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authorLinus Torvalds <torvalds@linux-foundation.org>2019-12-15 12:24:44 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-12-15 12:24:44 -0800
commitb01d7cb41ff51b7779977de601a984406e2a5ba9 (patch)
tree8905489ee1520843a5737e670d61465b96141463 /drivers/block/xen-blkback
parent2e6d304515ba9936d85265ad93dddc4c13c17d06 (diff)
parentc673ec61ade89bf2f417960f986bc25671762efb (diff)
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Merge tag 'for-linus-5.5b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross: "Two fixes: one for a resource accounting bug in some configurations and a fix for another patch which went into rc1" * tag 'for-linus-5.5b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/balloon: fix ballooned page accounting without hotplug enabled xen-blkback: prevent premature module unload
Diffstat (limited to 'drivers/block/xen-blkback')
-rw-r--r--drivers/block/xen-blkback/xenbus.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index e8c5c54e1d26..d6a6adfd5159 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -171,6 +171,15 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
blkif->domid = domid;
atomic_set(&blkif->refcnt, 1);
init_completion(&blkif->drain_complete);
+
+ /*
+ * Because freeing back to the cache may be deferred, it is not
+ * safe to unload the module (and hence destroy the cache) until
+ * this has completed. To prevent premature unloading, take an
+ * extra module reference here and release only when the object
+ * has been freed back to the cache.
+ */
+ __module_get(THIS_MODULE);
INIT_WORK(&blkif->free_work, xen_blkif_deferred_free);
return blkif;
@@ -320,6 +329,7 @@ static void xen_blkif_free(struct xen_blkif *blkif)
/* Make sure everything is drained before shutting down */
kmem_cache_free(xen_blkif_cachep, blkif);
+ module_put(THIS_MODULE);
}
int __init xen_blkif_interface_init(void)