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authorStefan Raspl <stefan.raspl@de.ibm.com>2018-02-22 12:16:24 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2018-02-24 01:43:42 +0100
commit1fd6a708c8438403dee17eb411cf81ffba13cf43 (patch)
treee15815f79eba376d438d921fbf1cb1c2fcd0abc4 /tools
parent1cd8bfb1ed9962be6d80d5020508922aa93653ac (diff)
downloadlwn-1fd6a708c8438403dee17eb411cf81ffba13cf43.tar.gz
lwn-1fd6a708c8438403dee17eb411cf81ffba13cf43.zip
tools/kvm_stat: fix debugfs handling
Te checks for debugfs assumed that debugfs is always mounted at /sys/kernel/debug - which is likely, but not guaranteed. This is addressed by checking /proc/mounts for the actual location. Furthermore, when debugfs was mounted, but the kvm module not loaded, a misleading error pointing towards debugfs not present was given. To reproduce, (a) run kvm_stat with debugfs mounted at a place different from /sys/kernel/debug (b) run kvm_stat with debugfs mounted but kvm module not loaded Signed-off-by: Stefan Raspl <raspl@linux.vnet.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'tools')
-rwxr-xr-xtools/kvm/kvm_stat/kvm_stat40
1 files changed, 26 insertions, 14 deletions
diff --git a/tools/kvm/kvm_stat/kvm_stat b/tools/kvm/kvm_stat/kvm_stat
index 08f842238c32..c5c8e9295b91 100755
--- a/tools/kvm/kvm_stat/kvm_stat
+++ b/tools/kvm/kvm_stat/kvm_stat
@@ -331,9 +331,6 @@ class perf_event_attr(ctypes.Structure):
PERF_TYPE_TRACEPOINT = 2
PERF_FORMAT_GROUP = 1 << 3
-PATH_DEBUGFS_TRACING = '/sys/kernel/debug/tracing'
-PATH_DEBUGFS_KVM = '/sys/kernel/debug/kvm'
-
class Group(object):
"""Represents a perf event group."""
@@ -1544,17 +1541,6 @@ Press any other key to refresh statistics immediately.
def check_access(options):
"""Exits if the current user can't access all needed directories."""
- if not os.path.exists('/sys/kernel/debug'):
- sys.stderr.write('Please enable CONFIG_DEBUG_FS in your kernel.')
- sys.exit(1)
-
- if not os.path.exists(PATH_DEBUGFS_KVM):
- sys.stderr.write("Please make sure, that debugfs is mounted and "
- "readable by the current user:\n"
- "('mount -t debugfs debugfs /sys/kernel/debug')\n"
- "Also ensure, that the kvm modules are loaded.\n")
- sys.exit(1)
-
if not os.path.exists(PATH_DEBUGFS_TRACING) and (options.tracepoints or
not options.debugfs):
sys.stderr.write("Please enable CONFIG_TRACING in your kernel "
@@ -1572,7 +1558,33 @@ def check_access(options):
return options
+def assign_globals():
+ global PATH_DEBUGFS_KVM
+ global PATH_DEBUGFS_TRACING
+
+ debugfs = ''
+ for line in file('/proc/mounts'):
+ if line.split(' ')[0] == 'debugfs':
+ debugfs = line.split(' ')[1]
+ break
+ if debugfs == '':
+ sys.stderr.write("Please make sure that CONFIG_DEBUG_FS is enabled in "
+ "your kernel, mounted and\nreadable by the current "
+ "user:\n"
+ "('mount -t debugfs debugfs /sys/kernel/debug')\n")
+ sys.exit(1)
+
+ PATH_DEBUGFS_KVM = os.path.join(debugfs, 'kvm')
+ PATH_DEBUGFS_TRACING = os.path.join(debugfs, 'tracing')
+
+ if not os.path.exists(PATH_DEBUGFS_KVM):
+ sys.stderr.write("Please make sure that CONFIG_KVM is enabled in "
+ "your kernel and that the modules are loaded.\n")
+ sys.exit(1)
+
+
def main():
+ assign_globals()
options = get_options()
options = check_access(options)