linux/include
WANG Cong 763dbf6328 net_sched: move the empty tp check from ->destroy() to ->delete()
We could have a race condition where in ->classify() path we
dereference tp->root and meanwhile a parallel ->destroy() makes it
a NULL. Daniel cured this bug in commit d936377414
("net, sched: respect rcu grace period on cls destruction").

This happens when ->destroy() is called for deleting a filter to
check if we are the last one in tp, this tp is still linked and
visible at that time. The root cause of this problem is the semantic
of ->destroy(), it does two things (for non-force case):

1) check if tp is empty
2) if tp is empty we could really destroy it

and its caller, if cares, needs to check its return value to see if it
is really destroyed. Therefore we can't unlink tp unless we know it is
empty.

As suggested by Daniel, we could actually move the test logic to ->delete()
so that we can safely unlink tp after ->delete() tells us the last one is
just deleted and before ->destroy().

Fixes: 1e052be69d ("net_sched: destroy proto tp when all filters are gone")
Cc: Roi Dayan <roid@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-21 13:58:15 -04:00
..
acpi Merge branches 'acpi-bus', 'acpi-sleep' and 'acpi-processor' 2017-02-20 14:28:03 +01:00
asm-generic vmlinux.lds: add missing VMLINUX_SYMBOL macros 2017-04-08 00:47:48 -07:00
clocksource
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-04-18 09:03:50 -07:00
drm drm/ttm, drm/vmwgfx: Relax permission checking when opening surfaces 2017-03-30 11:43:39 +02:00
dt-bindings scripts/spelling.txt: add "overide" pattern and fix typo instances 2017-03-09 17:01:09 -08:00
keys KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload() 2017-03-02 10:09:00 +11:00
kvm KVM: arm64: Ensure LRs are clear when they should be 2017-04-04 14:33:58 +02:00
linux Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning 2017-04-21 13:22:34 -04:00
math-emu
media media fixes for v4.11-rc2 2017-03-09 15:50:56 -08:00
memory
misc
net net_sched: move the empty tp check from ->destroy() to ->delete() 2017-04-21 13:58:15 -04:00
pcmcia
ras
rdma IB/core: Restore I/O MMU, s390 and powerpc support 2017-03-24 21:51:16 -04:00
rxrpc
scsi scsi: mpt3sas: Avoid sleeping in interrupt context 2017-03-01 21:52:13 -05:00
soc ARC updates for 4.11 rc1 2017-02-22 10:33:53 -08:00
sound sched/headers: Prepare to remove spurious <linux/sched.h> inclusion dependencies 2017-03-02 08:42:41 +01:00
target target: Fix ALUA transition state race between multiple initiators 2017-03-30 23:12:40 -07:00
trace rxrpc: Trace client call connection 2017-04-06 11:10:41 +01:00
uapi bpf: add napi_id read access to __sk_buff 2017-04-21 13:53:27 -04:00
video drm/exynos/decon5433: signal frame done interrupt at front porch 2017-03-21 13:17:22 +09:00
xen Merge branch 'stable/for-linus-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb 2017-03-07 10:23:17 -08:00
Kbuild