From 8ce371f9846ef1e8b3cc8f6865766cb5c1f17e40 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 20 Mar 2017 12:26:55 +0100 Subject: lockdep: Fix per-cpu static objects Since commit 383776fa7527 ("locking/lockdep: Handle statically initialized PER_CPU locks properly") we try to collapse per-cpu locks into a single class by giving them all the same key. For this key we choose the canonical address of the per-cpu object, which would be the offset into the per-cpu area. This has two problems: - there is a case where we run !0 lock->key through static_obj() and expect this to pass; it doesn't for canonical pointers. - 0 is a valid canonical address. Cure both issues by redefining the canonical address as the address of the per-cpu variable on the boot CPU. Since I didn't want to rely on CPU0 being the boot-cpu, or even existing at all, track the boot CPU in a variable. Fixes: 383776fa7527 ("locking/lockdep: Handle statically initialized PER_CPU locks properly") Reported-by: kernel test robot Signed-off-by: Peter Zijlstra (Intel) Tested-by: Borislav Petkov Cc: Sebastian Andrzej Siewior Cc: linux-mm@kvack.org Cc: wfg@linux.intel.com Cc: kernel test robot Cc: LKP Link: http://lkml.kernel.org/r/20170320114108.kbvcsuepem45j5cr@hirez.programming.kicks-ass.net Signed-off-by: Thomas Gleixner --- mm/percpu.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'mm/percpu.c') diff --git a/mm/percpu.c b/mm/percpu.c index 7d3b728c0254..bd7416752819 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1293,8 +1293,11 @@ bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr) void *va = (void *)addr; if (va >= start && va < start + static_size) { - if (can_addr) + if (can_addr) { *can_addr = (unsigned long) (va - start); + *can_addr += (unsigned long) + per_cpu_ptr(base, get_boot_cpu_id()); + } return true; } } -- cgit v1.2.3