diff options
Diffstat (limited to 'lib/idr.c')
| -rw-r--r-- | lib/idr.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/lib/idr.c b/lib/idr.c index 1a30272066c6..73f4d53c02f3 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -569,6 +569,7 @@ void idr_remove(struct idr *idp, int id) struct idr_layer *p; struct idr_layer *to_free; + /* see comment in idr_find_slowpath() */ if (WARN_ON_ONCE(id < 0)) return; @@ -666,6 +667,14 @@ void *idr_find_slowpath(struct idr *idp, int id) int n; struct idr_layer *p; + /* + * If @id is negative, idr_find() used to ignore the sign bit and + * performed lookup with the rest of bits, which is weird and can + * lead to very obscure bugs. We're now returning NULL for all + * negative IDs but just in case somebody was depending on the sign + * bit being ignored, let's trigger WARN_ON_ONCE() so that they can + * be detected and fixed. WARN_ON_ONCE() can later be removed. + */ if (WARN_ON_ONCE(id < 0)) return NULL; @@ -815,6 +824,7 @@ void *idr_replace(struct idr *idp, void *ptr, int id) int n; struct idr_layer *p, *old_p; + /* see comment in idr_find_slowpath() */ if (WARN_ON_ONCE(id < 0)) return ERR_PTR(-EINVAL); |