diff options
| author | Niklas Schnelle <schnelle@linux.ibm.com> | 2025-12-16 23:14:03 +0100 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2026-03-04 07:20:51 -0500 |
| commit | 7c37920c96b85ef4255a7acc795e99e63dd38d59 (patch) | |
| tree | 5403d1e32d6d216ee127ff836ab97a5b4f392245 | |
| parent | 83651d37474c762920e345a3a0828f975ca4d732 (diff) | |
PCI/IOV: Fix race between SR-IOV enable/disable and hotplug
[ Upstream commit a5338e365c4559d7b4d7356116b0eb95b12e08d5 ]
Commit 05703271c3cd ("PCI/IOV: Add PCI rescan-remove locking when
enabling/disabling SR-IOV") tried to fix a race between the VF removal
inside sriov_del_vfs() and concurrent hot unplug by taking the PCI
rescan/remove lock in sriov_del_vfs(). Similarly the PCI rescan/remove lock
was also taken in sriov_add_vfs() to protect addition of VFs.
This approach however causes deadlock on trying to remove PFs with SR-IOV
enabled because PFs disable SR-IOV during removal and this removal happens
under the PCI rescan/remove lock. So the original fix had to be reverted.
Instead of taking the PCI rescan/remove lock in sriov_add_vfs() and
sriov_del_vfs(), fix the race that occurs with SR-IOV enable and disable vs
hotplug higher up in the callchain by taking the lock in
sriov_numvfs_store() before calling into the driver's sriov_configure()
callback.
Fixes: 05703271c3cd ("PCI/IOV: Add PCI rescan-remove locking when enabling/disabling SR-IOV")
Reported-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Reviewed-by: Gerd Bayer <gbayer@linux.ibm.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251216-revert_sriov_lock-v3-2-dac4925a7621@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/pci/iov.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index b2e8322755c1..132bd4447534 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -448,7 +448,9 @@ static ssize_t sriov_numvfs_store(struct device *dev, if (num_vfs == 0) { /* disable VFs */ + pci_lock_rescan_remove(); ret = pdev->driver->sriov_configure(pdev, 0); + pci_unlock_rescan_remove(); goto exit; } @@ -460,7 +462,9 @@ static ssize_t sriov_numvfs_store(struct device *dev, goto exit; } + pci_lock_rescan_remove(); ret = pdev->driver->sriov_configure(pdev, num_vfs); + pci_unlock_rescan_remove(); if (ret < 0) goto exit; |