The patch titled
Subject: userfaultfd: cleanup superfluous _irq locking
has been added to the -mm tree. Its filename is
userfaultfd-add-new-syscall-to-provide-memory-externalization-fix-fix-fix.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-add-new-syscall-to-provide-memory-externalization-fix-fix-fix.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-add-new-syscall-to-provide-memory-externalization-fix-fix-fix.patch
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------------------------------------------------------
From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Subject: userfaultfd: cleanup superfluous _irq locking
This leftover shouldn't have caused any malfunction because the loop
either schedules or it re-enables irqs immediately and schedule()
doesn't seem to BUG_ON(irqs_disabled()). However lately we've been
using the non blocking model so the schedule isn't really exercised
here. Regardless of the side effects this must be fixed as it's not ok
to enter schedule with irq disabled and it's not beneficial to toggle
irqs in the first place.
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/userfaultfd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN fs/userfaultfd.c~userfaultfd-add-new-syscall-to-provide-memory-externalization-fix-fix-fix fs/userfaultfd.c
--- a/fs/userfaultfd.c~userfaultfd-add-new-syscall-to-provide-memory-externalization-fix-fix-fix
+++ a/fs/userfaultfd.c
@@ -433,11 +433,11 @@ static ssize_t userfaultfd_ctx_read(stru
}
spin_unlock(&ctx->fd_wqh.lock);
schedule();
- spin_lock_irq(&ctx->fd_wqh.lock);
+ spin_lock(&ctx->fd_wqh.lock);
}
__remove_wait_queue(&ctx->fd_wqh, &wait);
__set_current_state(TASK_RUNNING);
- spin_unlock_irq(&ctx->fd_wqh.lock);
+ spin_unlock(&ctx->fd_wqh.lock);
return ret;
}
_
Patches currently in -mm which might be from aarcange@xxxxxxxxxx are
thp-cleanup-how-khugepaged-enters-freezer.patch
mm-drop-bogus-vm_bug_on_page-assert-in-put_page-codepath.patch
mm-avoid-tail-page-refcounting-on-non-thp-compound-pages.patch
userfaultfd-linux-documentation-vm-userfaultfdtxt.patch
userfaultfd-linux-documentation-vm-userfaultfdtxt-fix.patch
userfaultfd-waitqueue-add-nr-wake-parameter-to-__wake_up_locked_key.patch
userfaultfd-uapi.patch
userfaultfd-linux-userfaultfd_kh.patch
userfaultfd-add-vm_userfaultfd_ctx-to-the-vm_area_struct.patch
userfaultfd-add-vm_uffd_missing-and-vm_uffd_wp.patch
userfaultfd-call-handle_userfault-for-userfaultfd_missing-faults.patch
userfaultfd-teach-vma_merge-to-merge-across-vma-vm_userfaultfd_ctx.patch
userfaultfd-prevent-khugepaged-to-merge-if-userfaultfd-is-armed.patch
userfaultfd-add-new-syscall-to-provide-memory-externalization.patch
userfaultfd-add-new-syscall-to-provide-memory-externalization-fix.patch
userfaultfd-add-new-syscall-to-provide-memory-externalization-fix-fix.patch
userfaultfd-add-new-syscall-to-provide-memory-externalization-fix-fix-fix.patch
userfaultfd-rename-uffd_apibits-into-features.patch
userfaultfd-rename-uffd_apibits-into-features-fixup.patch
userfaultfd-change-the-read-api-to-return-a-uffd_msg.patch
userfaultfd-change-the-read-api-to-return-a-uffd_msg-fix.patch
userfaultfd-wake-pending-userfaults.patch
userfaultfd-optimize-read-and-poll-to-be-o1.patch
userfaultfd-optimize-read-and-poll-to-be-o1-fix.patch
userfaultfd-allocate-the-userfaultfd_ctx-cacheline-aligned.patch
userfaultfd-solve-the-race-between-uffdio_copyzeropage-and-read.patch
userfaultfd-buildsystem-activation.patch
userfaultfd-activate-syscall.patch
userfaultfd-uffdio_copyuffdio_zeropage-uapi.patch
userfaultfd-mcopy_atomicmfill_zeropage-uffdio_copyuffdio_zeropage-preparation.patch
userfaultfd-avoid-mmap_sem-read-recursion-in-mcopy_atomic.patch
userfaultfd-avoid-mmap_sem-read-recursion-in-mcopy_atomic-fix.patch
userfaultfd-uffdio_copy-and-uffdio_zeropage.patch
fs-userfaultfdc-work-around-i386-build-error.patch
mm-oom_kill-remove-unnecessary-locking-in-oom_enable.patch
mm-oom_kill-clean-up-victim-marking-and-exiting-interfaces.patch
mm-oom_kill-switch-test-and-clear-of-known-tif_memdie-to-clear.patch
mm-oom_kill-generalize-oom-progress-waitqueue.patch
mm-oom_kill-remove-unnecessary-locking-in-exit_oom_victim.patch
mm-oom_kill-simplify-oom-killer-locking.patch
mm-page_alloc-inline-should_alloc_retry.patch
mm-thp-split-out-pmd-collpase-flush-into-a-separate-functions.patch
powerpc-mm-use-generic-version-of-pmdp_clear_flush.patch
mm-clarify-that-the-function-operates-on-hugepage-pte.patch
page-flags-trivial-cleanup-for-pagetrans-helpers.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages.patch
page-flags-define-pg_locked-behavior-on-compound-pages.patch
page-flags-define-behavior-of-fs-io-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-lru-related-flags-on-compound-pages.patch
page-flags-define-behavior-slb-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-xen-related-flags-on-compound-pages.patch
page-flags-define-pg_reserved-behavior-on-compound-pages.patch
page-flags-define-pg_swapbacked-behavior-on-compound-pages.patch
page-flags-define-pg_swapcache-behavior-on-compound-pages.patch
page-flags-define-pg_mlocked-behavior-on-compound-pages.patch
page-flags-define-pg_uncached-behavior-on-compound-pages.patch
page-flags-define-pg_uptodate-behavior-on-compound-pages.patch
page-flags-look-on-head-page-if-the-flag-is-encoded-in-page-mapping.patch
mm-sanitize-page-mapping-for-tail-pages.patch
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