[U-Boot] [PATCH v2] cmd: usb_mass_storage: add protection for block_dev

[Patrick Delaunay]

solve data abort for the command "ums 0 ubi 0"
because result of case blk_get_device_part_str() result is OK
but with block_dev = 0 when CONFIG_CMD_UBIFS is activate and
ubi volume is mounted

Signed-off-by: Patrick Delaunay <patrick.delaunay at st.com>
---
I check and the issue is still present on U-Boot v2018.09,
on my board stm32mp1 (with NAND device and UBI volume):

STM32MP> ubi part UBI
STM32MP> ubifsmount ubi0:boot
STM32MP> ums 0 ubi 0
data abort
pc : [<ffc60abc>]	   lr : [<ffc60ab3>]
reloc pc : [<c0110abc>]	   lr : [<c0110ab3>]
sp : fdc3e460  ip : fdc3e518	 fp : fdcf06a8
r10: fdcf06b8  r9 : fdc4eed8	 r8 : 00000000
r7 : ffce3d84  r6 : fdcf0740	 r5 : fdcf0740  r4 : ffce3d88
r3 : 00000000  r2 : 00000000	 r1 : 0000003a  r0 : 00000000
Flags: nZCv  IRQs off  FIQs off  Mode SVC_32
Code: f04f4628 9b06fd2a bf082800 0800f04f (f5b3695b) Resetting CPU ...

Even If the command is invalid (ums not allowed on ubi device),
the data abort can be avoid by this patch.


Changes in v2:
    - Rebase on master branch

 cmd/usb_mass_storage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmd/usb_mass_storage.c b/cmd/usb_mass_storage.c
index 26b41b4c4..a3a338c 100644
--- a/cmd/usb_mass_storage.c
+++ b/cmd/usb_mass_storage.c
@@ -85,7 +85,7 @@ static int ums_init(const char *devtype, const char *devnums_part_str)
 			partnum = 0;
 
 		/* f_mass_storage.c assumes SECTOR_SIZE sectors */
-		if (block_dev->blksz != SECTOR_SIZE)
+		if (!block_dev || block_dev->blksz != SECTOR_SIZE)
 			goto cleanup;
 
 		ums_new = realloc(ums, (ums_count + 1) * sizeof(*ums));
-- 
2.7.4