Add proper cleanup when virtfn setup fails to prevent NULL pointer
dereference during device removal. The kernel oops[1] occurred due to
Incorrect error handling flow when pci_setup_device() fails.
Fix it by introducing pci_iov_scan_device() which handle virtfn
allocation and setup properly, instead of invoking
pci_stop_and_remove_bus_device() whenever pci_setup_device is failed.
This prevents accessing partially initialized virtfn devices during
removal.
[1]
BUG: kernel NULL pointer dereference, address: 00000000000000d0
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP
CPU: 22 UID: 0 PID: 1151 Comm: bash Not tainted 6.13.0+ #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
RIP: 0010:device_del+0x3d/0x3d0
Call Trace:
<TASK>
? __die+0x20/0x60
? page_fault_oops+0x150/0x3e0
? exc_page_fault+0x74/0x130
? asm_exc_page_fault+0x22/0x30
? device_del+0x3d/0x3d0
pci_remove_bus_device+0x7c/0x100
pci_iov_add_virtfn+0xfa/0x200
sriov_enable+0x208/0x420
mlx5_core_sriov_configure+0x6a/0x160 [mlx5_core]
sriov_numvfs_store+0xae/0x1a0
kernfs_fop_write_iter+0x109/0x1a0
vfs_write+0x2c0/0x3e0
ksys_write+0x62/0xd0
do_syscall_64+0x4c/0x100
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Fixes: e3f30d563a38 ("PCI: Make pci_destroy_dev() concurrent safe")
CC: Keith Busch <kbusch@xxxxxxxxxx>
Change-Id: I7cee1123c90ce184661470dcafab45cec919bc72
Signed-off-by: Shay Drory <shayd@xxxxxxxxxx>
---
changes from v1:
- add pci_iov_scan_device() helper (Bjorn)
---
drivers/pci/iov.c | 47 +++++++++++++++++++++++++++++++++--------------
1 file changed, 33 insertions(+), 14 deletions(-)
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 9e4770cdd4d5..9f08df0e7208 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -285,23 +285,16 @@ const struct attribute_group sriov_vf_dev_attr_group = {
.is_visible = sriov_vf_attrs_are_visible,
};
-int pci_iov_add_virtfn(struct pci_dev *dev, int id)
+static struct pci_dev *pci_iov_scan_device(struct pci_dev *dev, int id,
+ struct pci_bus *bus)
{
- int i;
- int rc = -ENOMEM;
- u64 size;
- struct pci_dev *virtfn;
- struct resource *res;
struct pci_sriov *iov = dev->sriov;
- struct pci_bus *bus;
-
- bus = virtfn_add_bus(dev->bus, pci_iov_virtfn_bus(dev, id));
- if (!bus)
- goto failed;
+ struct pci_dev *virtfn;
+ int rc = -ENOMEM;
virtfn = pci_alloc_dev(bus);
if (!virtfn)
- goto failed0;
+ return ERR_PTR(rc);
virtfn->devfn = pci_iov_virtfn_devfn(dev, id);
virtfn->vendor = dev->vendor;
@@ -314,8 +307,34 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id)
pci_read_vf_config_common(virtfn);
rc = pci_setup_device(virtfn);
- if (rc)
- goto failed1;
+ if (rc) {
+ pci_dev_put(dev);
+ pci_bus_put(virtfn->bus);
+ kfree(virtfn);
+ return ERR_PTR(rc);
+ }
+
+ return virtfn;
+}
+
+int pci_iov_add_virtfn(struct pci_dev *dev, int id)
+{
+ int i;
+ int rc = -ENOMEM;
+ u64 size;
+ struct pci_dev *virtfn;
+ struct resource *res;
+ struct pci_bus *bus;
+
+ bus = virtfn_add_bus(dev->bus, pci_iov_virtfn_bus(dev, id));
+ if (!bus)
+ goto failed;
+
+ virtfn = pci_iov_scan_device(dev, id, bus);
+ if (IS_ERR(virtfn)) {
+ rc = PTR_ERR(virtfn);
+ goto failed0;
+ }
virtfn->dev.parent = dev->dev.parent;
virtfn->multifunction = 0;
--
2.38.1
