From: Alex Belits abelits@marvell.com
mainline inclusion from mainline-v5.9-rc1 commit 69a18b18699b59654333651d95f8ca09d01048f8 category: bugfix bugzilla: 45956 CVE: NA
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pci_call_probe() prevents the nesting of work_on_cpu() for a scenario where a VF device is probed from work_on_cpu() of the PF.
Replace the cpumask used in pci_call_probe() from all online CPUs to only housekeeping CPUs. This is to ensure that there are no additional latency overheads caused due to the pinning of jobs on isolated CPUs.
Signed-off-by: Alex Belits abelits@marvell.com Signed-off-by: Nitesh Narayan Lal nitesh@redhat.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Liu Chao liuchao173@huawei.com Reviewed-by: Frederic Weisbecker frederic@kernel.org Acked-by: Bjorn Helgaas bhelgaas@google.com Link: https://lkml.kernel.org/r/20200625223443.2684-3-nitesh@redhat.com Reviewed-by: Jian Cheng cj.chengjian@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/pci/pci-driver.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 45c3a78d6004..d6b2ac4bf266 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -12,6 +12,7 @@ #include <linux/string.h> #include <linux/slab.h> #include <linux/sched.h> +#include <linux/sched/isolation.h> #include <linux/cpu.h> #include <linux/pm_runtime.h> #include <linux/suspend.h> @@ -332,6 +333,7 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev, const struct pci_device_id *id) { int error, node, cpu; + int hk_flags = HK_FLAG_DOMAIN | HK_FLAG_WQ; struct drv_dev_and_id ddi = { drv, dev, id };
/* @@ -352,7 +354,8 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev, pci_physfn_is_probed(dev)) cpu = nr_cpu_ids; else - cpu = cpumask_any_and(cpumask_of_node(node), cpu_online_mask); + cpu = cpumask_any_and(cpumask_of_node(node), + housekeeping_cpumask(hk_flags));
if (cpu < nr_cpu_ids) error = work_on_cpu(cpu, local_pci_probe, &ddi);