From 1c0e883e86ece31880fac2f84b260545d66a39e0 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Wed, 10 Jul 2013 23:41:15 +0100 Subject: [PATCH] dm ioctl: set noio flag to avoid __vmalloc deadlock Set noio flag while calling __vmalloc() because it doesn't fully respect gfp flags to avoid a possible deadlock (see commit 502624bdad3dba45dfaacaf36b7d83e39e74b2d2). This should be backported to stable kernels 3.8 and newer. The kernel 3.8 doesn't have memalloc_noio_save(), so we should set and restore process flag PF_MEMALLOC instead. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Alasdair G Kergon --- drivers/md/dm-ioctl.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index aa04f0224642..81a79b739e97 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1644,7 +1644,10 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern } if (!dmi) { + unsigned noio_flag; + noio_flag = memalloc_noio_save(); dmi = __vmalloc(param_kernel->data_size, GFP_NOIO | __GFP_REPEAT | __GFP_HIGH, PAGE_KERNEL); + memalloc_noio_restore(noio_flag); if (dmi) *param_flags |= DM_PARAMS_VMALLOC; } -- 2.20.1