From 1c0e883e86ece31880fac2f84b260545d66a39e0 Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@redhat.com>
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 <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
---
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 aa04f02246421..81a79b739e973 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;
}
--
GitLab