From 07d6063d3d3beb3168d3ac9fdef7bca81254d983 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 27 Nov 2023 17:02:48 -0700 Subject: io_uring/kbuf: prune deferred locked cache when tearing down We used to just use our page list for final teardown, which would ensure that we got all the buffers, even the ones that were not on the normal cached list. But while moving to slab for the io_buffers, we know only prune this list, not the deferred locked list that we have. This can cause a leak of memory, if the workload ends up using the intermediate locked list. Fix this by always pruning both lists when tearing down. Fixes: b3a4dbc89d40 ("io_uring/kbuf: Use slab for struct io_buffer objects") Signed-off-by: Jens Axboe --- io_uring/kbuf.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'io_uring') diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c index 325ca7f8b0a0f..39d15a27eb92d 100644 --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -306,6 +306,14 @@ void io_destroy_buffers(struct io_ring_ctx *ctx) kfree(bl); } + /* + * Move deferred locked entries to cache before pruning + */ + spin_lock(&ctx->completion_lock); + if (!list_empty(&ctx->io_buffers_comp)) + list_splice_init(&ctx->io_buffers_comp, &ctx->io_buffers_cache); + spin_unlock(&ctx->completion_lock); + list_for_each_safe(item, tmp, &ctx->io_buffers_cache) { buf = list_entry(item, struct io_buffer, list); kmem_cache_free(io_buf_cachep, buf); -- cgit 1.2.3-korg