diff options
| author | Peter Xu <peterx@redhat.com> | 2020-04-01 21:08:29 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-02 09:35:29 -0700 |
| commit | 8b9a65fd282c1d2e5b8ba8d8afaf652cde27b5e7 (patch) | |
| tree | b89b766763cdc2ae0e895cae8e997498d9e42e1d /include | |
| parent | fb027ada051a9e2d70a069b2aa62fb6f52100bbf (diff) | |
mm: return faster for non-fatal signals in user mode faults
The idea comes from the upstream discussion between Linus and Andrea:
https://lore.kernel.org/lkml/20171102193644.GB22686@redhat.com/
A summary to the issue: there was a special path in handle_userfault() in
the past that we'll return a VM_FAULT_NOPAGE when we detected non-fatal
signals when waiting for userfault handling. We did that by reacquiring
the mmap_sem before returning. However that brings a risk in that the
vmas might have changed when we retake the mmap_sem and even we could be
holding an invalid vma structure.
This patch is a preparation of removing that special path by allowing the
page fault to return even faster if we were interrupted by a non-fatal
signal during a user-mode page fault handling routine.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Brian Geffon <bgeffon@google.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Link: http://lkml.kernel.org/r/20200220160230.9598-1-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sched/signal.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index 7e7271374799..65ea429daaa2 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -381,7 +381,8 @@ static inline bool fault_signal_pending(vm_fault_t fault_flags, struct pt_regs *regs) { return unlikely((fault_flags & VM_FAULT_RETRY) && - fatal_signal_pending(current)); + (fatal_signal_pending(current) || + (user_mode(regs) && signal_pending(current)))); } /* |