This is a note to let you know that I've just added the patch titled io_uring: convert io_buffer_idr to XArray to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: io_uring-convert-io_buffer_idr-to-xarray.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Jul 15 01:10:15 PM CEST 2021 From: Hanjun Guo <guohanjun@xxxxxxxxxx> Date: Tue, 13 Jul 2021 17:18:35 +0800 Subject: io_uring: convert io_buffer_idr to XArray To: <stable@xxxxxxxxxxxxxxx> Cc: <linux-kernel@xxxxxxxxxxxxxxx>, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Sasha Levin <sashal@xxxxxxxxxx>, Jens Axboe <axboe@xxxxxxxxx>, Matthew Wilcox <willy@xxxxxxxxxxxxx>, yangerkun <yangerkun@xxxxxxxxxx>, Hanjun Guo <guohanjun@xxxxxxxxxx> Message-ID: <1626167917-11972-6-git-send-email-guohanjun@xxxxxxxxxx> From: Jens Axboe <axboe@xxxxxxxxx> commit 9e15c3a0ced5a61f320b989072c24983cb1620c1 upstream. Like we did for the personality idr, convert the IO buffer idr to use XArray. This avoids a use-after-free on removal of entries, since idr doesn't like doing so from inside an iterator, and it nicely reduces the amount of code we need to support this feature. Fixes: 5a2e745d4d43 ("io_uring: buffer registration infrastructure") Cc: stable@xxxxxxxxxxxxxxx Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: yangerkun <yangerkun@xxxxxxxxxx> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Hanjun Guo <guohanjun@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/io_uring.c | 43 +++++++++++++++---------------------------- 1 file changed, 15 insertions(+), 28 deletions(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -344,7 +344,7 @@ struct io_ring_ctx { struct socket *ring_sock; #endif - struct idr io_buffer_idr; + struct xarray io_buffers; struct xarray personalities; u32 pers_next; @@ -1212,7 +1212,7 @@ static struct io_ring_ctx *io_ring_ctx_a INIT_LIST_HEAD(&ctx->cq_overflow_list); init_completion(&ctx->ref_comp); init_completion(&ctx->sq_thread_comp); - idr_init(&ctx->io_buffer_idr); + xa_init_flags(&ctx->io_buffers, XA_FLAGS_ALLOC1); xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1); mutex_init(&ctx->uring_lock); init_waitqueue_head(&ctx->wait); @@ -2990,7 +2990,7 @@ static struct io_buffer *io_buffer_selec lockdep_assert_held(&req->ctx->uring_lock); - head = idr_find(&req->ctx->io_buffer_idr, bgid); + head = xa_load(&req->ctx->io_buffers, bgid); if (head) { if (!list_empty(&head->list)) { kbuf = list_last_entry(&head->list, struct io_buffer, @@ -2998,7 +2998,7 @@ static struct io_buffer *io_buffer_selec list_del(&kbuf->list); } else { kbuf = head; - idr_remove(&req->ctx->io_buffer_idr, bgid); + xa_erase(&req->ctx->io_buffers, bgid); } if (*len > kbuf->len) *len = kbuf->len; @@ -3960,7 +3960,7 @@ static int __io_remove_buffers(struct io } i++; kfree(buf); - idr_remove(&ctx->io_buffer_idr, bgid); + xa_erase(&ctx->io_buffers, bgid); return i; } @@ -3978,7 +3978,7 @@ static int io_remove_buffers(struct io_k lockdep_assert_held(&ctx->uring_lock); ret = -ENOENT; - head = idr_find(&ctx->io_buffer_idr, p->bgid); + head = xa_load(&ctx->io_buffers, p->bgid); if (head) ret = __io_remove_buffers(ctx, head, p->bgid, p->nbufs); if (ret < 0) @@ -4069,21 +4069,14 @@ static int io_provide_buffers(struct io_ lockdep_assert_held(&ctx->uring_lock); - list = head = idr_find(&ctx->io_buffer_idr, p->bgid); + list = head = xa_load(&ctx->io_buffers, p->bgid); ret = io_add_buffers(p, &head); - if (ret < 0) - goto out; - - if (!list) { - ret = idr_alloc(&ctx->io_buffer_idr, head, p->bgid, p->bgid + 1, - GFP_KERNEL); - if (ret < 0) { + if (ret >= 0 && !list) { + ret = xa_insert(&ctx->io_buffers, p->bgid, head, GFP_KERNEL); + if (ret < 0) __io_remove_buffers(ctx, head, p->bgid, -1U); - goto out; - } } -out: if (ret < 0) req_set_fail_links(req); @@ -8411,19 +8404,13 @@ static int io_eventfd_unregister(struct return -ENXIO; } -static int __io_destroy_buffers(int id, void *p, void *data) -{ - struct io_ring_ctx *ctx = data; - struct io_buffer *buf = p; - - __io_remove_buffers(ctx, buf, id, -1U); - return 0; -} - static void io_destroy_buffers(struct io_ring_ctx *ctx) { - idr_for_each(&ctx->io_buffer_idr, __io_destroy_buffers, ctx); - idr_destroy(&ctx->io_buffer_idr); + struct io_buffer *buf; + unsigned long index; + + xa_for_each(&ctx->io_buffers, index, buf) + __io_remove_buffers(ctx, buf, index, -1U); } static void io_ring_ctx_free(struct io_ring_ctx *ctx) Patches currently in stable-queue which might be from guohanjun@xxxxxxxxxx are queue-5.10/io_uring-simplify-io_remove_personalities.patch queue-5.10/io_uring-convert-personality_idr-to-xarray.patch queue-5.10/loop-fix-i-o-error-on-fsync-in-detached-loop-devices.patch queue-5.10/io_uring-convert-io_buffer_idr-to-xarray.patch queue-5.10/mm-hwpoison-return-ebusy-when-migration-fails.patch queue-5.10/scsi-iscsi-fix-iscsi-cls-conn-state.patch queue-5.10/scsi-iscsi-fix-race-condition-between-login-and-sync-thread.patch