[PATCH] if_xl: Fix a possible sleep-under-mutex bug in xl_list_rx_init

[Jia-Ju Bai]

The driver may sleep under a mutex, and the code path is:
xl_resume [acquire the mutex]
  xl_init_locked
    xl_list_rx_init
      bus_dmamap_create(BUS_DMA_WAITOK) --> 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 at 163.com>
---
 sys/dev/xl/if_xl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/dev/xl/if_xl.c b/sys/dev/xl/if_xl.c
index 4c1c238981d..59b29ddc7ca 100644
--- a/sys/dev/xl/if_xl.c
+++ b/sys/dev/xl/if_xl.c
@@ -1726,7 +1726,7 @@ xl_list_rx_init(struct xl_softc *sc)
 
 	for (i = 0; i < XL_RX_LIST_CNT; i++) {
 		cd->xl_rx_chain[i].xl_ptr = &ld->xl_rx_list[i];
-		error = bus_dmamap_create(sc->xl_mtag, 0,
+		error = bus_dmamap_create(sc->xl_mtag, BUS_DMA_NOWAIT,
 		    &cd->xl_rx_chain[i].xl_map);
 		if (error)
 			return (error);
-- 
2.13.0