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SubjectRe: [PATCH V2] mm, memory_failure: don't send BUS_MCEERR_AO for action required error
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On Sat, May 30, 2020 at 09:08:43AM +0200, Pankaj Gupta wrote:
> > Some processes dont't want to be killed early, but in "Action Required"
> > case, those also may be killed by BUS_MCEERR_AO when sharing memory
> > with other which is accessing the fail memory.
> > And sending SIGBUS with BUS_MCEERR_AO for action required error is
> > strange, so ignore the non-current processes here.
> >
> > Suggested-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
> > Signed-off-by: Wetp Zhang <wetp.zy@linux.alibaba.com>
> > ---
> > mm/memory-failure.c | 15 +++++++++------
> > 1 file changed, 9 insertions(+), 6 deletions(-)
> >
> > diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> > index a96364be8ab4..dd3862fcf2e9 100644
> > --- a/mm/memory-failure.c
> > +++ b/mm/memory-failure.c
> > @@ -210,14 +210,17 @@ static int kill_proc(struct to_kill *tk, unsigned long pfn, int flags)
> > {
> > struct task_struct *t = tk->tsk;
> > short addr_lsb = tk->size_shift;
> > - int ret;
> > + int ret = 0;
> >
> > - pr_err("Memory failure: %#lx: Sending SIGBUS to %s:%d due to hardware memory corruption\n",
> > - pfn, t->comm, t->pid);
> > + if ((t->mm == current->mm) || !(flags & MF_ACTION_REQUIRED))
> > + pr_err("Memory failure: %#lx: Sending SIGBUS to %s:%d due to hardware memory corruption\n",
> > + pfn, t->comm, t->pid);
>
> Maybe we can generalize the message condition for better readability.
> Thought a bit but did not get any other idea.

This odd condition might imply that we could have better fix in
task_early_kill(), but that should come after fixing priority issue of
early-kill flag, so let's go with this fix for now.

> >
> > - if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) {
> > - ret = force_sig_mceerr(BUS_MCEERR_AR, (void __user *)tk->addr,
> > - addr_lsb);
> > + if (flags & MF_ACTION_REQUIRED) {
> > + if (t->mm == current->mm)
> > + ret = force_sig_mceerr(BUS_MCEERR_AR,
> > + (void __user *)tk->addr, addr_lsb);
> > + /* send no signal to non-current processes */
> > } else {
> > /*
> > * Don't use force here, it's convenient if the signal
> > --
>
> Looks good to me.
> Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>

Thanks!

Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
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