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authorPotyra, Stefan <Stefan.Potyra@elektrobit.com>2019-06-13 15:55:55 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-06-13 17:34:56 -1000
commitdedca63504a204dc8410d98883fdc16dffa8cb80 (patch)
tree9c0cf66ad0333054241acc8bf3c32e32efe25109 /mm
parentc04e32e911653442fc834be6e92e072aeebe01a1 (diff)
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mm/mlock.c: mlockall error for flag MCL_ONFAULT
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 without 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. Link: http://lkml.kernel.org/r/20190527075333.GA6339@er01809n.ebgroup.elektrobit.com Fixes: b0f205c2a308 ("mm: mlock: add mlock flags to enable VM_LOCKONFAULT usage") Signed-off-by: Stefan Potyra <Stefan.Potyra@elektrobit.com> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mlock.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/mlock.c b/mm/mlock.c
index 080f3b36415b..cef65bf3964c 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())