From: Randy Dunlap Date: Tue, 22 Mar 2022 21:42:27 +0000 (-0700) Subject: mm/mmap: return 1 from stack_guard_gap __setup() handler X-Git-Tag: v5.16.19~48 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=82656b259721b3ecec87c72d11d7a7ddaa79b435;p=thirdparty%2Fkernel%2Fstable.git mm/mmap: return 1 from stack_guard_gap __setup() handler commit e6d094936988910ce6e8197570f2753898830081 upstream. __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: /sbin/init with environment: HOME=/ TERM=linux BOOT_IMAGE=/boot/bzImage-517rc5 stack_guard_gap=100 Return 1 to indicate that the boot option has been handled. Note that there is no warning message if someone enters: stack_guard_gap=anything_invalid 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. Link: https://lkml.kernel.org/r/20220222005817.11087-1-rdunlap@infradead.org Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Fixes: 1be7107fbe18e ("mm: larger stack guard gap, between vmas") Signed-off-by: Randy Dunlap Reported-by: Igor Zhbanov Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- diff --git a/mm/mmap.c b/mm/mmap.c index bfb0ea164a90a..22f2469bb2458 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2550,7 +2550,7 @@ static int __init cmdline_parse_stack_guard_gap(char *p) if (!*endptr) stack_guard_gap = val << PAGE_SHIFT; - return 0; + return 1; } __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap);