| Message ID | 20190527075333.GA6339@er01809n.ebgroup.elektrobit.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] mm: mlockall error for flag MCL_ONFAULT | expand |
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 <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> Thanks, shame we didn't catch it during review. Hope nobody will report a regression. > --- > 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()) >
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())
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 <Stefan.Potyra@elektrobit.com> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> --- mm/mlock.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)