Message ID | 1358967548-25491-1-git-send-email-paul.gortmaker@windriver.com |
---|---|
State | New, archived |
Headers | show |
On Wed, 2013-01-23 at 13:59 -0500, Paul Gortmaker wrote: > Here is the output from an mpc8548 based board. There are > three instances of missing device name here: A similar fix is already in the linux-mtd.git tree.
On 13-02-04 03:05 AM, Artem Bityutskiy wrote: > On Wed, 2013-01-23 at 13:59 -0500, Paul Gortmaker wrote: >> Here is the output from an mpc8548 based board. There are >> three instances of missing device name here: > > A similar fix is already in the linux-mtd.git tree. OK, I see it in linux-next for 3.9 (commit 7dfe4be351e816) but it needs to get to mainline/Linus before 3.8 gets released, since that is where the regression is introduced (and that is why I ended up not seeing the fix, and redoing it, as I was working off of mainline). $ git describe --contains d68cbdd4fb v3.8-rc1~47^2~53 Thanks, Paul. >
diff --git a/drivers/mtd/maps/physmap_of.c b/drivers/mtd/maps/physmap_of.c index 67cc73c..a70c1c4 100644 --- a/drivers/mtd/maps/physmap_of.c +++ b/drivers/mtd/maps/physmap_of.c @@ -170,7 +170,7 @@ static int of_flash_probe(struct platform_device *dev) resource_size_t res_size; struct mtd_part_parser_data ppdata; bool map_indirect; - const char *mtd_name; + const char *mtd_name = NULL; match = of_match_device(of_flash_match, &dev->dev); if (!match) @@ -237,7 +237,8 @@ static int of_flash_probe(struct platform_device *dev) goto err_out; } - info->list[i].map.name = mtd_name ?: dev_name(&dev->dev); + info->list[i].map.name = mtd_name ? + mtd_name : dev_name(&dev->dev); info->list[i].map.phys = res.start; info->list[i].map.size = res_size; info->list[i].map.bankwidth = be32_to_cpup(width);
Here is the output from an mpc8548 based board. There are three instances of missing device name here: 1 |: Found 4 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x008989 Chip ID 0x001818 2 |Intel/Sharp Extended Query Table at 0x0031 3 |Intel/Sharp Extended Query Table at 0x0031 4 |Using buffer write method 5 |cfi_cmdset_0001: Erase suspend on write enabled 6 |2 ofpart partitions found on MTD device 7 |Creating 2 MTD partitions on "": 8 |0x000000000000-0x000003f00000 : "space" 9 |0x000003f00000-0x000004000000 : "bootloader" Lines 1 (BOL), 6 (EOL) and 7 (inside quotes) have the missing device name issue. Problem introduced with commit d68cbdd4fb04d2b756ad53c22f36943167b16340 "mtd: physmap_of: allow to specify the mtd name for retro compatiblity" There are actually two bugs here. The 1st is that mtd_name is on the stack and never initialized. It uses a call to of_property_read_string() to get the pointer. However this function is explicitly documented as saying that the char "...pointer is modified only if a valid string can be decoded." Hence it isn't NULL, and we use a pointer off in the weeds as the device name, leading to undefined behaviour. The second issue is in the NULL check itself. It uses a "?" operator to choose between mtd_name and the devicetree based name. But the operator isn't given two choices. One choice (mtd_name) is missing from the RHS of the "?". With these fixed, the output appears as follows: 1 |fc000000.flash: Found 4 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x008989 Chip ID 0x001818 2 |Intel/Sharp Extended Query Table at 0x0031 3 |Intel/Sharp Extended Query Table at 0x0031 4 |Using buffer write method 5 |cfi_cmdset_0001: Erase suspend on write enabled 6 |2 ofpart partitions found on MTD device fc000000.flash 7 |Creating 2 MTD partitions on "fc000000.flash": 8 |0x000000000000-0x000003f00000 : "space" 9 |0x000003f00000-0x000004000000 : "bootloader" All the names are now appearing where they should be. Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- [Introduced into mainline at v3.8-rc1~47 ; hence no need for stable Cc] drivers/mtd/maps/physmap_of.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)