Re: [syzbot] [can?] WARNING: refcount bug in j1939_session_put

From: Edward Adam Davis
Date: Wed Aug 07 2024 - 04:42:54 EST


Fixes: c9c0ee5f20c5 ("net: skbuff: Skip early return in skb_unref when debugging")

Root cause: In commit c9c0ee5f20c5, There are following rules:
In debug builds (CONFIG_DEBUG_NET set), the reference count is always decremented, even when it's 1

This rule will cause the reference count to be 0 after calling skc_unref,
which will affect the release of skb.

#syz test: upstream master