6.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steven Rostedt <rostedt@xxxxxxxxxxx> [ Upstream commit fae4078c289a2f24229c0de652249948b1cd6bdb ] The ret_stack_list is an array of ret_stack shadow stacks for the function graph usage. When the first function graph is enabled, all tasks in the system get a shadow stack. The ret_stack_list is a 32 element array of pointers to these shadow stacks. It allocates the shadow stack in batches (32 stacks at a time), assigns them to running tasks, and continues until all tasks are covered. When the function graph shadow stack changed from an array of ftrace_ret_stack structures to an array of longs, the allocation of ret_stack_list went from allocating an array of 32 elements to just a block defined by SHADOW_STACK_SIZE. Luckily, that's defined as PAGE_SIZE and is much more than enough to hold 32 pointers. But it is way overkill for the amount needed to allocate. Change the allocation of ret_stack_list back to a kcalloc() of FTRACE_RETSTACK_ALLOC_SIZE pointers. Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Link: https://lore.kernel.org/20241018215212.23f13f40@rorschach Fixes: 42675b723b484 ("function_graph: Convert ret_stack to a series of longs") Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- kernel/trace/fgraph.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 43f4e3f57438b..41e7a15dcb50c 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -1162,7 +1162,8 @@ static int start_graph_tracing(void) unsigned long **ret_stack_list; int ret; - ret_stack_list = kmalloc(SHADOW_STACK_SIZE, GFP_KERNEL); + ret_stack_list = kcalloc(FTRACE_RETSTACK_ALLOC_SIZE, + sizeof(*ret_stack_list), GFP_KERNEL); if (!ret_stack_list) return -ENOMEM; -- 2.43.0
