Revert "ipc/shm: Fix shmat mmap nil-page protection"

[mirror_ubuntu-jammy-kernel.git] / ipc / shm.c

diff --git a/ipc/shm.c b/ipc/shm.c
index 3cf48988d68cec1e3a899f932de846818d4c729a..930be3aa80cf7e69e49b730a07e794c0d0a0feee 100644 (file)
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1363,13 +1363,8 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg,
 
        if (addr) {
                if (addr & (shmlba - 1)) {
-                       /*
-                        * 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);
+                       if (shmflg & SHM_RND)
+                               addr &= ~(shmlba - 1);  /* round down */
                        else
 #ifndef __ARCH_FORCE_SHMLBA
                                if (addr & ~PAGE_MASK)