net: cadence: Fix a sleep-in-atomic-context bug in macb_halt_tx()

BugLink: https://bugs.launchpad.net/bugs/1836426
[ Upstream commit 16fe10cf92783ed9ceb182d6ea2b8adf5e8ec1b8 ]

The kernel module may sleep with holding a spinlock.

The function call paths (from bottom to top) in Linux-4.16 are:

[FUNC] usleep_range
drivers/net/ethernet/cadence/macb_main.c, 648:
	usleep_range in macb_halt_tx
drivers/net/ethernet/cadence/macb_main.c, 730:
	macb_halt_tx in macb_tx_error_task
drivers/net/ethernet/cadence/macb_main.c, 721:
	_raw_spin_lock_irqsave in macb_tx_error_task

To fix this bug, usleep_range() is replaced with udelay().

This bug is found by my static analysis tool DSAC.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 2bf22f21e0266e64cb35d15e158cbe388e3f8d8c..df22247cb5644dc1676461c3e5f0d8af006b978b 100644 (file)
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -645,7 +645,7 @@ static int macb_halt_tx(struct macb *bp)
                if (!(status & MACB_BIT(TGO)))
                        return 0;
 
-               usleep_range(10, 250);
+               udelay(250);
        } while (time_before(halt_time, timeout));
 
        return -ETIMEDOUT;