diff options
authorHelge Deller <deller@gmx.de>2017-07-14 14:49:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-14 15:05:12 -0700
commit37511fb5c91db93d8bd6e3f52f86e5a7ff7cfcdf (patch)
parentb86faee6d111294fa95a2e89b5f771b2da3c9782 (diff)
mm: fix overflow check in expand_upwards()
Jörn Engel noticed that the expand_upwards() function might not return -ENOMEM in case the requested address is (unsigned long)-PAGE_SIZE and if the architecture didn't defined TASK_SIZE as multiple of PAGE_SIZE. Affected architectures are arm, frv, m68k, blackfin, h8300 and xtensa which all define TASK_SIZE as 0xffffffff, but since none of those have an upwards-growing stack we currently have no actual issue. Nevertheless let's fix this just in case any of the architectures with an upward-growing stack (currently parisc, metag and partly ia64) define TASK_SIZE similar. Link: http://lkml.kernel.org/r/20170702192452.GA11868@p100.box Fixes: bd726c90b6b8 ("Allow stack to grow up to address space limit") Signed-off-by: Helge Deller <deller@gmx.de> Reported-by: Jörn Engel <joern@purestorage.com> Cc: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 7fa6759322d1..f19efcf75418 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2231,7 +2231,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
/* Guard against exceeding limits of the address space. */
address &= PAGE_MASK;
- if (address >= TASK_SIZE)
+ if (address >= (TASK_SIZE & PAGE_MASK))
return -ENOMEM;
address += PAGE_SIZE;

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