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600462834f
In many files there are header comments that contain an Author: statement, supposedly reflecting who originally wrote the code. In a large collaborative project like libvirt, any non-trivial file will have been modified by a large number of different contributors. IOW, the Author: comments are quickly out of date, omitting people who have made significant contribitions. In some places Author: lines have been added despite the person merely being responsible for creating the file by moving existing code out of another file. IOW, the Author: lines give an incorrect record of authorship. With this all in mind, the comments are useless as a means to identify who to talk to about code in a particular file. Contributors will always be better off using 'git log' and 'git blame' if they need to find the author of a particular bit of code. This commit thus deletes all Author: comments from the source and adds a rule to prevent them reappearing. The Copyright headers are similarly misleading and inaccurate, however, we cannot delete these as they have legal meaning, despite being largely inaccurate. In addition only the copyright holder is permitted to change their respective copyright statement. Reviewed-by: Erik Skultety <eskultet@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
118 lines
2.6 KiB
Plaintext
118 lines
2.6 KiB
Plaintext
#!/usr/bin/stap --ldd -d /usr/sbin/libvirtd -c libvirtd
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#
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# Usage with installed libvirt daemon:
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# stap --ldd -d /usr/sbin/libvirtd -c libvirtd \
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# lock-debug.stp /usr/lib/libvirt.so
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#
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# If made executable; simple './lock-debug.stp' should work too.
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#
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# TODOs:
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#
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# Document usage with uninstalled daemon and libs. Assuming CWD is toplevel
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# source git directory, it should be only slight modification to the following:
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#
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# ./run stap --ldd -c src/libvirtd -d src/libvirtd
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# examples/systemtap/lock-debug.stp src/.libs/libvirt.so
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#
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# Debug RWLock mechanisms as well.
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#
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global mx_tolock
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global mx_locked
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function filter()
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{
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if (pid() != target())
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return 1
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return 0
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}
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probe library = process( %( $# > 0 %? @1 %: "/usr/lib/libvirt.so" %) )
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{
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if (filter()) next
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}
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probe lock = library.function("virMutexLock")
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{
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lockname = usymdata($m)
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}
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probe unlock = library.function("virMutexUnlock")
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{
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lockname = usymdata($m)
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}
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probe begin
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{
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%( $# > 1 %? println("error: Too many parameters"); exit();
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%: print("Started, press ^C when the process hangs\n"); %)
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}
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probe lock.call
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{
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mx_tolock[lockname, tid()] = sprint_usyms(ubacktrace())
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}
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probe lock.return
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{
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if ([lockname, tid()] in mx_tolock) {
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mx_locked[lockname, tid()] = mx_tolock[lockname, tid()]
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delete mx_tolock[lockname, tid()]
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} else {
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printf("internal error: lock acquired unwillingly?\n")
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}
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}
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probe unlock.call
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{
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found = 0
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foreach ([lock, tid] in mx_locked) {
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if (lock != lockname)
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continue
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if (tid != tid()) {
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printf("Warning: lock released on different thread that locked it.\n")
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printf("Lock trace:\n%s\n", mx_locked[lock, tid])
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printf("Unlock trace:\n%s\n", sprint_usyms(ubacktrace()))
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}
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found = tid
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break
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}
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if (found && [lockname, found] in mx_locked)
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delete mx_locked[lockname, found]
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}
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probe end
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{
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tmp = 0
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printf("\n=============\n")
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foreach (bt1 = [lock1, tid1] in mx_tolock) {
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deadlock = 0
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foreach (bt2 = [lock2, tid2] in mx_tolock) {
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if (lock1 == lock2) {
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if (!tmp++)
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printf("The following locks cannot be acquired:\n")
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if (!deadlock++)
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printf("Lock %s was locked in thread %d with this trace:\n%s\n",
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lock1, tid1, bt1)
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printf("and is waiting to be locked by thread %d here:\n%s\n",
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tid2, bt2)
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}
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}
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if (deadlock)
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printf("---\n")
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}
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if (!tmp)
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printf("No deadlocks found, sorry.\n")
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}
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