Messages in this thread Patch in this message | | | Date | Tue, 09 Mar 2010 10:54:20 +0900 | From | Tejun Heo <> | Subject | Re: odd lockdep messages |
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On 03/09/2010 03:43 AM, Peter Zijlstra wrote: >> [ 1.899537] BUG: key ffff88011c57e670 not in .data! >> >> (-0302 threw BUG: 3 times, the first 2 and the last. In -0304, the third >> one appears as well). >> >> Worth instrumenting and chasing down? If so, what should a crash test dummy >> be doing here? ;) > > Can that be wreckage due to the new per-cpu stuff? > > Its a message printed when the below function fails, and that per-cpu > stuff seems the one most likely to break, given that there was quite a > lot of churn in that department recently.
Yeap, PERCPU_ENOUGH_ROOM test doesn't hold anymore. Does the following patch fix the problem?
Thanks.
diff --git a/include/linux/percpu.h b/include/linux/percpu.h index a93e5bf..6d300f5 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -137,6 +137,7 @@ extern int __init pcpu_page_first_chunk(size_t reserved_size, extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align); extern void __percpu *__alloc_percpu(size_t size, size_t align); extern void free_percpu(void __percpu *__pdata); +extern bool is_static_percpu_address(unsigned long addr); extern phys_addr_t per_cpu_ptr_to_phys(void *addr); #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA @@ -163,6 +164,12 @@ static inline void free_percpu(void __percpu *p) kfree(p); } +/* can't distinguish from other static vars, always %false */ +static inline bool is_static_percpu_address(unsigned long addr) +{ + return false; +} + static inline phys_addr_t per_cpu_ptr_to_phys(void *addr) { return __pa(addr); diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 0c30d04..4206f6f 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -582,9 +582,6 @@ static int static_obj(void *obj) unsigned long start = (unsigned long) &_stext, end = (unsigned long) &_end, addr = (unsigned long) obj; -#ifdef CONFIG_SMP - int i; -#endif /* * static variable? @@ -595,19 +592,11 @@ static int static_obj(void *obj) if (arch_is_kernel_data(addr)) return 1; -#ifdef CONFIG_SMP /* * percpu var? */ - for_each_possible_cpu(i) { - start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); - end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM - + per_cpu_offset(i); - - if ((addr >= start) && (addr < end)) - return 1; - } -#endif + if (is_static_percpu_address(addr)) + return 1; /* * module var? diff --git a/mm/percpu.c b/mm/percpu.c index 768419d..ae4d058 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1304,6 +1304,32 @@ void free_percpu(void __percpu *ptr) EXPORT_SYMBOL_GPL(free_percpu); /** + * is_static_percpu_address - test whether address is from static percpu area + * @addr: address to test + * + * Test whether @addr belongs to static percpu area. Module static + * percpu areas allocated via __alloc_reserved_percpu() is not + * considered. Use is_module_address() for those. + * + * RETURNS: + * %true if @addr is from static percpu area, %false otherwise. + */ +bool is_static_percpu_address(unsigned long addr) +{ + const size_t static_size = __per_cpu_end - __per_cpu_start; + void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr); + unsigned int cpu; + + for_each_possible_cpu(cpu) { + void *start = per_cpu_ptr(base, cpu); + + if ((void *)addr >= start && (void *)addr < start + static_size) + return true; + } + return false; +} + +/** * per_cpu_ptr_to_phys - convert translated percpu address to physical address * @addr: the address to be converted to physical address * -- tejun
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