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br2684: fix module_put() race 

The br2684 code used module_put() during unassignment from vcc with
hope that we have BKL. This assumption is no longer true.

Now owner field in atmvcc is used to move this module_put()
to vcc_destroy_socket().

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Acked-by: Krzysztof Mazur <krzysiek@podlesie.net>
This commit is contained in:
David Woodhouse 2012-11-28 00:46:45 +00:00
parent 0e56d99a5b
commit d71ffeb123
1 changed files with 4 additions and 1 deletions
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5
net/atm/br2684.c
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@ -69,6 +69,7 @@ struct br2684_vcc {
void (*old_push)(struct atm_vcc *vcc, struct sk_buff *skb);
void (*old_pop)(struct atm_vcc *vcc, struct sk_buff *skb);
void (*old_release_cb)(struct atm_vcc *vcc);
struct module *old_owner;
enum br2684_encaps encaps;
struct list_head brvccs;
#ifdef CONFIG_ATM_BR2684_IPFILTER
@ -414,8 +415,8 @@ static void br2684_close_vcc(struct br2684_vcc *brvcc)
brvcc->atmvcc->user_back = NULL; /* what about vcc->recvq ??? */
brvcc->atmvcc->release_cb = brvcc->old_release_cb;
brvcc->old_push(brvcc->atmvcc, NULL); /* pass on the bad news */
module_put(brvcc->old_owner);
kfree(brvcc);
module_put(THIS_MODULE);
}
/* when AAL5 PDU comes in: */
@ -590,10 +591,12 @@ static int br2684_regvcc(struct atm_vcc *atmvcc, void __user * arg)
brvcc->old_push = atmvcc->push;
brvcc->old_pop = atmvcc->pop;
brvcc->old_release_cb = atmvcc->release_cb;
brvcc->old_owner = atmvcc->owner;
barrier();
atmvcc->push = br2684_push;
atmvcc->pop = br2684_pop;
atmvcc->release_cb = br2684_release_cb;
atmvcc->owner = THIS_MODULE;
/* initialize netdev carrier state */
if (atmvcc->dev->signal == ATM_PHY_SIG_LOST)