kernel/linux.git/drivers/pci/bus.c, branch v6.3

PCI: s390: Fix use-after-free of PCI resources with per-function hotplug

2023-03-13T08:15:11+00:00

On s390 PCI functions may be hotplugged individually even when they belong to a multi-function device. In particular on an SR-IOV device VFs may be removed and later re-added. In commit a50297cf8235 ("s390/pci: separate zbus creation from scanning") it was missed however that struct pci_bus and struct zpci_bus's resource list retained a reference to the PCI functions MMIO resources even though those resources are released and freed on hot-unplug. These stale resources may subsequently be claimed when the PCI function re-appears resulting in use-after-free. One idea of fixing this use-after-free in s390 specific code that was investigated was to simply keep resources around from the moment a PCI function first appeared until the whole virtual PCI bus created for a multi-function device disappears. The problem with this however is that due to the requirement of artificial MMIO addreesses (address cookies) extra logic is then needed to keep the address cookies compatible on re-plug. At the same time the MMIO resources semantically belong to the PCI function so tying their lifecycle to the function seems more logical. Instead a simpler approach is to remove the resources of an individually hot-unplugged PCI function from the PCI bus's resource list while keeping the resources of other PCI functions on the PCI bus untouched. This is done by introducing pci_bus_remove_resource() to remove an individual resource. Similarly the resource also needs to be removed from the struct zpci_bus's resource list. It turns out however, that there is really no need to add the MMIO resources to the struct zpci_bus's resource list at all and instead we can simply use the zpci_bar_struct's resource pointer directly. Fixes: a50297cf8235 ("s390/pci: separate zbus creation from scanning") Signed-off-by: Niklas Schnelle Reviewed-by: Matthew Rosato Acked-by: Bjorn Helgaas Link: https://lore.kernel.org/r/20230306151014.60913-2-schnelle@linux.ibm.com Signed-off-by: Vasily Gorbik

PCI: Skip allocate_resource() if too little space available

2022-12-10T16:31:47+00:00

pci_bus_alloc_from_region() allocates MMIO space by iterating through all the resources available on the bus. The available resource might be reduced if the caller requires 32-bit space or we're avoiding BIOS or E820 areas. Don't bother calling allocate_resource() if we need more space than is available in this resource. This prevents some pointless and annoying messages about avoided areas. Link: https://lore.kernel.org/r/20221208190341.1560157-3-helgaas@kernel.org Signed-off-by: Bjorn Helgaas Acked-by: Hans de Goede

PCI: Add device even if driver attach failed

2020-07-07T22:33:41+00:00

device_attach() returning failure indicates a driver error while trying to probe the device. In such a scenario, the PCI device should still be added in the system and be visible to the user. When device_attach() fails, merely warn about it and keep the PCI device in the system. This partially reverts ab1a187bba5c ("PCI: Check device_attach() return value always"). Link: https://lore.kernel.org/r/20200706233240.3245512-1-rajatja@google.com Signed-off-by: Rajat Jain Signed-off-by: Bjorn Helgaas Reviewed-by: Greg Kroah-Hartman Cc: stable@vger.kernel.org # v4.6+

PCI: Unexport pci_bus_get() and pci_bus_put()

2019-07-23T23:32:49+00:00

pci_bus_get() and pci_bus_put() are not used by a loadable kernel module and do not need to be exported. These were exported by fe830ef62ac6 ("PCI: Introduce pci_bus_{get|put}() to manage PCI bus reference count"), but there are no loadable modules in the tree that use them. Link: https://lore.kernel.org/r/20190717182353.45557-1-skunberg.kelsey@gmail.com Signed-off-by: Kelsey Skunberg Signed-off-by: Bjorn Helgaas Acked-by: Greg Kroah-Hartman

PCI: Replace dev_printk(KERN_DEBUG) with dev_info(), etc

2019-05-09T12:49:58+00:00

Replace dev_printk(KERN_DEBUG) with dev_info(), etc to be more consistent with other logging and avoid checkpatch warnings. The KERN_DEBUG messages could be converted to dev_dbg(), but that depends on CONFIG_DYNAMIC_DEBUG and DEBUG, and we want most of these messages to *always* be in the dmesg log. Link: https://lore.kernel.org/lkml/1555733240-19875-1-git-send-email-mohankumar718@gmail.com Signed-off-by: Mohan Kumar [bhelgaas: commit log] Signed-off-by: Bjorn Helgaas

PCI: Replace printk(KERN_INFO) with pr_info(), etc

2019-05-09T12:49:54+00:00

Replace printk() with pr_*() to be more consistent with other logging and avoid checkpatch warnings. Link: https://lore.kernel.org/lkml/1555733026-19609-1-git-send-email-mohankumar718@gmail.com Link: https://lore.kernel.org/lkml/1555733130-19804-1-git-send-email-mohankumar718@gmail.com Signed-off-by: Mohan Kumar [bhelgaas: squash in similar changes from second patch in series] Signed-off-by: Bjorn Helgaas

PCI: Fix is_added/is_busmaster race condition

2018-07-31T16:27:54+00:00

When a PCI device is detected, pdev->is_added is set to 1 and proc and sysfs entries are created. When the device is removed, pdev->is_added is checked for one and then device is detached with clearing of proc and sys entries and at end, pdev->is_added is set to 0. is_added and is_busmaster are bit fields in pci_dev structure sharing same memory location. A strange issue was observed with multiple removal and rescan of a PCIe NVMe device using sysfs commands where is_added flag was observed as zero instead of one while removing device and proc,sys entries are not cleared. This causes issue in later device addition with warning message "proc_dir_entry" already registered. Debugging revealed a race condition between the PCI core setting the is_added bit in pci_bus_add_device() and the NVMe driver reset work-queue setting the is_busmaster bit in pci_set_master(). As these fields are not handled atomically, that clears the is_added bit. Move the is_added bit to a separate private flag variable and use atomic functions to set and retrieve the device addition state. This avoids the race because is_added no longer shares a memory location with is_busmaster. Link: https://bugzilla.kernel.org/show_bug.cgi?id=200283 Signed-off-by: Hari Vyas Signed-off-by: Bjorn Helgaas Reviewed-by: Lukas Wunner Acked-by: Michael Ellerman

PCI: remove CONFIG_PCI_BUS_ADDR_T_64BIT

2018-05-09T04:57:18+00:00

This symbol is now always identical to CONFIG_ARCH_DMA_ADDR_T_64BIT, so remove it. Signed-off-by: Christoph Hellwig Acked-by: Bjorn Helgaas

PCI: Tidy comments

2018-03-19T19:20:43+00:00

Remove pointless comments that tell us the file name, remove blank line comments, follow multi-line comment conventions. No functional change intended. Signed-off-by: Bjorn Helgaas

Merge branch 'pci/spdx' into next

2018-02-01T17:40:07+00:00

* pci/spdx: PCI: Add SPDX GPL-2.0+ to replace implicit GPL v2 or later statement PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate PCI: Add SPDX GPL-2.0 to replace COPYING boilerplate PCI: Add SPDX GPL-2.0 to replace GPL v2 boilerplate PCI: Add SPDX GPL-2.0 when no license was specified