Re: [PATCH v2] mm: mlockall error for flag MCL_ONFAULT
flat view
From: Vlastimil Babka <hidden>
Date: 2019-05-27 13:19:48
Also in:
linux-mm, lkml
On 5/27/19 9:53 AM, Potyra, Stefan wrote:
If mlockall() is called with only MCL_ONFAULT as flag,
it removes any previously applied lockings and does
nothing else.
This behavior is counter-intuitive and doesn't match the
Linux man page.
For mlockall():
EINVAL Unknown flags were specified or MCL_ONFAULT was specified with‐
out either MCL_FUTURE or MCL_CURRENT.
Consequently, return the error EINVAL, if only MCL_ONFAULT
is passed. That way, applications will at least detect that
they are calling mlockall() incorrectly.
Fixes: b0f205c2a308 ("mm: mlock: add mlock flags to enable VM_LOCKONFAULT usage")
Signed-off-by: Stefan Potyra <redacted>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>Acked-by: Vlastimil Babka <redacted> Thanks, shame we didn't catch it during review. Hope nobody will report a regression.
quoted hunk ↗ jump to hunk
--- mm/mlock.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)diff --git a/mm/mlock.c b/mm/mlock.c index e492a155c51a..03f39cbdd4c4 100644 --- a/mm/mlock.c +++ b/mm/mlock.c@@ -797,7 +797,8 @@ SYSCALL_DEFINE1(mlockall, int, flags) unsigned long lock_limit; int ret; - if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT))) + if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT)) || + flags == MCL_ONFAULT) return -EINVAL; if (!can_do_mlock())