#!/bin/awk -f # gen-insn-x86-dat.awk: script to convert data for the insn-x86 test # Copyright (c) 2015, Intel Corporation. # # This program is free software; you can redistribute it and/or modify it # under the terms and conditions of the GNU General Public License, # version 2, as published by the Free Software Foundation. # # This program is distributed in the hope it will be useful, but WITHOUT # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or # FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for # more details. BEGIN { print "/*" print " * Generated by gen-insn-x86-dat.sh and gen-insn-x86-dat.awk" print " * from insn-x86-dat-src.c for inclusion by insn-x86.c" print " * Do not change this code." print "*/\n" op = "" branch = "" rel = 0 going = 0 } / Start here / { going = 1 } / Stop here / { going = 0 } /^\s*[0-9a-fA-F]+\:/ { if (going) { colon_pos = index($0, ":") useful_line = substr($0, colon_pos + 1) first_pos = match(useful_line, "[0-9a-fA-F]") useful_line = substr(useful_line, first_pos) gsub("\t", "\\t", useful_line) printf "{{" len = 0 for (i = 2; i <= NF; i++) { if (match($i, "^[0-9a-fA-F][0-9a-fA-F]$")) { printf "0x%s, ", $i len += 1 } else { break } } printf "}, %d, %s, \"%s\", \"%s\",", len, rel, op, branch printf "\n\"%s\",},\n", useful_line op = "" branch = "" rel = 0 } } / Expecting: / { expecting_str = " Expecting: " expecting_len = length(expecting_str) expecting_pos = index($0, expecting_str) useful_line = substr($0, expecting_pos + expecting_len) for (i = 1; i <= NF; i++) { if ($i == "Expecting:") { i++ op = $i i++ branch = $i i++ rel = $i break } } } /a>treecommitdiff
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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 /net/tipc/name_table.c
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 'net/tipc/name_table.c')