[PATCH 2/6] mac80211: reduce stack usage in debugfs
From: Johannes Berg <johannes@sipsolutions.net>
Date: 2021-09-20 13:31:40
Subsystem:
mac80211, the rest · Maintainers:
Johannes Berg, Linus Torvalds
From: Johannes Berg <redacted> We put a few large buffers on the stack here, but it's easy to just allocate them on the heap, so do that. Signed-off-by: Johannes Berg <redacted> --- net/mac80211/debugfs_sta.c | 36 ++++++++++++++++++++++++++++++------ 1 file changed, 30 insertions(+), 6 deletions(-)
diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c
index 8be28cfd6f64..adb586a73b05 100644
--- a/net/mac80211/debugfs_sta.c
+++ b/net/mac80211/debugfs_sta.c@@ -314,11 +314,17 @@ STA_OPS_RW(aql); static ssize_t sta_agg_status_read(struct file *file, char __user *userbuf, size_t count, loff_t *ppos) { - char buf[71 + IEEE80211_NUM_TIDS * 40], *p = buf; + char *buf, *p; int i; struct sta_info *sta = file->private_data; struct tid_ampdu_rx *tid_rx; struct tid_ampdu_tx *tid_tx; + ssize_t ret; + + buf = kzalloc(71 + IEEE80211_NUM_TIDS * 40, GFP_KERNEL); + if (!buf) + return -ENOMEM; + p = buf; rcu_read_lock();
@@ -352,7 +358,9 @@ static ssize_t sta_agg_status_read(struct file *file, char __user *userbuf, } rcu_read_unlock(); - return simple_read_from_buffer(userbuf, count, ppos, buf, p - buf); + ret = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf); + kfree(buf); + return ret; } static ssize_t sta_agg_status_write(struct file *file, const char __user *userbuf,
@@ -434,10 +442,16 @@ static ssize_t sta_ht_capa_read(struct file *file, char __user *userbuf, if (_cond) \ p += scnprintf(p, sizeof(buf)+buf-p, "\t" _str "\n"); \ } while (0) - char buf[512], *p = buf; + char *buf, *p; int i; struct sta_info *sta = file->private_data; struct ieee80211_sta_ht_cap *htc = &sta->sta.ht_cap; + ssize_t ret; + + buf = kzalloc(512, GFP_KERNEL); + if (!buf) + return -ENOMEM; + p = buf; p += scnprintf(p, sizeof(buf) + buf - p, "ht %ssupported\n", htc->ht_supported ? "" : "not ");
@@ -504,16 +518,24 @@ static ssize_t sta_ht_capa_read(struct file *file, char __user *userbuf, htc->mcs.tx_params); } - return simple_read_from_buffer(userbuf, count, ppos, buf, p - buf); + ret = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf); + kfree(buf); + return ret; } STA_OPS(ht_capa); static ssize_t sta_vht_capa_read(struct file *file, char __user *userbuf, size_t count, loff_t *ppos) { - char buf[512], *p = buf; + char *buf, *p; struct sta_info *sta = file->private_data; struct ieee80211_sta_vht_cap *vhtc = &sta->sta.vht_cap; + ssize_t ret; + + buf = kzalloc(512, GFP_KERNEL); + if (!buf) + return -ENOMEM; + p = buf; p += scnprintf(p, sizeof(buf) + buf - p, "VHT %ssupported\n", vhtc->vht_supported ? "" : "not ");
@@ -609,7 +631,9 @@ static ssize_t sta_vht_capa_read(struct file *file, char __user *userbuf, #undef PFLAG } - return simple_read_from_buffer(userbuf, count, ppos, buf, p - buf); + ret = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf); + kfree(buf); + return ret; } STA_OPS(vht_capa);
--
2.31.1