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authorMikulas Patocka <mpatocka@redhat.com>2013-07-10 23:41:15 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-08-04 16:51:02 +0800
commitba0e6dd5e64bbf820669f7451ac03f4f11cd64f7 (patch)
tree2dd11d8443f7d329235132d6296b14f22d1e11bc
parent565ff95cdc72f76d53d4e98d5e84254368b9a041 (diff)
dm ioctl: set noio flag to avoid __vmalloc deadlock
commit 1c0e883e86ece31880fac2f84b260545d66a39e0 upstream. 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> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/md/dm-ioctl.c3
1 files changed, 3 insertions, 0 deletions
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;
}