On Tue, May 3, 2022 at 4:40 AM <patchwork-bot+netdevbpf@xxxxxxxxxx> wrote: > > Hello: > > This patch was applied to netdev/net.git (master) > by Paolo Abeni <pabeni@xxxxxxxxxx>: > > On Mon, 2 May 2022 10:40:18 +0900 you wrote: > > syzbot is reporting use-after-free read in tcp_retransmit_timer() [1], > > for TCP socket used by RDS is accessing sock_net() without acquiring a > > refcount on net namespace. Since TCP's retransmission can happen after > > a process which created net namespace terminated, we need to explicitly > > acquire a refcount. > > > > Link: https://syzkaller.appspot.com/bug?extid=694120e1002c117747ed [1] > > Reported-by: syzbot <syzbot+694120e1002c117747ed@xxxxxxxxxxxxxxxxxxxxxxxxx> > > Fixes: 26abe14379f8e2fa ("net: Modify sk_alloc to not reference count the netns of kernel sockets.") > > Fixes: 8a68173691f03661 ("net: sk_clone_lock() should only do get_net() if the parent is not a kernel socket") > > Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> > > Tested-by: syzbot <syzbot+694120e1002c117747ed@xxxxxxxxxxxxxxxxxxxxxxxxx> > > > > [...] > > Here is the summary with links: > - [v2] net: rds: acquire refcount on TCP sockets > https://git.kernel.org/netdev/net/c/3a58f13a881e > > You are awesome, thank you! > -- > Deet-doot-dot, I am a bot. > https://korg.docs.kernel.org/patchwork/pwbot.html > > I think we merged this patch too soon. My question is : What prevents rds_tcp_conn_path_connect(), and thus rds_tcp_tune() to be called after the netns refcount already reached 0 ? I guess we can wait for next syzbot report, but I think that get_net() should be replaced by maybe_get_net()
