[PATCH net 1/2] net: macb: fix clk handling on PCI glue driver removal
From: Fedor Pchelkin
Date: Mon Mar 30 2026 - 14:47:53 EST
platform_device_unregister() may still want to use the registered clks
during runtime resume callback.
Note that there is a commit d82d5303c4c5 ("net: macb: fix use after free
on rmmod") that addressed the similar problem of clk vs platform device
unregistration but just moved the bug to another place.
Save the pointers to clks into local variables for reuse after platform
device is unregistered.
BUG: KASAN: use-after-free in clk_prepare+0x5a/0x60
Read of size 8 at addr ffff888104f85e00 by task modprobe/597
CPU: 2 PID: 597 Comm: modprobe Not tainted 6.1.164+ #114
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.1-0-g3208b098f51a-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x8d/0xba
print_report+0x17f/0x496
kasan_report+0xd9/0x180
clk_prepare+0x5a/0x60
macb_runtime_resume+0x13d/0x410 [macb]
pm_generic_runtime_resume+0x97/0xd0
__rpm_callback+0xc8/0x4d0
rpm_callback+0xf6/0x230
rpm_resume+0xeeb/0x1a70
__pm_runtime_resume+0xb4/0x170
bus_remove_device+0x2e3/0x4b0
device_del+0x5b3/0xdc0
platform_device_del+0x4e/0x280
platform_device_unregister+0x11/0x50
pci_device_remove+0xae/0x210
device_remove+0xcb/0x180
device_release_driver_internal+0x529/0x770
driver_detach+0xd4/0x1a0
bus_remove_driver+0x135/0x260
driver_unregister+0x72/0xb0
pci_unregister_driver+0x26/0x220
__do_sys_delete_module+0x32e/0x550
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
</TASK>
Allocated by task 519:
kasan_save_stack+0x2c/0x50
kasan_set_track+0x21/0x30
__kasan_kmalloc+0x8e/0x90
__clk_register+0x458/0x2890
clk_hw_register+0x1a/0x60
__clk_hw_register_fixed_rate+0x255/0x410
clk_register_fixed_rate+0x3c/0xa0
macb_probe+0x1d8/0x42e [macb_pci]
local_pci_probe+0xd7/0x190
pci_device_probe+0x252/0x600
really_probe+0x255/0x7f0
__driver_probe_device+0x1ee/0x330
driver_probe_device+0x4c/0x1f0
__driver_attach+0x1df/0x4e0
bus_for_each_dev+0x15d/0x1f0
bus_add_driver+0x486/0x5e0
driver_register+0x23a/0x3d0
do_one_initcall+0xfd/0x4d0
do_init_module+0x18b/0x5a0
load_module+0x5663/0x7950
__do_sys_finit_module+0x101/0x180
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Freed by task 597:
kasan_save_stack+0x2c/0x50
kasan_set_track+0x21/0x30
kasan_save_free_info+0x2a/0x50
__kasan_slab_free+0x106/0x180
__kmem_cache_free+0xbc/0x320
clk_unregister+0x6de/0x8d0
macb_remove+0x73/0xc0 [macb_pci]
pci_device_remove+0xae/0x210
device_remove+0xcb/0x180
device_release_driver_internal+0x529/0x770
driver_detach+0xd4/0x1a0
bus_remove_driver+0x135/0x260
driver_unregister+0x72/0xb0
pci_unregister_driver+0x26/0x220
__do_sys_delete_module+0x32e/0x550
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: d82d5303c4c5 ("net: macb: fix use after free on rmmod")
Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx>
---
drivers/net/ethernet/cadence/macb_pci.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/cadence/macb_pci.c b/drivers/net/ethernet/cadence/macb_pci.c
index fc4f5aee6ab3..0ce5b736ea43 100644
--- a/drivers/net/ethernet/cadence/macb_pci.c
+++ b/drivers/net/ethernet/cadence/macb_pci.c
@@ -109,10 +109,12 @@ static void macb_remove(struct pci_dev *pdev)
{
struct platform_device *plat_dev = pci_get_drvdata(pdev);
struct macb_platform_data *plat_data = dev_get_platdata(&plat_dev->dev);
+ struct clk *pclk = plat_data->pclk;
+ struct clk *hclk = plat_data->hclk;
- clk_unregister(plat_data->pclk);
- clk_unregister(plat_data->hclk);
platform_device_unregister(plat_dev);
+ clk_unregister(pclk);
+ clk_unregister(hclk);
}
static const struct pci_device_id dev_id_table[] = {
--
2.53.0