lkml.org 
[lkml]   [2020]   [Oct]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.8 012/633] net: sched: Fix suspicious RCU usage while accessing tcf_tunnel_info
    Date
    From: Leon Romanovsky <leonro@nvidia.com>

    [ Upstream commit d086a1c65aabb5a4e1edc580ca583e2964c62b44 ]

    The access of tcf_tunnel_info() produces the following splat, so fix it
    by dereferencing the tcf_tunnel_key_params pointer with marker that
    internal tcfa_liock is held.

    =============================
    WARNING: suspicious RCU usage
    5.9.0+ #1 Not tainted
    -----------------------------
    include/net/tc_act/tc_tunnel_key.h:59 suspicious rcu_dereference_protected() usage!
    other info that might help us debug this:

    rcu_scheduler_active = 2, debug_locks = 1
    1 lock held by tc/34839:
    #0: ffff88828572c2a0 (&p->tcfa_lock){+...}-{2:2}, at: tc_setup_flow_action+0xb3/0x48b5
    stack backtrace:
    CPU: 1 PID: 34839 Comm: tc Not tainted 5.9.0+ #1
    Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
    Call Trace:
    dump_stack+0x9a/0xd0
    tc_setup_flow_action+0x14cb/0x48b5
    fl_hw_replace_filter+0x347/0x690 [cls_flower]
    fl_change+0x2bad/0x4875 [cls_flower]
    tc_new_tfilter+0xf6f/0x1ba0
    rtnetlink_rcv_msg+0x5f2/0x870
    netlink_rcv_skb+0x124/0x350
    netlink_unicast+0x433/0x700
    netlink_sendmsg+0x6f1/0xbd0
    sock_sendmsg+0xb0/0xe0
    ____sys_sendmsg+0x4fa/0x6d0
    ___sys_sendmsg+0x12e/0x1b0
    __sys_sendmsg+0xa4/0x120
    do_syscall_64+0x2d/0x40
    entry_SYSCALL_64_after_hwframe+0x44/0xa9
    RIP: 0033:0x7f1f8cd4fe57
    Code: 0c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10
    RSP: 002b:00007ffdc1e193b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
    RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1f8cd4fe57
    RDX: 0000000000000000 RSI: 00007ffdc1e19420 RDI: 0000000000000003
    RBP: 000000005f85aafa R08: 0000000000000001 R09: 00007ffdc1e1936c
    R10: 000000000040522d R11: 0000000000000246 R12: 0000000000000001
    R13: 0000000000000000 R14: 00007ffdc1e1d6f0 R15: 0000000000482420

    Fixes: 3ebaf6da0716 ("net: sched: Do not assume RTNL is held in tunnel key action helpers")
    Fixes: 7a47281439ba ("net: sched: lock action when translating it to flow_action infra")
    Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
    Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    include/net/tc_act/tc_tunnel_key.h | 5 ++++-
    1 file changed, 4 insertions(+), 1 deletion(-)

    --- a/include/net/tc_act/tc_tunnel_key.h
    +++ b/include/net/tc_act/tc_tunnel_key.h
    @@ -56,7 +56,10 @@ static inline struct ip_tunnel_info *tcf
    {
    #ifdef CONFIG_NET_CLS_ACT
    struct tcf_tunnel_key *t = to_tunnel_key(a);
    - struct tcf_tunnel_key_params *params = rtnl_dereference(t->params);
    + struct tcf_tunnel_key_params *params;
    +
    + params = rcu_dereference_protected(t->params,
    + lockdep_is_held(&a->tcfa_lock));

    return &params->tcft_enc_metadata->u.tun_info;
    #else

    \
     
     \ /
      Last update: 2020-10-27 16:10    [W:5.057 / U:0.692 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site