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ixgbe: fix use after free adapter->state test in ixgbe_remove/ixgbe_p…
…robe commit b5b2ffc 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: [<ffffffffa01c77dc>] 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:[<ffffffffa01c77dc>] [<ffffffffa01c77dc>] 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] [<ffffffff8137720f>] pci_device_remove+0x3f/0xc0 [ 8642.783395] [<ffffffff8144180f>] __device_release_driver+0x7f/0xf0 [ 8642.784876] [<ffffffff814421f8>] driver_detach+0xb8/0xc0 [ 8642.786352] [<ffffffff814414a9>] bus_remove_driver+0x59/0xe0 [ 8642.787783] [<ffffffff814429d0>] driver_unregister+0x30/0x70 [ 8642.789202] [<ffffffff81375c65>] pci_unregister_driver+0x25/0xa0 [ 8642.790657] [<ffffffffa01eb38e>] ixgbe_exit_module+0x1c/0xc8e [ixgbe] [ 8642.792064] [<ffffffff810f93a2>] SyS_delete_module+0x132/0x1c0 [ 8642.793450] [<ffffffff81012c61>] ? do_notify_resume+0x61/0xa0 [ 8642.794837] [<ffffffff816d2029>] 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 41c6284 ("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: 41c6284 ("ixgbe: Fix rcu warnings induced by LER") Cc: Mark Rustad <mark.d.rustad@intel.com> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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