From 0701995aaf8fc2281154db829ca85e231951e51d Mon Sep 17 00:00:00 2001 From: Donggeun Yoo Date: Sun, 6 Sep 2026 12:44:06 +0900 Subject: [PATCH] function_graph: Use the saved entry's size when reprinting it When a graph entry does not fit in the trace_seq, print_graph_entry() saves it in the iterator's fgraph_data and reprints it on the next read. The entry has already been consumed from the ring buffer by then, so the copy is all that is left of it. The copy is sized with iter->ent_size, which no longer describes the saved entry but whatever entry the iterator has moved on to. The argument count is derived from the same field, so a 72 byte entry saved and then reprinted ahead of a 48 byte return entry loses its arguments. Record the size next to the failure flag, so that the two are always set together, and restore it before reprinting. Cc: stable@vger.kernel.org Fixes: ff5c9c576e75 ("ftrace: Add support for function argument to graph tracer") Link: https://patch.msgid.link/20260906034406.1335316-1-donggeunyoo.kernel@gmail.com Signed-off-by: Donggeun Yoo Signed-off-by: Steven Rostedt --- kernel/trace/trace_functions_graph.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index ff7cb1a76b95..c5befd0c5b9a 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -52,6 +52,7 @@ struct fgraph_data { }; struct ftrace_graph_ret_entry ret; int failed; + int ent_size; int cpu; }; @@ -1274,6 +1275,7 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s, if (s->full) { data->failed = 1; data->cpu = cpu; + data->ent_size = iter->ent_size; } else data->failed = 0; } @@ -1457,6 +1459,7 @@ print_graph_function_flags(struct trace_iterator *iter, u32 flags) if (data && data->failed) { field = &data->ent.ent; iter->cpu = data->cpu; + iter->ent_size = data->ent_size; ret = print_graph_entry(field, s, iter, flags); if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) { per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;