4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> commit d66a270be3310d7aa132fec0cea77d3d32a0ff75 upstream. 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@xxxxxxxxxx Link: https://lkml.kernel.org/r/001a1140e0de15fc910567464190@xxxxxxxxxx Link: http://lkml.kernel.org/r/20180315124424.32319-1-mathieu.desnoyers@xxxxxxxxxxxx CC: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CC: Jiri Olsa <jolsa@xxxxxxxxxx> CC: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> CC: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> CC: Namhyung Kim <namhyung@xxxxxxxxxx> CC: stable@xxxxxxxxxxxxxxx Fixes: de7b2973903c6 ("tracepoint: Use struct pointer instead of name hash for reg/unreg tracepoints") Reported-by: syzbot+9c0d616860575a73166a@xxxxxxxxxxxxxxxxxxxxxxxxx Reported-by: syzbot+4e9ae7fa46233396f64d@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/tracepoint.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -207,7 +207,7 @@ static int tracepoint_add_func(struct tr 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 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); }
