The patch titled
Subject: mm: fix overflow check in expand_upwards()
has been added to the -mm tree. Its filename is
mm-fix-overflow-check-in-expand_upwards.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-fix-overflow-check-in-expand_upwards.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-overflow-check-in-expand_upwards.patch
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------------------------------------------------------
From: Helge Deller <deller@xxxxxx>
Subject: 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@xxxxxxxx
Fixes: bd726c90b6b8 ("Allow stack to grow up to address space limit")
Signed-off-by: Helge Deller <deller@xxxxxx>
Reported-by: Jörn Engel <joern@xxxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/mmap.c~mm-fix-overflow-check-in-expand_upwards mm/mmap.c
--- a/mm/mmap.c~mm-fix-overflow-check-in-expand_upwards
+++ a/mm/mmap.c
@@ -2231,7 +2231,7 @@ int expand_upwards(struct vm_area_struct
/* 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;
_
Patches currently in -mm which might be from deller@xxxxxx are
mm-fix-overflow-check-in-expand_upwards.patch
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