tree 2a4b0dc2da7c65711221ad99347f969bcf0edcdd
parent 625637bf4afa45204bd87e4218645182a919485a
author Xin Long <lucien.xin@gmail.com> 1516006896 +0800
committer David S. Miller <davem@davemloft.net> 1516130571 -0500

sctp: return error if the asoc has been peeled off in sctp_wait_for_sndbuf

After commit cea0cc80a677 ("sctp: use the right sk after waking up from
wait_buf sleep"), it may change to lock another sk if the asoc has been
peeled off in sctp_wait_for_sndbuf.

However, the asoc's new sk could be already closed elsewhere, as it's in
the sendmsg context of the old sk that can't avoid the new sk's closing.
If the sk's last one refcnt is held by this asoc, later on after putting
this asoc, the new sk will be freed, while under it's own lock.

This patch is to revert that commit, but fix the old issue by returning
error under the old sk's lock.

Fixes: cea0cc80a677 ("sctp: use the right sk after waking up from wait_buf sleep")
Reported-by: syzbot+ac6ea7baa4432811eb50@syzkaller.appspotmail.com
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>