#! /usr/bin/python
# -*- python -*-
# -*- coding: utf-8 -*-
import perf
class tracepoint(perf.evsel):
def __init__(self, sys, name):
config = perf.tracepoint(sys, name)
perf.evsel.__init__(self,
type = perf.TYPE_TRACEPOINT,
config = config,
freq = 0, sample_period = 1, wakeup_events = 1,
sample_type = perf.SAMPLE_PERIOD | perf.SAMPLE_TID | perf.SAMPLE_CPU | perf.SAMPLE_RAW | perf.SAMPLE_TIME)
def main():
tp = tracepoint("sched", "sched_switch")
cpus = perf.cpu_map()
threads = perf.thread_map(-1)
evlist = perf.evlist(cpus, threads)
evlist.add(tp)
evlist.open()
evlist.mmap()
while True:
evlist.poll(timeout = -1)
for cpu in cpus:
event = evlist.read_on_cpu(cpu)
if not event:
continue
if not isinstance(event, perf.sample_event):
continue
print "time %u prev_comm=%s prev_pid=%d prev_prio=%d prev_state=0x%x ==> next_comm=%s next_pid=%d next_prio=%d" % (
event.sample_time,
event.prev_comm,
event.prev_pid,
event.prev_prio,
event.prev_state,
event.next_comm,
event.next_pid,
event.next_prio)
if __name__ == '__main__':
main()
summaryrefslogtreecommitdiff|
|
PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies
In a struct pcie_link_state, link->root points to the pcie_link_state of
the root of the PCIe hierarchy. For the topmost link, this points to
itself (link->root = link). For others, we copy the pointer from the
parent (link->root = link->parent->root).
Previously we recognized that Root Ports originated PCIe hierarchies, but
we treated PCI/PCI-X to PCIe Bridges as being in the middle of the
hierarchy, and when we tried to copy the pointer from link->parent->root,
there was no parent, and we dereferenced a NULL pointer:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000090
IP: [<ffffffff9e424350>] pcie_aspm_init_link_state+0x170/0x820
Recognize that PCI/PCI-X to PCIe Bridges originate PCIe hierarchies just
like Root Ports do, so link->root for these devices should also point to
itself.
Fixes: 51ebfc92b72b ("PCI: Enumerate switches below PCI-to-PCIe bridges")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=193411
Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1022181
Tested-by: lists@ssl-mail.com
Tested-by: Jayachandran C. <jnair@caviumnetworks.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org # v4.2+