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[NET] pktgen: Fix races between control/worker threads.

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There's a race in pktgen which can lead to a double
free of a pktgen_dev's skb. If a worker thread is in
the midst of doing fill_packet(), and the controlling
thread gets a "stop" message, the already freed skb
can be freed once again in pktgen_stop_device(). This
patch gives all responsibility for cleaning up a
pktgen_dev's skb to the associated worker thread.

Signed-off-by: Arthur Kepner <akepner@sgi.com>
Acked-by: Robert Olsson <Robert.Olsson@data.slu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Arthur Kepner 2006-03-20 21:26:56 -08:00 committed by David S. Miller
parent 4bf07ef3fd
commit 95ed63f791
1 changed files with 110 additions and 25 deletions
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135
net/core/pktgen.c
View file

@ -153,7 +153,7 @@
#include <asm/timex.h>
#define VERSION "pktgen v2.63: Packet Generator for packet performance testing.\n"
#define VERSION "pktgen v2.64: Packet Generator for packet performance testing.\n"
/* #define PG_DEBUG(a) a */
#define PG_DEBUG(a)
@ -176,7 +176,8 @@
#define T_TERMINATE (1<<0)
#define T_STOP (1<<1) /* Stop run */
#define T_RUN (1<<2) /* Start run */
#define T_REMDEV (1<<3) /* Remove all devs */
#define T_REMDEVALL (1<<3) /* Remove all devs */
#define T_REMDEV (1<<4) /* Remove one dev */
/* Locks */
#define thread_lock() down(&pktgen_sem)
@ -218,6 +219,8 @@ struct pktgen_dev {
* we will do a random selection from within the range.
*/
__u32 flags;
int removal_mark; /* non-zero => the device is marked for
* removal by worker thread */
int min_pkt_size; /* = ETH_ZLEN; */
int max_pkt_size; /* = ETH_ZLEN; */
@ -481,7 +484,7 @@ static void pktgen_stop_all_threads_ifs(void);
static int pktgen_stop_device(struct pktgen_dev *pkt_dev);
static void pktgen_stop(struct pktgen_thread* t);
static void pktgen_clear_counters(struct pktgen_dev *pkt_dev);
static struct pktgen_dev *pktgen_NN_threads(const char* dev_name, int remove);
static int pktgen_mark_device(const char* ifname);
static unsigned int scan_ip6(const char *s,char ip[16]);
static unsigned int fmt_ip6(char *s,const char ip[16]);
@ -1406,7 +1409,7 @@ static ssize_t pktgen_thread_write(struct file *file,
if (!strcmp(name, "rem_device_all")) {
thread_lock();
t->control |= T_REMDEV;
t->control |= T_REMDEVALL;
thread_unlock();
schedule_timeout_interruptible(msecs_to_jiffies(125)); /* Propagate thread->control */
ret = count;
@ -1457,7 +1460,8 @@ static struct pktgen_dev *__pktgen_NN_threads(const char* ifname, int remove)
if (pkt_dev) {
if(remove) {
if_lock(t);
pktgen_remove_device(t, pkt_dev);
pkt_dev->removal_mark = 1;
t->control |= T_REMDEV;
if_unlock(t);
}
break;
@ -1467,13 +1471,44 @@ static struct pktgen_dev *__pktgen_NN_threads(const char* ifname, int remove)
return pkt_dev;
}
static struct pktgen_dev *pktgen_NN_threads(const char* ifname, int remove)
/*
* mark a device for removal
*/
static int pktgen_mark_device(const char* ifname)
{
struct pktgen_dev *pkt_dev = NULL;
const int max_tries = 10, msec_per_try = 125;
int i = 0;
int ret = 0;
thread_lock();
pkt_dev = __pktgen_NN_threads(ifname, remove);
thread_unlock();
return pkt_dev;
PG_DEBUG(printk("pktgen: pktgen_mark_device marking %s for removal\n",
ifname));
while(1) {
pkt_dev = __pktgen_NN_threads(ifname, REMOVE);
if (pkt_dev == NULL) break; /* success */
thread_unlock();
PG_DEBUG(printk("pktgen: pktgen_mark_device waiting for %s "
"to disappear....\n", ifname));
schedule_timeout_interruptible(msecs_to_jiffies(msec_per_try));
thread_lock();
if (++i >= max_tries) {
printk("pktgen_mark_device: timed out after waiting "
"%d msec for device %s to be removed\n",
msec_per_try*i, ifname);
ret = 1;
break;
}
}
thread_unlock();
return ret;
}
static int pktgen_device_event(struct notifier_block *unused, unsigned long event, void *ptr)
@ -1493,7 +1528,7 @@ static int pktgen_device_event(struct notifier_block *unused, unsigned long even
break;
case NETDEV_UNREGISTER:
pktgen_NN_threads(dev->name, REMOVE);
pktgen_mark_device(dev->name);
break;
};
@ -2303,11 +2338,11 @@ static void pktgen_stop_all_threads_ifs(void)
{
struct pktgen_thread *t = pktgen_threads;
PG_DEBUG(printk("pktgen: entering pktgen_stop_all_threads.\n"));
PG_DEBUG(printk("pktgen: entering pktgen_stop_all_threads_ifs.\n"));
thread_lock();
while(t) {
pktgen_stop(t);
t->control |= T_STOP;
t = t->next;
}
thread_unlock();
@ -2431,7 +2466,9 @@ static void show_results(struct pktgen_dev *pkt_dev, int nr_frags)
static int pktgen_stop_device(struct pktgen_dev *pkt_dev)
{
int nr_frags = pkt_dev->skb ?
skb_shinfo(pkt_dev->skb)->nr_frags: -1;
if (!pkt_dev->running) {
printk("pktgen: interface: %s is already stopped\n", pkt_dev->ifname);
return -EINVAL;
@ -2440,13 +2477,8 @@ static int pktgen_stop_device(struct pktgen_dev *pkt_dev)
pkt_dev->stopped_at = getCurUs();
pkt_dev->running = 0;
show_results(pkt_dev, skb_shinfo(pkt_dev->skb)->nr_frags);
show_results(pkt_dev, nr_frags);
if (pkt_dev->skb)
kfree_skb(pkt_dev->skb);
pkt_dev->skb = NULL;
return 0;
}
@ -2469,26 +2501,66 @@ static struct pktgen_dev *next_to_run(struct pktgen_thread *t )
static void pktgen_stop(struct pktgen_thread *t) {
struct pktgen_dev *next = NULL;
PG_DEBUG(printk("pktgen: entering pktgen_stop.\n"));
PG_DEBUG(printk("pktgen: entering pktgen_stop\n"));
if_lock(t);
for(next=t->if_list; next; next=next->next)
for(next=t->if_list; next; next=next->next) {
pktgen_stop_device(next);
if (next->skb)
kfree_skb(next->skb);
next->skb = NULL;
}
if_unlock(t);
}
/*
* one of our devices needs to be removed - find it
* and remove it
*/
static void pktgen_rem_one_if(struct pktgen_thread *t)
{
struct pktgen_dev *cur, *next = NULL;
PG_DEBUG(printk("pktgen: entering pktgen_rem_one_if\n"));
if_lock(t);
for(cur=t->if_list; cur; cur=next) {
next = cur->next;
if (!cur->removal_mark) continue;
if (cur->skb)
kfree_skb(cur->skb);
cur->skb = NULL;
pktgen_remove_device(t, cur);
break;
}
if_unlock(t);
}
static void pktgen_rem_all_ifs(struct pktgen_thread *t)
{
struct pktgen_dev *cur, *next = NULL;
/* Remove all devices, free mem */
/* Remove all devices, free mem */
PG_DEBUG(printk("pktgen: entering pktgen_rem_all_ifs\n"));
if_lock(t);
for(cur=t->if_list; cur; cur=next) {
next = cur->next;
if (cur->skb)
kfree_skb(cur->skb);
cur->skb = NULL;
pktgen_remove_device(t, cur);
}
@ -2550,6 +2622,9 @@ static __inline__ void pktgen_xmit(struct pktgen_dev *pkt_dev)
if (!netif_running(odev)) {
pktgen_stop_device(pkt_dev);
if (pkt_dev->skb)
kfree_skb(pkt_dev->skb);
pkt_dev->skb = NULL;
goto out;
}
if (need_resched())
@ -2581,7 +2656,7 @@ static __inline__ void pktgen_xmit(struct pktgen_dev *pkt_dev)
pkt_dev->clone_count = 0; /* reset counter */
}
}
spin_lock_bh(&odev->xmit_lock);
if (!netif_queue_stopped(odev)) {
@ -2644,6 +2719,9 @@ static __inline__ void pktgen_xmit(struct pktgen_dev *pkt_dev)
/* Done with this */
pktgen_stop_device(pkt_dev);
if (pkt_dev->skb)
kfree_skb(pkt_dev->skb);
pkt_dev->skb = NULL;
}
out:;
}
@ -2685,6 +2763,7 @@ static void pktgen_thread_worker(struct pktgen_thread *t)
t->control &= ~(T_TERMINATE);
t->control &= ~(T_RUN);
t->control &= ~(T_STOP);
t->control &= ~(T_REMDEVALL);
t->control &= ~(T_REMDEV);
t->pid = current->pid;
@ -2748,8 +2827,13 @@ static void pktgen_thread_worker(struct pktgen_thread *t)
t->control &= ~(T_RUN);
}
if(t->control & T_REMDEV) {
if(t->control & T_REMDEVALL) {
pktgen_rem_all_ifs(t);
t->control &= ~(T_REMDEVALL);
}
if(t->control & T_REMDEV) {
pktgen_rem_one_if(t);
t->control &= ~(T_REMDEV);
}
@ -2833,6 +2917,7 @@ static int pktgen_add_device(struct pktgen_thread *t, const char* ifname)
}
memset(pkt_dev->flows, 0, MAX_CFLOWS*sizeof(struct flow_state));
pkt_dev->removal_mark = 0;
pkt_dev->min_pkt_size = ETH_ZLEN;
pkt_dev->max_pkt_size = ETH_ZLEN;
pkt_dev->nfrags = 0;