Patch "io_uring: Fix release of pinned pages when __io_uaddr_map fails" has been added to the 6.7-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    io_uring: Fix release of pinned pages when __io_uaddr_map fails

to the 6.7-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-fix-release-of-pinned-pages-when-__io_uaddr.patch
and it can be found in the queue-6.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 222107f9c0975f5fd773f00db237ce30b752ba74
Author: Gabriel Krisman Bertazi <krisman@xxxxxxx>
Date:   Wed Mar 13 17:39:12 2024 -0400

    io_uring: Fix release of pinned pages when __io_uaddr_map fails
    
    [ Upstream commit 67d1189d1095d471ed7fa426c7e384a7140a5dd7 ]
    
    Looking at the error path of __io_uaddr_map, if we fail after pinning
    the pages for any reasons, ret will be set to -EINVAL and the error
    handler won't properly release the pinned pages.
    
    I didn't manage to trigger it without forcing a failure, but it can
    happen in real life when memory is heavily fragmented.
    
    Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxx>
    Fixes: 223ef4743164 ("io_uring: don't allow IORING_SETUP_NO_MMAP rings on highmem pages")
    Link: https://lore.kernel.org/r/20240313213912.1920-1-krisman@xxxxxxx
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 205dad9603733..45d6e440bdc04 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2683,7 +2683,7 @@ static void *__io_uaddr_map(struct page ***pages, unsigned short *npages,
 	struct page **page_array;
 	unsigned int nr_pages;
 	void *page_addr;
-	int ret, i;
+	int ret, i, pinned;
 
 	*npages = 0;
 
@@ -2697,12 +2697,12 @@ static void *__io_uaddr_map(struct page ***pages, unsigned short *npages,
 	if (!page_array)
 		return ERR_PTR(-ENOMEM);
 
-	ret = pin_user_pages_fast(uaddr, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
-					page_array);
-	if (ret != nr_pages) {
-err:
-		io_pages_free(&page_array, ret > 0 ? ret : 0);
-		return ret < 0 ? ERR_PTR(ret) : ERR_PTR(-EFAULT);
+
+	pinned = pin_user_pages_fast(uaddr, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
+				     page_array);
+	if (pinned != nr_pages) {
+		ret = (pinned < 0) ? pinned : -EFAULT;
+		goto free_pages;
 	}
 
 	page_addr = page_address(page_array[0]);
@@ -2716,7 +2716,7 @@ static void *__io_uaddr_map(struct page ***pages, unsigned short *npages,
 		 * didn't support this feature.
 		 */
 		if (PageHighMem(page_array[i]))
-			goto err;
+			goto free_pages;
 
 		/*
 		 * No support for discontig pages for now, should either be a
@@ -2725,13 +2725,17 @@ static void *__io_uaddr_map(struct page ***pages, unsigned short *npages,
 		 * just fail them with EINVAL.
 		 */
 		if (page_address(page_array[i]) != page_addr)
-			goto err;
+			goto free_pages;
 		page_addr += PAGE_SIZE;
 	}
 
 	*pages = page_array;
 	*npages = nr_pages;
 	return page_to_virt(page_array[0]);
+
+free_pages:
+	io_pages_free(&page_array, pinned > 0 ? pinned : 0);
+	return ERR_PTR(ret);
 }
 
 static void *io_rings_map(struct io_ring_ctx *ctx, unsigned long uaddr,