[PATCH 4.7 21/45] i40e: avoid NULL pointer dereference and recursive errors on early PCI error

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	[PATCH 4.7 21/45] i40e: avoid NULL pointer dereference and recursive errors on early PCI error
Date	2016-10-21 11:50 +0200
Message-ID	<suECB-3Ib-11@gated-at.bofh.it> (permalink)
References	<suE9A-3xe-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

4.7-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Guilherme G Piccoli <gpiccoli@linux.vnet.ibm.com>

commit edfc23ee3e0ebbb6713d7574ab1b00abff178f6c upstream.

Although rare, it's possible to hit PCI error early on device
probe, meaning possibly some structs are not entirely initialized,
and some might even be completely uninitialized, leading to NULL
pointer dereference.

The i40e driver currently presents a "bad" behavior if device hits
such early PCI error: firstly, the struct i40e_pf might not be
attached to pci_dev yet, leading to a NULL pointer dereference on
access to pf->state.

Even checking if the struct is NULL and avoiding the access in that
case isn't enough, since the driver cannot recover from PCI error
that early; in our experiments we saw multiple failures on kernel
log, like:

  [549.664] i40e 0007:01:00.1: Initial pf_reset failed: -15
  [549.664] i40e: probe of 0007:01:00.1 failed with error -15
  [...]
  [871.644] i40e 0007:01:00.1: The driver for the device stopped because the
  device firmware failed to init. Try updating your NVM image.
  [871.644] i40e: probe of 0007:01:00.1 failed with error -32
  [...]
  [872.516] i40e 0007:01:00.0: ARQ: Unknown event 0x0000 ignored

Between the first probe failure (error -15) and the second (error -32)
another PCI error happened due to the first bad probe. Also, driver
started to flood console with those ARQ event messages.

This patch will prevent these issues by allowing error recovery
mechanism to remove the failed device from the system instead of
trying to recover from early PCI errors during device probe.

Signed-off-by: Guilherme G Piccoli <gpiccoli@linux.vnet.ibm.com>
Acked-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.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>

---
 drivers/net/ethernet/intel/i40e/i40e_main.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -11415,6 +11415,12 @@ static pci_ers_result_t i40e_pci_error_d
 
 	dev_info(&pdev->dev, "%s: error %d\n", __func__, error);
 
+	if (!pf) {
+		dev_info(&pdev->dev,
+			 "Cannot recover - error happened during device probe\n");
+		return PCI_ERS_RESULT_DISCONNECT;
+	}
+
 	/* shutdown all operations */
 	if (!test_bit(__I40E_SUSPENDED, &pf->state)) {
 		rtnl_lock();

Thread

[PATCH 4.7 00/45] 4.7.10-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:40 +0200
  [PATCH 4.7 06/45] debugfs: introduce a public file_operations accessor Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:40 +0200
  [PATCH 4.7 44/45] cachefiles: Fix attempt to read i_blocks after deleting file [ver #2] Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:40 +0200
  [PATCH 4.7 38/45] ext4: release bh in make_indexed_dir Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:40 +0200
  [PATCH 4.7 33/45] ext4: enforce online defrag restriction for encrypted files Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:40 +0200
  [PATCH 4.7 45/45] cfq: fix starvation of asynchronous writes Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:40 +0200
  [PATCH 4.7 08/45] b43legacy: fix debugfs crash Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:40 +0200
  [PATCH 4.7 20/45] fuse: fix killing s[ug]id in setattr Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.7 21/45] i40e: avoid NULL pointer dereference and recursive errors on early PCI error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.7 14/45] drivers: base: dma-mapping: page align the size when unmap_kernel_range Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.7 02/45] serial: 8250_dw: Check the data->pclk when get apb_pclk Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.7 30/45] scsi: arcmsr: Simplify user_len checking Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.7 29/45] scsi: arcmsr: Buffer overflow in arcmsr_iop_message_xfer() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.7 05/45] ARCv2: fix local_save_flags Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.7 17/45] clk: mvebu: dynamically allocate resources in Armada CP110 system controller Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.7 23/45] brcmfmac: fix pmksa->bssid usage Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  [PATCH 4.7 15/45] IB/hfi1: Fix defered ack race with qp destroy Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-21 11:50 +0200
  Re: [PATCH 4.7 00/45] 4.7.10-stable review Shuah Khan <shuah.kh@samsung.com> - 2016-10-21 17:50 +0200
  Re: [PATCH 4.7 00/45] 4.7.10-stable review Guenter Roeck <linux@roeck-us.net> - 2016-10-21 21:20 +0200
  Re: [PATCH 4.7 00/45] 4.7.10-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-22 12:00 +0200

csiph-web