Frederic Weisbecker f08b2d078c xfrm: Fix RCU vs hash_resize_mutex lock inversion ... commit 2580d3f400 upstream. xfrm_bydst_resize() calls synchronize_rcu() while holding hash_resize_mutex. But then on PREEMPT_RT configurations, xfrm_policy_lookup_bytype() may acquire that mutex while running in an RCU read side critical section. This results in a deadlock. In fact the scope of hash_resize_mutex is way beyond the purpose of xfrm_policy_lookup_bytype() to just fetch a coherent and stable policy for a given destination/direction, along with other details. The lower level net->xfrm.xfrm_policy_lock, which among other things protects per destination/direction references to policy entries, is enough to serialize and benefit from priority inheritance against the write side. As a bonus, it makes it officially a per network namespace synchronization business where a policy table resize on namespace A shouldn't block a policy lookup on namespace B. Fixes: 77cc278f7b (xfrm: policy: Use sequence counters with associated lock) Cc: stable@vger.kernel.org Cc: Ahmed S. Darwish <a.darwish@linutronix.de> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Varad Gautam <varad.gautam@suse.com> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-08-12 13:22:16 +02:00
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bpf.h	bpf, netns: Keep a list of attached bpf_link's	2020-06-30 10:45:08 -07:00
can.h	can: remove obsolete version strings	2020-10-12 10:06:39 +02:00
conntrack.h	netfilter: conntrack: limit sysctl setting for boolean options	2019-04-30 14:18:56 +02:00
core.h
dccp.h
generic.h
hash.h	netns: provide pure entropy for net_hash_mix()	2019-03-28 17:00:45 -07:00
ieee802154_6lowpan.h	net: dynamically allocate fqdir structures	2019-05-26 14:08:05 -07:00
ipv4.h	tcp: reflect tos value received in SYN to the socket	2020-09-10 13:15:40 -07:00
ipv6.h	ipv6: keep track of routes using src	2019-11-21 14:45:55 -08:00
mib.h	mptcp: add and use MIB counter infrastructure	2020-03-29 22:14:49 -07:00
mpls.h
netfilter.h
nexthop.h	nexthop: Convert to blocking notification chain	2020-09-15 16:31:17 -07:00
nftables.h	netfilter: nf_tables: coalesce multiple notifications into one skbuff	2020-09-08 13:02:44 +02:00
packet.h
sctp.h	sctp: add support for Primary Path Switchover	2019-11-08 14:18:32 -08:00
unix.h
x_tables.h
xdp.h	net: xsk: track AF_XDP sockets on a per-netns list	2019-01-25 01:50:03 +01:00
xfrm.h	xfrm: Fix RCU vs hash_resize_mutex lock inversion	2021-08-12 13:22:16 +02:00