X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=ipc%2Fshm.c;h=df1d6085396faacfb792bfaef3de4c6c4b5633e6;hp=326a20bdba3ab6938267b33ffbd7cda2d970e3df;hb=f63b2b3204ea962e9cc34a223771ec973694f8bf;hpb=5a467624b1c06db5a47bf2fe58e41347686af512

diff --git a/ipc/shm.c b/ipc/shm.c
index 326a20bdba3a..df1d6085396f 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -498,12 +498,6 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 	if (IS_ERR(file))
 		goto no_file;
 
-	id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
-	if (id < 0) {
-		error = id;
-		goto no_id;
-	}
-
 	shp->shm_cprid = task_tgid_vnr(current);
 	shp->shm_lprid = 0;
 	shp->shm_atim = shp->shm_dtim = 0;
@@ -512,6 +506,13 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 	shp->shm_nattch = 0;
 	shp->shm_file = file;
 	shp->shm_creator = current;
+
+	id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
+	if (id < 0) {
+		error = id;
+		goto no_id;
+	}
+
 	/*
 	 * shmid gets reported as "inode#" in /proc/pid/maps.
 	 * proc-ps tools use this. Changing this will break them.
@@ -962,8 +963,13 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 		goto out;
 	else if ((addr = (ulong)shmaddr)) {
 		if (addr & (SHMLBA-1)) {
-			if (shmflg & SHM_RND)
-				addr &= ~(SHMLBA-1);	   /* round down */
+			/*
+			 * Round down to the nearest multiple of shmlba.
+			 * For sane do_mmap_pgoff() parameters, avoid
+			 * round downs that trigger nil-page and MAP_FIXED.
+			 */
+			if ((shmflg & SHM_RND) && addr >= SHMLBA)
+				addr &= ~(SHMLBA - 1);
 			else
 #ifndef __ARCH_FORCE_SHMLBA
 				if (addr & ~PAGE_MASK)