3.10-stable review patch. If anyone has any objections, please let me know.
------------------ From: Davidlohr Bueso <[email protected]> commit 05603c44a7627793219b0bd9a7b236099dc9cd9d upstream. As suggested by Andrew, add a generic initial locking scheme used throughout all sysv ipc mechanisms. Documenting the ids rwsem, how rcu can be enough to do the initial checks and when to actually acquire the kern_ipc_perm.lock spinlock. I found that adding it to util.c was generic enough. Signed-off-by: Davidlohr Bueso <[email protected]> Tested-by: Sedat Dilek <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Manfred Spraul <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Cc: Mike Galbraith <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- ipc/util.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/ipc/util.c +++ b/ipc/util.c @@ -15,6 +15,14 @@ * Jun 2006 - namespaces ssupport * OpenVZ, SWsoft Inc. * Pavel Emelianov <[email protected]> + * + * General sysv ipc locking scheme: + * when doing ipc id lookups, take the ids->rwsem + * rcu_read_lock() + * obtain the ipc object (kern_ipc_perm) + * perform security, capabilities, auditing and permission checks, etc. + * acquire the ipc lock (kern_ipc_perm.lock) throught ipc_lock_object() + * perform data updates (ie: SET, RMID, LOCK/UNLOCK commands) */ #include <linux/mm.h> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
