From: Steven Rostedt rostedt@goodmis.org
The functions wakeup_graph_entry() and wakeup_graph_return() both call func_prolog_preempt_disable() that will test if the data->disable is already set and if not, increment it and disable preemption. If it was set, it returns false and the caller exits.
The caller of this function must decrement the disable counter, but misses doing so if the calltime fails to be acquired.
Instead of exiting out when calltime is NULL, change the logic to do the work if it is not NULL and still do the clean up at the end of the function if it is NULL.
Cc: stable@vger.kernel.org Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Link: https://lore.kernel.org/20251008114835.027b878a@gandalf.local.home Fixes: a485ea9e3ef3 ("tracing: Fix irqsoff and wakeup latency tracers when using function graph") Reported-by: Sasha Levin sashal@kernel.org Closes: https://lore.kernel.org/linux-trace-kernel/20251006175848.1906912-1-sashal@k... Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org --- kernel/trace/trace_sched_wakeup.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index bf1cb80742ae..e3f2e4f56faa 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -138,12 +138,10 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace, return 0;
calltime = fgraph_reserve_data(gops->idx, sizeof(*calltime)); - if (!calltime) - return 0; - - *calltime = trace_clock_local(); - - ret = __trace_graph_entry(tr, trace, trace_ctx); + if (calltime) { + *calltime = trace_clock_local(); + ret = __trace_graph_entry(tr, trace, trace_ctx); + } local_dec(&data->disabled); preempt_enable_notrace();
@@ -169,12 +167,10 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace, rettime = trace_clock_local();
calltime = fgraph_retrieve_data(gops->idx, &size); - if (!calltime) - return; + if (calltime) + __trace_graph_return(tr, trace, trace_ctx, *calltime, rettime);
- __trace_graph_return(tr, trace, trace_ctx, *calltime, rettime); local_dec(&data->disabled); - preempt_enable_notrace(); return; }