4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Mathieu Desnoyers <[email protected]> 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/[email protected] Link: https://lkml.kernel.org/r/[email protected] Link: http://lkml.kernel.org/r/[email protected] CC: Peter Zijlstra <[email protected]> CC: Jiri Olsa <[email protected]> CC: Arnaldo Carvalho de Melo <[email protected]> CC: Alexander Shishkin <[email protected]> CC: Namhyung Kim <[email protected]> CC: [email protected] Fixes: de7b2973903c6 ("tracepoint: Use struct pointer instead of name hash for reg/unreg tracepoints") Reported-by: [email protected] Reported-by: [email protected] Signed-off-by: Mathieu Desnoyers <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- kernel/tracepoint.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -202,7 +202,7 @@ 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); } @@ -235,7 +235,7 @@ 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); }
