[PATCH] lib/idr: fix memory leak in ida_alloc_range() error path

Josh Law
2026-03-12T17:18:38Z

In ida_alloc_range(), if the XArray operation encounters an error
(e.g., -ENOSPC) during allocation, the function exits early via
return xas_error(&xas). However, if an intermediate `alloc` bitmap
was allocated via kzalloc() earlier in the function but the XArray
insertion failed, the error path returns without freeing `alloc`.

Reorder the error handling to ensure `alloc` is properly freed when
an XArray error occurs.

Signed-off-by: Josh Law <objecting@objecting.org>
---
lib/idr.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/idr.c b/lib/idr.c
index 07098eb4ddc3..2ad96befa17a 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -460,10 +460,12 @@ int ida_alloc_range(struct ida *ida, unsigned int min, unsigned int max,
bit = min % IDA_BITMAP_BITS;
goto retry;
}
- if (bitmap != alloc)
+ if (xas_error(&xas)) {
kfree(alloc);
- if (xas_error(&xas))
return xas_error(&xas);
+ }
+ if (bitmap != alloc)
+ kfree(alloc);
return xas.xa_index * IDA_BITMAP_BITS + bit;
alloc:
xas_unlock_irqrestore(&xas, flags);
--
2.34.1