diff options
| author | Wojciech Lukowicz <wlukowicz01@gmail.com> | 2023-04-01 20:50:39 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-04-01 16:52:12 -0600 |
| commit | b4a72c0589fdea6259720375426179888969d6a2 (patch) | |
| tree | ada64f1c07c40c8b248bb1807d6af15db18fc18f /io_uring | |
| parent | c0921e51dab767ef5adf6175c4a0ba3c6e1074a3 (diff) | |
| download | lwn-b4a72c0589fdea6259720375426179888969d6a2.tar.gz lwn-b4a72c0589fdea6259720375426179888969d6a2.zip | |
io_uring: fix memory leak when removing provided buffers
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>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/io_uring.c | 2 | ||||
| -rw-r--r-- | 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 722624b6d0dc..2a8b8c304d2a 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -2789,8 +2789,8 @@ 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 0fdcc0adbdbc..a90c820ce99e 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(); |