From 72fd6c7be701d80eef34da305a6294c61520fe13 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 28 Nov 2017 15:50:12 -0500 Subject: [PATCH] idr: Warn if old iterators see large IDs Now that the IDR can be used to store large IDs, it is possible somebody might only partially convert their old code and use the iterators which can only handle IDs up to INT_MAX. It's probably unwise to show them a truncated ID, so settle for spewing warnings to dmesg, and terminating the iteration. Signed-off-by: Matthew Wilcox --- lib/idr.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/lib/idr.c b/lib/idr.c index 3df44d528b68..b47055efceb0 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -159,7 +159,11 @@ int idr_for_each(const struct idr *idr, void __rcu **slot; radix_tree_for_each_slot(slot, &idr->idr_rt, &iter, 0) { - int ret = fn(iter.index, rcu_dereference_raw(*slot), data); + int ret; + + if (WARN_ON_ONCE(iter.index > INT_MAX)) + break; + ret = fn(iter.index, rcu_dereference_raw(*slot), data); if (ret) return ret; } @@ -187,6 +191,9 @@ void *idr_get_next(struct idr *idr, int *nextid) if (!slot) return NULL; + if (WARN_ON_ONCE(iter.index > INT_MAX)) + return NULL; + *nextid = iter.index; return rcu_dereference_raw(*slot); }