#!/usr/bin/python # # Copyright 2004 Matt Mackall # # inspired by perl Bloat-O-Meter (c) 1997 by Andi Kleen # # This software may be used and distributed according to the terms # of the GNU General Public License, incorporated herein by reference. import sys, os, re from signal import signal, SIGPIPE, SIG_DFL signal(SIGPIPE, SIG_DFL) if len(sys.argv) != 3: sys.stderr.write("usage: %s file1 file2\n" % sys.argv[0]) sys.exit(-1) re_NUMBER = re.compile(r'\.[0-9]+') def getsizes(file): sym = {} with os.popen("nm --size-sort " + file) as f: for line in f: size, type, name = line.split() if type in "tTdDbBrR": # strip generated symbols if name.startswith("__mod_"): continue if name.startswith("SyS_"): continue if name.startswith("compat_SyS_"): continue if name == "linux_banner": continue # statics and some other optimizations adds random .NUMBER name = re_NUMBER.sub('', name) sym[name] = sym.get(name, 0) + int(size, 16) return sym old = getsizes(sys.argv[1]) new = getsizes(sys.argv[2]) grow, shrink, add, remove, up, down = 0, 0, 0, 0, 0, 0 delta, common = [], {} otot, ntot = 0, 0 for a in old: if a in new: common[a] = 1 for name in old: otot += old[name] if name not in common: remove += 1 down += old[name] delta.append((-old[name], name)) for name in new: ntot += new[name] if name not in common: add += 1 up += new[name] delta.append((new[name], name)) for name in common: d = new.get(name, 0) - old.get(name, 0) if d>0: grow, up = grow+1, up+d if d<0: shrink, down = shrink+1, down-d delta.append((d, name)) delta.sort() delta.reverse() print("add/remove: %s/%s grow/shrink: %s/%s up/down: %s/%s (%s)" % \ (add, remove, grow, shrink, up, -down, up-down)) print("%-40s %7s %7s %+7s" % ("function", "old", "new", "delta")) for d, n in delta: if d: print("%-40s %7s %7s %+7d" % (n, old.get(n,"-"), new.get(n,"-"), d)) print("Total: Before=%d, After=%d, chg %+.2f%%" % \ (otot, ntot, (ntot - otot)*100.0/otot)) ec09e0144dc3341'>diff
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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/ceph/buffer.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/ceph/buffer.c')