On 26/09/2019 13.42, Jens Axboe wrote: > On 9/26/19 1:33 PM, Dan Carpenter wrote: >> On Thu, Sep 26, 2019 at 11:56:30AM +0200, Jens Axboe wrote: >>> On 9/26/19 11:50 AM, Colin King wrote: >>>> From: Colin Ian King <colin.king@xxxxxxxxxxxxx> >>>> >>>> In the case where sig is NULL the error variable ret is not initialized >>>> and may contain a garbage value on the final checks to see if ret is >>>> -ERESTARTSYS. Best to initialize ret to zero before the do loop to >>>> ensure the ret does not accidentially contain -ERESTARTSYS before the >>>> loop. >>> >>> Oops, weird it didn't complain. I've folded in this fix, as that commit >>> isn't upstream yet. Thanks! >> >> There is a bug in GCC where at certain optimization levels, instead of >> complaining, it initializes it to zero. > > That's awfully nice of it ;-) > > Tried with -O0 and still didn't complain for me. > > $ gcc --version > gcc (Ubuntu 9.1.0-2ubuntu2~18.04) 9.1.0 > > Tried gcc 5/6/7/8 as well. Might have to go look at what code it's > generating. > I think it's essentially the same as https://lore.kernel.org/lkml/CAHk-=whP-9yPAWuJDwA6+rQ-9owuYZgmrMA9AqO3EGJVefe8vg@xxxxxxxxxxxxxx/ (thread "tmpfs: fix uninitialized return value in shmem_link"). Rasmus
