[PATCH 6.19 067/781] io_uring/kbuf: fix memory leak if io_buffer_add_list fails

Greg Kroah-Hartman
2026-02-25T01:28:33Z

From: Jens Axboe <axboe@kernel.dk>

[ Upstream commit 442ae406603a94f1a263654494f425302ceb0445 ]

io_register_pbuf_ring() ignores the return value of io_buffer_add_list(),
which can fail if xa_store() returns an error (e.g., -ENOMEM). When this
happens, the function returns 0 (success) to the caller, but the
io_buffer_list structure is neither added to the xarray nor freed.

In practice this requires failure injection to hit, hence not a real
issue. But it should get fixed up none the less.

Fixes: c7fb19428d67 ("io_uring: add support for ring mapped supplied buffers")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
io_uring/kbuf.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index 796d131107ddb..67d4fe576473a 100644
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -669,8 +669,9 @@ int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
bl->buf_ring = br;
if (reg.flags & IOU_PBUF_RING_INC)
bl->flags |= IOBL_INC;
- io_buffer_add_list(ctx, bl, reg.bgid);
- return 0;
+ ret = io_buffer_add_list(ctx, bl, reg.bgid);
+ if (!ret)
+ return 0;
fail:
io_free_region(ctx->user, &bl->region);
kfree(bl);
--
2.51.0