Subject: [PATCH AUTOSEL 4.19 55/84] cxgb4: Fix kernel panic while accessing sge_info

From: Sasha Levin <[email-masked]>
Date: Fri, 27 Dec 2019 12:43:23 -0500

From: Vishal Kulkarni <[email-masked]>

[ Upstream commit 479a0d1376f6d97c60871442911f1394d4446a25 ]

The sge_info debugfs collects offload queue info even when offload
capability is disabled and leads to panic.

[  144.139871] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  144.139874] CR2: 0000000000000000 CR3: 000000082d456005 CR4: 00000000001606e0
[  144.139876] Call Trace:
[  144.139887]  sge_queue_start+0x12/0x30 [cxgb4]
[  144.139897]  seq_read+0x1d4/0x3d0
[  144.139906]  full_proxy_read+0x50/0x70
[  144.139913]  vfs_read+0x89/0x140
[  144.139916]  ksys_read+0x55/0xd0
[  144.139924]  do_syscall_64+0x5b/0x1d0
[  144.139933]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  144.139936] RIP: 0033:0x7f4b01493990

Fix this crash by skipping the offload queue access in sge_qinfo when
offload capability is disabled

Signed-off-by: Herat Ramani <[email-masked]>
Signed-off-by: Vishal Kulkarni <[email-masked]>
Signed-off-by: Jakub Kicinski <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
index b429b726b987..d320e9afab88 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
@@ -3035,6 +3035,9 @@ static int sge_queue_entries(const struct adapter *adap)
 	int tot_uld_entries = 0;
 	int i;
 
+	if (!is_uld(adap))
+		goto lld_only;
+
 	mutex_lock(&uld_mutex);
 	for (i = 0; i < CXGB4_TX_MAX; i++)
 		tot_uld_entries += sge_qinfo_uld_txq_entries(adap, i);
@@ -3045,6 +3048,7 @@ static int sge_queue_entries(const struct adapter *adap)
 	}
 	mutex_unlock(&uld_mutex);
 
+lld_only:
 	return DIV_ROUND_UP(adap->sge.ethqsets, 4) +
 	       tot_uld_entries +
 	       DIV_ROUND_UP(MAX_CTRL_QUEUES, 4) + 1;
-- 
2.20.1