Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

s390/pci: Avoid deadlock between PCI error recovery and mlx5 crdump

Do not block PCI config accesses through pci_cfg_access_lock() when executing the s390 variant of PCI error recovery: Acquire just device_lock() instead of pci_dev_lock() as powerpc's EEH and generig PCI AER processing do.

During error recovery testing a pair of tasks was reported to be hung:

mlx5_core 0000:00:00.1: mlx5_health_try_recover:338:(pid 5553): health recovery flow aborted, PCI reads still not working INFO: task kmcheck:72 blocked for more than 122 seconds. Not tainted 5.14.0-570.12.1.bringup7.el9.s390x #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kmcheck state:D stack:0 pid:72 tgid:72 ppid:2 flags:0x00000000 Call Trace: [<000000065256f030>] __schedule+0x2a0/0x590 [<000000065256f356>] schedule+0x36/0xe0 [<000000065256f572>] schedule_preempt_disabled+0x22/0x30 [<0000000652570a94>] __mutex_lock.constprop.0+0x484/0x8a8 [<000003ff800673a4>] mlx5_unload_one+0x34/0x58 [mlx5_core] [<000003ff8006745c>] mlx5_pci_err_detected+0x94/0x140 [mlx5_core] [<0000000652556c5a>] zpci_event_attempt_error_recovery+0xf2/0x398 [<0000000651b9184a>] __zpci_event_error+0x23a/0x2c0 INFO: task kworker/u1664:6:1514 blocked for more than 122 seconds. Not tainted 5.14.0-570.12.1.bringup7.el9.s390x #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:k…