Re: [PATCH v4 2/2] vfio/pci: add msi interrupt affinity support

From: Dan Carpenter
Date: Sun Jun 09 2024 - 11:30:06 EST

Hi Fred,

kernel test robot noticed the following build warnings:

url: https://github.com/intel-lab-lkp/linux/commits/Fred-Griffoul/cgroup-cpuset-export-cpuset_cpus_allowed/20240608-031332
base: cbb325e77fbe62a06184175aa98c9eb98736c3e8
patch link: https://lore.kernel.org/r/20240607190955.15376-3-fgriffo%40amazon.co.uk
patch subject: [PATCH v4 2/2] vfio/pci: add msi interrupt affinity support
config: mips-randconfig-r081-20240609 (https://download.01.org/0day-ci/archive/20240609/202406092245.Hgx6MqK9-lkp@xxxxxxxxx/config)
compiler: mips-linux-gcc (GCC) 13.2.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202406092245.Hgx6MqK9-lkp@xxxxxxxxx/

New smatch warnings:
drivers/vfio/pci/vfio_pci_core.c:1241 vfio_pci_ioctl_set_irqs() warn: maybe return -EFAULT instead of the bytes remaining?

vim +1241 drivers/vfio/pci/vfio_pci_core.c

2ecf3b58ed7bc5 drivers/vfio/pci/vfio_pci_core.c Jason Gunthorpe 2022-08-31 1190 static int vfio_pci_ioctl_set_irqs(struct vfio_pci_core_device *vdev,
663eab456e072b drivers/vfio/pci/vfio_pci_core.c Jason Gunthorpe 2022-08-31 1191 struct vfio_irq_set __user *arg)
2ecf3b58ed7bc5 drivers/vfio/pci/vfio_pci_core.c Jason Gunthorpe 2022-08-31 1192 {
2ecf3b58ed7bc5 drivers/vfio/pci/vfio_pci_core.c Jason Gunthorpe 2022-08-31 1193 unsigned long minsz = offsetofend(struct vfio_irq_set, count);
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1194 struct vfio_irq_set hdr;
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1195 cpumask_var_t mask;
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1196 u8 *data = NULL;
05692d7005a364 drivers/vfio/pci/vfio_pci.c Vlad Tsyrklevich 2016-10-12 1197 int max, ret = 0;
ef198aaa169c61 drivers/vfio/pci/vfio_pci.c Kirti Wankhede 2016-11-17 1198 size_t data_size = 0;
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1199
663eab456e072b drivers/vfio/pci/vfio_pci_core.c Jason Gunthorpe 2022-08-31 1200 if (copy_from_user(&hdr, arg, minsz))
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1201 return -EFAULT;
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1202
05692d7005a364 drivers/vfio/pci/vfio_pci.c Vlad Tsyrklevich 2016-10-12 1203 max = vfio_pci_get_irq_count(vdev, hdr.index);
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1204
ea3fc04d4fad2d drivers/vfio/pci/vfio_pci_core.c Jason Gunthorpe 2022-08-31 1205 ret = vfio_set_irqs_validate_and_prepare(&hdr, max, VFIO_PCI_NUM_IRQS,
ea3fc04d4fad2d drivers/vfio/pci/vfio_pci_core.c Jason Gunthorpe 2022-08-31 1206 &data_size);
ef198aaa169c61 drivers/vfio/pci/vfio_pci.c Kirti Wankhede 2016-11-17 1207 if (ret)
ef198aaa169c61 drivers/vfio/pci/vfio_pci.c Kirti Wankhede 2016-11-17 1208 return ret;
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1209
ef198aaa169c61 drivers/vfio/pci/vfio_pci.c Kirti Wankhede 2016-11-17 1210 if (data_size) {
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1211 if (hdr.flags & VFIO_IRQ_SET_DATA_AFFINITY) {
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1212 if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1213 return -ENOMEM;
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1214
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1215 ret = copy_from_user(mask, &arg->data, data_size);

copy_from_user() returns the number of bytes remaining to be copied.
This should be:

if (copy_from_user(mask, &arg->data, data_size)) {
ret = -EFAULT;
goto out;
}

66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1216 if (ret)
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1217 goto out;
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1218
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1219 data = (u8 *)mask;
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1220
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1221 } else {
663eab456e072b drivers/vfio/pci/vfio_pci_core.c Jason Gunthorpe 2022-08-31 1222 data = memdup_user(&arg->data, data_size);
3a1f7041ddd59e drivers/vfio/pci/vfio_pci.c Fengguang Wu 2012-12-07 1223 if (IS_ERR(data))
3a1f7041ddd59e drivers/vfio/pci/vfio_pci.c Fengguang Wu 2012-12-07 1224 return PTR_ERR(data);
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1225 }
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1226 }
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1227
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1228 mutex_lock(&vdev->igate);
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1229
ea3fc04d4fad2d drivers/vfio/pci/vfio_pci_core.c Jason Gunthorpe 2022-08-31 1230 ret = vfio_pci_set_irqs_ioctl(vdev, hdr.flags, hdr.index, hdr.start,
ea3fc04d4fad2d drivers/vfio/pci/vfio_pci_core.c Jason Gunthorpe 2022-08-31 1231 hdr.count, data);
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1232
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1233 mutex_unlock(&vdev->igate);
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1234
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1235 out:
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1236 if (hdr.flags & VFIO_IRQ_SET_DATA_AFFINITY && data_size)
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1237 free_cpumask_var(mask);
66c926fb7b2507 drivers/vfio/pci/vfio_pci_core.c Fred Griffoul 2024-06-07 1238 else
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1239 kfree(data);
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 1240
89e1f7d4c66d85 drivers/vfio/pci/vfio_pci.c Alex Williamson 2012-07-31 @1241 return ret;
2ecf3b58ed7bc5 drivers/vfio/pci/vfio_pci_core.c Jason Gunthorpe 2022-08-31 1242 }

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