patch-2.2.16 linux/ipc/shm.c

• Lines: 30
• Date: Wed Jun 7 14:26:44 2000
• Orig file: v2.2.15/linux/ipc/shm.c
• Orig date: Wed May 3 17:16:53 2000

diff -urN v2.2.15/linux/ipc/shm.c linux/ipc/shm.c
@@ -12,6 +12,7 @@
 #include <linux/smp_lock.h>
 #include <linux/init.h>
 #include <linux/vmalloc.h>
+#include <linux/tasks.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -517,7 +518,7 @@
 	shmd->vm_ops = &shm_vm_ops;
 
 	shp->u.shm_nattch++;            /* prevent destruction */
-	if ((err = shm_map (shmd))) {
+	if (shp->u.shm_nattch > 0xffff - NR_TASKS || (err = shm_map (shmd))) {
 		if (--shp->u.shm_nattch <= 0 && shp->u.shm_perm.mode & SHM_DEST)
 			killseg(id);
 		kmem_cache_free(vm_area_cachep, shmd);
@@ -549,8 +550,11 @@
 		printk("shm_open: unused id=%d PANIC\n", id);
 		return;
 	}
+	if (!++shp->u.shm_nattch) {
+		shp->u.shm_nattch--;
+		return; /* XXX: should be able to report failure */
+	}
 	insert_attach(shp,shmd);  /* insert shmd into shp->attaches */
-	shp->u.shm_nattch++;
 	shp->u.shm_atime = CURRENT_TIME;
 	shp->u.shm_lpid = current->pid;
 }