diff mbox series

[2/6] mac80211: reduce stack usage in debugfs

Message ID 20210920153122.92b77da1ad42.Ife043c169e6a44edace516fea9f8311a5ca4282a@changeid (mailing list archive)
State Superseded
Delegated to: Johannes Berg
Headers show
Series [1/6] mac80211: mesh: fix potentially unaligned access | expand

Commit Message

Johannes Berg Sept. 20, 2021, 1:31 p.m. UTC 
From: Johannes Berg <johannes.berg@intel.com>

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 <johannes.berg@intel.com>
---
 net/mac80211/debugfs_sta.c | 36 ++++++++++++++++++++++++++++++------
 1 file changed, 30 insertions(+), 6 deletions(-)
diff mbox series

Patch

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);