From: Wojciech Lukowicz wlukowicz01@gmail.com
[ Upstream commit b4a72c0589fdea6259720375426179888969d6a2 ]
When removing provided buffers, io_buffer structs are not being disposed of, leading to a memory leak. They can't be freed individually, because they are allocated in page-sized groups. They need to be added to some free list instead, such as io_buffers_cache. All callers already hold the lock protecting it, apart from when destroying buffers, so had to extend the lock there.
Fixes: cc3cec8367cb ("io_uring: speedup provided buffer handling") Signed-off-by: Wojciech Lukowicz wlukowicz01@gmail.com Link: https://lore.kernel.org/r/20230401195039.404909-2-wlukowicz01@gmail.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- io_uring/io_uring.c | 2 +- io_uring/kbuf.c | 5 ++++- 2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index ce4969d3e20de..cc35aba1e4957 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -2585,8 +2585,8 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx) io_eventfd_unregister(ctx); io_alloc_cache_free(&ctx->apoll_cache, io_apoll_cache_free); io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free); - mutex_unlock(&ctx->uring_lock); io_destroy_buffers(ctx); + mutex_unlock(&ctx->uring_lock); if (ctx->sq_creds) put_cred(ctx->sq_creds); if (ctx->submitter_task) diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c index 9a9db1fcdc14d..acc37e5a6d4e1 100644 --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -228,11 +228,14 @@ static int __io_remove_buffers(struct io_ring_ctx *ctx, return i; }
+ /* protects io_buffers_cache */ + lockdep_assert_held(&ctx->uring_lock); + while (!list_empty(&bl->buf_list)) { struct io_buffer *nxt;
nxt = list_first_entry(&bl->buf_list, struct io_buffer, list); - list_del(&nxt->list); + list_move(&nxt->list, &ctx->io_buffers_cache); if (++i == nbufs) return i; cond_resched();