From mboxrd@z Thu Jan 1 00:00:00 1970 From: akepner Subject: Re: e1000e: avoid NULL pointer deref in e1000_print_hw_hang() Date: Wed, 20 Mar 2013 18:52:58 -0700 Message-ID: <20130321015258.GA910@riverbed.com> References: <20130321014005.GD6755@riverbed.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: e1000-devel@lists.sourceforge.net To: netdev@vger.kernel.org Return-path: Received: from incomingmail.riverbed.com ([208.70.196.45]:41607 "EHLO smtp1.riverbed.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754214Ab3CUBxA (ORCPT ); Wed, 20 Mar 2013 21:53:00 -0400 Content-Disposition: inline In-Reply-To: <20130321014005.GD6755@riverbed.com> Sender: netdev-owner@vger.kernel.org List-ID: (Resending - the previous version was against our local tree, not the upstream tree.) If an e1000e interface is brought down, and subsequently 'print_hang_task' is run we'll dereference a NULL 'buffer_info' pointer and crash with something like this: Mar 19 13:20:27 BUG: unable to handle kernel NULL pointer dereference at 000000000000001a Mar 19 13:20:27 IP: [] e1000_print_hw_hang+0x4c/0x390 Mar 19 13:20:27 PGD 82668067 PUD 763f6067 PMD 0 Mar 19 13:20:27 Oops: 0000 [#1] SMP Mar 19 13:20:27 last sysfs file: /sys/devices/virtual/bypass/2-3/ping_watchdog Mar 19 13:20:27 CPU 3 Mar 19 13:20:27 Pid: 18, comm: events/3 Tainted: P ---------------- 2.6.32 #1 empty Mar 19 13:20:28 RIP: 0010:[] [] e1000_print_hw_hang+0x4c/0x390 Mar 19 13:20:28 RSP: 0000:ffff88019ee71d40 EFLAGS: 00010202 Mar 19 13:20:28 RAX: 0000000000000000 RBX: ffff88019b64b3a0 RCX: ffff88019b648700 Mar 19 13:20:28 RDX: 0000000000000000 RSI: ffff88019b648000 RDI: ffff88019b64b3a0 Mar 19 13:20:28 RBP: ffff88019ee71e30 R08: 0000000000000000 R09: 0000000000000000 Mar 19 13:20:28 R10: ffff880028401340 R11: 0000000000000006 R12: ffff88019b5865c0 Mar 19 13:20:28 R13: ffffffff814503c0 R14: 0000000000000000 R15: ffff8800282d8a08 Mar 19 13:20:28 FS: 0000000000000000(0000) GS:ffff8800282c0000(0000) knlGS:0000000000000000 Mar 19 13:20:28 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b Mar 19 13:20:28 CR2: 000000000000001a CR3: 0000000076364000 CR4: 00000000000406e0 Mar 19 13:20:28 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 Mar 19 13:20:28 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Mar 19 13:20:28 Process events/3 (pid: 18, threadinfo ffff88019ee70000, task ffff88019ee6f560) Mar 19 13:20:28 Stack: Mar 19 13:20:28 0000000000000000 0000000000000001 ffff88019ee71fd8 ffffea000173d740 Mar 19 13:20:28 <0> ffff88019ee71dd0 0000000000000282 ffff88019ee71fd8 ffff8800282d8a08 Mar 19 13:20:29 <0> ffff88019ee71da0 ffffffff811045ed ffffea000173d740 0000000000000000 Mar 19 13:20:29 Call Trace: Mar 19 13:20:29 [] ? free_hot_page+0x2d/0x60 Mar 19 13:20:29 [] ? __vunmap+0x9c/0x120 Mar 19 13:20:29 [] ? free_fdtable_work+0x0/0x90 Mar 19 13:20:29 [] ? e1000_print_hw_hang+0x0/0x390 Mar 19 13:20:29 [] worker_thread+0x170/0x2a0 Mar 19 13:20:29 [] ? autoremove_wake_function+0x0/0x40 Mar 19 13:20:29 [] ? worker_thread+0x0/0x2a0 Mar 19 13:20:29 [] kthread+0x96/0xa0 Mar 19 13:20:29 [] child_rip+0xa/ (This was seen on a pretty old kernel/driver, but looks like the same bug is still possible.) Signed-off-by: --- diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c index 948b86ff..46a3ea4 100644 --- a/drivers/net/ethernet/intel/e1000e/netdev.c +++ b/drivers/net/ethernet/intel/e1000e/netdev.c @@ -1070,18 +1070,25 @@ static void e1000_print_hw_hang(struct work_struct *work) struct e1000_adapter *adapter = container_of(work, struct e1000_adapter, print_hang_task); - struct net_device *netdev = adapter->netdev; - struct e1000_ring *tx_ring = adapter->tx_ring; - unsigned int i = tx_ring->next_to_clean; - unsigned int eop = tx_ring->buffer_info[i].next_to_watch; - struct e1000_tx_desc *eop_desc = E1000_TX_DESC(*tx_ring, eop); - struct e1000_hw *hw = &adapter->hw; + struct net_device *netdev; + struct e1000_ring *tx_ring; + unsigned int i; + unsigned int eop; + struct e1000_tx_desc *eop_desc; + struct e1000_hw *hw; u16 phy_status, phy_1000t_status, phy_ext_status; u16 pci_status; if (test_bit(__E1000_DOWN, &adapter->state)) return; + netdev = adapter->netdev; + tx_ring = adapter->tx_ring; + i = tx_ring->next_to_clean; + eop = tx_ring->buffer_info[i].next_to_watch; + eop_desc = E1000_TX_DESC(*tx_ring, eop); + hw = &adapter->hw; + if (!adapter->tx_hang_recheck && (adapter->flags2 & FLAG2_DMA_BURST)) { /* May be block on write-back, flush and detect again