android/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Revert "net/sctp: fix race condition in sctp_destroy_sock"

Browse Source 
commit 01bfe5e8e428b475982a98a46cca5755726f3f7f upstream.

This reverts commit b166a20b07382b8bc1dcee2a448715c9c2c81b5b.

This one has to be reverted as it introduced a dead lock, as
syzbot reported:

       CPU0                    CPU1
       ----                    ----
  lock(&net->sctp.addr_wq_lock);
                               lock(slock-AF_INET6);
                               lock(&net->sctp.addr_wq_lock);
  lock(slock-AF_INET6);

CPU0 is the thread of sctp_addr_wq_timeout_handler(), and CPU1
is that of sctp_close().

The original issue this commit fixed will be fixed in the next
patch.

Reported-by: syzbot+959223586843e69a2674@syzkaller.appspotmail.com
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Xin Long 2021-05-03 05:11:41 +08:00 committed by Greg Kroah-Hartman
parent 41f1aed56d
commit 14919cdf68
1 changed files with 8 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
net/sctp/socket.c
View File

@ -1520,9 +1520,11 @@ static void sctp_close(struct sock *sk, long timeout)
/* Supposedly, no process has access to the socket, but /* Supposedly, no process has access to the socket, but
* the net layers still may. * the net layers still may.
* Also, sctp_destroy_sock() needs to be called with addr_wq_lock
* held and that should be grabbed before socket lock.
*/ */
local_bh_disable(); spin_lock_bh(&net->sctp.addr_wq_lock);
bh_lock_sock(sk); bh_lock_sock_nested(sk);
/* Hold the sock, since sk_common_release() will put sock_put() /* Hold the sock, since sk_common_release() will put sock_put()
* and we have just a little more cleanup. * and we have just a little more cleanup.
@ -1531,7 +1533,7 @@ static void sctp_close(struct sock *sk, long timeout)
sk_common_release(sk); sk_common_release(sk);
bh_unlock_sock(sk); bh_unlock_sock(sk);
local_bh_enable(); spin_unlock_bh(&net->sctp.addr_wq_lock);
sock_put(sk); sock_put(sk);
@ -4937,6 +4939,9 @@ static int sctp_init_sock(struct sock *sk)
sk_sockets_allocated_inc(sk); sk_sockets_allocated_inc(sk);
sock_prot_inuse_add(net, sk->sk_prot, 1); sock_prot_inuse_add(net, sk->sk_prot, 1);
/* Nothing can fail after this block, otherwise
* sctp_destroy_sock() will be called without addr_wq_lock held
*/
if (net->sctp.default_auto_asconf) { if (net->sctp.default_auto_asconf) {
spin_lock(&sock_net(sk)->sctp.addr_wq_lock); spin_lock(&sock_net(sk)->sctp.addr_wq_lock);
list_add_tail(&sp->auto_asconf_list, list_add_tail(&sp->auto_asconf_list,
@ -4971,9 +4976,7 @@ static void sctp_destroy_sock(struct sock *sk)
if (sp->do_auto_asconf) { if (sp->do_auto_asconf) {
sp->do_auto_asconf = 0; sp->do_auto_asconf = 0;
spin_lock_bh(&sock_net(sk)->sctp.addr_wq_lock);
list_del(&sp->auto_asconf_list); list_del(&sp->auto_asconf_list);
spin_unlock_bh(&sock_net(sk)->sctp.addr_wq_lock);
} }
sctp_endpoint_free(sp->ep); sctp_endpoint_free(sp->ep);
local_bh_disable(); local_bh_disable();