From: Hongchen Zhang zhanghongchen@loongson.cn
When the best selected CPU is offline, work_on_cpu() will stuck forever. This can be happen if a node is online while all its CPUs are offline (we can use "maxcpus=1" without "nr_cpus=1" to reproduce it), Therefore, in this case, we should call local_pci_probe() instead of work_on_cpu().
Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Hongchen Zhang zhanghongchen@loongson.cn --- drivers/pci/pci-driver.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index c8bd71a739f7..602838416e6a 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -386,7 +386,7 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev, free_cpumask_var(wq_domain_mask); }
- if (cpu < nr_cpu_ids) + if ((cpu < nr_cpu_ids) && cpu_online(cpu)) error = work_on_cpu(cpu, local_pci_probe, &ddi); else error = local_pci_probe(&ddi);
On Sun, May 11, 2025 at 04:34:12PM +0800, Huacai Chen wrote:
From: Hongchen Zhang zhanghongchen@loongson.cn
When the best selected CPU is offline, work_on_cpu() will stuck forever. This can be happen if a node is online while all its CPUs are offline (we can use "maxcpus=1" without "nr_cpus=1" to reproduce it), Therefore, in this case, we should call local_pci_probe() instead of work_on_cpu().
Just curious, did you encounter this problem in a real world usecase or just found the issue while playing with maxcpus/nr_cpus parameters?
I believe the fixes tag for this patch is 873392ca514f8.
- Mani
Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Hongchen Zhang zhanghongchen@loongson.cn
drivers/pci/pci-driver.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index c8bd71a739f7..602838416e6a 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -386,7 +386,7 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev, free_cpumask_var(wq_domain_mask); }
- if (cpu < nr_cpu_ids)
- if ((cpu < nr_cpu_ids) && cpu_online(cpu)) error = work_on_cpu(cpu, local_pci_probe, &ddi); else error = local_pci_probe(&ddi);
-- 2.47.1
Hi, Manivannan,
Sorry for the late reply.
On Fri, Jun 13, 2025 at 3:11 PM Manivannan Sadhasivam mani@kernel.org wrote:
On Sun, May 11, 2025 at 04:34:12PM +0800, Huacai Chen wrote:
From: Hongchen Zhang zhanghongchen@loongson.cn
When the best selected CPU is offline, work_on_cpu() will stuck forever. This can be happen if a node is online while all its CPUs are offline (we can use "maxcpus=1" without "nr_cpus=1" to reproduce it), Therefore, in this case, we should call local_pci_probe() instead of work_on_cpu().
Just curious, did you encounter this problem in a real world usecase or just found the issue while playing with maxcpus/nr_cpus parameters?
When we debug kdump we tried to use different maxcpus/nr_cpus combinations, and we found this problem.
I believe the fixes tag for this patch is 873392ca514f8.
Yes, but the code has changed many times, this patch cannot be applied as early as 873392ca514f8.
Huacai
- Mani
Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Hongchen Zhang zhanghongchen@loongson.cn
drivers/pci/pci-driver.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index c8bd71a739f7..602838416e6a 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -386,7 +386,7 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev, free_cpumask_var(wq_domain_mask); }
if (cpu < nr_cpu_ids)
if ((cpu < nr_cpu_ids) && cpu_online(cpu)) error = work_on_cpu(cpu, local_pci_probe, &ddi); else error = local_pci_probe(&ddi);-- 2.47.1
-- மணிவண்ணன் சதாசிவம்
linux-stable-mirror@lists.linaro.org
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Huacai Chen -
Huacai Chen -
Manivannan Sadhasivam