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author | Ding Hui <dinghui@sangfor.com.cn> | 2023-05-07 11:40:57 +0800 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-07-19 16:21:35 +0200 |
commit | 7aecdd47910c51707696e8b0e045b9f88bd4230f (patch) | |
tree | fe01924e6669c6030217f7aec417101c4831c42b | |
parent | 3a080e1b11452eef4c1e80ab616f159b224be9b0 (diff) | |
download | linux-stable-7aecdd47910c51707696e8b0e045b9f88bd4230f.tar.gz linux-stable-7aecdd47910c51707696e8b0e045b9f88bd4230f.tar.bz2 linux-stable-7aecdd47910c51707696e8b0e045b9f88bd4230f.zip |
PCI/ASPM: Disable ASPM on MFD function removal to avoid use-after-free
[ Upstream commit 456d8aa37d0f56fc9e985e812496e861dcd6f2f2 ]
Struct pcie_link_state->downstream is a pointer to the pci_dev of function
0. Previously we retained that pointer when removing function 0, and
subsequent ASPM policy changes dereferenced it, resulting in a
use-after-free warning from KASAN, e.g.:
# echo 1 > /sys/bus/pci/devices/0000:03:00.0/remove
# echo powersave > /sys/module/pcie_aspm/parameters/policy
BUG: KASAN: slab-use-after-free in pcie_config_aspm_link+0x42d/0x500
Call Trace:
kasan_report+0xae/0xe0
pcie_config_aspm_link+0x42d/0x500
pcie_aspm_set_policy+0x8e/0x1a0
param_attr_store+0x162/0x2c0
module_attr_store+0x3e/0x80
PCIe spec r6.0, sec 7.5.3.7, recommends that software program the same ASPM
Control value in all functions of multi-function devices.
Disable ASPM and free the pcie_link_state when any child function is
removed so we can discard the dangling pcie_link_state->downstream pointer
and maintain the same ASPM Control configuration for all functions.
[bhelgaas: commit log and comment]
Debugged-by: Zongquan Qin <qinzongquan@sangfor.com.cn>
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Fixes: b5a0a9b59c81 ("PCI/ASPM: Read and set up L1 substate capabilities")
Link: https://lore.kernel.org/r/20230507034057.20970-1-dinghui@sangfor.com.cn
Signed-off-by: Ding Hui <dinghui@sangfor.com.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r-- | drivers/pci/pcie/aspm.c | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 4b4184563a92..74b8183c305d 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -1010,21 +1010,24 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev) down_read(&pci_bus_sem); mutex_lock(&aspm_lock); - /* - * All PCIe functions are in one slot, remove one function will remove - * the whole slot, so just wait until we are the last function left. - */ - if (!list_empty(&parent->subordinate->devices)) - goto out; link = parent->link_state; root = link->root; parent_link = link->parent; - /* All functions are removed, so just disable ASPM for the link */ + /* + * link->downstream is a pointer to the pci_dev of function 0. If + * we remove that function, the pci_dev is about to be deallocated, + * so we can't use link->downstream again. Free the link state to + * avoid this. + * + * If we're removing a non-0 function, it's possible we could + * retain the link state, but PCIe r6.0, sec 7.5.3.7, recommends + * programming the same ASPM Control value for all functions of + * multi-function devices, so disable ASPM for all of them. + */ pcie_config_aspm_link(link, 0); list_del(&link->sibling); - /* Clock PM is for endpoint device */ free_link_state(link); /* Recheck latencies and configure upstream links */ @@ -1032,7 +1035,7 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev) pcie_update_aspm_capable(root); pcie_config_aspm_path(parent_link); } -out: + mutex_unlock(&aspm_lock); up_read(&pci_bus_sem); } |