FAILED: patch "[PATCH] io_uring: fix leaking reg files on exit" failed to apply to 5.12-stable tree
From: <gregkh@linuxfoundation.org>
Date: 2021-05-10 08:18:13
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
The patch below does not apply to the 5.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to [off-list ref]. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 084804002e512427bfe52b448cb7cac0d4209b64 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov <asml.silence@gmail.com> Date: Tue, 13 Apr 2021 02:58:38 +0100 Subject: [PATCH] io_uring: fix leaking reg files on exit If io_sqe_files_unregister() faults on io_rsrc_ref_quiesce(), it will fail to do unregister leaving files referenced. And that may well happen because of a strayed signal or just because it does allocations inside. In io_ring_ctx_free() do an unsafe version of unregister, as it's guaranteed to not have requests by that point and so quiesce is useless. Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/e696e9eade571b51997d0dc1d01f144c6d685c05.1618278933.git.asml.silence@gmail.com (local) Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8564c7908126..1af8bb5f7d56 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c@@ -7089,6 +7089,10 @@ static void __io_sqe_files_unregister(struct io_ring_ctx *ctx) fput(file); } #endif + io_free_file_tables(&ctx->file_table, ctx->nr_user_files); + kfree(ctx->file_data); + ctx->file_data = NULL; + ctx->nr_user_files = 0; } static inline void io_rsrc_ref_lock(struct io_ring_ctx *ctx)
@@ -7195,21 +7199,14 @@ static struct io_rsrc_data *io_rsrc_data_alloc(struct io_ring_ctx *ctx, static int io_sqe_files_unregister(struct io_ring_ctx *ctx) { - struct io_rsrc_data *data = ctx->file_data; int ret; - if (!data) + if (!ctx->file_data) return -ENXIO; - ret = io_rsrc_ref_quiesce(data, ctx); - if (ret) - return ret; - - __io_sqe_files_unregister(ctx); - io_free_file_tables(&ctx->file_table, ctx->nr_user_files); - kfree(data); - ctx->file_data = NULL; - ctx->nr_user_files = 0; - return 0; + ret = io_rsrc_ref_quiesce(ctx->file_data, ctx); + if (!ret) + __io_sqe_files_unregister(ctx); + return ret; } static void io_sq_thread_unpark(struct io_sq_data *sqd)
@@ -7659,7 +7656,7 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, ret = io_sqe_files_scm(ctx); if (ret) { - io_sqe_files_unregister(ctx); + __io_sqe_files_unregister(ctx); return ret; }
@@ -8460,7 +8457,11 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx) } mutex_lock(&ctx->uring_lock); - io_sqe_files_unregister(ctx); + if (ctx->file_data) { + if (!atomic_dec_and_test(&ctx->file_data->refs)) + wait_for_completion(&ctx->file_data->done); + __io_sqe_files_unregister(ctx); + } if (ctx->rings) __io_cqring_overflow_flush(ctx, true); mutex_unlock(&ctx->uring_lock);