lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 9 Oct 2013 15:26:56 -0700 From: Josh Triplett <josh@...htriplett.org> To: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com> Cc: linux-kernel@...r.kernel.org, mingo@...nel.org, laijs@...fujitsu.com, dipankar@...ibm.com, akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com, niv@...ibm.com, tglx@...utronix.de, peterz@...radead.org, rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com, darren@...art.com, fweisbec@...il.com, sbw@....edu Subject: Re: [PATCH v2 tip/core/rcu 01/13] rcu: Make rcu_assign_pointer's assignment volatile and type-safe On Wed, Oct 09, 2013 at 02:29:34PM -0700, Paul E. McKenney wrote: > From: Josh Triplett <josh@...htriplett.org> > > rcu_assign_pointer needs to use ACCESS_ONCE to make the assignment to > the destination pointer volatile, to protect against compilers too > clever for their own good. > > In addition, since rcu_assign_pointer force-casts the source pointer to > add the __rcu address space (overriding any existing address space), add > an explicit check that the source pointer has the __kernel address space > to start with. > > This new check produces warnings like this, when attempting to assign > from a __user pointer: > > test.c:25:9: warning: incorrect type in argument 2 (different address spaces) > test.c:25:9: expected struct foo *<noident> > test.c:25:9: got struct foo [noderef] <asn:1>*badsrc > > Signed-off-by: Josh Triplett <josh@...htriplett.org> > Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com> See my responses to the cover letter; I'd suggest making this the last patch of the series to avoid introducing and subsequently fixing warnings. I'd suggest adding the comment I mentioned in my second response as the new first patch of the series, since it applies to the old version as well; thus, the series would first add the comment documenting the evaluate-once constraint, then add all the calls to rcu_access_pointer, and finally add this patch introducing the sparse checking. - Josh Triplett -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists