PCI/aspm: Fix link->downstream setting
PATCH 1/1 PCI/aspm: Fix link->downstream setting
~ # 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 <[email protected]>
--- drivers/pci/pcie/aspm.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
drivers/pci/pcie/aspm.c +2 -3
@@ -478,7 +478,7 @@ static void aspm_calc_l1ss_info(struct pstatic 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_pciINIT_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
Quoted 24 lines · Yinghai Lu
~ # 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 ]---
Quoted 1 line
set downstream even with blacklist path.
Thanks for fixing this.
Quoted 3 lines
Signed-off-by Yinghai Lu <[email protected]>
Acked-by Rajat Jain <[email protected]>
Quoted 36 lines
--- drivers/pci/pcie/aspm.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)Index:
linux-2.6/drivers/pci/pcie/aspm.c
===================================================================drivers/pci/pcie/aspm.c +2
-3@@ -478,7 +478,7 @@ static void aspm_calc_l1ss_info(struct pstatic 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_pciINIT_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
Quoted 23 lines · Yinghai Lu
~ # 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 ]---
Quoted 3 lines
set downstream even with blacklist path.
Signed-off-by Yinghai Lu <[email protected]>
Applied with Rajat's ack to for-linus for v4.11, thanks!
I added a stable tag, since I think this bug has been there a long time and it causes a NULL pointer dereference.
Quoted 35 lines
--- drivers/pci/pcie/aspm.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)Index:
linux-2.6/drivers/pci/pcie/aspm.c
===================================================================drivers/pci/pcie/aspm.c +2
-3@@ -478,7 +478,7 @@ static void aspm_calc_l1ss_info(struct pstatic 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_pciINIT_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