[ { "EventCode": "0x8", "Counter": "0,1,2,3", "UMask": "0x1", "EventName": "DTLB_LOAD_MISSES.ANY", "SampleAfterValue": "200000", "BriefDescription": "DTLB load misses" }, { "EventCode": "0x8", "Counter": "0,1,2,3", "UMask": "0x80", "EventName": "DTLB_LOAD_MISSES.LARGE_WALK_COMPLETED", "SampleAfterValue": "200000", "BriefDescription": "DTLB load miss large page walks" }, { "EventCode": "0x8", "Counter": "0,1,2,3", "UMask": "0x20", "EventName": "DTLB_LOAD_MISSES.PDE_MISS", "SampleAfterValue": "200000", "BriefDescription": "DTLB load miss caused by low part of address" }, { "EventCode": "0x8", "Counter": "0,1,2,3", "UMask": "0x10", "EventName": "DTLB_LOAD_MISSES.STLB_HIT", "SampleAfterValue": "2000000", "BriefDescription": "DTLB second level hit" }, { "EventCode": "0x8", "Counter": "0,1,2,3", "UMask": "0x2", "EventName": "DTLB_LOAD_MISSES.WALK_COMPLETED", "SampleAfterValue": "200000", "BriefDescription": "DTLB load miss page walks complete" }, { "EventCode": "0x8", "Counter": "0,1,2,3", "UMask": "0x4", "EventName": "DTLB_LOAD_MISSES.WALK_CYCLES", "SampleAfterValue": "200000", "BriefDescription": "DTLB load miss page walk cycles" }, { "EventCode": "0x49", "Counter": "0,1,2,3", "UMask": "0x1", "EventName": "DTLB_MISSES.ANY", "SampleAfterValue": "200000", "BriefDescription": "DTLB misses" }, { "EventCode": "0x49", "Counter": "0,1,2,3", "UMask": "0x80", "EventName": "DTLB_MISSES.LARGE_WALK_COMPLETED", "SampleAfterValue": "200000", "BriefDescription": "DTLB miss large page walks" }, { "EventCode": "0x49", "Counter": "0,1,2,3", "UMask": "0x20", "EventName": "DTLB_MISSES.PDE_MISS", "SampleAfterValue": "200000", "BriefDescription": "DTLB misses casued by low part of address" }, { "EventCode": "0x49", "Counter": "0,1,2,3", "UMask": "0x10", "EventName": "DTLB_MISSES.STLB_HIT", "SampleAfterValue": "200000", "BriefDescription": "DTLB first level misses but second level hit" }, { "EventCode": "0x49", "Counter": "0,1,2,3", "UMask": "0x2", "EventName": "DTLB_MISSES.WALK_COMPLETED", "SampleAfterValue": "200000", "BriefDescription": "DTLB miss page walks" }, { "EventCode": "0x49", "Counter": "0,1,2,3", "UMask": "0x4", "EventName": "DTLB_MISSES.WALK_CYCLES", "SampleAfterValue": "2000000", "BriefDescription": "DTLB miss page walk cycles" }, { "EventCode": "0x4F", "Counter": "0,1,2,3", "UMask": "0x10", "EventName": "EPT.WALK_CYCLES", "SampleAfterValue": "2000000", "BriefDescription": "Extended Page Table walk cycles" }, { "EventCode": "0xAE", "Counter": "0,1,2,3", "UMask": "0x1", "EventName": "ITLB_FLUSH", "SampleAfterValue": "2000000", "BriefDescription": "ITLB flushes" }, { "PEBS": "1", "EventCode": "0xC8", "Counter": "0,1,2,3", "UMask": "0x20", "EventName": "ITLB_MISS_RETIRED", "SampleAfterValue": "200000", "BriefDescription": "Retired instructions that missed the ITLB (Precise Event)" }, { "EventCode": "0x85", "Counter": "0,1,2,3", "UMask": "0x1", "EventName": "ITLB_MISSES.ANY", "SampleAfterValue": "200000", "BriefDescription": "ITLB miss" }, { "EventCode": "0x85", "Counter": "0,1,2,3", "UMask": "0x80", "EventName": "ITLB_MISSES.LARGE_WALK_COMPLETED", "SampleAfterValue": "200000", "BriefDescription": "ITLB miss large page walks" }, { "EventCode": "0x85", "Counter": "0,1,2,3", "UMask": "0x2", "EventName": "ITLB_MISSES.WALK_COMPLETED", "SampleAfterValue": "200000", "BriefDescription": "ITLB miss page walks" }, { "EventCode": "0x85", "Counter": "0,1,2,3", "UMask": "0x4", "EventName": "ITLB_MISSES.WALK_CYCLES", "SampleAfterValue": "2000000", "BriefDescription": "ITLB miss page walk cycles" }, { "PEBS": "1", "EventCode": "0xCB", "Counter": "0,1,2,3", "UMask": "0x80", "EventName": "MEM_LOAD_RETIRED.DTLB_MISS", "SampleAfterValue": "200000", "BriefDescription": "Retired loads that miss the DTLB (Precise Event)" }, { "PEBS": "1", "EventCode": "0xC", "Counter": "0,1,2,3", "UMask": "0x1", "EventName": "MEM_STORE_RETIRED.DTLB_MISS", "SampleAfterValue": "200000", "BriefDescription": "Retired stores that miss the DTLB (Precise Event)" } ]-info'> 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/usb/ffs-aio-example/multibuff/host_app/Makefile 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/usb/ffs-aio-example/multibuff/host_app/Makefile')