Revision 4a33d4f17a19ece50ccf5ccbb8bc4ee539fb492e authored by Masahiro Yamada on 20 May 2019, 02:54:37 UTC, committed by Masahiro Yamada on 20 May 2019, 23:54:05 UTC
I just thought it was a good idea to scan builtin.modules in the name
uniqueness checking, but a couple of false positives were found.

Stephen reported a false positive for ppc64_defconfig:

  warning: same basename if the following are built as modules:
    arch/powerpc/platforms/powermac/nvram.ko
    drivers/char/nvram.ko

The former is never built as a module as you see in
arch/powerpc/platforms/powermac/Makefile:

  # CONFIG_NVRAM is an arch. independent tristate symbol, for pmac32 we really
  # need this to be a bool.  Cheat here and pretend CONFIG_NVRAM=m is really
  # CONFIG_NVRAM=y
  obj-$(CONFIG_NVRAM:m=y)         += nvram.o

Another example of false positive is arm64 defconfig:

  warning: same basename if the following are built as modules:
    arch/arm64/lib/crc32.ko
    lib/crc32.ko

It is true CONFIG_CRC32 is a tristate option but it is always 'y' since
it is select'ed by ARM64. Hence, neither of them is built as a module
for the arm64 build.

From the above, modules.builtin essentially contains false positives.
I do not think it is a big deal as far as kmod is concerned, but false
positive warnings in the kernel build make people upset. It is better
to not check it.

Even without builtin.modules checked, we have enough (and more solid)
test coverage with allmodconfig.

While I touched this part, I replaced the sed code with neater one
provided by Stephen.

Link: https://lkml.org/lkml/2019/5/19/120
Link: https://lkml.org/lkml/2019/5/19/123
Fixes: 3a48a91901c5 ("kbuild: check uniqueness of module names")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 parent 055efab
Raw File
bloat-o-meter
#!/usr/bin/python
#
# Copyright 2004 Matt Mackall <mpm@selenic.com>
#
# 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 [option] file1 file2\n" % sys.argv[0])
    sys.stderr.write("The options are:\n")
    sys.stderr.write("-c	categorize output based on symbol type\n")
    sys.stderr.write("-d	Show delta of Data Section\n")
    sys.stderr.write("-t	Show delta of text Section\n")
    sys.exit(-1)

re_NUMBER = re.compile(r'\.[0-9]+')

def getsizes(file, format):
    sym = {}
    with os.popen("nm --size-sort " + file) as f:
        for line in f:
            size, type, name = line.split()
            if type in format:
                # strip generated symbols
                if name.startswith("__mod_"): continue
                if name.startswith("__se_sys"): continue
                if name.startswith("__se_compat_sys"): continue
                if name.startswith("__addressable_"): 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

def calc(oldfile, newfile, format):
    old = getsizes(oldfile, format)
    new = getsizes(newfile, format)
    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()
    return grow, shrink, add, remove, up, down, delta, old, new, otot, ntot

def print_result(symboltype, symbolformat, argc):
    grow, shrink, add, remove, up, down, delta, old, new, otot, ntot = \
    calc(sys.argv[argc - 1], sys.argv[argc], symbolformat)

    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" % (symboltype, "old", "new", "delta"))
    for d, n in delta:
        if d: print("%-40s %7s %7s %+7d" % (n, old.get(n,"-"), new.get(n,"-"), d))

    if otot:
        percent = (ntot - otot) * 100.0 / otot
    else:
        percent = 0
    print("Total: Before=%d, After=%d, chg %+.2f%%" % (otot, ntot, percent))

if sys.argv[1] == "-c":
    print_result("Function", "tT", 3)
    print_result("Data", "dDbB", 3)
    print_result("RO Data", "rR", 3)
elif sys.argv[1] == "-d":
    print_result("Data", "dDbBrR", 3)
elif sys.argv[1] == "-t":
    print_result("Function", "tT", 3)
else:
    print_result("Function", "tTdDbBrR", 2)
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