diff options
author | Steven Rostedt <rostedt@goodmis.org> | 2024-10-18 21:52:12 -0400 |
---|---|---|
committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2024-10-18 21:57:20 -0400 |
commit | fae4078c289a2f24229c0de652249948b1cd6bdb (patch) | |
tree | ceae6889f6104c43ec1e29b74e0ebe51d2960f5c | |
parent | 2c02f7375e658ae93d57a31a66f91b62754ef8f1 (diff) |
fgraph: Allocate ret_stack_list with proper size
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@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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@goodmis.org>
-rw-r--r-- | kernel/trace/fgraph.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 43f4e3f57438..41e7a15dcb50 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; |