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The iavf watchdog task overrides adapter->state to __IAVF_RESETTING when it detects a pending reset. Then schedules iavf_reset_task() which takes care of the reset. The reset task is capable of handling the reset without changing adapter->state. In fact we lose the state information when the watchdog task prematurely changes the adapter state. This may lead to a crash if instead of the reset task the iavf_remove() function gets called before the reset task. In that case (if we were in state __IAVF_RUNNING previously) the iavf_remove() function triggers iavf_close() which fails to close the device because of the incorrect state information. This may result in a crash due to pending interrupts. kernel BUG at drivers/pci/msi.c:357! [...] Call Trace: [<ffffffffbddf24dd>] pci_disable_msix+0x3d/0x50 [<ffffffffc08d2a63>] iavf_reset_interrupt_capability+0x23/0x40 [iavf] [<ffffffffc08d312a>] iavf_remove+0x10a/0x350 [iavf] [<ffffffffbddd3359>] pci_device_remove+0x39/0xc0 [<ffffffffbdeb492f>] __device_release_driver+0x7f/0xf0 [<ffffffffbdeb49c3>] device_release_driver+0x23/0x30 [<ffffffffbddcabb4>] pci_stop_bus_device+0x84/0xa0 [<ffffffffbddcacc2>] pci_stop_and_remove_bus_device+0x12/0x20 [<ffffffffbddf361f>] pci_iov_remove_virtfn+0xaf/0x160 [<ffffffffbddf3bcc>] sriov_disable+0x3c/0xf0 [<ffffffffbddf3ca3>] pci_disable_sriov+0x23/0x30 [<ffffffffc0667365>] i40e_free_vfs+0x265/0x2d0 [i40e] [<ffffffffc0667624>] i40e_pci_sriov_configure+0x144/0x1f0 [i40e] [<ffffffffbddd5307>] sriov_numvfs_store+0x177/0x1d0 Code: 00 00 e8 3c 25 e3 ff 49 c7 86 88 08 00 00 00 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48 8b 7b 28 e8 0d 44 RIP [<ffffffffbbbf1068>] free_msi_irqs+0x188/0x190 The solution is to not touch the adapter->state in iavf_watchdog_task() and let the reset task handle the state transition. Signed-off-by: Stefan Assmann <sassmann@kpanic.de> Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.