From: Mark Mielke mark.mielke@gmail.com
commit bcf3a2953d36bbfb9bd44ccb3db0897d935cc485 upstream.
The kernel may fail to boot or devices may fail to come up when initializing iscsi_tcp devices starting with Linux 5.8.
Commit a79af8a64d39 ("[SCSI] iscsi_tcp: use iscsi_conn_get_addr_param libiscsi function") introduced getpeername() within the session spinlock.
Commit 1b66d253610c ("bpf: Add get{peer, sock}name attach types for sock_addr") introduced BPF_CGROUP_RUN_SA_PROG_LOCK() within getpeername(), which acquires a mutex and when used from iscsi_tcp devices can now lead to "BUG: scheduling while atomic:" and subsequent damage.
Ensure that the spinlock is released before calling getpeername() or getsockname(). sock_hold() and sock_put() are used to ensure that the socket reference is preserved until after the getpeername() or getsockname() complete.
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1877345 Link: https://lkml.org/lkml/2020/7/28/1085 Link: https://lkml.org/lkml/2020/8/31/459 Link: https://lore.kernel.org/r/20200928043329.606781-1-mark.mielke@gmail.com Fixes: a79af8a64d39 ("[SCSI] iscsi_tcp: use iscsi_conn_get_addr_param libiscsi function") Fixes: 1b66d253610c ("bpf: Add get{peer, sock}name attach types for sock_addr") Cc: stable@vger.kernel.org Reported-by: Marc Dionne marc.c.dionne@gmail.com Tested-by: Marc Dionne marc.c.dionne@gmail.com Reviewed-by: Mike Christie michael.christie@oracle.com Signed-off-by: Mark Mielke mark.mielke@gmail.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/scsi/iscsi_tcp.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-)
--- a/drivers/scsi/iscsi_tcp.c +++ b/drivers/scsi/iscsi_tcp.c @@ -736,6 +736,7 @@ static int iscsi_sw_tcp_conn_get_param(s struct iscsi_tcp_conn *tcp_conn = conn->dd_data; struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data; struct sockaddr_in6 addr; + struct socket *sock; int rc;
switch(param) { @@ -747,13 +748,17 @@ static int iscsi_sw_tcp_conn_get_param(s spin_unlock_bh(&conn->session->frwd_lock); return -ENOTCONN; } + sock = tcp_sw_conn->sock; + sock_hold(sock->sk); + spin_unlock_bh(&conn->session->frwd_lock); + if (param == ISCSI_PARAM_LOCAL_PORT) - rc = kernel_getsockname(tcp_sw_conn->sock, + rc = kernel_getsockname(sock, (struct sockaddr *)&addr); else - rc = kernel_getpeername(tcp_sw_conn->sock, + rc = kernel_getpeername(sock, (struct sockaddr *)&addr); - spin_unlock_bh(&conn->session->frwd_lock); + sock_put(sock->sk); if (rc < 0) return rc;
@@ -775,6 +780,7 @@ static int iscsi_sw_tcp_host_get_param(s struct iscsi_tcp_conn *tcp_conn; struct iscsi_sw_tcp_conn *tcp_sw_conn; struct sockaddr_in6 addr; + struct socket *sock; int rc;
switch (param) { @@ -789,16 +795,18 @@ static int iscsi_sw_tcp_host_get_param(s return -ENOTCONN; } tcp_conn = conn->dd_data; - tcp_sw_conn = tcp_conn->dd_data; - if (!tcp_sw_conn->sock) { + sock = tcp_sw_conn->sock; + if (!sock) { spin_unlock_bh(&session->frwd_lock); return -ENOTCONN; } + sock_hold(sock->sk); + spin_unlock_bh(&session->frwd_lock);
- rc = kernel_getsockname(tcp_sw_conn->sock, + rc = kernel_getsockname(sock, (struct sockaddr *)&addr); - spin_unlock_bh(&session->frwd_lock); + sock_put(sock->sk); if (rc < 0) return rc;