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| author | Mikulas Patocka <mpatocka@redhat.com> | 2013-07-10 23:41:15 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-08-04 16:51:02 +0800 |
| commit | ba0e6dd5e64bbf820669f7451ac03f4f11cd64f7 (patch) | |
| tree | 2dd11d8443f7d329235132d6296b14f22d1e11bc | |
| parent | 565ff95cdc72f76d53d4e98d5e84254368b9a041 (diff) | |
| download | lwn-ba0e6dd5e64bbf820669f7451ac03f4f11cd64f7.tar.gz lwn-ba0e6dd5e64bbf820669f7451ac03f4f11cd64f7.zip | |
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.c | 3 |
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; } |