Re: [U-Boot] [PATCH] w1: fix data abort if no one wire bus master present

On 22.10.2018 19:31, Martin Fuzzey wrote:

When the "w1 bus" command is used with no bus master present a data abort may occur.

This is because uclass_first_device() returns zero, but sets the output struct udevice pointer to NULL in the no device found case.

Fix w1_get_bus() to account for this and return an error code as is expected by the callers.

Signed-off-by: Martin Fuzzey martin.fuzzey@flowbird.group

drivers/w1/w1-uclass.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/w1/w1-uclass.c b/drivers/w1/w1-uclass.c index aecf7fe..cb41b68 100644 --- a/drivers/w1/w1-uclass.c +++ b/drivers/w1/w1-uclass.c @@ -115,17 +115,19 @@ int w1_get_bus(int busnum, struct udevice **busp) struct udevice *dev;

for (ret = uclass_first_device(UCLASS_W1, &dev);

•     !ret;
  

•     uclass_next_device(&dev), i++) {
  

• if (ret) {
  

• 	debug("Cannot find w1 bus %d\n", busnum);
  

• 	return ret;
  

• }
  

•     dev && !ret;
  

•     ret = uclass_next_device(&dev), i++) {
  

  if (i == busnum) { *busp = dev; return 0; } }
• if (!ret) {

Hi Martin,

Does this mean that if ret != 0 , we had errors, but we are not printing this debug message ? Perhaps we should print out here the debug error regardless of the ret value ? Since we exited with a return 0 if we did find the proper bus.

May I also ask on which board setup you tested this ? And which defconfig.

Thanks, Eugen

• debug("Cannot find w1 bus %d\n", busnum);
  

• ret = -ENODEV;
  

• }
• return ret; }