diff mbox series

[2/2] mm/mmap: return 1 from stack_guard_gap __setup() handler

Message ID 20220222005817.11087-1-rdunlap@infradead.org (mailing list archive)
State New
Headers show
Series [1/2] mm/memcontrol: return 1 from cgroup.memory __setup() handler | expand

Commit Message

Randy Dunlap Feb. 22, 2022, 12:58 a.m. UTC
__setup() handlers should return 1 if the command line option is handled
and 0 if not (or maybe never return 0; it just pollutes init's
environment). This prevents:

  Unknown kernel command line parameters \
  "BOOT_IMAGE=/boot/bzImage-517rc5 stack_guard_gap=100", will be \
  passed to user space.

  Run /sbin/init as init process
   with arguments:
   with environment:

Return 1 to indicate that the boot option has been handled.

Note that there is no warning message if someone enters:
and 'val' and stack_guard_gap are both set to 0 due to the use of
simple_strtoul(). This could be improved by using kstrtoxxx() and
checking for an error.

It appears that having stack_guard_gap == 0 is valid (if unexpected)
since using "stack_guard_gap=0" on the kernel command line does that.

Fixes: 1be7107fbe18e ("mm: larger stack guard gap, between vmas")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru>
Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
 mm/mmap.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series


--- linux-next-20220217.orig/mm/mmap.c
+++ linux-next-20220217/mm/mmap.c
@@ -2557,7 +2557,7 @@  static int __init cmdline_parse_stack_gu
 	if (!*endptr)
 		stack_guard_gap = val << PAGE_SHIFT;
-	return 0;
+	return 1;
 __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap);