3.10-stable review patch. If anyone has any objections, please let me know.
------------------ From: Davidlohr Bueso <[email protected]> commit 79ccf0f8c8e04e8b9eda6645ba0f63b0915a3075 upstream. Instead of holding the ipc lock for the entire function, use the ipcctl_pre_down_nolock and only acquire the lock for specific commands: RMID and SET. 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/shm.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/ipc/shm.c +++ b/ipc/shm.c @@ -780,11 +780,10 @@ static int shmctl_down(struct ipc_namesp down_write(&shm_ids(ns).rw_mutex); rcu_read_lock(); - ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd, - &shmid64.shm_perm, 0); + ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd, + &shmid64.shm_perm, 0); if (IS_ERR(ipcp)) { err = PTR_ERR(ipcp); - /* the ipc lock is not held upon failure */ goto out_unlock1; } @@ -792,14 +791,16 @@ static int shmctl_down(struct ipc_namesp err = security_shm_shmctl(shp, cmd); if (err) - goto out_unlock0; + goto out_unlock1; switch (cmd) { case IPC_RMID: + ipc_lock_object(&shp->shm_perm); /* do_shm_rmid unlocks the ipc object and rcu */ do_shm_rmid(ns, ipcp); goto out_up; case IPC_SET: + ipc_lock_object(&shp->shm_perm); err = ipc_update_perm(&shmid64.shm_perm, ipcp); if (err) goto out_unlock0; @@ -807,6 +808,7 @@ static int shmctl_down(struct ipc_namesp break; default: err = -EINVAL; + goto out_unlock1; } out_unlock0: -- 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/
