From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Sun, 3 Jun 2018 20:07:36 +0000 (+0200)
Subject: 4.9-stable patches
X-Git-Tag: v4.9.106~9
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b3722861a82059f655d0c77d2841259e45a6bdc1;p=thirdparty%2Fkernel%2Fstable-queue.git

4.9-stable patches

added patches:
	fix-io_destroy-aio_complete-race.patch
---

diff --git a/queue-4.9/fix-io_destroy-aio_complete-race.patch b/queue-4.9/fix-io_destroy-aio_complete-race.patch
new file mode 100644
index 00000000000..feaa697765e
--- /dev/null
+++ b/queue-4.9/fix-io_destroy-aio_complete-race.patch
@@ -0,0 +1,42 @@
+From 4faa99965e027cc057c5145ce45fa772caa04e8d Mon Sep 17 00:00:00 2001
+From: Al Viro <viro@zeniv.linux.org.uk>
+Date: Wed, 23 May 2018 22:53:22 -0400
+Subject: fix io_destroy()/aio_complete() race
+
+From: Al Viro <viro@zeniv.linux.org.uk>
+
+commit 4faa99965e027cc057c5145ce45fa772caa04e8d upstream.
+
+If io_destroy() gets to cancelling everything that can be cancelled and
+gets to kiocb_cancel() calling the function driver has left in ->ki_cancel,
+it becomes vulnerable to a race with IO completion.  At that point req
+is already taken off the list and aio_complete() does *NOT* spin until
+we (in free_ioctx_users()) releases ->ctx_lock.  As the result, it proceeds
+to kiocb_free(), freing req just it gets passed to ->ki_cancel().
+
+Fix is simple - remove from the list after the call of kiocb_cancel().  All
+instances of ->ki_cancel() already have to cope with the being called with
+iocb still on list - that's what happens in io_cancel(2).
+
+Cc: stable@kernel.org
+Fixes: 0460fef2a921 "aio: use cancellation list lazily"
+Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/aio.c |    3 +--
+ 1 file changed, 1 insertion(+), 2 deletions(-)
+
+--- a/fs/aio.c
++++ b/fs/aio.c
+@@ -636,9 +636,8 @@ static void free_ioctx_users(struct perc
+ 	while (!list_empty(&ctx->active_reqs)) {
+ 		req = list_first_entry(&ctx->active_reqs,
+ 				       struct aio_kiocb, ki_list);
+-
+-		list_del_init(&req->ki_list);
+ 		kiocb_cancel(req);
++		list_del_init(&req->ki_list);
+ 	}
+ 
+ 	spin_unlock_irq(&ctx->ctx_lock);
diff --git a/queue-4.9/series b/queue-4.9/series
index 7a1523ea4d8..906678e12d1 100644
--- a/queue-4.9/series
+++ b/queue-4.9/series
@@ -55,3 +55,4 @@ ib-core-fix-error-code-for-invalid-gid-entry.patch
 drm-psr-fix-missed-entry-in-psr-setup-time-table.patch
 drm-i915-disable-lvds-on-radiant-p845.patch
 sparc64-fix-build-warnings-with-gcc-7.patch
+fix-io_destroy-aio_complete-race.patch