From d9b9c7e10668449eaa7d033ff6bd0538612b1eac Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sun, 3 Jun 2018 22:07:16 +0200 Subject: [PATCH] 4.4-stable patches added patches: fix-io_destroy-aio_complete-race.patch --- .../fix-io_destroy-aio_complete-race.patch | 42 +++++++++++++++++++ queue-4.4/series | 1 + 2 files changed, 43 insertions(+) create mode 100644 queue-4.4/fix-io_destroy-aio_complete-race.patch diff --git a/queue-4.4/fix-io_destroy-aio_complete-race.patch b/queue-4.4/fix-io_destroy-aio_complete-race.patch new file mode 100644 index 00000000000..e1d93624b2c --- /dev/null +++ b/queue-4.4/fix-io_destroy-aio_complete-race.patch @@ -0,0 +1,42 @@ +From 4faa99965e027cc057c5145ce45fa772caa04e8d Mon Sep 17 00:00:00 2001 +From: Al Viro +Date: Wed, 23 May 2018 22:53:22 -0400 +Subject: fix io_destroy()/aio_complete() race + +From: Al Viro + +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 +Signed-off-by: Greg Kroah-Hartman + +--- + fs/aio.c | 3 +-- + 1 file changed, 1 insertion(+), 2 deletions(-) + +--- a/fs/aio.c ++++ b/fs/aio.c +@@ -628,9 +628,8 @@ 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-4.4/series b/queue-4.4/series index 24704fde9ef..a74ebdec6e2 100644 --- a/queue-4.4/series +++ b/queue-4.4/series @@ -30,4 +30,5 @@ stm-class-use-vmalloc-for-the-master-map.patch hwtracing-stm-fix-build-error-on-some-arches.patch drm-i915-disable-lvds-on-radiant-p845.patch kbuild-change-cc_optimize_for_size-definition.patch +fix-io_destroy-aio_complete-race.patch sparc64-fix-build-warnings-with-gcc-7.patch -- 2.47.3