On 6/17/25 10:07, Damien Le Moal wrote:
> An endpoint driver configfs attributes group is added to the
> epf_group list of struct pci_epf_driver pci_epf_add_cfs() but not
> removed from this list when the attribute group is unregistered with
> pci_ep_cfs_remove_epf_group(). Add the missing list_del_init() call in
> that function to correctly remove the attribute group from the driver
> list.
>
> Furthermore, doing a list_del() on the epf_group field of struct
> pci_epf_driver in pci_epf_remove_cfs() is not correct as this field is a
> list head, not a list entry, and triggers a KASAN warning:
Ping ?
>
> ==================================================================
> BUG: KASAN: slab-use-after-free in pci_epf_remove_cfs+0x17c/0x198
> Write of size 8 at addr ffff00010f4a0d80 by task rmmod/319
>
> CPU: 3 UID: 0 PID: 319 Comm: rmmod Not tainted 6.16.0-rc2 #1 NONE
> Hardware name: Radxa ROCK 5B (DT)
> Call trace:
> show_stack+0x2c/0x84 (C)
> dump_stack_lvl+0x70/0x98
> print_report+0x17c/0x538
> kasan_report+0xb8/0x190
> __asan_report_store8_noabort+0x20/0x2c
> pci_epf_remove_cfs+0x17c/0x198
> pci_epf_unregister_driver+0x18/0x30
> nvmet_pci_epf_cleanup_module+0x24/0x30 [nvmet_pci_epf]
> __arm64_sys_delete_module+0x264/0x424
> invoke_syscall+0x70/0x260
> el0_svc_common.constprop.0+0xac/0x230
> do_el0_svc+0x40/0x58
> el0_svc+0x48/0xdc
> el0t_64_sync_handler+0x10c/0x138
> el0t_64_sync+0x198/0x19c
> ...
>
> Remove this list_del() call from pci_epf_remove_cfs() and replace it
> with a warning if the epf_group list is not empty.
>
> Fixes: ef1433f717a2 ("PCI: endpoint: Create configfs entry for each pci_epf_device_id table entry")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
> ---
> drivers/pci/endpoint/pci-ep-cfs.c | 1 +
> drivers/pci/endpoint/pci-epf-core.c | 2 +-
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c
> index d712c7a866d2..63876537e7dc 100644
> --- a/drivers/pci/endpoint/pci-ep-cfs.c
> +++ b/drivers/pci/endpoint/pci-ep-cfs.c
> @@ -691,6 +691,7 @@ void pci_ep_cfs_remove_epf_group(struct config_group *group)
> if (IS_ERR_OR_NULL(group))
> return;
>
> + list_del_init(&group->group_entry);
> configfs_unregister_default_group(group);
> }
> EXPORT_SYMBOL(pci_ep_cfs_remove_epf_group);
> diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
> index 577a9e490115..167dc6ee63f7 100644
> --- a/drivers/pci/endpoint/pci-epf-core.c
> +++ b/drivers/pci/endpoint/pci-epf-core.c
> @@ -338,7 +338,7 @@ static void pci_epf_remove_cfs(struct pci_epf_driver *driver)
> mutex_lock(&pci_epf_mutex);
> list_for_each_entry_safe(group, tmp, &driver->epf_group, group_entry)
> pci_ep_cfs_remove_epf_group(group);
> - list_del(&driver->epf_group);
> + WARN_ON(!list_empty(&driver->epf_group));
> mutex_unlock(&pci_epf_mutex);
> }
>
--
Damien Le Moal
Western Digital Research
