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| author | Matthew Wilcox <willy@infradead.org> | 2018-11-01 16:55:19 -0400 |
|---|---|---|
| committer | Matthew Wilcox <willy@infradead.org> | 2018-11-05 14:56:46 -0500 |
| commit | 8229706e03e4147f3e22d1de0d30630cde6d18a9 (patch) | |
| tree | 1994f5ff08f7b5c459eba5e26c868ee182d2392a /lib | |
| parent | 651022382c7f8da46cb4872a545ee1da6d097d2a (diff) | |
| download | linux-8229706e03e4147f3e22d1de0d30630cde6d18a9.tar.gz | |
XArray: Fix xa_for_each with a single element at 0
The following sequence of calls would result in an infinite loop in
xa_find_after():
xa_store(xa, 0, x, GFP_KERNEL);
index = 0;
xa_for_each(xa, entry, index, ULONG_MAX, XA_PRESENT) { }
xa_find_after() was confusing the situation where we found no entry in
the tree with finding a multiorder entry, so it would look for the
successor entry forever. Just check for this case explicitly. Includes
a few new checks in the test suite to be sure this doesn't reappear.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/test_xarray.c | 30 | ||||
| -rw-r--r-- | lib/xarray.c | 2 |
2 files changed, 31 insertions, 1 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c index aa47754150ce..126127658b49 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -702,7 +702,7 @@ static noinline void check_multi_find_2(struct xarray *xa) } } -static noinline void check_find(struct xarray *xa) +static noinline void check_find_1(struct xarray *xa) { unsigned long i, j, k; @@ -748,6 +748,34 @@ static noinline void check_find(struct xarray *xa) XA_BUG_ON(xa, xa_get_mark(xa, i, XA_MARK_0)); } XA_BUG_ON(xa, !xa_empty(xa)); +} + +static noinline void check_find_2(struct xarray *xa) +{ + void *entry; + unsigned long i, j, index = 0; + + xa_for_each(xa, entry, index, ULONG_MAX, XA_PRESENT) { + XA_BUG_ON(xa, true); + } + + for (i = 0; i < 1024; i++) { + xa_store_index(xa, index, GFP_KERNEL); + j = 0; + index = 0; + xa_for_each(xa, entry, index, ULONG_MAX, XA_PRESENT) { + XA_BUG_ON(xa, xa_mk_value(index) != entry); + XA_BUG_ON(xa, index != j++); + } + } + + xa_destroy(xa); +} + +static noinline void check_find(struct xarray *xa) +{ + check_find_1(xa); + check_find_2(xa); check_multi_find(xa); check_multi_find_2(xa); } diff --git a/lib/xarray.c b/lib/xarray.c index 8b176f009c08..c991ff4523ef 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1829,6 +1829,8 @@ void *xa_find_after(struct xarray *xa, unsigned long *indexp, entry = xas_find_marked(&xas, max, filter); else entry = xas_find(&xas, max); + if (xas.xa_node == XAS_BOUNDS) + break; if (xas.xa_shift) { if (xas.xa_index & ((1UL << xas.xa_shift) - 1)) continue; |