616860575a73166a@syzkaller.appspotmail.com>
Reported-by:  <syzbot+4e9ae7fa46233396f64d@syzkaller.appspotmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parent dcf23457

kernel/tracepoint.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -207,7 +207,7 @@ static int tracepoint_add_func(struct tracepoint *tp,
		lockdep_is_held(&tracepoints_mutex));
		old = func_add(&tp_funcs, func, prio);
		if (IS_ERR(old)) {
		WARN_ON_ONCE(1);
		WARN_ON_ONCE(PTR_ERR(old) != -ENOMEM);
		return PTR_ERR(old);
		}

		@@ -239,7 +239,7 @@ static int tracepoint_remove_func(struct tracepoint *tp,
		lockdep_is_held(&tracepoints_mutex));
		old = func_remove(&tp_funcs, func);
		if (IS_ERR(old)) {
		WARN_ON_ONCE(1);
		WARN_ON_ONCE(PTR_ERR(old) != -ENOMEM);
		return PTR_ERR(old);
		}

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