lkml.org 
[lkml]   [2018]   [Jun]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [lkp-robot] [bisect done] ef1433f717 [ 7.049860] BUG: unable to handle kernel NULL pointer dereference at 0000004c
On Tue, Jun 26, 2018 at 09:10:07AM +0800, kernel test robot wrote:
>
> Greetings,
>
> 0day kernel testing robot got the below dmesg and the first bad commit is
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>
> commit ef1433f717a2c63747a519d86965d73ff9bd08b3
> Author: Kishon Vijay Abraham I <kishon@ti.com>
> AuthorDate: Mon Apr 2 18:59:35 2018 +0530
> Commit: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> CommitDate: Fri May 18 16:40:50 2018 +0100
>
> PCI: endpoint: Create configfs entry for each pci_epf_device_id table entry
>
> In order to be able to provide correct driver_data for pci_epf device,
> a separate configfs entry for each pci_epf_device_id table entry in
> pci_epf_driver is required.
>
> Add support to create configfs entry for each pci_epf_device_id
> table entry here.
>
> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Tested-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>

From the .config below:

# CONFIG_PCI_ENDPOINT_CONFIGFS is not set

From include/linux/pci-ep-cfs.h:

#ifdef CONFIG_PCI_ENDPOINT_CONFIGFS
...
#else
static inline struct config_group *pci_ep_cfs_add_epf_group(const char *name)
{
return 0;
}

From ef1433f717a2:

+ id = driver->id_table;
+ while (id->name[0]) {
+ group = pci_ep_cfs_add_epf_group(id->name);
+ mutex_lock(&pci_epf_mutex);
+ list_add_tail(&group->group_entry, &driver->epf_group);

Obviously group == 0 and the list_add_tail() is a NULL pointer
dereference.

Looks like we need either some sort of #ifdef CONFIG_PCI_ENDPOINT_CONFIGFS
in __pci_epf_register_driver() and pci_epf_unregister_driver(), or
higher-level interfaces and corresponding stubs that add/remove all
the IDs.

Bjorn

\
 
 \ /
  Last update: 2018-06-26 23:15    [W:0.046 / U:0.052 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site