Commit 92a0acce authored by David S. Miller's avatar David S. Miller
Browse files

net: Kill skb_truesize_check(), it only catches false-positives. 



A long time ago we had bugs, primarily in TCP, where we would modify
skb->truesize (for TSO queue collapsing) in ways which would corrupt
the socket memory accounting.

skb_truesize_check() was added in order to try and catch this error
more systematically.

However this debugging check has morphed into a Frankenstein of sorts
and these days it does nothing other than catch false-positives.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 34edaa88

include/linux/skbuff.h

+0 −9
Original line number Diff line number Diff line
@@ -416,15 +416,6 @@ extern void skb_over_panic(struct sk_buff *skb, int len, 
				     void *here);

extern void	      skb_under_panic(struct sk_buff *skb, int len,

				      void *here);

extern void	      skb_truesize_bug(struct sk_buff *skb);



static inline void skb_truesize_check(struct sk_buff *skb)

{

	int len = sizeof(struct sk_buff) + skb->len;



	if (unlikely((int)skb->truesize < len))

		skb_truesize_bug(skb);

}



extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,

			int getfrag(void *from, char *to, int offset,

include/net/sock.h

+0 −1
Original line number Diff line number Diff line
@@ -860,7 +860,6 @@ static inline void sk_mem_uncharge(struct sock *sk, int size) 


static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)

{

	skb_truesize_check(skb);

	sock_set_flag(sk, SOCK_QUEUE_SHRUNK);

	sk->sk_wmem_queued -= skb->truesize;

	sk_mem_uncharge(sk, skb->truesize);

net/core/skbuff.c

+0 −8
Original line number Diff line number Diff line
@@ -143,14 +143,6 @@ void skb_under_panic(struct sk_buff *skb, int sz, void *here) 
	BUG();

}



void skb_truesize_bug(struct sk_buff *skb)

{

	WARN(net_ratelimit(), KERN_ERR "SKB BUG: Invalid truesize (%u) "

	       "len=%u, sizeof(sk_buff)=%Zd\n",

	       skb->truesize, skb->len, sizeof(struct sk_buff));

}

EXPORT_SYMBOL(skb_truesize_bug);



/* 	Allocate a new skbuff. We do this ourselves so we can fill in a few

 *	'private' fields and also do memory statistics to find all the

 *	[BEEP] leaks.

net/core/sock.c

+0 −1
Original line number Diff line number Diff line
@@ -1137,7 +1137,6 @@ void sock_rfree(struct sk_buff *skb) 
{

	struct sock *sk = skb->sk;



	skb_truesize_check(skb);

	atomic_sub(skb->truesize, &sk->sk_rmem_alloc);

	sk_mem_uncharge(skb->sk, skb->truesize);

}

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