Re: [PATCH] RDMA/nldev: add mutual exclusion in nldev_dellink()

[Edward Adam Davis]

On Thu, 7 May 2026 06:25:54 -0700, Zhu Yanjun wrote:
> > We must serialize calls to nldev_dellink() or risk a crash as syzbot
> > reported:
> >
> > KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
> > Call Trace:
> >   udp_tunnel_sock_release+0x6d/0x80 net/ipv4/udp_tunnel_core.c:197
> >   rxe_release_udp_tunnel drivers/infiniband/sw/rxe/rxe_net.c:294 [inline]
> >   rxe_sock_put drivers/infiniband/sw/rxe/rxe_net.c:639 [inline]
> >   rxe_net_del+0xfb/0x290 drivers/infiniband/sw/rxe/rxe_net.c:660
> >   rxe_dellink+0x15/0x20 drivers/infiniband/sw/rxe/rxe.c:254
> >
> > Fixes: a60e3f3d6fba ("RDMA/nldev: Add dellink function pointer")
> > Reported-by: syzbot+d8f76778263ab65c2b21@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Closes: https://syzkaller.appspot.com/bug?extid=d8f76778263ab65c2b21
> > Tested-by: syzbot+d8f76778263ab65c2b21@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
> 
> Thanks a lot. This looks like a good solution. Since the issue is
> reproducible,
> 
> have you sent this commit to syzbot for verification?
The patch has been verified by syzbot.

BR,
Edward