mausezahn-libs = -lcli \ -lnet \ -lpcap \ -lrt \ -lpthread \ -lm mausezahn-objs = str.o \ staging/layer1.o \ staging/layer2.o \ staging/layer3.o \ staging/layer4.o \ staging/hextools.o \ staging/tools.o \ staging/lookupdev.o \ staging/time.o \ staging/modifications.o \ staging/send_eth.o \ staging/send.o \ staging/cdp.o \ staging/rtp.o \ staging/dns.o \ staging/rcv_rtp.o \ staging/syslog.o \ staging/cli.o \ staging/cli_cmds.o \ staging/cli_launch.o \ staging/cli_legacy.o \ staging/cli_packet.o \ staging/cli_interface.o \ staging/cli_set.o \ staging/cli_dns.o \ staging/cli_arp.o \ staging/cli_bpdu.o \ staging/cli_eth.o \ staging/cli_ip.o \ staging/cli_udp.o \ staging/cli_tcp.o \ staging/cli_rtp.o \ staging/cli_tools.o \ staging/cli_igmp.o \ staging/cli_lldp.o \ staging/cli_sequence.o \ staging/mops.o \ staging/mops_update.o \ staging/mops_tools.o \ staging/mops_checksums.o \ staging/mops_threads.o \ staging/mops_dot1Q.o \ staging/mops_mpls.o \ staging/mops_ip.o \ staging/mops_tcp.o \ staging/mops_ext.o \ staging/mops_ext_arp.o \ staging/mops_ext_bpdu.o \ staging/mops_ext_rtp.o \ staging/mopsrx_arp.o \ staging/mops_ext_igmp.o \ staging/mops_ext_lldp.o \ staging/mops_sequence.o \ staging/automops.o \ staging/parse_xml.o \ staging/tx_switch.o \ staging/llist.o \ staging/directmops.o \ staging/mausezahn.o mausezahn-eflags = -O2 -I. -I.. \ -DVERSION_STRING=\"$(VERSION_STRING)\" \ -DPREFIX_STRING=\"$(PREFIX)\" \ -DVERSION_LONG=\"$(VERSION_LONG)\" mausezahn-confs = s-private-remove&id=966d2b04e070bc040319aaebfec09e0144dc3341'>refslogtreecommitdiff
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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 /include/drm
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/drm')