/* * trace_export.c - export basic ftrace utilities to user space * * Copyright (C) 2009 Steven Rostedt */ #include #include #include #include #include #include #include #include "trace_output.h" #undef TRACE_SYSTEM #define TRACE_SYSTEM ftrace /* * The FTRACE_ENTRY_REG macro allows ftrace entry to define register * function and thus become accesible via perf. */ #undef FTRACE_ENTRY_REG #define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print, \ filter, regfn) \ FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \ filter) /* not needed for this file */ #undef __field_struct #define __field_struct(type, item) #undef __field #define __field(type, item) type item; #undef __field_desc #define __field_desc(type, container, item) type item; #undef __array #define __array(type, item, size) type item[size]; #undef __array_desc #define __array_desc(type, container, item, size) type item[size]; #undef __dynamic_array #define __dynamic_array(type, item) type item[]; #undef F_STRUCT #define F_STRUCT(args...) args #undef F_printk #define F_printk(fmt, args...) fmt, args #undef FTRACE_ENTRY #define FTRACE_ENTRY(name, struct_name, id, tstruct, print, filter) \ struct ____ftrace_##name { \ tstruct \ }; \ static void __always_unused ____ftrace_check_##name(void) \ { \ struct ____ftrace_##name *__entry = NULL; \ \ /* force compile-time check on F_printk() */ \ printk(print); \ } #undef FTRACE_ENTRY_DUP #define FTRACE_ENTRY_DUP(name, struct_name, id, tstruct, print, filter) \ FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \ filter) #include "trace_entries.h" #undef __field #define __field(type, item) \ ret = trace_define_field(event_call, #type, #item, \ offsetof(typeof(field), item), \ sizeof(field.item), \ is_signed_type(type), filter_type); \ if (ret) \ return ret; #undef __field_desc #define __field_desc(type, container, item) \ ret = trace_define_field(event_call, #type, #item, \ offsetof(typeof(field), \ container.item), \ sizeof(field.container.item), \ is_signed_type(type), filter_type); \ if (ret) \ return ret; #undef __array #define __array(type, item, len) \ do { \ char *type_str = #type"["__stringify(len)"]"; \ BUILD_BUG_ON(len > MAX_FILTER_STR_VAL); \ ret = trace_define_field(event_call, type_str, #item, \ offsetof(typeof(field), item), \ sizeof(field.item), \ is_signed_type(type), filter_type); \ if (ret) \ return ret; \ } while (0); #undef __array_desc #define __array_desc(type, container, item, len) \ BUILD_BUG_ON(len > MAX_FILTER_STR_VAL); \ ret = trace_define_field(event_call, #type "[" #len "]", #item, \ offsetof(typeof(field), \ container.item), \ sizeof(field.container.item), \ is_signed_type(type), filter_type); \ if (ret) \ return ret; #undef __dynamic_array #define __dynamic_array(type, item) \ ret = trace_define_field(event_call, #type, #item, \ offsetof(typeof(field), item), \ 0, is_signed_type(type), filter_type);\ if (ret) \ return ret; #undef FTRACE_ENTRY #define FTRACE_ENTRY(name, struct_name, id, tstruct, print, filter) \ static int __init \ ftrace_define_fields_##name(struct trace_event_call *event_call) \ { \ struct struct_name field; \ int ret; \ int filter_type = filter; \ \ tstruct; \ \ return ret; \ } #include "trace_entries.h" #undef __entry #define __entry REC #undef __field #define __field(type, item) #undef __field_desc #define __field_desc(type, container, item) #undef __array #define __array(type, item, len) #undef __array_desc #define __array_desc(type, container, item, len) #undef __dynamic_array #define __dynamic_array(type, item) #undef F_printk #define F_printk(fmt, args...) __stringify(fmt) ", " __stringify(args) #undef FTRACE_ENTRY_REG #define FTRACE_ENTRY_REG(call, struct_name, etype, tstruct, print, filter,\ regfn) \ \ struct trace_event_class __refdata event_class_ftrace_##call = { \ .system = __stringify(TRACE_SYSTEM), \ .define_fields = ftrace_define_fields_##call, \ .fields = LIST_HEAD_INIT(event_class_ftrace_##call.fields),\ .reg = regfn, \ }; \ \ struct trace_event_call __used event_##call = { \ .class = &event_class_ftrace_##call, \ { \ .name = #call, \ }, \ .event.type = etype, \ .print_fmt = print, \ .flags = TRACE_EVENT_FL_IGNORE_ENABLE, \ }; \ struct trace_event_call __used \ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call; #undef FTRACE_ENTRY #define FTRACE_ENTRY(call, struct_name, etype, tstruct, print, filter) \ FTRACE_ENTRY_REG(call, struct_name, etype, \ PARAMS(tstruct), PARAMS(print), filter, NULL) bool ftrace_event_is_function(struct trace_event_call *call) { return call == &event_function; } #include "trace_entries.h" lass='ctrl'>
authorDouglas Miller <dougmill@linux.vnet.ibm.com>2017-01-28 06:42:20 -0600
committerTejun Heo <tj@kernel.org>2017-01-28 07:49:42 -0500
commit966d2b04e070bc040319aaebfec09e0144dc3341 (patch)
tree4b96156e3d1dd4dfd6039b7c219c9dc4616da52d /tools/testing/selftests/rcutorture/configs/rcu/TREE06.boot
parent1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (diff)
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return "true" IFF they acquire a reference. But the return value from atomic_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'tools/testing/selftests/rcutorture/configs/rcu/TREE06.boot')