net_sched: fix an oops in tcindex filter
Kelly reported the following crash: IP: [<ffffffff817a993d>] tcf_action_exec+0x46/0x90 PGD 3009067 PUD 300c067 PMD 11ff30067 PTE 800000011634b060 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC CPU: 1 PID: 639 Comm: dhclient Not tainted 3.15.0-rc4+ #342 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff8801169ecd00 ti: ffff8800d21b8000 task.ti: ffff8800d21b8000 RIP: 0010:[<ffffffff817a993d>] [<ffffffff817a993d>] tcf_action_exec+0x46/0x90 RSP: 0018:ffff8800d21b9b90 EFLAGS: 00010283 RAX: 00000000ffffffff RBX: ffff88011634b8e8 RCX: ffff8800cf7133d8 RDX: ffff88011634b900 RSI: ffff8800cf7133e0 RDI: ffff8800d210f840 RBP: ffff8800d21b9bb0 R08: ffffffff8287bf60 R09: 0000000000000001 R10: ffff8800d2b22b24 R11: 0000000000000001 R12: ffff8800d210f840 R13: ffff8800d21b9c50 R14: ffff8800cf7133e0 R15: ffff8800cad433d8 FS: 00007f49723e1840(0000) GS:ffff88011a800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88011634b8f0 CR3: 00000000ce469000 CR4: 00000000000006e0 Stack: ffff8800d2170188 ffff8800d210f840 ffff8800d2171b90 0000000000000000 ffff8800d21b9be8 ffffffff817c55bb ffff8800d21b9c50 ffff8800d2171b90 ffff8800d210f840 ffff8800d21b0300 ffff8800d21b9c50 ffff8800d21b9c18 Call Trace: [<ffffffff817c55bb>] tcindex_classify+0x88/0x9b [<ffffffff817a7f7d>] tc_classify_compat+0x3e/0x7b [<ffffffff817a7fdf>] tc_classify+0x25/0x9f [<ffffffff817b0e68>] htb_enqueue+0x55/0x27a [<ffffffff817b6c2e>] dsmark_enqueue+0x165/0x1a4 [<ffffffff81775642>] __dev_queue_xmit+0x35e/0x536 [<ffffffff8177582a>] dev_queue_xmit+0x10/0x12 [<ffffffff818f8ecd>] packet_sendmsg+0xb26/0xb9a [<ffffffff810b1507>] ? __lock_acquire+0x3ae/0xdf3 [<ffffffff8175cf08>] __sock_sendmsg_nosec+0x25/0x27 [<ffffffff8175d916>] sock_aio_write+0xd0/0xe7 [<ffffffff8117d6b8>] do_sync_write+0x59/0x78 [<ffffffff8117d84d>] vfs_write+0xb5/0x10a [<ffffffff8117d96a>] SyS_write+0x49/0x7f [<ffffffff8198e212>] system_call_fastpath+0x16/0x1b This is because we memcpy struct tcindex_filter_result which contains struct tcf_exts, obviously struct list_head can not be simply copied. This is a regression introduced by commit 33be6271 (net_sched: act: use standard struct list_head). It's not very easy to fix it as the code is a mess: if (old_r) memcpy(&cr, r, sizeof(cr)); else { memset(&cr, 0, sizeof(cr)); tcf_exts_init(&cr.exts, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE); } ... tcf_exts_change(tp, &cr.exts, &e); ... memcpy(r, &cr, sizeof(cr)); the above code should equal to: tcindex_filter_result_init(&cr); if (old_r) cr.res = r->res; ... if (old_r) tcf_exts_change(tp, &r->exts, &e); else tcf_exts_change(tp, &cr.exts, &e); ... r->res = cr.res; after this change, since there is no need to copy struct tcf_exts. And it also fixes other places zero'ing struct's contains struct tcf_exts. Fixes: commit 33be6271 (net_sched: act: use standard struct list_head) Reported-by: NKelly Anderson <kelly@xilka.com> Tested-by: NKelly Anderson <kelly@xilka.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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