* [PATCH] staging: dgnc: Fix a sleep-in-atomic-context bug in cls_assert_modem_signals()
@ 2018-09-15 3:13 Jia-Ju Bai
0 siblings, 0 replies; only message in thread
From: Jia-Ju Bai @ 2018-09-15 3:13 UTC (permalink / raw)
To: lidza.louina, markh, gregkh
Cc: driverdev-devel, devel, linux-kernel, Jia-Ju Bai
The driver may sleep with holding a spinlock.
The function call path (from bottom to top) in Linux-4.17 is:
[FUNC] usleep_range
drivers/staging/dgnc/dgnc_cls.c, 391:
usleep_range in cls_assert_modem_signals
drivers/staging/dgnc/dgnc_cls.c, 449:
cls_assert_modem_signals in cls_copy_data_from_queue_to_uart
drivers/staging/dgnc/dgnc_cls.c, 406:
_raw_spin_lock_irqsave in cls_copy_data_from_queue_to_uart
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>
---
drivers/staging/dgnc/dgnc_cls.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/staging/dgnc/dgnc_cls.c b/drivers/staging/dgnc/dgnc_cls.c
index 7e6cbfe4e4ee..a1e98ee7f9e0 100644
--- a/drivers/staging/dgnc/dgnc_cls.c
+++ b/drivers/staging/dgnc/dgnc_cls.c
@@ -388,7 +388,7 @@ static void cls_assert_modem_signals(struct channel_t *ch)
writeb(out, &ch->ch_cls_uart->mcr);
/* Give time for the UART to actually drop the signals */
- usleep_range(10, 20);
+ udelay(20);
}
static void cls_copy_data_from_queue_to_uart(struct channel_t *ch)
--
2.17.0
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2018-09-15 3:13 [PATCH] staging: dgnc: Fix a sleep-in-atomic-context bug in cls_assert_modem_signals() Jia-Ju Bai
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