Messages in this thread | | | Date | Tue, 26 Jun 2018 16:15:01 -0500 | From | Bjorn Helgaas <> | Subject | Re: [lkp-robot] [bisect done] ef1433f717 [ 7.049860] BUG: unable to handle kernel NULL pointer dereference at 0000004c |
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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
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