Overview
About vulnerability
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 [email protected] [kwilczynski: commit log] [bhelgaas: add back report info from https://lore.kernel.org/lkml/[email protected]/]
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 6 ELS , CloudLinux 7 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- kernel @ 2.6.32 (+16 more)
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 [email protected] [kwilczynski: commit log] [bhelgaas: add back report info from https://lore.kernel.org/lkml/[email protected]/]