fix #29415191

commit 03151c6e0b66c63c3e9980edf78c3a7a99801764 upstream

Action Required memory error should happen only when a processor is
about to access to a corrupted memory, so it's synchronous and only
affects current process/thread.

Recently commit 872e9a205c84 ("mm, memory_failure: don't send
BUS_MCEERR_AO for action required error") fixed the issue that Action
Required memory could unnecessarily send SIGBUS to the processes which
share the error memory.  But we still have another issue that we could
send SIGBUS to a wrong thread.

This is because collect_procs() and task_early_kill() fails to add the
current process to "to-kill" list.  So this patch is suggesting to fix
it.  With this fix, SIGBUS(BUS_MCEERR_AR) is never sent to non-current
process/thread.
Signed-off-by: NNaoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NTony Luck <tony.luck@intel.com>
Acked-by: NPankaj Gupta <pankaj.gupta.linux@gmail.com>
Link: http://lkml.kernel.org/r/1591321039-22141-3-git-send-email-naoya.horiguchi@nec.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NWetp Zhang <wetp.zy@linux.alibaba.com>
Reviewed-by: NArtie Ding <artie.ding@linux.alibaba.com>