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authorPeter Zijlstra <peterz@infradead.org>2017-03-20 14:26:55 +0300
committerThomas Gleixner <tglx@linutronix.de>2017-03-26 16:09:45 +0300
commit8ce371f9846ef1e8b3cc8f6865766cb5c1f17e40 (patch)
treeae7406dc794c7cf642b9c37bf85408e3a38c5dca /kernel/cpu.c
parent56222b212e8edb1cf51f5dd73ff645809b082b40 (diff)
downloadlinux-8ce371f9846ef1e8b3cc8f6865766cb5c1f17e40.tar.xz
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 <fengguang.wu@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Borislav Petkov <bp@suse.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: linux-mm@kvack.org Cc: wfg@linux.intel.com Cc: kernel test robot <fengguang.wu@intel.com> Cc: LKP <lkp@01.org> Link: http://lkml.kernel.org/r/20170320114108.kbvcsuepem45j5cr@hirez.programming.kicks-ass.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r--kernel/cpu.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index f7c063239fa5..a795725774c5 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1125,6 +1125,8 @@ core_initcall(cpu_hotplug_pm_sync_init);
#endif /* CONFIG_PM_SLEEP_SMP */
+int __boot_cpu_id;
+
#endif /* CONFIG_SMP */
/* Boot processor state steps */
@@ -1815,6 +1817,10 @@ void __init boot_cpu_init(void)
set_cpu_active(cpu, true);
set_cpu_present(cpu, true);
set_cpu_possible(cpu, true);
+
+#ifdef CONFIG_SMP
+ __boot_cpu_id = cpu;
+#endif
}
/*