Tomas Bortoli 3665a4d9dc 9p: Add refcount to p9_req_t ... [ Upstream commit 728356dedeff8ef999cb436c71333ef4ac51a81c ] To avoid use-after-free(s), use a refcount to keep track of the usable references to any instantiated struct p9_req_t. This commit adds p9_req_put(), p9_req_get() and p9_req_try_get() as wrappers to kref_put(), kref_get() and kref_get_unless_zero(). These are used by the client and the transports to keep track of valid requests' references. p9_free_req() is added back and used as callback by kref_put(). Add SLAB_TYPESAFE_BY_RCU as it ensures that the memory freed by kmem_cache_free() will not be reused for another type until the rcu synchronisation period is over, so an address gotten under rcu read lock is safe to inc_ref() without corrupting random memory while the lock is held. Link: http://lkml.kernel.org/r/1535626341-20693-1-git-send-email-asmadeus@codewreck.org Co-developed-by: Dominique Martinet <dominique.martinet@cea.fr> Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com> Reported-by: syzbot+467050c1ce275af2a5b8@syzkaller.appspotmail.com Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr> Signed-off-by: Sasha Levin <sashal@kernel.org>		2019-07-03 13:14:42 +02:00
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9p.h	9p: add a per-client fcall kmem_cache	2019-07-03 13:14:42 +02:00
client.h	9p: Add refcount to p9_req_t	2019-07-03 13:14:42 +02:00
transport.h