Re: [PATCH v2 0/2] pci: endpoint: Fix double free in pci_epf_create()
From: Bjorn Helgaas
Date: Mon Feb 26 2018 - 13:23:07 EST
On Mon, Feb 26, 2018 at 06:16:15PM +0100, Rolf Evers-Fischer wrote:
> This is version 2 of a patchset to avoid double free in function
> 'pci_epf_create()'.
>
> When I accidentally created a new endpoint device with an empty name,
> the kernel warned about "attempted to be registered with empty name!"
> and crashed afterwards.
>
> It turned out that the crash was not caused by the 'device_add()'
> function itself, but by a double kfree of 'epf->name' and 'epf'.
>
> The first patch just simplifies the code, while the second patch
> fixes the problem.
>
> Changes in v2:
> - Based on feedback from Lorenzo, Andy and Kishon (thanks!)
> - Change IDs removed
> - First patch completely reworked in order to eliminate the
> need for the second 'kstrdup' allocation and the 'kfree' of
> the first allocation.
> It was tested with name="pci_epf_test.0" and name="pci_epb":
> The 'epf->name' was "pci_epf_test" or "pci_epb" (=unchanged).
>
> Rolf Evers-Fischer (2):
> pci: endpoint: Simplify name allocation for epf device
> pci: endpoint: Fix kernel panic after put_device()
$ git log --oneline --no-merges drivers/pci/endpoint/
fc41df28f89e PCI: endpoint: Fix EPF device name to support multi-function devices
4494738de0d9 PCI: endpoint: Add the function number as argument to EPC ops
b330104fa76d PCI: endpoint: Use EPC's device in dma_alloc_coherent()/dma_free_coherent()
35ad61921f49 PCI: endpoint: Fix find_first_zero_bit() usage
0c47cd7a9b6c PCI: endpoint: Populate func_no before calling pci_epc_add_epf()
...
Please make yours match.