* [PATCH net] net: refine debug info in skb_checksum_help()
@ 2023-10-06 17:33 Eric Dumazet
2023-10-07 8:53 ` Willem de Bruijn
2023-10-10 2:50 ` patchwork-bot+netdevbpf
0 siblings, 2 replies; 3+ messages in thread
From: Eric Dumazet @ 2023-10-06 17:33 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: netdev, eric.dumazet, Eric Dumazet, Willem de Bruijn
syzbot uses panic_on_warn.
This means that the skb_dump() I added in the blamed commit are
not even called.
Rewrite this so that we get the needed skb dump before syzbot crashes.
Fixes: eeee4b77dc52 ("net: add more debug info in skb_checksum_help()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Willem de Bruijn <willemb@google.com>
---
net/core/dev.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 85df22f05c38b663f050410b9f7bcd32dd781951..5aaf5753d4e46c7c4b67b00daadeda9784708dfe 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3292,15 +3292,19 @@ int skb_checksum_help(struct sk_buff *skb)
offset = skb_checksum_start_offset(skb);
ret = -EINVAL;
- if (WARN_ON_ONCE(offset >= skb_headlen(skb))) {
+ if (unlikely(offset >= skb_headlen(skb))) {
DO_ONCE_LITE(skb_dump, KERN_ERR, skb, false);
+ WARN_ONCE(true, "offset (%d) >= skb_headlen() (%u)\n",
+ offset, skb_headlen(skb));
goto out;
}
csum = skb_checksum(skb, offset, skb->len - offset, 0);
offset += skb->csum_offset;
- if (WARN_ON_ONCE(offset + sizeof(__sum16) > skb_headlen(skb))) {
+ if (unlikely(offset + sizeof(__sum16) > skb_headlen(skb))) {
DO_ONCE_LITE(skb_dump, KERN_ERR, skb, false);
+ WARN_ONCE(true, "offset+2 (%zu) > skb_headlen() (%u)\n",
+ offset + sizeof(__sum16), skb_headlen(skb));
goto out;
}
ret = skb_ensure_writable(skb, offset + sizeof(__sum16));
--
2.42.0.609.gbb76f46606-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net] net: refine debug info in skb_checksum_help()
2023-10-06 17:33 [PATCH net] net: refine debug info in skb_checksum_help() Eric Dumazet
@ 2023-10-07 8:53 ` Willem de Bruijn
2023-10-10 2:50 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: Willem de Bruijn @ 2023-10-07 8:53 UTC (permalink / raw)
To: Eric Dumazet
Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, netdev,
eric.dumazet, Willem de Bruijn
On Fri, Oct 6, 2023 at 12:34 PM Eric Dumazet <edumazet@google.com> wrote:
>
> syzbot uses panic_on_warn.
>
> This means that the skb_dump() I added in the blamed commit are
> not even called.
>
> Rewrite this so that we get the needed skb dump before syzbot crashes.
>
> Fixes: eeee4b77dc52 ("net: add more debug info in skb_checksum_help()")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net] net: refine debug info in skb_checksum_help()
2023-10-06 17:33 [PATCH net] net: refine debug info in skb_checksum_help() Eric Dumazet
2023-10-07 8:53 ` Willem de Bruijn
@ 2023-10-10 2:50 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+netdevbpf @ 2023-10-10 2:50 UTC (permalink / raw)
To: Eric Dumazet; +Cc: davem, kuba, pabeni, netdev, eric.dumazet, willemb
Hello:
This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:
On Fri, 6 Oct 2023 17:33:54 +0000 you wrote:
> syzbot uses panic_on_warn.
>
> This means that the skb_dump() I added in the blamed commit are
> not even called.
>
> Rewrite this so that we get the needed skb dump before syzbot crashes.
>
> [...]
Here is the summary with links:
- [net] net: refine debug info in skb_checksum_help()
https://git.kernel.org/netdev/net/c/26c29961b142
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-10-06 17:33 [PATCH net] net: refine debug info in skb_checksum_help() Eric Dumazet
2023-10-07 8:53 ` Willem de Bruijn
2023-10-10 2:50 ` patchwork-bot+netdevbpf
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