#include #include #include #include #include "tests.h" #include "thread_map.h" #include "debug.h" #define NAME (const char *) "perf" #define NAMEUL (unsigned long) NAME int test__thread_map(int subtest __maybe_unused) { struct thread_map *map; TEST_ASSERT_VAL("failed to set process name", !prctl(PR_SET_NAME, NAMEUL, 0, 0, 0)); /* test map on current pid */ map = thread_map__new_by_pid(getpid()); TEST_ASSERT_VAL("failed to alloc map", map); thread_map__read_comms(map); TEST_ASSERT_VAL("wrong nr", map->nr == 1); TEST_ASSERT_VAL("wrong pid", thread_map__pid(map, 0) == getpid()); TEST_ASSERT_VAL("wrong comm", thread_map__comm(map, 0) && !strcmp(thread_map__comm(map, 0), NAME)); TEST_ASSERT_VAL("wrong refcnt", atomic_read(&map->refcnt) == 1); thread_map__put(map); /* test dummy pid */ map = thread_map__new_dummy(); TEST_ASSERT_VAL("failed to alloc map", map); thread_map__read_comms(map); TEST_ASSERT_VAL("wrong nr", map->nr == 1); TEST_ASSERT_VAL("wrong pid", thread_map__pid(map, 0) == -1); TEST_ASSERT_VAL("wrong comm", thread_map__comm(map, 0) && !strcmp(thread_map__comm(map, 0), "dummy")); TEST_ASSERT_VAL("wrong refcnt", atomic_read(&map->refcnt) == 1); thread_map__put(map); return 0; } static int process_event(struct perf_tool *tool __maybe_unused, union perf_event *event, struct perf_sample *sample __maybe_unused, struct machine *machine __maybe_unused) { struct thread_map_event *map = &event->thread_map; struct thread_map *threads; TEST_ASSERT_VAL("wrong nr", map->nr == 1); TEST_ASSERT_VAL("wrong pid", map->entries[0].pid == (u64) getpid()); TEST_ASSERT_VAL("wrong comm", !strcmp(map->entries[0].comm, NAME)); threads = thread_map__new_event(&event->thread_map); TEST_ASSERT_VAL("failed to alloc map", threads); TEST_ASSERT_VAL("wrong nr", threads->nr == 1); TEST_ASSERT_VAL("wrong pid", thread_map__pid(threads, 0) == getpid()); TEST_ASSERT_VAL("wrong comm", thread_map__comm(threads, 0) && !strcmp(thread_map__comm(threads, 0), NAME)); TEST_ASSERT_VAL("wrong refcnt", atomic_read(&threads->refcnt) == 1); thread_map__put(threads); return 0; } int test__thread_map_synthesize(int subtest __maybe_unused) { struct thread_map *threads; TEST_ASSERT_VAL("failed to set process name", !prctl(PR_SET_NAME, NAMEUL, 0, 0, 0)); /* test map on current pid */ threads = thread_map__new_by_pid(getpid()); TEST_ASSERT_VAL("failed to alloc map", threads); thread_map__read_comms(threads); TEST_ASSERT_VAL("failed to synthesize map", !perf_event__synthesize_thread_map2(NULL, threads, process_event, NULL)); return 0; } int test__thread_map_remove(int subtest __maybe_unused) { struct thread_map *threads; char *str; int i; TEST_ASSERT_VAL("failed to allocate map string", asprintf(&str, "%d,%d", getpid(), getppid()) >= 0); threads = thread_map__new_str(str, NULL, 0); TEST_ASSERT_VAL("failed to allocate thread_map", threads); if (verbose) thread_map__fprintf(threads, stderr); TEST_ASSERT_VAL("failed to remove thread", !thread_map__remove(threads, 0)); TEST_ASSERT_VAL("thread_map count != 1", threads->nr == 1); if (verbose) thread_map__fprintf(threads, stderr); TEST_ASSERT_VAL("failed to remove thread", !thread_map__remove(threads, 0)); TEST_ASSERT_VAL("thread_map count != 0", threads->nr == 0); if (verbose) thread_map__fprintf(threads, stderr); TEST_ASSERT_VAL("failed to not remove thread", thread_map__remove(threads, 0)); for (i = 0; i < threads->nr; i++) free(threads->map[i].comm); free(threads); return 0; } ion value='8'>8space:mode:
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 /include/rdma/ib_verbs.h
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 'include/rdma/ib_verbs.h')