Sachin Sant

Name of the Vulnerable Software and Affected Versions: Linux kernel versions prior to 5.16.0-rc5-03218-g798527287598 Description: The vulnerability is related to the powerpc/perf component of the Linux kernel. It is caused by an error in the power pmu disable function, which can lead to a situation where the MSR EE flag is set (interrupt enabled) when a PMC overflow is detected. This can happen because the function runs under interrupt soft disable condition (local irq save) and not with interrupts hard disabled. The issue can be exploited to cause a denial of service. Recommendations: To resolve the issue, update the Linux kernel to a version that includes the fix for the powerpc/perf vulnerability. Specifically, update to a version that includes the commit 2c9ac51b850d ("powerpc/perf: Fix PMU callbacks to clear pending PMI before resetting an overflown PMC"). As a temporary workaround, consider disabling the power pmu disable function until a patch is available. However, this may have performance implications and should be carefully evaluated before implementation. Note: The provided information does not specify the exact version that includes the fix, so it is recommended to update to the latest available version of the Linux kernel.

**Name of the Vulnerable Software and Affected Versions** Linux kernel (affected versions not specified) **Description** The issue is related to a race condition in the powerpc/64s/interrupt component of the Linux kernel, specifically with the security mitigation switch. The RFI and STF security mitigation options can flip the interrupt exit not reentrant static branch condition concurrently with the interrupt exit code, which tests that branch. This can lead to corruption of the MSR and irq soft-mask state, resulting in warnings and possible crashes. The vulnerability is associated with errors in resource management in the exit must hard disable() function. **Recommendations** At the moment, there is no information about a newer version that contains a fix for this vulnerability.

**Name of the Vulnerable Software and Affected Versions** Linux kernel (affected versions not specified) **Description** A vulnerability in the Linux kernel has been identified, where a kernel panic occurs when the `papr scm` probe is called without the 'Enable Performance Information Collection' option enabled. This issue arises due to a missing check for the `stat buffer len` in the `papr scm pmu check events()` function, causing the `drc pmem query stats()` function to be called with a 'stat buffer' of size 0. The panic is characterized by a kernel NULL pointer dereference on write. The issue is observed on a POWER-10 LPAR with vPMEM. **Recommendations** To resolve this issue, introduce a check for `p->stat buffer len` at the beginning of the `papr scm pmu check events()` function to prevent the `drc pmem query stats()` function from being called when the NVDIMM does not support performance stats. At the moment, there is no information about a newer version that contains a fix for this vulnerability.