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| author | Krzysztof Mazur <krzysiek@podlesie.net> | 2012-11-06 23:16:59 +0100 |
|---|---|---|
| committer | David Woodhouse <David.Woodhouse@intel.com> | 2012-11-28 00:37:04 +0000 |
| commit | e41faed9cde1acce657f75a0b19a1787e9850d3f (patch) | |
| tree | 92354ef7b85f7684d247a9e8ebb402c5f0d86ed5 /net/atm | |
| parent | 3b1a914595f3f9beb9e38ff3ddc7bdafa092ba22 (diff) | |
| download | linux-stable-e41faed9cde1acce657f75a0b19a1787e9850d3f.tar.gz linux-stable-e41faed9cde1acce657f75a0b19a1787e9850d3f.tar.bz2 linux-stable-e41faed9cde1acce657f75a0b19a1787e9850d3f.zip | |
pppoatm: fix module_put() race
The pppoatm 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: Krzysztof Mazur <krzysiek@podlesie.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'net/atm')
| -rw-r--r-- | net/atm/pppoatm.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/net/atm/pppoatm.c b/net/atm/pppoatm.c index f27a07a3c546..b23c6723e87c 100644 --- a/net/atm/pppoatm.c +++ b/net/atm/pppoatm.c @@ -60,6 +60,7 @@ struct pppoatm_vcc { struct atm_vcc *atmvcc; /* VCC descriptor */ void (*old_push)(struct atm_vcc *, struct sk_buff *); void (*old_pop)(struct atm_vcc *, struct sk_buff *); + struct module *old_owner; /* keep old push/pop for detaching */ enum pppoatm_encaps encaps; atomic_t inflight; @@ -155,8 +156,6 @@ static void pppoatm_unassign_vcc(struct atm_vcc *atmvcc) ppp_unregister_channel(&pvcc->chan); atmvcc->user_back = NULL; kfree(pvcc); - /* Gee, I hope we have the big kernel lock here... */ - module_put(THIS_MODULE); } /* Called when an AAL5 PDU comes in */ @@ -165,9 +164,13 @@ static void pppoatm_push(struct atm_vcc *atmvcc, struct sk_buff *skb) struct pppoatm_vcc *pvcc = atmvcc_to_pvcc(atmvcc); pr_debug("\n"); if (skb == NULL) { /* VCC was closed */ + struct module *module; + pr_debug("removing ATMPPP VCC %p\n", pvcc); + module = pvcc->old_owner; pppoatm_unassign_vcc(atmvcc); atmvcc->push(atmvcc, NULL); /* Pass along bad news */ + module_put(module); return; } atm_return(atmvcc, skb->truesize); @@ -362,6 +365,7 @@ static int pppoatm_assign_vcc(struct atm_vcc *atmvcc, void __user *arg) atomic_set(&pvcc->inflight, NONE_INFLIGHT); pvcc->old_push = atmvcc->push; pvcc->old_pop = atmvcc->pop; + pvcc->old_owner = atmvcc->owner; pvcc->encaps = (enum pppoatm_encaps) be.encaps; pvcc->chan.private = pvcc; pvcc->chan.ops = &pppoatm_ops; @@ -378,6 +382,7 @@ static int pppoatm_assign_vcc(struct atm_vcc *atmvcc, void __user *arg) atmvcc->push = pppoatm_push; atmvcc->pop = pppoatm_pop; __module_get(THIS_MODULE); + atmvcc->owner = THIS_MODULE; /* re-process everything received between connection setup and backend setup */ |