PCI: vmd: Make vmd_dev::cfg_lock a raw_spinlock_t type

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: PCI: vmd: Make vmd_dev::cfg_lock a raw_spinlock_t type The access to the PCI config space via pci_ops::read and pci_ops::write is a low-level hardware access. The functions can be accessed with disabled interrupts even on PREEMPT_RT. The pci_lock is a raw_spinlock_t for this purpose. A spinlock_t becomes a sleeping lock on PREEMPT_RT, so it cannot be acquired with disabled interrupts. The vmd_dev::cfg_lock is accessed in the same context as the pci_lock. Make vmd_dev::cfg_lock a raw_spinlock_t type so it can be used with interrupts disabled. This was reported as: BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 Call Trace: rt_spin_lock+0x4e/0x130 vmd_pci_read+0x8d/0x100 [vmd] pci_user_read_config_byte+0x6f/0xe0 pci_read_config+0xfe/0x290 sysfs_kf_bin_read+0x68/0x90 [bigeasy: reword commit message] Tested-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com> [kwilczynski: commit log] [bhelgaas: add back report info from https://lore.kernel.org/lkml/20241218115951.83062-1-ryotkkr98@gmail.com/]

References

• https://git.kernel.org/stable/c/c250262d6485ca333e9821f85b07eb383ec546b1
• https://git.kernel.org/stable/c/c2968c812339593ac6e2bdd5cc3adabe3f05fa53
• https://git.kernel.org/stable/c/13e5148f70e81991acbe0bab5b1b50ba699116e7
• https://git.kernel.org/stable/c/5c3cfcf0b4bf43530788b08a8eaf7896ec567484
• https://git.kernel.org/stable/c/2358046ead696ca5c7c628d6c0e2c6792619a3e5
• https://git.kernel.org/stable/c/20d0a9062c031068fa39f725a32f182b709b5525
• https://git.kernel.org/stable/c/18056a48669a040bef491e63b25896561ee14d90