From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Protection Keys never affect kernel mappings. But, they can affect whether the kernel will fault when it touches a user mapping. The kernel doesn't touch user mappings without some careful choreography and these accesses don't generally result in oopses. But, if one does, we definitely want to have PKRU available so we can figure out if protection keys played a role. Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> --- b/arch/x86/kernel/process_64.c | 2 ++ 1 file changed, 2 insertions(+) diff -puN arch/x86/kernel/process_64.c~pkeys-30-kernel-error-dumps arch/x86/kernel/process_64.c --- a/arch/x86/kernel/process_64.c~pkeys-30-kernel-error-dumps 2016-01-28 15:52:25.978661494 -0800 +++ b/arch/x86/kernel/process_64.c 2016-01-28 15:52:25.981661632 -0800 @@ -116,6 +116,8 @@ void __show_regs(struct pt_regs *regs, i printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2); printk(KERN_DEFAULT "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7); + if (boot_cpu_has(X86_FEATURE_OSPKE)) + printk(KERN_DEFAULT "PKRU: %08x\n", read_pkru()); } void release_thread(struct task_struct *dead_task) _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>