Ido Schimmel 3ebaf6da07 net: sched: Do not assume RTNL is held in tunnel key action helpers ... The cited commit removed RTNL from tc_setup_flow_action(), but the function calls two tunnel key action helpers that use rtnl_dereference() to fetch the action's parameters. This leads to "suspicious RCU usage" warnings [1][2]. Change the helpers to use rcu_dereference_protected() while requiring the action's lock to be held. This is safe because the two helpers are only called from tc_setup_flow_action() which acquires the lock. [1] [ 156.950855] ============================= [ 156.955463] WARNING: suspicious RCU usage [ 156.960085] 5.6.0-rc5-custom-47426-gdfe43878d573 #2409 Not tainted [ 156.967116] ----------------------------- [ 156.971728] include/net/tc_act/tc_tunnel_key.h:31 suspicious rcu_dereference_protected() usage! [ 156.981583] [ 156.981583] other info that might help us debug this: [ 156.981583] [ 156.990675] [ 156.990675] rcu_scheduler_active = 2, debug_locks = 1 [ 156.998205] 1 lock held by tc/877: [ 157.002187] #0: ffff8881cbf7bea0 (&(&p->tcfa_lock)->rlock){+...}, at: tc_setup_flow_action+0xbe/0x4f78 [ 157.012866] [ 157.012866] stack backtrace: [ 157.017886] CPU: 2 PID: 877 Comm: tc Not tainted 5.6.0-rc5-custom-47426-gdfe43878d573 #2409 [ 157.027253] Hardware name: Mellanox Technologies Ltd. MSN2100-CB2FO/SA001017, BIOS 5.6.5 06/07/2016 [ 157.037389] Call Trace: [ 157.040170] dump_stack+0xfd/0x178 [ 157.044034] lockdep_rcu_suspicious+0x14a/0x153 [ 157.049157] tc_setup_flow_action+0x89f/0x4f78 [ 157.054227] fl_hw_replace_filter+0x375/0x640 [ 157.064348] fl_change+0x28ec/0x4f6b [ 157.088843] tc_new_tfilter+0x15e2/0x2260 [ 157.176801] rtnetlink_rcv_msg+0x8d6/0xb60 [ 157.190915] netlink_rcv_skb+0x177/0x460 [ 157.208884] rtnetlink_rcv+0x21/0x30 [ 157.212925] netlink_unicast+0x5d0/0x7f0 [ 157.227728] netlink_sendmsg+0x981/0xe90 [ 157.245416] ____sys_sendmsg+0x76d/0x8f0 [ 157.255348] ___sys_sendmsg+0x10f/0x190 [ 157.320308] __sys_sendmsg+0x115/0x1f0 [ 157.342553] __x64_sys_sendmsg+0x7d/0xc0 [ 157.346987] do_syscall_64+0xc1/0x600 [ 157.351142] entry_SYSCALL_64_after_hwframe+0x49/0xbe [2] [ 157.432346] ============================= [ 157.436937] WARNING: suspicious RCU usage [ 157.441537] 5.6.0-rc5-custom-47426-gdfe43878d573 #2409 Not tainted [ 157.448559] ----------------------------- [ 157.453204] include/net/tc_act/tc_tunnel_key.h:43 suspicious rcu_dereference_protected() usage! [ 157.463042] [ 157.463042] other info that might help us debug this: [ 157.463042] [ 157.472112] [ 157.472112] rcu_scheduler_active = 2, debug_locks = 1 [ 157.479529] 1 lock held by tc/877: [ 157.483442] #0: ffff8881cbf7bea0 (&(&p->tcfa_lock)->rlock){+...}, at: tc_setup_flow_action+0xbe/0x4f78 [ 157.494119] [ 157.494119] stack backtrace: [ 157.499114] CPU: 2 PID: 877 Comm: tc Not tainted 5.6.0-rc5-custom-47426-gdfe43878d573 #2409 [ 157.508485] Hardware name: Mellanox Technologies Ltd. MSN2100-CB2FO/SA001017, BIOS 5.6.5 06/07/2016 [ 157.518628] Call Trace: [ 157.521416] dump_stack+0xfd/0x178 [ 157.525293] lockdep_rcu_suspicious+0x14a/0x153 [ 157.530425] tc_setup_flow_action+0x993/0x4f78 [ 157.535505] fl_hw_replace_filter+0x375/0x640 [ 157.545650] fl_change+0x28ec/0x4f6b [ 157.570204] tc_new_tfilter+0x15e2/0x2260 [ 157.658199] rtnetlink_rcv_msg+0x8d6/0xb60 [ 157.672315] netlink_rcv_skb+0x177/0x460 [ 157.690278] rtnetlink_rcv+0x21/0x30 [ 157.694320] netlink_unicast+0x5d0/0x7f0 [ 157.709129] netlink_sendmsg+0x981/0xe90 [ 157.726813] ____sys_sendmsg+0x76d/0x8f0 [ 157.736725] ___sys_sendmsg+0x10f/0x190 [ 157.801721] __sys_sendmsg+0x115/0x1f0 [ 157.823967] __x64_sys_sendmsg+0x7d/0xc0 [ 157.828403] do_syscall_64+0xc1/0x600 [ 157.832558] entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: b15e7a6e8d ("net: sched: don't take rtnl lock during flow_action setup") Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Reviewed-by: Vlad Buslov <vladbu@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2020-03-19 20:25:52 -07:00
..
acpi	ACPI fixes for 5.6-rc4	2020-02-28 09:02:18 -08:00
asm-generic	Microblaze patches for 5.6-rc1	2020-02-04 11:58:07 +00:00
clocksource
crypto	crypto: x86/curve25519 - support assemblers with no adx support	2020-03-05 18:28:09 +11:00
drm	drm/dp_mst: Use full_pbn instead of available_pbn for bandwidth checks	2020-03-12 19:07:24 -04:00
dt-bindings	ARM: SoC: late updates	2020-02-08 14:17:27 -08:00
keys
kunit
kvm
linux	mlx5-updates-2020-03-17	2020-03-18 19:13:37 -07:00
math-emu
media
misc
net	net: sched: Do not assume RTNL is held in tunnel key action helpers	2020-03-19 20:25:52 -07:00
pcmcia
ras
rdma	RDMA/core: Make the entire API tree static	2020-01-30 16:28:52 -04:00
scsi	scsi: Revert "target: iscsi: Wait for all commands to finish before freeing a session"	2020-02-14 17:13:54 -05:00
soc	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2020-03-12 22:34:48 -07:00
sound	ASoC: Fixes for v5.6	2020-03-07 07:24:36 +01:00
target
trace	bpf: Reliably preserve btf_trace_xxx types	2020-03-02 16:49:55 -08:00
uapi	net: bridge: vlan: include stats in dumps if requested	2020-03-19 20:21:47 -07:00
vdso
video
xen	xen/xenbus: fix locking	2020-03-05 09:42:23 -06:00