Nam Cao

**Name of the Vulnerable Software and Affected Versions** Linux kernel versions prior to 6.6.74 **Description** The issue is related to the Linux kernel, specifically with the riscv architecture. The problem arises when the `die()` function is called in an exception handler, which cannot sleep. However, `die()` uses `spinlock t`, which can sleep when `PREEMPT RT` is enabled, causing a warning. The warning indicates a sleeping function called from an invalid context. The solution involves switching to use `raw spinlock t`, which does not sleep even with `PREEMPT RT` enabled. **Recommendations** To resolve the issue, update to Linux kernel version 6.6.74 or later. As a temporary workaround, consider disabling the `PREEMPT RT` feature until a patch is available. Restrict access to the vulnerable `die()` function to minimize the risk of exploitation. Avoid using the `spinlock t` variable in the affected API endpoint until the issue is resolved.

**Name of the Vulnerable Software and Affected Versions** Linux kernel versions prior to 6.9.0 **Description** The issue is related to the ` kernel map pages()` function, which is a debug function that clears the valid bit in page table entries for deallocated pages to detect illegal memory accesses to freed pages. This function uses ` set memory()` to set or clear the valid bit, and ` set memory()` acquires init mm's semaphore, which may sleep. However, ` kernel map pages()` can be called in atomic context, making it illegal to sleep. An example warning is provided, showing a BUG message indicating a sleeping function called from an invalid context. **Recommendations** At the moment, there is no information about a newer version that contains a fix for this vulnerability.