From 06c2d9a078abe784fd9fd0f1534e318e827712b4 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 27 Sep 2021 14:41:40 +0200 Subject: [PATCH] firmware: tegra: Reduce stack usage Building the bpmp-debugfs driver for Arm results in a warning for stack usage: drivers/firmware/tegra/bpmp-debugfs.c:321:16: error: stack frame size of 1224 bytes in function 'bpmp_debug_store' [-Werror,-Wframe-larger-than=] static ssize_t bpmp_debug_store(struct file *file, const char __user *buf, It should be possible to rearrange the code to not require two separate buffers for the file name, but the easiest workaround is to use dynamic allocation. Fixes: 5e37b9c137ee ("firmware: tegra: Add support for in-band debug") Link: https://lore.kernel.org/all/20201204193714.3134651-1-arnd@kernel.org/ Signed-off-by: Arnd Bergmann [treding@nvidia.com: consistently return NULL on failure] Signed-off-by: Thierry Reding --- drivers/firmware/tegra/bpmp-debugfs.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/drivers/firmware/tegra/bpmp-debugfs.c b/drivers/firmware/tegra/bpmp-debugfs.c index 3e9fa4b54358..6d66fe03fb6a 100644 --- a/drivers/firmware/tegra/bpmp-debugfs.c +++ b/drivers/firmware/tegra/bpmp-debugfs.c @@ -74,28 +74,36 @@ static void seqbuf_seek(struct seqbuf *seqbuf, ssize_t offset) static const char *get_filename(struct tegra_bpmp *bpmp, const struct file *file, char *buf, int size) { - char root_path_buf[512]; - const char *root_path; - const char *filename; + const char *root_path, *filename = NULL; + char *root_path_buf; size_t root_len; + root_path_buf = kzalloc(512, GFP_KERNEL); + if (!root_path_buf) + goto out; + root_path = dentry_path(bpmp->debugfs_mirror, root_path_buf, sizeof(root_path_buf)); if (IS_ERR(root_path)) - return NULL; + goto out; root_len = strlen(root_path); filename = dentry_path(file->f_path.dentry, buf, size); - if (IS_ERR(filename)) - return NULL; + if (IS_ERR(filename)) { + filename = NULL; + goto out; + } - if (strlen(filename) < root_len || - strncmp(filename, root_path, root_len)) - return NULL; + if (strlen(filename) < root_len || strncmp(filename, root_path, root_len)) { + filename = NULL; + goto out; + } filename += root_len; +out: + kfree(root_path_buf); return filename; }