From df6f8c4d72aebaf66aaa8658c723fd360c272e59 Mon Sep 17 00:00:00 2001 From: Yi Lai Date: Fri, 28 Feb 2025 15:00:59 +0800 Subject: [PATCH 1/3] selftests/pcie_bwctrl: Add 'set_pcie_speed.sh' to TEST_PROGS The test shell script "set_pcie_speed.sh" is not installed in INSTALL_PATH. Attempting to execute set_pcie_cooling_state.sh shows warning: ./set_pcie_cooling_state.sh: line 119: ./set_pcie_speed.sh: No such file or directory Add "set_pcie_speed.sh" to TEST_PROGS. Link: https://lore.kernel.org/r/Z8FfK8rN30lKzvVV@ly-workstation Fixes: 838f12c3d551 ("selftests/pcie_bwctrl: Create selftests") Signed-off-by: Yi Lai Signed-off-by: Bjorn Helgaas --- tools/testing/selftests/pcie_bwctrl/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/pcie_bwctrl/Makefile b/tools/testing/selftests/pcie_bwctrl/Makefile index 3e84e26341d1..48ec048f47af 100644 --- a/tools/testing/selftests/pcie_bwctrl/Makefile +++ b/tools/testing/selftests/pcie_bwctrl/Makefile @@ -1,2 +1,2 @@ -TEST_PROGS = set_pcie_cooling_state.sh +TEST_PROGS = set_pcie_cooling_state.sh set_pcie_speed.sh include ../lib.mk From 026e4bffb0af9632f5a0bbf8d594f2aace44cf07 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 21 Mar 2025 18:31:03 +0200 Subject: [PATCH 2/3] PCI/bwctrl: Fix pcie_bwctrl_select_speed() return type MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit pcie_bwctrl_select_speed() should take __fls() of the speed bit, not return it as a raw value. Instead of directly returning 2.5GT/s speed bit, simply assign the fallback speed (2.5GT/s) into supported_speeds variable to share the normal return path that calls pcie_supported_speeds2target_speed() to calculate __fls(). This code path is not very likely to execute because pcie_get_supported_speeds() should provide valid ->supported_speeds but a spec violating device could fail to synthesize any speed in pcie_get_supported_speeds(). It could also happen in case the supported_speeds intersection is empty (also a violation of the current PCIe specs). Link: https://lore.kernel.org/r/20250321163103.5145-1-ilpo.jarvinen@linux.intel.com Fixes: de9a6c8d5dbf ("PCI/bwctrl: Add pcie_set_target_speed() to set PCIe Link Speed") Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas --- drivers/pci/pcie/bwctrl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/pcie/bwctrl.c b/drivers/pci/pcie/bwctrl.c index 0a5e7efbce2c..58ba8142c9a3 100644 --- a/drivers/pci/pcie/bwctrl.c +++ b/drivers/pci/pcie/bwctrl.c @@ -113,7 +113,7 @@ static u16 pcie_bwctrl_select_speed(struct pci_dev *port, enum pci_bus_speed spe up_read(&pci_bus_sem); } if (!supported_speeds) - return PCI_EXP_LNKCAP2_SLS_2_5GB; + supported_speeds = PCI_EXP_LNKCAP2_SLS_2_5GB; return pcie_supported_speeds2target_speed(supported_speeds & desired_speeds); } From 667f053b05f00a007738cd7ed6fa1901de19dc7e Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Sat, 22 Mar 2025 19:52:08 +0100 Subject: [PATCH 3/3] PCI/bwctrl: Fix NULL pointer dereference on bus number exhaustion MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When BIOS neglects to assign bus numbers to PCI bridges, the kernel attempts to correct that during PCI device enumeration. If it runs out of bus numbers, no pci_bus is allocated and the "subordinate" pointer in the bridge's pci_dev remains NULL. The PCIe bandwidth controller erroneously does not check for a NULL subordinate pointer and dereferences it on probe. Bandwidth control of unusable devices below the bridge is of questionable utility, so simply error out instead. This mirrors what PCIe hotplug does since commit 62e4492c3063 ("PCI: Prevent NULL dereference during pciehp probe"). The PCI core emits a message with KERN_INFO severity if it has run out of bus numbers. PCIe hotplug emits an additional message with KERN_ERR severity to inform the user that hotplug functionality is disabled at the bridge. A similar message for bandwidth control does not seem merited, given that its only purpose so far is to expose an up-to-date link speed in sysfs and throttle the link speed on certain laptops with limited Thermal Design Power. So error out silently. User-visible messages: pci 0000:16:02.0: bridge configuration invalid ([bus 00-00]), reconfiguring [...] pci_bus 0000:45: busn_res: [bus 45-74] end is updated to 74 pci 0000:16:02.0: devices behind bridge are unusable because [bus 45-74] cannot be assigned for them [...] pcieport 0000:16:02.0: pciehp: Hotplug bridge without secondary bus, ignoring [...] BUG: kernel NULL pointer dereference RIP: pcie_update_link_speed pcie_bwnotif_enable pcie_bwnotif_probe pcie_port_probe_service really_probe Fixes: 665745f27487 ("PCI/bwctrl: Re-add BW notification portdrv as PCIe BW controller") Reported-by: Wouter Bijlsma Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219906 Signed-off-by: Lukas Wunner Signed-off-by: Krzysztof Wilczyński Tested-by: Wouter Bijlsma Cc: stable@vger.kernel.org # v6.13+ Link: https://lore.kernel.org/r/3b6c8d973aedc48860640a9d75d20528336f1f3c.1742669372.git.lukas@wunner.de --- drivers/pci/pcie/bwctrl.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/pci/pcie/bwctrl.c b/drivers/pci/pcie/bwctrl.c index 58ba8142c9a3..d8d2aa85a229 100644 --- a/drivers/pci/pcie/bwctrl.c +++ b/drivers/pci/pcie/bwctrl.c @@ -294,6 +294,10 @@ static int pcie_bwnotif_probe(struct pcie_device *srv) struct pci_dev *port = srv->port; int ret; + /* Can happen if we run out of bus numbers during enumeration. */ + if (!port->subordinate) + return -ENODEV; + struct pcie_bwctrl_data *data = devm_kzalloc(&srv->device, sizeof(*data), GFP_KERNEL); if (!data)