[dm-devel] Regression introduced with commit 2a0b4682e09d76 ("dm: convert dm_dev_internal.count from atomic_t to refcount_t)
Hannes Reinecke
hare at suse.de
Thu Feb 1 14:54:23 UTC 2018
Hi Mike,
yet another refcount_t regression:
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -451,15 +451,15 @@ int dm_get_device(struct dm_target *ti, const char
*path, fmode_t mode,
return r;
}
- atomic_set(&dd->count, 0);
+ refcount_set(&dd->count, 1);
list_add(&dd->list, &t->devices);
} else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
r = upgrade_mode(dd, mode, t->md);
if (r)
return r;
+ refcount_inc(&dd->count);
}
- atomic_inc(&dd->count);
*result = dd->dm_dev;
return 0;
is _NOT_ an equivalent modification.
If the second 'if' claus is not taken, the reference count is never
increased and the system goes 'boom'.
Will be sending a patch shortly.
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare at suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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