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authorThomas Gleixner <tglx@linutronix.de>2017-02-27 15:37:36 +0100
committerIngo Molnar <mingo@kernel.org>2017-03-16 09:57:08 +0100
commit383776fa7527745224446337f2dcfb0f0d1b8b56 (patch)
treed9c5427418b5f6e1f6fdde58016c8347e45f7ec1 /include/linux/module.h
parent6419c4af777a773a45a1b1af735de0fcd9a7dcc7 (diff)
locking/lockdep: Handle statically initialized PER_CPU locks properly
If a PER_CPU struct which contains a spin_lock is statically initialized via: DEFINE_PER_CPU(struct foo, bla) = { .lock = __SPIN_LOCK_UNLOCKED(bla.lock) }; then lockdep assigns a seperate key to each lock because the logic for assigning a key to statically initialized locks is to use the address as the key. With per CPU locks the address is obvioulsy different on each CPU. That's wrong, because all locks should have the same key. To solve this the following modifications are required: 1) Extend the is_kernel/module_percpu_addr() functions to hand back the canonical address of the per CPU address, i.e. the per CPU address minus the per CPU offset. 2) Check the lock address with these functions and if the per CPU check matches use the returned canonical address as the lock key, so all per CPU locks have the same key. 3) Move the static_obj(key) check into look_up_lock_class() so this check can be avoided for statically initialized per CPU locks. That's required because the canonical address fails the static_obj(key) check for obvious reasons. Reported-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [ Merged Dan's fixups for !MODULES and !SMP into this patch. ] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dan Murphy <dmurphy@ti.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20170227143736.pectaimkjkan5kow@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/module.h')
-rw-r--r--include/linux/module.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/module.h b/include/linux/module.h
index 0297c5cd7cdf..9ad68561d8c2 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -493,6 +493,7 @@ static inline int module_is_live(struct module *mod)
struct module *__module_text_address(unsigned long addr);
struct module *__module_address(unsigned long addr);
bool is_module_address(unsigned long addr);
+bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr);
bool is_module_percpu_address(unsigned long addr);
bool is_module_text_address(unsigned long addr);
@@ -660,6 +661,11 @@ static inline bool is_module_percpu_address(unsigned long addr)
return false;
}
+static inline bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
+{
+ return false;
+}
+
static inline bool is_module_text_address(unsigned long addr)
{
return false;