Commit 2e56571d authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'inet-frags-followup' 



Eric Dumazet says:

====================
inet: frags: followup to 'inet-frags-avoid-possible-races-at-netns-dismantle'

Latest patch series ('inet-frags-avoid-possible-races-at-netns-dismantle')
brought another syzbot report shown in the third patch changelog.

While fixing the issue, I had to call inet_frags_fini() later
in IPv6 and ilowpan.

Also I believe a completion is needed to ensure proper dismantle
at module removal.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 3fb321fd dc93f46b

include/net/inet_frag.h

+4 −19
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#define __NET_FRAG_H__



#include <linux/rhashtable-types.h>

#include <linux/completion.h>



/* Per netns frag queues directory */

struct fqdir {
@@ -104,30 +105,14 @@ struct inet_frags { 
	struct kmem_cache	*frags_cachep;

	const char		*frags_cache_name;

	struct rhashtable_params rhash_params;

	refcount_t		refcnt;

	struct completion	completion;

};



int inet_frags_init(struct inet_frags *);

void inet_frags_fini(struct inet_frags *);



static inline int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f,

			     struct net *net)

{

	struct fqdir *fqdir = kzalloc(sizeof(*fqdir), GFP_KERNEL);

	int res;



	if (!fqdir)

		return -ENOMEM;

	fqdir->f = f;

	fqdir->net = net;

	res = rhashtable_init(&fqdir->rhashtable, &fqdir->f->rhash_params);

	if (res < 0) {

		kfree(fqdir);

		return res;

	}

	*fqdirp = fqdir;

	return 0;

}



int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net);

void fqdir_exit(struct fqdir *fqdir);



void inet_frag_kill(struct inet_frag_queue *q);

net/ieee802154/6lowpan/reassembly.c

+1 −1
Original line number Diff line number Diff line
@@ -540,7 +540,7 @@ err_sysctl: 


void lowpan_net_frag_exit(void)

{

	inet_frags_fini(&lowpan_frags);

	lowpan_frags_sysctl_unregister();

	unregister_pernet_subsys(&lowpan_frags_ops);

	inet_frags_fini(&lowpan_frags);

}

net/ipv4/inet_fragment.c

+37 −2
Original line number Diff line number Diff line
@@ -110,14 +110,18 @@ int inet_frags_init(struct inet_frags *f) 
	if (!f->frags_cachep)

		return -ENOMEM;



	refcount_set(&f->refcnt, 1);

	init_completion(&f->completion);

	return 0;

}

EXPORT_SYMBOL(inet_frags_init);



void inet_frags_fini(struct inet_frags *f)

{

	/* We must wait that all inet_frag_destroy_rcu() have completed. */

	rcu_barrier();

	if (refcount_dec_and_test(&f->refcnt))

		complete(&f->completion);



	wait_for_completion(&f->completion);



	kmem_cache_destroy(f->frags_cachep);

	f->frags_cachep = NULL;
@@ -149,11 +153,42 @@ static void fqdir_rwork_fn(struct work_struct *work) 
{

	struct fqdir *fqdir = container_of(to_rcu_work(work),

					   struct fqdir, destroy_rwork);

	struct inet_frags *f = fqdir->f;



	rhashtable_free_and_destroy(&fqdir->rhashtable, inet_frags_free_cb, NULL);



	/* We need to make sure all ongoing call_rcu(..., inet_frag_destroy_rcu)

	 * have completed, since they need to dereference fqdir.

	 * Would it not be nice to have kfree_rcu_barrier() ? :)

	 */

	rcu_barrier();



	if (refcount_dec_and_test(&f->refcnt))

		complete(&f->completion);



	kfree(fqdir);

}



int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net)

{

	struct fqdir *fqdir = kzalloc(sizeof(*fqdir), GFP_KERNEL);

	int res;



	if (!fqdir)

		return -ENOMEM;

	fqdir->f = f;

	fqdir->net = net;

	res = rhashtable_init(&fqdir->rhashtable, &fqdir->f->rhash_params);

	if (res < 0) {

		kfree(fqdir);

		return res;

	}

	refcount_inc(&f->refcnt);

	*fqdirp = fqdir;

	return 0;

}

EXPORT_SYMBOL(fqdir_init);



void fqdir_exit(struct fqdir *fqdir)

{

	fqdir->high_thresh = 0; /* prevent creation of new frags */

net/ipv6/reassembly.c

+1 −1
Original line number Diff line number Diff line
@@ -583,8 +583,8 @@ err_protocol: 


void ipv6_frag_exit(void)

{

	inet_frags_fini(&ip6_frags);

	ip6_frags_sysctl_unregister();

	unregister_pernet_subsys(&ip6_frags_ops);

	inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT);

	inet_frags_fini(&ip6_frags);

}

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