Hi, here are 3 patches which update the PTI-x86-32 patches recently merged into the tip-tree. The patches are ordered by importance: Patch 1: Very important, it fixes a vmalloc-fault in NMI context when PTI is enabled. This is pretty unlikely to hit when starting perf on an idle machine, which is why I didn't find it earlier in my testing. I always started 'perf top' first :/ But when I start 'perf top' last when the kernel-compile already runs, it hits almost immediatly. Patch 2: Fix the 'from-kernel-check' in SWITCH_TO_KERNEL_STACK to also take VM86 into account. This is not strictly necessary because the slow-path also works for VM86 mode but it is not how the code was intended to work. And it breaks when Patch 3 is applied on-top. Patch 3: Implement the reduced copying in the paranoid entry/exit path as suggested by Andy Lutomirski while reviewing version 7 of the original patches. I have the x86/tip branch with these patches on-top running my test for 6h now, with no issues so far. So for now it looks like there are no scheduling points or irq-enabled sections reached from the paranoid entry/exit paths and we always return to the entry-stack we came from. I keep the test running over the weekend at least. Please review. [ If Patch 1 looks good to the maintainers I suggest applying it soon, before too many linux-next testers run into this issue. It is actually the reason why I send out the patches _now_ and didn't wait until next week when the other two patches got more testing from my side. ] Thanks, Joerg Joerg Roedel (3): perf/core: Make sure the ring-buffer is mapped in all page-tables x86/entry/32: Check for VM86 mode in slow-path check x86/entry/32: Copy only ptregs on paranoid entry/exit path arch/x86/entry/entry_32.S | 82 ++++++++++++++++++++++++++------------------- kernel/events/ring_buffer.c | 10 ++++++ 2 files changed, 58 insertions(+), 34 deletions(-) -- 2.7.4
