This is a note to let you know that I've just added the patch titled

x86/oprofile/ppro: Do not use __this_cpu*() in preemptible context

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: x86-oprofile-ppro-do-not-use-__this_cpu-in-preemptible-context.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From a743bbeef27b9176987ec0cb7f906ab0ab52d1da Mon Sep 17 00:00:00 2001

From: Borislav Petkov bp@suse.de Date: Tue, 7 Nov 2017 18:53:07 +0100 Subject: x86/oprofile/ppro: Do not use __this_cpu*() in preemptible context

From: Borislav Petkov bp@suse.de

commit a743bbeef27b9176987ec0cb7f906ab0ab52d1da upstream.

The warning below says it all:

BUG: using __this_cpu_read() in preemptible [00000000] code: swapper/0/1 caller is __this_cpu_preempt_check CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.14.0-rc8 #4 Call Trace: dump_stack check_preemption_disabled ? do_early_param __this_cpu_preempt_check arch_perfmon_init op_nmi_init ? alloc_pci_root_info oprofile_arch_init oprofile_init do_one_initcall ...

These accessors should not have been used in the first place: it is PPro so no mixed silicon revisions and thus it can simply use boot_cpu_data.

Reported-by: Fengguang Wu fengguang.wu@intel.com Tested-by: Fengguang Wu fengguang.wu@intel.com Fix-creation-mandated-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Borislav Petkov bp@suse.de Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: Robert Richter rric@kernel.org Cc: x86@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/x86/oprofile/op_model_ppro.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/oprofile/op_model_ppro.c +++ b/arch/x86/oprofile/op_model_ppro.c @@ -212,8 +212,8 @@ static void arch_perfmon_setup_counters( eax.full = cpuid_eax(0xa);

/* Workaround for BIOS bugs in 6/15. Taken from perfmon2 */ - if (eax.split.version_id == 0 && __this_cpu_read(cpu_info.x86) == 6 && - __this_cpu_read(cpu_info.x86_model) == 15) { + if (eax.split.version_id == 0 && boot_cpu_data.x86 == 6 && + boot_cpu_data.x86_model == 15) { eax.split.version_id = 2; eax.split.num_counters = 2; eax.split.bit_width = 40;

Patches currently in stable-queue which might be from bp@suse.de are

queue-4.4/x86-oprofile-ppro-do-not-use-__this_cpu-in-preemptible-context.patch