lkml.org 
[lkml]   [2020]   [Jan]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: WARNING in bpf_warn_invalid_xdp_action
From
Date


On 1/22/20 1:01 PM, syzbot wrote:
> syzbot has bisected this bug to:
>
> commit 58956317c8de52009d1a38a721474c24aef74fe7
> Author: David Ahern <dsahern@gmail.com>
> Date: Fri Dec 7 20:24:57 2018 +0000
>
> neighbor: Improve garbage collection
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=124a5985e00000
> start commit: d0f41851 net, ip_tunnel: fix namespaces move
> git tree: net
> final crash: https://syzkaller.appspot.com/x/report.txt?x=114a5985e00000
> console output: https://syzkaller.appspot.com/x/log.txt?x=164a5985e00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d9290aeb7e6cf1c4
> dashboard link: https://syzkaller.appspot.com/bug?extid=8ce4113dadc4789fac74
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11f99369e00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13d85601e00000
>
> Reported-by: syzbot+8ce4113dadc4789fac74@syzkaller.appspotmail.com
> Fixes: 58956317c8de ("neighbor: Improve garbage collection")
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>

bisection looks bogus...

It would be nice to have alternative helpers to conveniently replace some WARN_ON/WARN_ONCE/...
and not having to hand-code stuff like :

diff --git a/net/core/filter.c b/net/core/filter.c
index 538f6a735a19f017df8e10149cb578107ddc8cbb..633988f7c81b3b4f015d827ccb485e8b227ad20b 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6913,11 +6913,15 @@ static bool xdp_is_valid_access(int off, int size,

void bpf_warn_invalid_xdp_action(u32 act)
{
+ static bool __section(.data.once) warned;
const u32 act_max = XDP_REDIRECT;

- WARN_ONCE(1, "%s XDP return value %u, expect packet loss!\n",
- act > act_max ? "Illegal" : "Driver unsupported",
- act);
+ if (!warned) {
+ warned = true;
+ pr_err("%s XDP return value %u, expect packet loss!\n",
+ act > act_max ? "Illegal" : "Driver unsupported", act);
+ dump_stack();
+ }
}
EXPORT_SYMBOL_GPL(bpf_warn_invalid_xdp_action);
\
 
 \ /
  Last update: 2020-01-22 22:38    [W:0.093 / U:0.084 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site