Commit 1c0e883e authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Alasdair G Kergon

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
502624bd).

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: default avatarMikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 6c182cd8
...@@ -1644,7 +1644,10 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern ...@@ -1644,7 +1644,10 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
} }
if (!dmi) { if (!dmi) {
unsigned noio_flag;
noio_flag = memalloc_noio_save();
dmi = __vmalloc(param_kernel->data_size, GFP_NOIO | __GFP_REPEAT | __GFP_HIGH, PAGE_KERNEL); dmi = __vmalloc(param_kernel->data_size, GFP_NOIO | __GFP_REPEAT | __GFP_HIGH, PAGE_KERNEL);
memalloc_noio_restore(noio_flag);
if (dmi) if (dmi)
*param_flags |= DM_PARAMS_VMALLOC; *param_flags |= DM_PARAMS_VMALLOC;
} }
......
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