Hi Alexander , On 2018/3/9 18:49, Alexander Potapenko wrote: > On Fri, Mar 9, 2018 at 6:21 AM, Yisheng Xie <xieyisheng1@xxxxxxxxxx> wrote: >> Alexander reported an use of uninitialized memory in __mpol_equal(), >> which is caused by incorrect use of preferred_node. >> >> When mempolicy in mode MPOL_PREFERRED with flags MPOL_F_LOCAL, it use >> numa_node_id() instead of preferred_node, however, __mpol_equeue() use >> preferred_node without check whether it is MPOL_F_LOCAL or not. >> >> Reported-by: Alexander Potapenko <glider@xxxxxxxxxx> >> Signed-off-by: Yisheng Xie <xieyisheng1@xxxxxxxxxx> > Tested-by: Alexander Potapenko <glider@xxxxxxxxxx> Thanks, > > I confirm that the patch fixes the problem. Thanks for the quick turnaround! > Any idea which commit had introduced the bug in the first place? IIUC, It is introduce by: Fixes: fc36b8d3d819 (mempolicy: use MPOL_F_LOCAL to Indicate Preferred Local Policy) Thanks Yisheng >> --- >> mm/mempolicy.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/mm/mempolicy.c b/mm/mempolicy.c >> index d879f1d..641545e 100644 >> --- a/mm/mempolicy.c >> +++ b/mm/mempolicy.c >> @@ -2124,6 +2124,9 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b) >> case MPOL_INTERLEAVE: >> return !!nodes_equal(a->v.nodes, b->v.nodes); >> case MPOL_PREFERRED: >> + /* a's flags is the same as b's */ >> + if (a->flags & MPOL_F_LOCAL) >> + return true; >> return a->v.preferred_node == b->v.preferred_node; >> default: >> BUG(); >> -- >> 1.8.3.1 >> > > >
