[Patch] Re: Bug in 2.4.0-test9 and test10 with sys_shmat()

From: Christoph Rohland (cr@sap.com)
Date: Fri Nov 17 2000 - 09:37:38 EST


Hi Linus,

The attached patch fixes two things:

1) shmat should not oops on shmid < 0
2) I think the shm tables should be allocated with GFP_USER instead of
   GFP_KERNEL since these are user requests.

Greetings
                Christoph

--- 4-11-6/ipc/shm.c Wed Oct 4 15:58:02 2000
+++ linux/ipc/shm.c Fri Nov 17 13:47:29 2000
@@ -572,13 +572,13 @@
         if (pages == 0)
                 return NULL;
 
- ret = kmalloc ((dir+1) * sizeof(pte_t *), GFP_KERNEL);
+ ret = kmalloc ((dir+1) * sizeof(pte_t *), GFP_USER);
         if (!ret)
                 goto nomem;
 
         for (ptr = ret; ptr < ret+dir ; ptr++)
         {
- *ptr = (pte_t *)__get_free_page (GFP_KERNEL);
+ *ptr = (pte_t *)__get_free_page (GFP_USER);
                 if (!*ptr)
                         goto free;
                 init_ptes (*ptr, PTES_PER_PAGE);
@@ -586,7 +586,7 @@
 
         /* The last one is probably not of PAGE_SIZE: we use kmalloc */
         if (last) {
- *ptr = kmalloc (last*sizeof(pte_t), GFP_KERNEL);
+ *ptr = kmalloc (last*sizeof(pte_t), GFP_USER);
                 if (!*ptr)
                         goto free;
                 init_ptes (*ptr, last);
@@ -724,7 +724,7 @@
         struct shmid_kernel *shp;
         pte_t **dir;
 
- shp = (struct shmid_kernel *) kmalloc (sizeof (*shp) + namelen, GFP_KERNEL);
+ shp = (struct shmid_kernel *) kmalloc (sizeof (*shp) + namelen, GFP_USER);
         if (!shp)
                 return ERR_PTR(-ENOMEM);
 
@@ -1202,7 +1202,7 @@
         char name[SHM_FMT_LEN+1];
         void *user_addr;
 
- if (!shm_sb || (shmid % SEQ_MULTIPLIER) == zero_id)
+ if (!shm_sb || shmid < 0 || (shmid % SEQ_MULTIPLIER) == zero_id)
                 return -EINVAL;
 
         if ((addr = (ulong)shmaddr)) {
-
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This archive was generated by hypermail 2b29 : Thu Nov 23 2000 - 21:00:13 EST