imrcpan/erofs-linux
1
0 Fork 0
mirror of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git synced 2026-10-31 14:23:49 +01:00
Code Issues Packages Projects Releases Wiki Activity

net: fix up truesize of cloned skb in skb_prepare_for_shift()

Browse Source 
Avoid the assumption that ksize(kmalloc(S)) == ksize(kmalloc(S)): when
cloning an skb, save and restore truesize after pskb_expand_head(). This
can occur if the allocator decides to service an allocation of the same
size differently (e.g. use a different size class, or pass the
allocation on to KFENCE).

Because truesize is used for bookkeeping (such as sk_wmem_queued), a
modified truesize of a cloned skb may result in corrupt bookkeeping and
relevant warnings (such as in sk_stream_kill_queues()).

Link: https://lkml.kernel.org/r/X9JR/[email protected]
Reported-by: [email protected]
Suggested-by: Eric Dumazet <[email protected]>
Signed-off-by: Marco Elver <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
This commit is contained in:
Marco Elver authored and Jakub Kicinski committed 2021-02-02 17:36:12 -08:00
1 parent ec99a470c7
commit 097b9146c0
1 file changed
+13 -1
Download Patch File Download Diff File Expand all files Collapse all files
net/core/skbuff.c
+13 -1
View File
@@ -3289,7 +3289,19 @@ EXPORT_SYMBOL(skb_split);
*/
static int skb_prepare_for_shift(struct sk_buff *skb)
{
return skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
int ret = 0;
if (skb_cloned(skb)) {
/* Save and restore truesize: pskb_expand_head() may reallocate
* memory where ksize(kmalloc(S)) != ksize(kmalloc(S)), but we
* cannot change truesize at this point.
*/
unsigned int save_truesize = skb->truesize;
ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
skb->truesize = save_truesize;
}
return ret;
}
/**