| From | Greg Kroah-Hartman <> | Subject | [ 64/99] dm ioctl: set noio flag to avoid __vmalloc deadlock | Date | Fri, 2 Aug 2013 18:08:17 +0800 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Mikulas Patocka <mpatocka@redhat.com>
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>
--- drivers/md/dm-ioctl.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1644,7 +1644,10 @@ static int copy_params(struct dm_ioctl _ } 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; }
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