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authorKarsten Keil <keil@b1-systems.de>2015-10-21 14:18:39 +0200
committerDavid S. Miller <davem@davemloft.net>2015-10-22 07:23:19 -0700
commitc96356a9baa2e3d628caf52f3b83df1968628b5f (patch)
tree01de4f3ad8098331f6c94d54c77b82398c92b3ec /drivers/isdn
parentc7a7c95e8e18a3598c4d0f99c35e69dce591daf1 (diff)
downloadlinux-c96356a9baa2e3d628caf52f3b83df1968628b5f.tar.bz2
mISDN: fix OOM condition for sending queued I-Frames
The old code did not check the return value of skb_clone(). The extra skb_clone() is not needed at all, if using skb_realloc_headroom() instead, which gives us a private copy with enough headroom as well. We need to requeue the original skb if the call failed, because we cannot inform upper layers about the data loss. Restructure the code to minimise rollback effort if it happens. This fix kernel bug #86091 Thanks to Insu Yun <wuninsu@gmail.com> to remind me on this issue. Signed-off-by: Karsten Keil <keil@b1-systems.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/isdn')
-rw-r--r--drivers/isdn/mISDN/layer2.c54
1 files changed, 20 insertions, 34 deletions
diff --git a/drivers/isdn/mISDN/layer2.c b/drivers/isdn/mISDN/layer2.c
index 949cabb88f1c..5eb380a25903 100644
--- a/drivers/isdn/mISDN/layer2.c
+++ b/drivers/isdn/mISDN/layer2.c
@@ -1476,7 +1476,7 @@ static void
l2_pull_iqueue(struct FsmInst *fi, int event, void *arg)
{
struct layer2 *l2 = fi->userdata;
- struct sk_buff *skb, *nskb, *oskb;
+ struct sk_buff *skb, *nskb;
u_char header[MAX_L2HEADER_LEN];
u_int i, p1;
@@ -1486,48 +1486,34 @@ l2_pull_iqueue(struct FsmInst *fi, int event, void *arg)
skb = skb_dequeue(&l2->i_queue);
if (!skb)
return;
-
- if (test_bit(FLG_MOD128, &l2->flag))
- p1 = (l2->vs - l2->va) % 128;
- else
- p1 = (l2->vs - l2->va) % 8;
- p1 = (p1 + l2->sow) % l2->window;
- if (l2->windowar[p1]) {
- printk(KERN_WARNING "%s: l2 try overwrite ack queue entry %d\n",
- mISDNDevName4ch(&l2->ch), p1);
- dev_kfree_skb(l2->windowar[p1]);
- }
- l2->windowar[p1] = skb;
i = sethdraddr(l2, header, CMD);
if (test_bit(FLG_MOD128, &l2->flag)) {
header[i++] = l2->vs << 1;
header[i++] = l2->vr << 1;
+ } else
+ header[i++] = (l2->vr << 5) | (l2->vs << 1);
+ nskb = skb_realloc_headroom(skb, i);
+ if (!nskb) {
+ printk(KERN_WARNING "%s: no headroom(%d) copy for IFrame\n",
+ mISDNDevName4ch(&l2->ch), i);
+ skb_queue_head(&l2->i_queue, skb);
+ return;
+ }
+ if (test_bit(FLG_MOD128, &l2->flag)) {
+ p1 = (l2->vs - l2->va) % 128;
l2->vs = (l2->vs + 1) % 128;
} else {
- header[i++] = (l2->vr << 5) | (l2->vs << 1);
+ p1 = (l2->vs - l2->va) % 8;
l2->vs = (l2->vs + 1) % 8;
}
-
- nskb = skb_clone(skb, GFP_ATOMIC);
- p1 = skb_headroom(nskb);
- if (p1 >= i)
- memcpy(skb_push(nskb, i), header, i);
- else {
- printk(KERN_WARNING
- "%s: L2 pull_iqueue skb header(%d/%d) too short\n",
- mISDNDevName4ch(&l2->ch), i, p1);
- oskb = nskb;
- nskb = mI_alloc_skb(oskb->len + i, GFP_ATOMIC);
- if (!nskb) {
- dev_kfree_skb(oskb);
- printk(KERN_WARNING "%s: no skb mem in %s\n",
- mISDNDevName4ch(&l2->ch), __func__);
- return;
- }
- memcpy(skb_put(nskb, i), header, i);
- memcpy(skb_put(nskb, oskb->len), oskb->data, oskb->len);
- dev_kfree_skb(oskb);
+ p1 = (p1 + l2->sow) % l2->window;
+ if (l2->windowar[p1]) {
+ printk(KERN_WARNING "%s: l2 try overwrite ack queue entry %d\n",
+ mISDNDevName4ch(&l2->ch), p1);
+ dev_kfree_skb(l2->windowar[p1]);
}
+ l2->windowar[p1] = skb;
+ memcpy(skb_push(nskb, i), header, i);
l2down(l2, PH_DATA_REQ, l2_newid(l2), nskb);
test_and_clear_bit(FLG_ACK_PEND, &l2->flag);
if (!test_and_set_bit(FLG_T200_RUN, &l2->flag)) {