David Ahern ba51b6be38 net: Fix RCU splat in af_key ... Hit the following splat testing VRF change for ipsec: [ 113.475692] =============================== [ 113.476194] [ INFO: suspicious RCU usage. ] [ 113.476667] 4.2.0-rc6-1+deb7u2+clUNRELEASED #3.2.65-1+deb7u2+clUNRELEASED Not tainted [ 113.477545] ------------------------------- [ 113.478013] /work/monster-14/dsa/kernel.git/include/linux/rcupdate.h:568 Illegal context switch in RCU read-side critical section! [ 113.479288] [ 113.479288] other info that might help us debug this: [ 113.479288] [ 113.480207] [ 113.480207] rcu_scheduler_active = 1, debug_locks = 1 [ 113.480931] 2 locks held by setkey/6829: [ 113.481371] #0: (&net->xfrm.xfrm_cfg_mutex){+.+.+.}, at: [<ffffffff814e9887>] pfkey_sendmsg+0xfb/0x213 [ 113.482509] #1: (rcu_read_lock){......}, at: [<ffffffff814e767f>] rcu_read_lock+0x0/0x6e [ 113.483509] [ 113.483509] stack backtrace: [ 113.484041] CPU: 0 PID: 6829 Comm: setkey Not tainted 4.2.0-rc6-1+deb7u2+clUNRELEASED #3.2.65-1+deb7u2+clUNRELEASED [ 113.485422] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5.1-0-g8936dbb-20141113_115728-nilsson.home.kraxel.org 04/01/2014 [ 113.486845] 0000000000000001 ffff88001d4c7a98 ffffffff81518af2 ffffffff81086962 [ 113.487732] ffff88001d538480 ffff88001d4c7ac8 ffffffff8107ae75 ffffffff8180a154 [ 113.488628] 0000000000000b30 0000000000000000 00000000000000d0 ffff88001d4c7ad8 [ 113.489525] Call Trace: [ 113.489813] [<ffffffff81518af2>] dump_stack+0x4c/0x65 [ 113.490389] [<ffffffff81086962>] ? console_unlock+0x3d6/0x405 [ 113.491039] [<ffffffff8107ae75>] lockdep_rcu_suspicious+0xfa/0x103 [ 113.491735] [<ffffffff81064032>] rcu_preempt_sleep_check+0x45/0x47 [ 113.492442] [<ffffffff8106404d>] ___might_sleep+0x19/0x1c8 [ 113.493077] [<ffffffff81064268>] __might_sleep+0x6c/0x82 [ 113.493681] [<ffffffff81133190>] cache_alloc_debugcheck_before.isra.50+0x1d/0x24 [ 113.494508] [<ffffffff81134876>] kmem_cache_alloc+0x31/0x18f [ 113.495149] [<ffffffff814012b5>] skb_clone+0x64/0x80 [ 113.495712] [<ffffffff814e6f71>] pfkey_broadcast_one+0x3d/0xff [ 113.496380] [<ffffffff814e7b84>] pfkey_broadcast+0xb5/0x11e [ 113.497024] [<ffffffff814e82d1>] pfkey_register+0x191/0x1b1 [ 113.497653] [<ffffffff814e9770>] pfkey_process+0x162/0x17e [ 113.498274] [<ffffffff814e9895>] pfkey_sendmsg+0x109/0x213 In pfkey_sendmsg the net mutex is taken and then pfkey_broadcast takes the RCU lock. Since pfkey_broadcast takes the RCU lock the allocation argument is pointless since GFP_ATOMIC must be used between the rcu_read_{,un}lock. The one call outside of rcu can be done with GFP_KERNEL. Fixes: 7f6b9dbd5a ("af_key: locking change") Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2015-08-24 14:48:10 -07:00
..
af_key.c
Makefile