Revision 9aea5a65aa7a1af9a4236dfaeb0088f1624f9919 authored by Roland McGrath on 08 September 2010, 02:37:06 UTC, committed by Linus Torvalds on 10 September 2010, 15:10:26 UTC
An execve with a very large total of argument/environment strings can take a really long time in the execve system call. It runs uninterruptibly to count and copy all the strings. This change makes it abort the exec quickly if sent a SIGKILL. Note that this is the conservative change, to interrupt only for SIGKILL, by using fatal_signal_pending(). It would be perfectly correct semantics to let any signal interrupt the string-copying in execve, i.e. use signal_pending() instead of fatal_signal_pending(). We'll save that change for later, since it could have user-visible consequences, such as having a timer set too quickly make it so that an execve can never complete, though it always happened to work before. Signed-off-by: Roland McGrath <roland@redhat.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 7993bc1
show_delta
#!/usr/bin/python
#
# show_deltas: Read list of printk messages instrumented with
# time data, and format with time deltas.
#
# Also, you can show the times relative to a fixed point.
#
# Copyright 2003 Sony Corporation
#
# GPL 2.0 applies.
import sys
import string
def usage():
print """usage: show_delta [<options>] <filename>
This program parses the output from a set of printk message lines which
have time data prefixed because the CONFIG_PRINTK_TIME option is set, or
the kernel command line option "time" is specified. When run with no
options, the time information is converted to show the time delta between
each printk line and the next. When run with the '-b' option, all times
are relative to a single (base) point in time.
Options:
-h Show this usage help.
-b <base> Specify a base for time references.
<base> can be a number or a string.
If it is a string, the first message line
which matches (at the beginning of the
line) is used as the time reference.
ex: $ dmesg >timefile
$ show_delta -b NET4 timefile
will show times relative to the line in the kernel output
starting with "NET4".
"""
sys.exit(1)
# returns a tuple containing the seconds and text for each message line
# seconds is returned as a float
# raise an exception if no timing data was found
def get_time(line):
if line[0]!="[":
raise ValueError
# split on closing bracket
(time_str, rest) = string.split(line[1:],']',1)
time = string.atof(time_str)
#print "time=", time
return (time, rest)
# average line looks like:
# [ 0.084282] VFS: Mounted root (romfs filesystem) readonly
# time data is expressed in seconds.useconds,
# convert_line adds a delta for each line
last_time = 0.0
def convert_line(line, base_time):
global last_time
try:
(time, rest) = get_time(line)
except:
# if any problem parsing time, don't convert anything
return line
if base_time:
# show time from base
delta = time - base_time
else:
# just show time from last line
delta = time - last_time
last_time = time
return ("[%5.6f < %5.6f >]" % (time, delta)) + rest
def main():
base_str = ""
filein = ""
for arg in sys.argv[1:]:
if arg=="-b":
base_str = sys.argv[sys.argv.index("-b")+1]
elif arg=="-h":
usage()
else:
filein = arg
if not filein:
usage()
try:
lines = open(filein,"r").readlines()
except:
print "Problem opening file: %s" % filein
sys.exit(1)
if base_str:
print 'base= "%s"' % base_str
# assume a numeric base. If that fails, try searching
# for a matching line.
try:
base_time = float(base_str)
except:
# search for line matching <base> string
found = 0
for line in lines:
try:
(time, rest) = get_time(line)
except:
continue
if string.find(rest, base_str)==1:
base_time = time
found = 1
# stop at first match
break
if not found:
print 'Couldn\'t find line matching base pattern "%s"' % base_str
sys.exit(1)
else:
base_time = 0.0
for line in lines:
print convert_line(line, base_time),
main()
Computing file changes ...