[Bug 220094][PATCH] scsi_sa: Fix a possible sleep-under-mutex bug in saioctl

[Jia-Ju Bai]

The driver may sleep under a mutex, and the function call path is:
saioctl [acquire the mutex]
   saextget
     malloc(M_WAITOK) --> may sleep

The possible fix of this bug is to replace "M_WAITOK" in malloc with 
"M_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/cam/scsi/scsi_sa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/cam/scsi/scsi_sa.c b/sys/cam/scsi/scsi_sa.c
index 8a8451c3bce..b884bd3d65f 100644
--- a/sys/cam/scsi/scsi_sa.c
+++ b/sys/cam/scsi/scsi_sa.c
@@ -4465,7 +4465,7 @@ saextget(struct cdev *dev, struct cam_periph *periph, struct sbuf *sb,
 		if (cgd.serial_num_len > sizeof(tmpstr)) {
 			ts2_len = cgd.serial_num_len + 1;
 			ts2_malloc = 1;
-			tmpstr2 = malloc(ts2_len, M_SCSISA, M_WAITOK | M_ZERO);
+			tmpstr2 = malloc(ts2_len, M_SCSISA, M_NOWAIT | M_ZERO);
 		} else {
 			ts2_len = sizeof(tmpstr);
 			ts2_malloc = 0;
-- 
2.13.0