diff options
| author | Matthew Wilcox <willy@linux.intel.com> | 2016-02-03 01:57:55 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-02-03 17:28:43 +0100 |
| commit | c6400ba7e13a41539342f1b6e1f9e78419cb0148 (patch) | |
| tree | 4ac7cac19e5d9cfc275a7d99f11ea21026f20275 | |
| parent | radix-tree: fix race in gang lookup (diff) | |
| download | linux-c6400ba7e13a41539342f1b6e1f9e78419cb0148.tar.xz linux-c6400ba7e13a41539342f1b6e1f9e78419cb0148.zip | |
drivers/hwspinlock: fix race between radix tree insertion and lookup
of_hwspin_lock_get_id() is protected by the RCU lock, which means that
insertions can occur simultaneously with the lookup. If the radix tree
transitions from a height of 0, we can see a slot with the indirect_ptr
bit set, which will cause us to at least read random memory, and could
cause other havoc.
Fix this by using the newly introduced radix_tree_iter_retry().
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/hwspinlock/hwspinlock_core.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/hwspinlock/hwspinlock_core.c b/drivers/hwspinlock/hwspinlock_core.c index 52f708bcf77f..d50c701b19d6 100644 --- a/drivers/hwspinlock/hwspinlock_core.c +++ b/drivers/hwspinlock/hwspinlock_core.c @@ -313,6 +313,10 @@ int of_hwspin_lock_get_id(struct device_node *np, int index) hwlock = radix_tree_deref_slot(slot); if (unlikely(!hwlock)) continue; + if (radix_tree_is_indirect_ptr(hwlock)) { + slot = radix_tree_iter_retry(&iter); + continue; + } if (hwlock->bank->dev->of_node == args.np) { ret = 0; |