[PATCH 4.4 59/62] bnxt: dont enable NAPI until rings are ready

Greg Kroah-Hartman
2020-09-11T17:28:32Z

From: Jakub Kicinski <kuba@kernel.org>

commit 96ecdcc992eb7f468b2cf829b0f5408a1fad4668 upstream.

Netpoll can try to poll napi as soon as napi_enable() is called.
It crashes trying to access a doorbell which is still NULL:

BUG: kernel NULL pointer dereference, address: 0000000000000000
CPU: 59 PID: 6039 Comm: ethtool Kdump: loaded Tainted: G S 5.9.0-rc1-00469-g5fd99b5d9950-dirty #26
RIP: 0010:bnxt_poll+0x121/0x1c0
Code: c4 20 44 89 e0 5b 5d 41 5c 41 5d 41 5e 41 5f c3 41 8b 86 a0 01 00 00 41 23 85 18 01 00 00 49 8b 96 a8 01 00 00 0d 00 00 00 24 <89> 02
41 f6 45 77 02 74 cb 49 8b ae d8 01 00 00 31 c0 c7 44 24 1a
netpoll_poll_dev+0xbd/0x1a0
__netpoll_send_skb+0x1b2/0x210
netpoll_send_udp+0x2c9/0x406
write_ext_msg+0x1d7/0x1f0
console_unlock+0x23c/0x520
vprintk_emit+0xe0/0x1d0
printk+0x58/0x6f
x86_vector_activate.cold+0xf/0x46
__irq_domain_activate_irq+0x50/0x80
__irq_domain_activate_irq+0x32/0x80
__irq_domain_activate_irq+0x32/0x80
irq_domain_activate_irq+0x25/0x40
__setup_irq+0x2d2/0x700
request_threaded_irq+0xfb/0x160
__bnxt_open_nic+0x3b1/0x750
bnxt_open_nic+0x19/0x30
ethtool_set_channels+0x1ac/0x220
dev_ethtool+0x11ba/0x2240
dev_ioctl+0x1cf/0x390
sock_do_ioctl+0x95/0x130

Reported-by: Rob Sherwood <rsher@fb.com>
Fixes: c0c050c58d84 ("bnxt_en: New Broadcom ethernet driver.")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/ethernet/broadcom/bnxt/bnxt.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -4612,14 +4612,14 @@ static int __bnxt_open_nic(struct bnxt *
}
}

- bnxt_enable_napi(bp);
-
rc = bnxt_init_nic(bp, irq_re_init);
if (rc) {
netdev_err(bp->dev, "bnxt_init_nic err: %x\n", rc);
- goto open_err;
+ goto open_err_irq;
}

+ bnxt_enable_napi(bp);
+
if (link_re_init) {
rc = bnxt_update_phy_setting(bp);
if (rc)
@@ -4644,9 +4644,6 @@ static int __bnxt_open_nic(struct bnxt *

return 0;

-open_err:
- bnxt_disable_napi(bp);
-
open_err_irq:
bnxt_del_napi(bp);