Linus, I am sorry for the annoyance. On 09/01/2015 08:47 AM, Linus Torvalds wrote:
Hmm: On Fri, Aug 14, 2015 at 4:57 PM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:Xiao Guangrong (9): KVM: MMU: fully check zero bits for sptesThe above commit causes an annoying new compiler warning. The warning is bogus ("variable 'leaf' possibly uninitialized"), because the use of the variable is protected by the 'bool reserved' flag, but gcc is apparently not smart enough to understand that. Since bogus warnings cause people to possibly ignore the *real* warnings, this should be fixed. Maybe the code should get rid of that 'reserved' flag, and instead initialize "leaf" to zero, and use that as the flag instead (since zero isn't a valid level)? That would actually avoid an extra variable, and would get rid of the warning.
The logic in that code is: if 'reserved' is true, print out the info in spte[root - leaf]. I am afraid it's not good to use 'leaf' both for the array index and reserved indicator. Or if i missed something please let me know. Actually i triggered this warning in my another box and posted a patch to fix it which can be found at: http://lkml.iu.edu/hypermail/linux/kernel/1508.2/02771.html I guess Paolo is currently busy with KVM forum so the patch has not been reviewed yet. The patch simply initialized 'leaf' to the highest value to stop printing the info, but as you noticed this is no real problem in the code just stop GCC's complaint. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
