* Re: sparc: Clashing values for O_PATH and FMODE_NONOTIFY? [not found] ` <20141119.153001.1273476178846053821.davem@davemloft.net> @ 2014-11-20 12:12 ` David Drysdale 2014-11-20 19:12 ` Eric Paris 0 siblings, 1 reply; 3+ messages in thread From: David Drysdale @ 2014-11-20 12:12 UTC (permalink / raw) To: David Miller, Eric Paris Cc: Alexander Viro, linux-kernel@vger.kernel.org, sparclinux, linux-fsdevel [+linux-fsdevel, without the typo this time] On Wed, Nov 19, 2014 at 8:30 PM, David Miller <davem@davemloft.net> wrote: > From: David Drysdale <drysdale@google.com> > Date: Tue, 18 Nov 2014 13:13:51 +0000 > >> Hi folks, >> >> It looks like the value for O_PATH on sparc: >> >> arch/sparc/include/uapi/asm/fcntl.h:37:#define O_PATH 0x1000000 >> >> clashes with the arch-independent value for __FMODE_NONOTIFY: >> >> include/linux/fs.h:137:#define FMODE_NONOTIFY ((__force fmode_t)0x1000000) >> include/linux/fs.h:2764:#define __FMODE_NONOTIFY ((__force int) >> FMODE_NONOTIFY) >> >> and they are both in the same numbering space, as indicated by the >> comment at the top of include/uapi/asm-generic/fcntl.h and the use in >> fs/notify/fanotify/fanotify_user.c:715. >> >> Presumably this could theoretically cause problems (no notifications for >> O_PATH files on SPARC?), so would it be a good idea to renumber >> FMODE_NONOTIFY? (I *think* that value is entirely kernel-internal.) >> >> Given that this has happened before (12ed2e36c98aec6c4155 "fanotify: >> FMODE_NONOTIFY and __O_SYNC in sparc conflict") it would probably >> also be a good idea to add __FMODE_NOTIFY to the uniqueness check in >> fs/fcntl.c:fcntl_init(). >> >> Thoughts? > > I think you will need to change the internal value, to not clash with > the sparc exported one, for sure. Well, I was sort of hoping someone else might volunteer to make the change :-) -- I don't use fanotify (or sparc for that matter), I just happened to notice the clash in passing. But I'm happy to have a go, although I can't test much. It would be good to hear from the fanotify maintainers first, though -- Eric? Thanks, David ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: sparc: Clashing values for O_PATH and FMODE_NONOTIFY? 2014-11-20 12:12 ` sparc: Clashing values for O_PATH and FMODE_NONOTIFY? David Drysdale @ 2014-11-20 19:12 ` Eric Paris 2014-11-20 19:31 ` David Drysdale 0 siblings, 1 reply; 3+ messages in thread From: Eric Paris @ 2014-11-20 19:12 UTC (permalink / raw) To: David Drysdale Cc: David Miller, Alexander Viro, linux-kernel@vger.kernel.org, sparclinux, linux-fsdevel On Thu, 2014-11-20 at 12:12 +0000, David Drysdale wrote: > [+linux-fsdevel, without the typo this time] > > On Wed, Nov 19, 2014 at 8:30 PM, David Miller <davem@davemloft.net> wrote: > > From: David Drysdale <drysdale@google.com> > > Date: Tue, 18 Nov 2014 13:13:51 +0000 > > > >> Hi folks, > >> > >> It looks like the value for O_PATH on sparc: > >> > >> arch/sparc/include/uapi/asm/fcntl.h:37:#define O_PATH 0x1000000 > >> > >> clashes with the arch-independent value for __FMODE_NONOTIFY: > >> > >> include/linux/fs.h:137:#define FMODE_NONOTIFY ((__force fmode_t)0x1000000) > >> include/linux/fs.h:2764:#define __FMODE_NONOTIFY ((__force int) > >> FMODE_NONOTIFY) > >> > >> and they are both in the same numbering space, as indicated by the > >> comment at the top of include/uapi/asm-generic/fcntl.h and the use in > >> fs/notify/fanotify/fanotify_user.c:715. > >> > >> Presumably this could theoretically cause problems (no notifications for > >> O_PATH files on SPARC?), so would it be a good idea to renumber > >> FMODE_NONOTIFY? (I *think* that value is entirely kernel-internal.) > >> > >> Given that this has happened before (12ed2e36c98aec6c4155 "fanotify: > >> FMODE_NONOTIFY and __O_SYNC in sparc conflict") it would probably > >> also be a good idea to add __FMODE_NOTIFY to the uniqueness check in > >> fs/fcntl.c:fcntl_init(). > >> > >> Thoughts? > > > > I think you will need to change the internal value, to not clash with > > the sparc exported one, for sure. > > Well, I was sort of hoping someone else might volunteer to make the > change :-) -- I don't use fanotify (or sparc for that matter), I just > happened to notice the clash in passing. > > But I'm happy to have a go, although I can't test much. It would be > good to hear from the fanotify maintainers first, though -- Eric? It's totally internal. And was picked to not clash with anyone. I don't know how to keep it from happening in the future..... ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: sparc: Clashing values for O_PATH and FMODE_NONOTIFY? 2014-11-20 19:12 ` Eric Paris @ 2014-11-20 19:31 ` David Drysdale 0 siblings, 0 replies; 3+ messages in thread From: David Drysdale @ 2014-11-20 19:31 UTC (permalink / raw) To: Eric Paris Cc: David Miller, Alexander Viro, linux-kernel@vger.kernel.org, sparclinux, linux-fsdevel On Thu, Nov 20, 2014 at 7:12 PM, Eric Paris <eparis@redhat.com> wrote: > On Thu, 2014-11-20 at 12:12 +0000, David Drysdale wrote: >> [+linux-fsdevel, without the typo this time] >> >> On Wed, Nov 19, 2014 at 8:30 PM, David Miller <davem@davemloft.net> wrote: >> > From: David Drysdale <drysdale@google.com> >> > Date: Tue, 18 Nov 2014 13:13:51 +0000 >> > >> >> Hi folks, >> >> >> >> It looks like the value for O_PATH on sparc: >> >> >> >> arch/sparc/include/uapi/asm/fcntl.h:37:#define O_PATH 0x1000000 >> >> >> >> clashes with the arch-independent value for __FMODE_NONOTIFY: >> >> >> >> include/linux/fs.h:137:#define FMODE_NONOTIFY ((__force fmode_t)0x1000000) >> >> include/linux/fs.h:2764:#define __FMODE_NONOTIFY ((__force int) >> >> FMODE_NONOTIFY) >> >> >> >> and they are both in the same numbering space, as indicated by the >> >> comment at the top of include/uapi/asm-generic/fcntl.h and the use in >> >> fs/notify/fanotify/fanotify_user.c:715. >> >> >> >> Presumably this could theoretically cause problems (no notifications for >> >> O_PATH files on SPARC?), so would it be a good idea to renumber >> >> FMODE_NONOTIFY? (I *think* that value is entirely kernel-internal.) >> >> >> >> Given that this has happened before (12ed2e36c98aec6c4155 "fanotify: >> >> FMODE_NONOTIFY and __O_SYNC in sparc conflict") it would probably >> >> also be a good idea to add __FMODE_NOTIFY to the uniqueness check in >> >> fs/fcntl.c:fcntl_init(). >> >> >> >> Thoughts? >> > >> > I think you will need to change the internal value, to not clash with >> > the sparc exported one, for sure. >> >> Well, I was sort of hoping someone else might volunteer to make the >> change :-) -- I don't use fanotify (or sparc for that matter), I just >> happened to notice the clash in passing. >> >> But I'm happy to have a go, although I can't test much. It would be >> good to hear from the fanotify maintainers first, though -- Eric? > > It's totally internal. OK, thanks, that makes me feel safer about changing its value. (fatrace still seemed to work (and not report its own activity) after I changed the value, which is also reassuring.) > And was picked to not clash with anyone. I > don't know how to keep it from happening in the future..... There's a compile-time check on the number of distinct O_* bits at the bottom of fs/fcntl.c -- if we update that to include FMODE_NONOTIFY then any future clashes should trigger a (cross-)compilation failure. I'll send out a patch tomorrow. Thanks, David ^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-11-20 12:12 ` sparc: Clashing values for O_PATH and FMODE_NONOTIFY? David Drysdale
2014-11-20 19:12 ` Eric Paris
2014-11-20 19:31 ` David Drysdale
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