Commit 01f84f0e authored by Johannes Berg's avatar Johannes Berg
Browse files

mac80211: reduce stack usage in debugfs 

We put a few large buffers on the stack here, but it's easy to
just allocate them on the heap, so do that.

Link: https://lore.kernel.org/r/20210920154009.1387f44e7382.Ife043c169e6a44edace516fea9f8311a5ca4282a@changeid


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 40f231e7

net/mac80211/debugfs_sta.c

+31 −7
Original line number Diff line number Diff line
@@ -5,7 +5,7 @@ 
 * Copyright 2007	Johannes Berg <johannes@sipsolutions.net>

 * Copyright 2013-2014  Intel Mobile Communications GmbH

 * Copyright(c) 2016 Intel Deutschland GmbH

 * Copyright (C) 2018 - 2020 Intel Corporation

 * Copyright (C) 2018 - 2021 Intel Corporation

 */



#include <linux/debugfs.h>
@@ -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);