# # This is a simple wrapper Makefile that calls the main Makefile.perf # with a -j option to do parallel builds # # If you want to invoke the perf build in some non-standard way then # you can use the 'make -f Makefile.perf' method to invoke it. # # # Clear out the built-in rules GNU make defines by default (such as .o targets), # so that we pass through all targets to Makefile.perf: # .SUFFIXES: # # We don't want to pass along options like -j: # unexport MAKEFLAGS # # Do a parallel build with multiple jobs, based on the number of CPUs online # in this system: 'make -j8' on a 8-CPU system, etc. # # (To override it, run 'make JOBS=1' and similar.) # ifeq ($(JOBS),) JOBS := $(shell (getconf _NPROCESSORS_ONLN || egrep -c '^processor|^CPU[0-9]' /proc/cpuinfo) 2>/dev/null) ifeq ($(JOBS),0) JOBS := 1 endif endif # # Only pass canonical directory names as the output directory: # ifneq ($(O),) FULL_O := $(shell readlink -f $(O) || echo $(O)) endif # # Only accept the 'DEBUG' variable from the command line: # ifeq ("$(origin DEBUG)", "command line") ifeq ($(DEBUG),) override DEBUG = 0 else SET_DEBUG = "DEBUG=$(DEBUG)" endif else override DEBUG = 0 endif define print_msg @printf ' BUILD: Doing '\''make \033[33m-j'$(JOBS)'\033[m'\'' parallel build\n' endef define make @$(MAKE) -f Makefile.perf --no-print-directory -j$(JOBS) O=$(FULL_O) $(SET_DEBUG) $@ endef # # Needed if no target specified: # (Except for tags and TAGS targets. The reason is that the # Makefile does not treat tags/TAGS as targets but as files # and thus won't rebuilt them once they are in place.) # all tags TAGS: $(print_msg) $(make) ifdef MAKECMDGOALS has_clean := 0 ifneq ($(filter clean,$(MAKECMDGOALS)),) has_clean := 1 endif # clean ifeq ($(has_clean),1) rest := $(filter-out clean,$(MAKECMDGOALS)) ifneq ($(rest),) $(rest): clean endif # rest endif # has_clean endif # MAKECMDGOALS # # The clean target is not really parallel, don't print the jobs info: # clean: $(make) # # The build-test target is not really parallel, don't print the jobs info, # it also uses only the tests/make targets that don't pollute the source # repository, i.e. that uses O= or builds the tarpkg outside the source # repo directories. # # For a full test, use: # # make -C tools/perf -f tests/make # build-test: @$(MAKE) SHUF=1 -f tests/make REUSE_FEATURES_DUMP=1 MK=Makefile SET_PARALLEL=1 --no-print-directory tarpkg out # # All other targets get passed through: # %: FORCE $(print_msg) $(make) .PHONY: tags TAGS FORCE Makefile hor
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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/net/.gitignore
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/net/.gitignore')