This patch makes the truesize warning be printed when the truesize

actually changed, not just when the header was increased and the

additional size actually used.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>

Cc: Herbert Xu <herbert@gondor.apana.org.au>

---

It'll trigger with mac80211, should hold it until I fixed that.
 include/linux/skbuff.h |    8 ++++++--

 net/core/skbuff.c      |   10 ++++++++--

 2 files changed, 14 insertions(+), 4 deletions(-)
--- everything.orig/include/linux/skbuff.h	2008-05-03 15:47:00.000000000 +0200

+++ everything/include/linux/skbuff.h	2008-05-04 00:30:34.000000000 +0200

@@ -387,9 +387,13 @@ extern void	      skb_truesize_bug(struc
 static inline void skb_truesize_check(struct sk_buff *skb)

 {

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

+#ifdef NET_SKBUFF_DATA_USES_OFFSET

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

+#else

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

+#endif
-	if (unlikely((int)skb->truesize < len))

+	if (unlikely((int)skb->truesize != len))

 		skb_truesize_bug(skb);

 }
--- everything.orig/net/core/skbuff.c	2008-05-03 16:29:23.000000000 +0200

+++ everything/net/core/skbuff.c	2008-05-04 00:31:32.000000000 +0200

@@ -151,9 +151,15 @@ void skb_under_panic(struct sk_buff *skb
 void skb_truesize_bug(struct sk_buff *skb)

 {

+#ifdef NET_SKBUFF_DATA_USES_OFFSET

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

+#else

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

+#endif

+

 	printk(KERN_ERR "SKB BUG: Invalid truesize (%u) "

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

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

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

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

 }

 EXPORT_SYMBOL(skb_truesize_bug);
--

Umm, is this even correct? Should it check data_len? I seem to get the

truesize warning a bit now:
[11381.081709] SKB BUG: Invalid truesize (16864) size=3D4112, sizeof(sk_buf=

f)=3D272

[11381.081725] last reallocate at:

[11381.081729]  [<c0274194>] __alloc_skb+0xdc/0x140

[11381.081745]  [<c02aeca8>] sk_stream_alloc_skb+0x38/0x134

[11381.081758]  [<c02af16c>] tcp_sendmsg+0x3c8/0xcbc

[11381.081767]  [<c026bcc4>] sock_sendmsg+0xac/0xe4

[11381.081780]  [<c026c058>] sys_sendto+0xbc/0xec

[11381.081790]  [<c026cbc8>] sys_socketcall+0x14c/0x1dc

[11381.081800]  [<c00124cc>] ret_from_syscall+0x0/0x38
johannes

It must check data_len.
Cheers,

--

Visit Openswan at http://www.openswan.org/

Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>

Home Page: http://gondor.apana.org.au/~herbert/

PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

--

I figured. Just add it?
johannes

With all the patches I posted it now no longer triggers with mac80211

but within netlink, e.g.:
[  152.607800] SKB BUG: Invalid truesize (556) size=560, sizeof(sk_buff)=272

[  152.607805] last reallocate at:

[  152.607807]  [<00000000>] 0x0

[  152.607822]  [<c02735ec>] pskb_expand_head+0xa4/0x1f8

[  152.607828]  [<c0296a9c>] netlink_broadcast+0xb0/0x42c

[  152.607834]  [<c0297680>] nlmsg_notify+0x4c/0xc8

[  152.607838]  [<c0287518>] rtnl_notify+0x30/0x40

[  152.607843]  [<c0320e68>] wireless_nlevent_process+0x28/0x60

[  152.607851]  [<c0035058>] tasklet_action+0x74/0xec

[  152.607858]  [<c0035964>] __do_softirq+0x8c/0xfc

[  152.607863]  [<c0006e40>] do_softirq+0x58/0x5c

[  152.607869]  [<c0035738>] ksoftirqd+0x7c/0x178

[  152.607874]  [<c0047944>] kthread+0x50/0x88

[  152.607879]  [<c0012310>] kernel_thread+0x44/0x60
below patch helps debug it, but I can't fix it all right now.
It most likely is a consequence of pskb_expand_head() not updating

truesize and some, but not all, callers doing it. IMHO pskb_expand_head

should do it and those callers that do it be changed to not (afaik it's

afpacket or something and mac80211 now)
johannes
---

 include/linux/skbuff.h |   12 ++++++++++++

 kernel/stacktrace.c    |    3 +++

 net/Kconfig            |   12 ++++++++++++

 net/core/skbuff.c      |   37 +++++++++++++++++++++++++++++++++++++

 4 files changed, 64 insertions(+)
--- everything.orig/include/linux/skbuff.h	2008-05-04 23:31:31.000000000 +0200

+++ everything/include/linux/skbuff.h	2008-05-04 23:35:21.000000000 +0200

@@ -28,6 +28,7 @@

 #include <linux/rcupdate.h>

 #include <linux/dmaengine.h>

 #include <linux/hrtimer.h>

+#include <linux/stacktrace.h>
 #define HAVE_ALLOC_SKB		/* For the drivers to know */

 #define HAVE_ALIGNABLE_SKB	/* Ditto 8)		   */

@@ -188,6 +189,8 @@ enum {

 #define NET_SKBUFF_DATA_USES_OFFSET 1

 #endif
+#define NET_SKBUFF_STACKTRACE_ENTRIES	20

...
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