* [merged] mm-gup-protect-unpin_user_pages-against-npages==-errno.patch removed from -mm tree
@ 2020-10-14 21:05 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2020-10-14 21:05 UTC (permalink / raw)
To: dan.carpenter, ira.weiny, jhubbard, jrdr.linux, mm-commits
The patch titled
Subject: mm/gup: protect unpin_user_pages() against npages==-ERRNO
has been removed from the -mm tree. Its filename was
mm-gup-protect-unpin_user_pages-against-npages==-errno.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: John Hubbard <jhubbard@nvidia.com>
Subject: mm/gup: protect unpin_user_pages() against npages==-ERRNO
As suggested by Dan Carpenter, fortify unpin_user_pages() just a bit,
against a typical caller mistake: check if the npages arg is really a
-ERRNO value, which would blow up the unpinning loop: WARN and return.
If this new WARN_ON() fires, then the system *might* be leaking pages (by
leaving them pinned), but probably not. More likely, gup/pup returned a
hard -ERRNO error to the caller, who erroneously passed it here.
Link: https://lkml.kernel.org/r/20200917065706.409079-1-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/gup.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/mm/gup.c~mm-gup-protect-unpin_user_pages-against-npages==-errno
+++ a/mm/gup.c
@@ -329,6 +329,13 @@ void unpin_user_pages(struct page **page
unsigned long index;
/*
+ * If this WARN_ON() fires, then the system *might* be leaking pages (by
+ * leaving them pinned), but probably not. More likely, gup/pup returned
+ * a hard -ERRNO error to the caller, who erroneously passed it here.
+ */
+ if (WARN_ON(IS_ERR_VALUE(npages)))
+ return;
+ /*
* TODO: this can be optimized for huge pages: if a series of pages is
* physically contiguous and part of the same compound page, then a
* single operation to the head page should suffice.
_
Patches currently in -mm which might be from jhubbard@nvidia.com are
mm-gup_benchmark-rename-to-mm-gup_test.patch
selftests-vm-use-a-common-gup_testh.patch
selftests-vm-rename-run_vmtests-run_vmtestssh.patch
selftests-vm-minor-cleanup-makefile-and-gup_testc.patch
selftests-vm-only-some-gup_test-items-are-really-benchmarks.patch
selftests-vm-gup_test-introduce-the-dump_pages-sub-test.patch
selftests-vm-run_vmtestsh-update-and-clean-up-gup_test-invocation.patch
selftests-vm-hmm-tests-remove-the-libhugetlbfs-dependency.patch
selftests-vm-hmm-tests-remove-the-libhugetlbfs-dependency-fix.patch
selftests-vm-10x-speedup-for-hmm-tests.patch
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2020-10-14 21:05 [merged] mm-gup-protect-unpin_user_pages-against-npages==-errno.patch removed from -mm tree akpm
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