When spawning a thread via our virThread APIs we let pthread
spawn this helper thread which sets couple of thread local
variables (e.g. thread job name or thread worker name) and as of
v6.1.0-40-gc85256b31b it also sets pthread name (which is then
visible in `ps' output for instance). Only after these steps the
intended function is called. However, just before calling it we
free the buffer that holds the thread name which results in
invalid memory reads:
==47027== Invalid read of size 1
==47027== at 0x48389C2: strlen (vg_replace_strmem.c:459)
==47027== by 0x58BB3D6: __vfprintf_internal (vfprintf-internal.c:1645)
==47027== by 0x58CE6E0: __vasprintf_internal (vasprintf.c:57)
==47027== by 0x574BA28: g_vasprintf (in /usr/lib64/libglib-2.0.so.0.6000.7)
==47027== by 0x57240CC: g_strdup_vprintf (in /usr/lib64/libglib-2.0.so.0.6000.7)
==47027== by 0x48E0EFA: vir_g_strdup_vprintf (glibcompat.c:209)
==47027== by 0x493AA05: virLogVMessage (virlog.c:573)
==47027== by 0x493A8FE: virLogMessage (virlog.c:513)
==47027== by 0x4992FC7: virThreadJobClear (virthreadjob.c:121)
==47027== by 0x4992844: virThreadHelper (virthread.c:237)
==47027== by 0x5817496: start_thread (pthread_create.c:486)
==47027== by 0x59563CE: clone (clone.S:95)
The problem is that neither virThreadJobSetWorker() nor
virThreadJobSet() create a copy of passed name. They just set a
thread local variable to point to the buffer which is then
freed. Moving the free towards the end of the wrapper function
solves the issue.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Setting the thread name makes it easier to debug libvirtd
when many threads are running.
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Neither virThreadInitialize or virThreadOnExit do anything since we
dropped the Win32 threads impl, in favour of win-pthreads with:
commit 0240d94c36
Author: Daniel P. Berrange <berrange@redhat.com>
Date: Wed Jan 22 16:17:10 2014 +0000
Remove windows thread implementation in favour of pthreads
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The manual page clearly states that
gettid() is Linux-specific and should not be used in programs
that are intended to be portable.
Unfortunately, it looks like macOS implemented the functionality
and defined SYS_gettid accordingly, only to deprecate syscall()
altogether with 10.12 (Sierra), released last late year.
To avoid compilation errors, call gettid() on Linux only.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
This reverts commit 328bd24443.
As it turns out, this is not portable and very Linux & glibc
specific. Worse, this may lead to not starving writers on Linux
but everywhere else. Revert this and if the starvation occurs
resolve it.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
We already have virRWLockInit. But this uses pthread defaults
which prefer reader to initialize the RW lock. This may lead to
writer starvation. Therefore we need to have the counterpart that
prefers writers. Now, according to the
pthread_rwlockattr_setkind_np() man page setting
PTHREAD_RWLOCK_PREFER_WRITER_NP attribute is no-op. Therefore we
need to use PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP
attribute. So much for good enum value names.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
ts.tv_nsec was off by a factor of 1000, making timeouts less than a
second in the future often expiring immediately.
Signed-off-by: Michael Chapman <mike@very.puzzling.org>
Automatically assign a job to every thread created by virThreadCreate.
The name of the virThreadFunc function passed to virThreadCreate is used
as the job or worker name in case no name is explicitly passed.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
There are a number of pthreads impls available on Win32
these days, in particular the mingw64 project has a good
impl. Delete the native windows thread implementation and
rely on using pthreads everywhere.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
