# Monitor the system for dropped packets and proudce a report of drop locations and counts
import os
import sys
sys.path.append(os.environ['PERF_EXEC_PATH'] + \
'/scripts/python/Perf-Trace-Util/lib/Perf/Trace')
from perf_trace_context import *
from Core import *
from Util import *
drop_log = {}
kallsyms = []
def get_kallsyms_table():
global kallsyms
try:
f = open("/proc/kallsyms", "r")
except:
return
for line in f:
loc = int(line.split()[0], 16)
name = line.split()[2]
kallsyms.append((loc, name))
kallsyms.sort()
def get_sym(sloc):
loc = int(sloc)
# Invariant: kallsyms[i][0] <= loc for all 0 <= i <= start
# kallsyms[i][0] > loc for all end <= i < len(kallsyms)
start, end = -1, len(kallsyms)
while end != start + 1:
pivot = (start + end) // 2
if loc < kallsyms[pivot][0]:
end = pivot
else:
start = pivot
# Now (start == -1 or kallsyms[start][0] <= loc)
# and (start == len(kallsyms) - 1 or loc < kallsyms[start + 1][0])
if start >= 0:
symloc, name = kallsyms[start]
return (name, loc - symloc)
else:
return (None, 0)
def print_drop_table():
print "%25s %25s %25s" % ("LOCATION", "OFFSET", "COUNT")
for i in drop_log.keys():
(sym, off) = get_sym(i)
if sym == None:
sym = i
print "%25s %25s %25s" % (sym, off, drop_log[i])
def trace_begin():
print "Starting trace (Ctrl-C to dump results)"
def trace_end():
print "Gathering kallsyms data"
get_kallsyms_table()
print_drop_table()
# called from perf, when it finds a correspoinding event
def skb__kfree_skb(name, context, cpu, sec, nsec, pid, comm, callchain,
skbaddr, location, protocol):
slocation = str(location)
try:
drop_log[slocation] = drop_log[slocation] + 1
except:
drop_log[slocation] = 1
c'>logtreecommitdiff
|
pid: fix lockdep deadlock warning due to ucount_lock
=========================================================
[ INFO: possible irq lock inversion dependency detected ]
4.10.0-rc2-00024-g4aecec9-dirty #118 Tainted: G W
---------------------------------------------------------
swapper/1/0 just changed the state of lock:
(&(&sighand->siglock)->rlock){-.....}, at: [<ffffffffbd0a1bc6>] __lock_task_sighand+0xb6/0x2c0
but this lock took another, HARDIRQ-unsafe lock in the past:
(ucounts_lock){+.+...}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this:
Chain exists of: &(&sighand->siglock)->rlock --> &(&tty->ctrl_lock)->rlock --> ucounts_lock
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(ucounts_lock);
local_irq_disable();
lock(&(&sighand->siglock)->rlock);
lock(&(&tty->ctrl_lock)->rlock);
<Interrupt>
lock(&(&sighand->siglock)->rlock);
*** DEADLOCK ***
This patch removes a dependency between rlock and ucount_lock.
Fixes: f333c700c610 ("pidns: Add a limit on the number of pid namespaces")
Cc: stable@vger.kernel.org
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>