~ # echo 1 > /sys/bus/pci/devices/0000\:0b\:00.0/remove
...
BUG: unable to handle kernel NULL pointer dereference at 0000000000000080
IP: pcie_config_aspm_link+0x5d/0x2b0
Call Trace:
pcie_aspm_exit_link_state+0x75/0x130
pci_stop_bus_device+0xa4/0xb0
pci_stop_and_remove_bus_device_locked+0x1a/0x30
remove_store+0x50/0x70
dev_attr_store+0x18/0x30
sysfs_kf_write+0x44/0x60
kernfs_fop_write+0x10e/0x190
__vfs_write+0x28/0x110
? rcu_read_lock_sched_held+0x5d/0x80
? rcu_sync_lockdep_assert+0x2c/0x60
? __sb_start_write+0x173/0x1a0
? vfs_write+0xb3/0x180
vfs_write+0xc4/0x180
SyS_write+0x49/0xa0
do_syscall_64+0xa6/0x1c0
entry_SYSCALL64_slow_path+0x25/0x25
---[ end trace bd187ee0267df5d9 ]---
set downstream even with blacklist path.
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
---
drivers/pci/pcie/aspm.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
Index: linux-2.6/drivers/pci/pcie/aspm.c
===================================================================
--- linux-2.6.orig/drivers/pci/pcie/aspm.c
+++ linux-2.6/drivers/pci/pcie/aspm.c
@@ -478,7 +478,7 @@ static void aspm_calc_l1ss_info(struct p
static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
{
- struct pci_dev *child, *parent = link->pdev;
+ struct pci_dev *child = link->downstream, *parent = link->pdev;
struct pci_bus *linkbus = parent->subordinate;
struct aspm_register_info upreg, dwreg;
@@ -491,9 +491,7 @@ static void pcie_aspm_cap_init(struct pc
/* Get upstream/downstream components' register state */
pcie_get_aspm_reg(parent, &upreg);
- child = pci_function_0(linkbus);
pcie_get_aspm_reg(child, &dwreg);
- link->downstream = child;
/*
* If ASPM not supported, don't mess with the clocks and link,
@@ -800,6 +798,7 @@ static struct pcie_link_state *alloc_pci
INIT_LIST_HEAD(&link->children);
INIT_LIST_HEAD(&link->link);
link->pdev = pdev;
+ link->downstream = pci_function_0(pdev->subordinate);
/*
* Root Ports and PCI/PCI-X to PCIe Bridges are roots of PCIe
