On Fri, Jun 13, 2014 at 08:05:37AM -0400, Jeff Layton wrote: > On Thu, 12 Jun 2014 18:06:25 +1000 > Vitaly Osipov <vitaly.osipov@xxxxxxxxx> wrote: > > > Nothing shows up for me on x86_64, allmodconfig, linux-next from 10 of > > June. My sparse has been compiled from sources. > > > > $ make fs/locks.o C=2 CHECK="/home/vosipov/bin/sparse" > > CHK include/config/kernel.release > > CHK include/generated/uapi/linux/version.h > > CHK include/generated/utsrelease.h > > CALL scripts/checksyscalls.sh > > CHECK scripts/mod/empty.c > > CHECK fs/locks.c > > > > $ sparse —version > > v0.5.0 > > > > $ which sparse > > /home/vosipov/bin/sparse > > > > Regards, > > Vitaly > > > > > > On Wed, Jun 11, 2014 at 11:51 PM, Jeff Layton <jlayton@xxxxxxxxxxxxxxx> wrote: > > > On Wed, 11 Jun 2014 16:11:46 +0300 > > > Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote: > > > > > >> On Wed, Jun 11, 2014 at 07:06:32AM -0400, Jeff Layton wrote: > > >> > $ rpm -q sparse > > >> > sparse-0.5.0-1.fc20.x86_64 > > >> > > > >> > I see it all over the tree, but an easy example is fs/locks.c: > > >> > > > >> > $ make fs/locks.o C=1 > > >> > make[1]: Nothing to be done for `all'. > > >> > make[1]: Nothing to be done for `relocs'. > > >> > CHK include/config/kernel.release > > >> > CHK include/generated/uapi/linux/version.h > > >> > CHK include/generated/utsrelease.h > > >> > CALL scripts/checksyscalls.sh > > >> > CHECK fs/locks.c > > >> > include/linux/err.h:35:16: warning: dereference of noderef expression > > >> > include/linux/err.h:30:23: warning: dereference of noderef expression > > >> > include/linux/err.h:35:16: warning: dereference of noderef expression > > >> > include/linux/err.h:30:23: warning: dereference of noderef expression > > >> > CC fs/locks.o > > >> > > > >> > It has two IS_ERR calls and two PTR_ERR calls, and each generates the > > >> > warning. > > >> > > > >> > > >> I downloaded the Fedora SRPM and built the binary but I still wasn't > > >> able to reproduce the bug. > > >> > > >> dcarpenter@speke:~/progs/kernel/devel$ /tmp/sparse/sparse-0.5.0/sparse --version > > >> 0.5.0 > > >> dcarpenter@speke:~/progs/kernel/devel$ make C=2 CHECK=/tmp/sparse/sparse-0.5.0/sparse fs/locks.o > > >> CHK include/config/kernel.release > > >> CHK include/generated/uapi/linux/version.h > > >> CHK include/generated/utsrelease.h > > >> CALL scripts/checksyscalls.sh > > >> <stdin>:1226:2: warning: #warning syscall finit_module not implemented [-Wcpp] > > >> <stdin>:1229:2: warning: #warning syscall sched_setattr not implemented [-Wcpp] > > >> <stdin>:1232:2: warning: #warning syscall sched_getattr not implemented [-Wcpp] > > >> <stdin>:1235:2: warning: #warning syscall renameat2 not implemented [-Wcpp] > > >> CHECK scripts/mod/empty.c > > >> CHECK fs/locks.c > > >> dcarpenter@speke:~/progs/kernel/devel$ > > >> > > >> I'm on today's linux-next. I can't think of a kernel configuration > > >> issue which would cause this... > > >> > > >> regards, > > >> dan carpenter > > > > > > Could it be arch-specific then? What arch are you using? I'm on x86_64. > > > I know that quite a few other people have mentioned seeing these > > > warnings as well, so I'm pretty sure it's not just me. > > > > > Ha! It turns out that my hand-built sparse also works fine, so the > problem seems to be in the Fedora package. > > With a little trial-and-error, I figured out what's causing the > problem, but I'm a little baffled as to why it's occurring. > > The Fedora SRPM builds the program with -fpic. When I remove that flag, > this problem goes away. I'd appreciate any insight into why that would > break things. I doubt PIC really makes much difference security-wise in > sparse, so removing it shouldn't matter much, but I wonder if this > indicates an underlying bug in sparse itself? Wow, that's horrifying. I wonder if it might indicate a miscompilation by GCC. Does the problem persist if you build with -fpic -g? If so, you could set a few breakpoints and try to determine at what point the behavior of the two sparse binaries diverges. - Josh Triplett -- To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
