In the Linux kernel, the following vulnerability has been resolved: powerpc/smp: do not decrement idle task preempt count in CPU offline With PREEMPT_COUNT=y, when a CPU is offlined and then onlined again, we get: BUG: scheduling while atomic: swapper/1/0/0x00000000 no locks held by swapper/1/0. CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.15.0-rc2+ #100 Call Trace: dump_stack_lvl+0xac/0x108 __schedule_bug+0xac/0xe0 __schedule+0xcf8/0x10d0 schedule_idle+0x3c/0x70 do_idle+0x2d8/0x4a0 cpu_startup_entry+0x38/0x40 start_secondary+0x2ec/0x3a0 start_secondary_prolog+0x10/0x14 This is because powerpc's arch_cpu_idle_dead() decrements the idle task's preempt count, for reasons explained in commit a7c2bb8279d2 ("powerpc: Re-enable preemption before cpu_die()"), specifically "start_secondary() expects a preempt_count() of 0." However, since commit 2c669ef6979c ("powerpc/preempt: Don't touch the idle task's preempt_count during hotplug") and commit f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled"), that justification no longer holds. The idle task isn't supposed to re-enable preemption, so remove the vestigial preempt_enable() from the CPU offline path. Tested with pseries and powernv in qemu, and pseries on PowerVM.

IBM PowerVM Hypervisor FW950.00 through FW950.90, FW1020.00 through FW1020.40, and FW1030.00 through FW1030.30 could allow a system administrator to obtain sensitive partition information. IBM X-Force ID: 269695.

IBM PowerVM Hypervisor FW950.00 through FW950.90, FW1020.00 through FW1020.40, and FW1030.00 through FW1030.30 could reveal sensitive partition data to a system administrator. IBM X-Force ID: 257135.

IBM PowerVM Hypervisor FW950.00 through FW950.71, FW1010.00 through FW1010.40, FW1020.00 through FW1020.20, and FW1030.00 through FW1030.11 could allow an attacker to obtain sensitive information if they gain service access to the HMC. IBM X-Force ID: 247592.

IBM PowerVM Hypervisor FW860.00 through FW860.B3, FW950.00 through FW950.70, FW1010.00 through FW1010.50, FW1020.00 through FW1020.30, and FW1030.00 through FW1030.10 could allow a local attacker with control a partition that has been assigned SRIOV virtual function (VF) to cause a denial of service to a peer partition or arbitrary data corruption. IBM X-Force ID: 253175.

An internally discovered vulnerability in PowerVM on IBM Power9 and Power10 systems could allow an attacker with privileged user access to a logical partition to perform an undetected violation of the isolation between logical partitions which could lead to data leakage or the execution of arbitrary code in other logical partitions on the same physical server. IBM X-Force ID: 252706.

IBM PowerVM VIOS 3.1 could allow a remote attacker to tamper with system configuration or cause a denial of service. IBM X-Force ID: 230956.

IBM PowerVM Hypervisor FW860, FW940, FW950, and FW1010, through a specific sequence of VM management operations could lead to a violation of the isolation between peer VMs. IBM X-Force ID: 210019.

IBM PowerVM Hypervisor FW940, FW950, and FW1010 could allow an authenticated user to cause the system to crash using a specially crafted IBMi Hypervisor call. IBM X-Force ID: 210894.

IBM PowerVM Hypervisor FW860, FW940, and FW950 could allow an attacker that gains service access to the FSP can read and write arbitrary host system memory through a series of carefully crafted service procedures. IBM X-Force ID: 210018.

IBM PowerVM Hypervisor FW1010 could allow a privileged user to gain access to another VM due to assigning duplicate WWPNs. IBM X-Force ID: 210162.

IBM PowerVM Hypervisor FW860, FW930, FW940, and FW950 could allow a local user to create a specially crafted sequence of hypervisor calls from a partition that could crash the system. IBM X-Force ID: 203557.

IBM PowerVM Hypervisor FW940 and FW950 could allow an attacker to obtain sensitive information if they gain service access to the FSP. IBM X-Force ID: 202476.

The PowerVM Logical Partition Mobility(LPM) (PowerVM Hypervisor FW920, FW930, FW940, and FW950) encryption key exchange protocol can be compromised. If an attacker has the ability to capture encrypted LPM network traffic and is able to gain service access to the FSP they can use this information to perform a series of PowerVM service procedures to decrypt the captured migration traffic IBM X-Force ID: 198232

A flaw was found in the way RTAS handled memory accesses in userspace to kernel communication. On a locked down (usually due to Secure Boot) guest system running on top of PowerVM or KVM hypervisors (pseries platform) a root like local user could use this flaw to further increase their privileges to that of a running kernel.