[MIPS] IRIX: Handle do_brk() error return correctly.

do_brk's return value was stored in an unsigned long variable before being
tested for less than zero making the test always fail.  Also do_brk's
called irix_map_prda_page wasn't forwarding do_brk() success.

Bug checking the return value of do_brk() and initial fix for it found
by Roel Kluin <12o3l@tiscali.nl>.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 7 insertions, 4 deletions

diff --git a/arch/mips/kernel/irixelf.c b/arch/mips/kernel/irixelf.c
index 290d8e3a664d..469c7237e5ba 100644
--- a/arch/mips/kernel/irixelf.c
+++ b/arch/mips/kernel/irixelf.c
@@ -578,7 +578,7 @@ static inline int map_interpreter(struct elf_phdr *epp, struct elfhdr *ihp,
  * process and the system, here we map the page and fill the
  * structure
  */
-static void irix_map_prda_page(void)
+static int irix_map_prda_page(void)
 {
         unsigned long v;
         struct prda *pp;
@@ -587,8 +587,8 @@ static void irix_map_prda_page(void)
         v =  do_brk(PRDA_ADDRESS, PAGE_SIZE);
         up_write(&current->mm->mmap_sem);
 
-        if (v < 0)
-                return;
+        if (v != PRDA_ADDRESS)
+                return v;               /* v must be an error code */
 
         pp = (struct prda *) v;
         pp->prda_sys.t_pid  = task_pid_vnr(current);
@@ -596,6 +596,8 @@ static void irix_map_prda_page(void)
         pp->prda_sys.t_rpid = task_pid_vnr(current);
 
         /* We leave the rest set to zero */
+
+        return 0;
 }
 
 
@@ -781,7 +783,8 @@ static int load_irix_binary(struct linux_binprm * bprm, struct pt_regs * regs)
          * IRIX maps a page at 0x200000 which holds some system
          * information.  Programs depend on this.
          */
-        irix_map_prda_page();
+        if (irix_map_prda_page())
+                goto out_free_dentry;
 
         padzero(elf_bss);