Re: [PATCH] net: skb: introduce kfree_skb_reason()

On Thu,  6 Jan 2022 14:36:26 +0800 Menglong Dong wrote:

Introduce the interface kfree_skb_reason(), which is able to pass
the reason why the skb is dropped to 'kfree_skb' tracepoint.

Add the 'reason' field to 'trace_kfree_skb', therefor user can get
more detail information about abnormal skb with 'drop_monitor' or
eBPF.

All drop reasons are defined in the enum 'skb_drop_reason', and
they will be print as string in 'kfree_skb' tracepoint in format
of 'reason: XXX'.

( Maybe the reasons should be defined in a uapi header file, so that
user space can use them? )

Since these drops are hardly hot path, why not simply use a string ?
An ENUM will not really help grep games.

tcp_drop(sk, skb, "csum error");


can refer to the previous discussion: https://lkml.org/lkml/2021/8/25/613