On Wednesday, July 13, 2016 11:41:50 AM CEST Jason Baron wrote:

Hi Arnd,

Ok, this is back in linux-next now (with hopefully a fix for arm). I was never able to quite reproduce the arm failure you saw. So if you get the chance to test this it would be great.

I've had a day's worth of randconfig tests without running into the problem so far.

However, I did get one new compiler warning that I have just bisected down to 21413cd0e4ed ("dynamic_debug: add jump label support"):

/git/arm-soc/drivers/media/dvb-frontends/cxd2841er.c: In function 'cxd2841er_tune_tc': /git/arm-soc/drivers/media/dvb-frontends/cxd2841er.c:3253:40: error: 'carrier_offset' may be used uninitialized in this function [-Werror=maybe-uninitialized] if (ret) ^ return ret; ~~~~~~~~~ /git/arm-soc/drivers/media/dvb-frontends/cxd2841er.c:3209:11: note: 'carrier_offset' was declared here int ret, carrier_offset; ^~~~~~~~~~~~~~

It's clearly a false positive warning, the code is correct, but if this is the only one that the dynamic_debug jump labels introduce, we may as well just work around it in the driver.

I think this is caused by the "unlikely" annotation in dynamic_dev_dbg(), which confuses the compiler trying to figure out whether the variable is initialized or not.

Arnd