diff options
| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2020-01-17 17:45:12 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-29 16:45:26 +0100 |
| commit | a5135ca1f92a7b201b7f8297f42b8579f92bc55d (patch) | |
| tree | 186501e471fdb0e5e845e9bddb03e5144d1c3051 /lib | |
| parent | b8560e3d90afad8c5ee1ae4fea41949a76b5bb8b (diff) | |
XArray: Fix infinite loop with entry at ULONG_MAX
commit 430f24f94c8a174d411a550d7b5529301922e67a upstream.
If there is an entry at ULONG_MAX, xa_for_each() will overflow the
'index + 1' in xa_find_after() and wrap around to 0. Catch this case
and terminate the loop by returning NULL.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/test_xarray.c | 17 | ||||
| -rw-r--r-- | lib/xarray.c | 3 |
2 files changed, 20 insertions, 0 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 7df4f7f395bf..e8eaafeebb17 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -1046,11 +1046,28 @@ static noinline void check_find_3(struct xarray *xa) xa_destroy(xa); } +static noinline void check_find_4(struct xarray *xa) +{ + unsigned long index = 0; + void *entry; + + xa_store_index(xa, ULONG_MAX, GFP_KERNEL); + + entry = xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT); + XA_BUG_ON(xa, entry != xa_mk_index(ULONG_MAX)); + + entry = xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT); + XA_BUG_ON(xa, entry); + + xa_erase_index(xa, ULONG_MAX); +} + static noinline void check_find(struct xarray *xa) { check_find_1(xa); check_find_2(xa); check_find_3(xa); + check_find_4(xa); check_multi_find(xa); check_multi_find_2(xa); } diff --git a/lib/xarray.c b/lib/xarray.c index 1237c213f52b..ab842cff4634 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1847,6 +1847,9 @@ void *xa_find_after(struct xarray *xa, unsigned long *indexp, XA_STATE(xas, xa, *indexp + 1); void *entry; + if (xas.xa_index == 0) + return NULL; + rcu_read_lock(); for (;;) { if ((__force unsigned int)filter < XA_MAX_MARKS) |