Date: Mon, 19 Jun 2017 09:51:19 +0800 From: Jia-Ju Bai <baijiaju1990@163.com> To: freebsdraid@lsi.com Cc: freebsd-drivers@freebsd.org, freebsd-bugs@freebsd.org, freebsd-hackers@freebsd.org, Jia-Ju Bai <baijiaju1990@163.com> Subject: [PATCH] tws: Fix a possible sleep-under-mutex bug in tws_init_reqs Message-ID: <20170619015119.43883-1-baijiaju1990@163.com>
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The driver may sleep under a mutex, and the code path is:
tws_init_reqs [line 684: acquire the mutex]
tws_init_reqs [line 685]
bus_dmamap_create(BUS_DMA_WAITOK) [line 687] --> may sleep
The possible fix of this bug is to replace "BUS_DMA_WAITOK" in bus_dmamap_create with "BUS_DMA_NOWAIT".
This bug is found by a static analysis tool written by myself, and it is
checked by my review of the FreeBSD code.
Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
---
sys/dev/tws/tws.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/sys/dev/tws/tws.c b/sys/dev/tws/tws.c
index 480f6f95489..6d21a524f18 100644
--- a/sys/dev/tws/tws.c
+++ b/sys/dev/tws/tws.c
@@ -684,7 +684,8 @@ tws_init_reqs(struct tws_softc *sc, u_int32_t dma_mem_size)
mtx_lock(&sc->q_lock);
for ( i=0; i< tws_queue_depth; i++)
{
- if (bus_dmamap_create(sc->data_tag, 0, &sc->reqs[i].dma_map)) {
+ if (bus_dmamap_create(sc->data_tag, BUS_DMA_NOWAIT,
+ &sc->reqs[i].dma_map)) {
/* log a ENOMEM failure msg here */
mtx_unlock(&sc->q_lock);
return(FAILURE);
--
2.13.0
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