From 461692058ec81c61ce2642097d256ffcaf8897cf Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 21 Nov 2014 23:52:53 -0800 Subject: [PATCH] ixgbe: fix use after free adapter->state test in ixgbe_remove/ixgbe_probe commit b5b2ffc0574e1f271d79b6b992ee382dc9d5eaa8 upstream. While working on a different issue, I noticed an annoying use after free bug on my machine when unloading the ixgbe driver: [ 8642.318797] ixgbe 0000:02:00.1: removed PHC on p2p2 [ 8642.742716] ixgbe 0000:02:00.1: complete [ 8642.743784] BUG: unable to handle kernel paging request at ffff8807d3740a90 [ 8642.744828] IP: [] ixgbe_remove+0xfc/0x1b0 [ixgbe] [ 8642.745886] PGD 20c6067 PUD 81c1f6067 PMD 81c15a067 PTE 80000007d3740060 [ 8642.746956] Oops: 0002 [#1] SMP DEBUG_PAGEALLOC [ 8642.748039] Modules linked in: [...] [ 8642.752929] CPU: 1 PID: 1225 Comm: rmmod Not tainted 3.18.0-rc2+ #49 [ 8642.754203] Hardware name: Supermicro X10SLM-F/X10SLM-F, BIOS 1.1b 11/01/2013 [ 8642.755505] task: ffff8807e34d3fe0 ti: ffff8807b7204000 task.ti: ffff8807b7204000 [ 8642.756831] RIP: 0010:[] [] ixgbe_remove+0xfc/0x1b0 [ixgbe] [...] [ 8642.774335] Stack: [ 8642.775805] ffff8807ee824098 ffff8807ee824098 ffffffffa01f3000 ffff8807ee824000 [ 8642.777326] ffff8807b7207e18 ffffffff8137720f ffff8807ee824098 ffff8807ee824098 [ 8642.778848] ffffffffa01f3068 ffff8807ee8240f8 ffff8807b7207e38 ffffffff8144180f [ 8642.780365] Call Trace: [ 8642.781869] [] pci_device_remove+0x3f/0xc0 [ 8642.783395] [] __device_release_driver+0x7f/0xf0 [ 8642.784876] [] driver_detach+0xb8/0xc0 [ 8642.786352] [] bus_remove_driver+0x59/0xe0 [ 8642.787783] [] driver_unregister+0x30/0x70 [ 8642.789202] [] pci_unregister_driver+0x25/0xa0 [ 8642.790657] [] ixgbe_exit_module+0x1c/0xc8e [ixgbe] [ 8642.792064] [] SyS_delete_module+0x132/0x1c0 [ 8642.793450] [] ? do_notify_resume+0x61/0xa0 [ 8642.794837] [] system_call_fastpath+0x12/0x17 The issue is that test_and_set_bit() done on adapter->state is being performed *after* the netdevice has been freed via free_netdev(). When netdev is being allocated on initialization time, it allocates a private area, here struct ixgbe_adapter, that resides after the net_device structure. In ixgbe_probe(), the device init routine, we set up the adapter after alloc_etherdev_mq() on the private area and add a reference for the pci_dev as well via pci_set_drvdata(). Both in the error path of ixgbe_probe(), but also on module unload when ixgbe_remove() is being called, commit 41c62843eb6a ("ixgbe: Fix rcu warnings induced by LER") accesses adapter after free_netdev(). The patch stores the result in a bool and thus fixes above oops on my side. Fixes: 41c62843eb6a ("ixgbe: Fix rcu warnings induced by LER") Cc: Mark Rustad Signed-off-by: Daniel Borkmann Signed-off-by: Jeff Kirsher Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index bbe0564125a300..e82821fdf9050a 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -8084,6 +8084,7 @@ static int ixgbe_probe(struct pci_dev *pdev, const struct pci_device_id *ent) int i, err, pci_using_dac, expected_gts; unsigned int indices = MAX_TX_QUEUES; u8 part_str[IXGBE_PBANUM_LENGTH]; + bool disable_dev = false; #ifdef IXGBE_FCOE u16 device_caps; #endif @@ -8477,13 +8478,14 @@ static int ixgbe_probe(struct pci_dev *pdev, const struct pci_device_id *ent) iounmap(adapter->io_addr); kfree(adapter->mac_table); err_ioremap: + disable_dev = !test_and_set_bit(__IXGBE_DISABLED, &adapter->state); free_netdev(netdev); err_alloc_etherdev: pci_release_selected_regions(pdev, pci_select_bars(pdev, IORESOURCE_MEM)); err_pci_reg: err_dma: - if (!adapter || !test_and_set_bit(__IXGBE_DISABLED, &adapter->state)) + if (!adapter || disable_dev) pci_disable_device(pdev); return err; } @@ -8501,6 +8503,7 @@ static void ixgbe_remove(struct pci_dev *pdev) { struct ixgbe_adapter *adapter = pci_get_drvdata(pdev); struct net_device *netdev = adapter->netdev; + bool disable_dev; ixgbe_dbg_adapter_exit(adapter); @@ -8550,11 +8553,12 @@ static void ixgbe_remove(struct pci_dev *pdev) e_dev_info("complete\n"); kfree(adapter->mac_table); + disable_dev = !test_and_set_bit(__IXGBE_DISABLED, &adapter->state); free_netdev(netdev); pci_disable_pcie_error_reporting(pdev); - if (!test_and_set_bit(__IXGBE_DISABLED, &adapter->state)) + if (disable_dev) pci_disable_device(pdev); }