io_uring/kbuf: fix memory leak if io_buffer_add_list fails

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: c7fb19428d ("io_uring: add support for ring mapped supplied buffers")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2026-02-05 08:38:20 -07:00
parent ccd18ce290
commit 442ae40660

View file

@ -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);