mm, aout: handle vm_brk failures

vm_brk is allowed to fail but load_aout_binary simply ignores the error
and happily continues.  I haven't noticed any problem from that in real
life but later patches will make the failure more likely because vm_brk
will become killable (resp.  mmap_sem for write waiting will become
killable) so we should be more careful now.

The error handling should be quite straightforward because there are
calls to vm_mmap which check the error properly already.  The only
notable exception is set_brk which is called after beyond_if label.  But
nothing indicates that we cannot move it above set_binfmt as the two do
not depend on each other and fail before we do set_binfmt and alter
reference counting.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 3 deletions

diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index 4c556680fa74..2fab9f130e51 100644
--- a/fs/binfmt_aout.c
+++ b/fs/binfmt_aout.c
@@ -297,7 +297,10 @@ static int load_aout_binary(struct linux_binprm * bprm)
                 }
 
                 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
-                        vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
+                        error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
+                        if (IS_ERR_VALUE(error))
+                                return error;
+
                         read_code(bprm->file, N_TXTADDR(ex), fd_offset,
                                   ex.a_text + ex.a_data);
                         goto beyond_if;
@@ -378,8 +381,10 @@ static int load_aout_library(struct file *file)
                                "N_TXTOFF is not page aligned. Please convert library: %pD\n",
                                file);
                 }
-                vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
-                
+                retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
+                if (IS_ERR_VALUE(retval))
+                        goto out;
+
                 read_code(file, start_addr, N_TXTOFF(ex),
                           ex.a_text + ex.a_data);
                 retval = 0;