January 2010 - Devel - libvirt List Archives

[libvirt] Nice libvirt article on IBM developer works
by Hugh O. Brock 12 Jan '10

12 Jan '10

http://www.ibm.com/developerworks/linux/library/l-libvirt/index.html?ca=dgr… Maybe we can get more like this (despite the factual errors...) --H -- ======================================================== Hugh Brock, hbrock(a)redhat.com, +1-215-564-3232 Deltacloud API + Portal http://deltacloud.org Libvirt virtualization library http://libvirt.org ========================================================

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Re: [libvirt] Segfault in event-test.c example
by pspreadborough＠comcast.net 12 Jan '10

12 Jan '10

----- pspreadborough(a)comcast.net wrote: > ----- "Matthias Bolte" <matthias.bolte(a)googlemail.com> wrote: > > > 2010/1/11 <pspreadborough(a)comcast.net>: > > > > > > ----- "Matthias Bolte" <matthias.bolte(a)googlemail.com> wrote: > > > > > >> 2010/1/10 <pspreadborough(a)comcast.net>: > > >> > > > >> > ----- "Matthias Bolte" <matthias.bolte(a)googlemail.com> wrote: > > >> > > > >> >> 2010/1/10 <pspreadborough(a)comcast.net>: > > >> >> > > > >> >> > Hello, > > >> >> > > > >> >> > I have been trying to use the domain event C code example > but > > >> >> > unfortunately it segfaults (signal 11) every time I run it: > > >> >> > > > >> >> > [root@Spring events-c]# ./event-test > > >> >> > myEventAddHandleFunc:221: Add handle 5 1 0xf081a0 0x8f727f8 > > >> >> > myEventAddHandleFunc:221: Add handle 7 1 0xf09990 0x8f727f8 > > >> >> > myEventAddHandleFunc:221: Add handle 8 1 0xed7940 0x8f727f8 > > >> >> > myEventAddTimeoutFunc:251: Adding Timeout -1 0xedefa0 > > 0x8f727f8 > > >> >> > myEventAddHandleFunc:221: Add handle 11 1 0xed7940 0x8f727f8 > > >> >> > myEventAddTimeoutFunc:251: Adding Timeout -1 0xedefa0 > > 0x8f727f8 > > >> >> > main:322 :: Registering domain event cbs > > >> >> > Segmentation fault (core dumped) > > >> >> > > > >> >> > Core was generated by > > >> >> > > > >> >> > > >> > > > `/root/libvirt-0.7.5/examples/domain-events/events-c/.libs/lt-event-test'. > > >> >> > Program terminated with signal 11, Segmentation fault. > > >> >> > [New process 21806] > > >> >> > [New process 21822] > > >> >> > #0 remoteDomainEventQueueFlush (timer=-1, opaque=0x8f727f8) > > at > > >> >> > remote/remote_driver.c:8720 > > >> >> > 8720 tempQueue.count = priv->domainEvents->count; > > >> >> > (gdb) bt > > >> >> > #0 remoteDomainEventQueueFlush (timer=-1, opaque=0x8f727f8) > > at > > >> >> > remote/remote_driver.c:8720 > > >> >> > #1 0x080490d3 in main (argc=Cannot access memory at address > > 0x1 > > >> >> > ) at event-test.c:347 > > >> >> > > > >> >> > The stack looks corrupted so I'm doubtful that this trace if > > of > > >> much > > >> >> value. > > >> >> > I have built > > >> >> > and installed libvirt-0.7.5 and it and it's tools seem to be > > >> >> operating > > >> >> > correctly. > > >> >> > > >> >> I tried the event-test with libvirt-0.7.5 and QEMU/Xen and > both > > >> are > > >> >> working as expected. No segfaults. > > >> >> > > >> >> Could you inspect the values of priv and priv->domainEvents in > > GDB > > >> >> using 'p priv' to see if they are NULL and try to dereference > > them > > >> in > > >> >> GDB using 'p *priv' to see if they point to valid memory > areas? > > >> >> > > >> >> Yes the backtrace looks corrupted. If there is stack/heap > > >> corruption > > >> >> involved valgrind may reveal it, so try to run the event-test > > in > > >> >> valgrind and see if that gives any hints. > > >> >> > > >> >> You can also try the GIT version of libvirt. There was a > > invalid > > >> free > > >> >> call (resulting in heap corruption) in the node device code > > fixed > > >> >> after the 0.7.5 release. But that should have no effect on the > > >> >> event-test. > > >> >> > > >> >> Matthias > > >> > > > >> > Matthias, > > >> > > > >> > priv->domainEvents is NULL, here's the gdb output: > > >> > > >> This explains the segfault. The next question is, why is it NULL? > > >> > > >> > (gdb) p *priv > > >> > $1 = {lock = {lock = {__data = {__lock = 1, __count = 0, > __owner > > = > > >> 21806, __kind = 0, __nusers = 1, {__spins = 0, __list = { > > >> > __next = 0x0}}}, __size = > > >> > > > "\001\000\000\000\000\000\000\000.U\000\000\000\000\000\000\001\000\000\000\000\000\000", > > >> > __align = 1}}, sock = 150469168, watch = 3, pid = 4, > > uses_tls = > > >> 1982791681, is_secure = 1815048801, session = 0x782f6269, > > >> > > >> Seeing uses_tls and is_secure being large numbers and knowing > that > > >> both are used as boolean values in the code and should have > values > > of > > >> 0 or 1 make me think that priv points to already freed memory > > here. > > >> > > >> > type = 0x2f646e65 <Address 0x2f646e65 out of bounds>, counter > = > > >> 1684956536, localUses = 1668248365, > > >> > hostname = 0x74656b <Address 0x74656b out of bounds>, debugLog > > = > > >> 0x0, saslconn = 0x0, saslDecoded = 0x0, saslDecodedLength = 0, > > >> > > >> type and hostname are char pointers, but the seem to point into > > >> nowhere, confirms that this is either freed memory or priv itself > > got > > >> overwritten due to heap corruption. > > >> > > >> > saslDecodedOffset = 0, saslEncoded = 0x0, saslEncodedLength = > > 0, > > >> saslEncodedOffset = 0, > > >> > buffer = '\0' <repeats 68 times>, > > >> > > > "n\000\000\000\001\000\000\000\000\000\000\000\001\000\000\000\000\000\000\000\001\000\000\000\001\000\000\000\000\000\000\000\001\000\000\000\bQ�\b��\030\034�\b\000\000\000\000�\033�\b\001\000\000\000\002\000\000\000�\033�\b\000\000\000\000\025|�\000\a", > > >> '\0' <repeats 11 times>, "X\000�\b", '\0' <repeats 12 times>, > > >> "\021\000\000\000\002\000\000\000P��\b\000\000\000\000\021", '\0' > > >> <repeats 15 times>, > > >> > > > "\021\000\000\0008\036�\b\f\000\000\000\020\000\000\000\021\000\000\000\a\000\000\000\b\000\000\000\t\000\000\000\021\000\000\000\002\000\000\000\230\034�\b\000\000\000\000A\000\000\000\003\000\000\000\001\000\000\000\001\000"..., > > >> bufferLength = 0, > > >> > bufferOffset = 0, callbackList = 0x0, domainEvents = 0x0, > > >> eventFlushTimer = 0, domainEventDispatching = 1, wakeupSendFD = > 0, > > >> > wakeupReadFD = 0, waitDispatch = 0x0, streams = 0x0} > > >> > > > >> > I'll try a run with valgrind and post the results. > > >> > > > >> > Pete > > >> > > > >> > > >> Could you test the Python version of this example found in > > >> examples/domain-events/events-python/event-test.py? Does this > > work? > > >> > > >> Otherwise lets see if valgrind gives any hints. > > >> > > >> Matthias > > > > > > > > > During initialization I notice that the myEventAddHandleFunc() > > method is > > > called multiple times, each time with a different fd value (5,7,8 > > and 11). > > > The way the code is written only the last fd value is recorded and > > then > > > used in the poll() call. Is this the intended? if so why are the > > preceding > > > fds ignored? > > > > > > myEventAddHandleFunc:223: Add handle 5 1 0xf13480 0x97b97d8 > > > myEventAddHandleFunc:223: Add handle 7 1 0xf14c70 0x97b97d8 > > > Allocating domainEvents:0x97c6b10 > > > myEventAddHandleFunc:223: Add handle 8 1 0xee2940 0x97b97d8 > > > myEventAddTimeoutFunc:260: Adding Timeout -1 0xee9fc0 0x97b97d8 > > > Allocating domainEvents:0x97c5780 > > > myEventAddHandleFunc:223: Add handle 11 1 0xee2940 0x97b97d8 > > > myEventAddTimeoutFunc:260: Adding Timeout -1 0xee9fc0 0x97b97d8 > > > main:333 :: Registering domain event cbs > > > > > > > > > Regards, > > > > > > Pete > > > > > > > That's strange. I can't reproduce this neither. I always get exactly > > one call to myEventAddHandleFunc: > > > > myEventAddHandleFunc:221: Add handle 3 1 0x7ff116f68b00 0x1d97f00 > > myEventAddTimeoutFunc:251: Adding Timeout -1 0x7ff116f68750 > 0x1d97f00 > > main:322 :: Registering domain event cbs > > myEventUpdateHandleFunc:232: Updated Handle 0 0 > > myEventUpdateHandleFunc:232: Updated Handle 0 1 > > > > You could try to run the event-test in GDB and set a breakpoint on > > myEventAddHandleFunc to see where 4 additional calls to > > myEventAddHandleFunc come from. > > > > In my case I get this backtrace when setting a breakpoint on > > myEventAddHandleFunc: > > > > (gdb) bt > > #0 myEventAddHandleFunc (fd=6, event=1, cb=0x7f1be6ec3b00 > > <remoteDomainEventFired>, opaque=0xc68f00, ff=0) at event-test.c:220 > > #1 0x00007f1be6ecbaaf in doRemoteOpen (conn=0xc68f00, > > priv=0x7f1be7350010, auth=0x0, flags=0) at > remote/remote_driver.c:893 > > #2 0x00007f1be6ece053 in remoteOpen (conn=0xc68f00, auth=0x0, > > flags=13007744) at remote/remote_driver.c:1076 > > #3 0x00007f1be6eb155d in do_open (name=0x7fff48400968 > > "qemu:///system", auth=0x0, flags=0) at libvirt.c:1117 > > #4 0x0000000000400eb3 in main (argc=<value optimized out>, > > argv=<value optimized out>) at event-test.c:313 > > > > Matthias > > > Matthias > > Here are the four stack traces, one for each time > myEventAddHandleFunc() was > called. > > #0 myEventAddHandleFunc (fd=8, event=1, cb=0x85b480 > <xenStoreWatchEvent>, opaque=0x824a7d8, ff=0) at event-test.c:223 > #1 0x007ccf55 in virEventAddHandle (fd=8, events=1, cb=0x85b480 > <xenStoreWatchEvent>, opaque=0x824a7d8, ff=0) > at util/event.c:45 > #2 0x0085b291 in xenStoreOpen (conn=0x824a7d8, auth=0x0, flags=<value > optimized out>) at xen/xs_internal.c:339 > #3 0x00844287 in xenUnifiedOpen (conn=0x824a7d8, auth=0x0, flags=0) > at xen/xen_driver.c:352 > #4 0x00811d05 in do_open (name=0xbf8c49d4 "xen:///", auth=0x0, > flags=0) at libvirt.c:1117 > #5 0x08048e92 in main (argc=Cannot access memory at address 0x2 > ) at event-test.c:325 > (gdb) c > Continuing. > (gdb) b > Note: breakpoint 1 also set at pc 0x8048bc9. > Breakpoint 2 at 0x8048bc9: file event-test.c, line 223. > (gdb) bt > #0 myEventAddHandleFunc (fd=10, event=1, cb=0x85cc70 > <xenInotifyEvent>, opaque=0x824a7d8, ff=0) at event-test.c:223 > #1 0x007ccf55 in virEventAddHandle (fd=10, events=1, cb=0x85cc70 > <xenInotifyEvent>, opaque=0x824a7d8, ff=0) at util/event.c:45 > #2 0x0085c827 in xenInotifyOpen (conn=0x824a7d8, auth=0x0, flags=0) > at xen/xen_inotify.c:460 > #3 0x008444f1 in xenUnifiedOpen (conn=0x824a7d8, auth=0x0, flags=0) > at xen/xen_driver.c:391 > #4 0x00811d05 in do_open (name=0xbf8c49d4 "xen:///", auth=0x0, > flags=0) at libvirt.c:1117 > #5 0x08048e92 in main (argc=Cannot access memory at address 0x1 > ) at event-test.c:325 > (gdb) c > Continuing. > (gdb) bt > #0 myEventAddHandleFunc (fd=11, event=1, cb=0x82a940 > <remoteDomainEventFired>, opaque=0x824a7d8, ff=0) at event-test.c:223 > #1 0x007ccf55 in virEventAddHandle (fd=11, events=1, cb=0x82a940 > <remoteDomainEventFired>, opaque=0x824a7d8, ff=0) > at util/event.c:45 > #2 0x0082c478 in doRemoteOpen (conn=0x824a7d8, priv=0xb7534008, > auth=0x0, flags=0) at remote/remote_driver.c:894 > #3 0x00830448 in remoteOpenSecondaryDriver (conn=0x824a7d8, auth=0x0, > flags=0, priv=0xbf8c2668) at remote/remote_driver.c:1006 > #4 0x0083082a in remoteNetworkOpen (conn=0x824a7d8, auth=0x0, > flags=0) at remote/remote_driver.c:3549 > #5 0x00811e2f in do_open (name=0xbf8c49d4 "xen:///", auth=0x0, > flags=0) at libvirt.c:1137 > #6 0x08048e92 in main (argc=1, argv=0xbf8c28b4) at event-test.c:325 > (gdb) c > Continuing. > (gdb) bt > #0 myEventAddHandleFunc (fd=14, event=1, cb=0x82a940 > <remoteDomainEventFired>, opaque=0x824a7d8, ff=0) at event-test.c:223 > #1 0x007ccf55 in virEventAddHandle (fd=14, events=1, cb=0x82a940 > <remoteDomainEventFired>, opaque=0x824a7d8, ff=0) > at util/event.c:45 > #2 0x0082c478 in doRemoteOpen (conn=0x824a7d8, priv=0x8258ab0, > auth=0x0, flags=0) at remote/remote_driver.c:894 > #3 0x00830448 in remoteOpenSecondaryDriver (conn=0x824a7d8, auth=0x0, > flags=0, priv=0xbf8c2668) at remote/remote_driver.c:1006 > #4 0x0083078a in remoteInterfaceOpen (conn=0x824a7d8, auth=0x0, > flags=0) at remote/remote_driver.c:4104 > #5 0x00811f4e in do_open (name=0xbf8c49d4 "xen:///", auth=0x0, > flags=0) at libvirt.c:1156 > #6 0x08048e92 in main (argc=1, argv=0xbf8c28b4) at event-test.c:325 > > Regards, > > Pete > > > -- > Libvir-list mailing list > Libvir-list(a)redhat.com > https://www.redhat.com/mailman/listinfo/libvir-list Matthias, Using the UIR xen+unix:/// works! I'm curious to know why when using the UIR xen:/// multiple myEventAddHandleFunc() calls occurred. Are there and fields I could use to identify and ignore the spurious calls? I'd like to use the event monitoring for several remote Xen hosts. I assume I'll have to modify the code to connect remotely to each host and hope for just one myEventAddHandleFunc() call per host. Thanks for your assistance it's much apprecied, Regards, Pete

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[libvirt] [PATCH] remote_driver.c: fix a NULL dereference in remoteDomainEventQueueFlush().
by kakuma 12 Jan '10

12 Jan '10

Hi, all. There is a case of a NULL dereference in function remoteDomainEventQueueFlush() in remote_driver.c In the case of local connection conn->privateData->domainEvents isn't reserved. In this case it will occurs segment fault. (for example examples/domain-events/events-c/event-test.c) I think the following patch will be available. Thanks. --- src/remote/remote_driver.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/remote/remote_driver.c b/src/remote/remote_driver.c index d6f5fce..b112fd3 100644 --- a/src/remote/remote_driver.c +++ b/src/remote/remote_driver.c @@ -8709,7 +8709,7 @@ void remoteDomainEventQueueFlush(int timer ATTRIBUTE_UNUSED, void *opaque) { virConnectPtr conn = opaque; - struct private_data *priv = conn->privateData; + struct private_data *priv = conn->networkPrivateData; virDomainEventQueue tempQueue; remoteDriverLock(priv); -- 1.5.6.1 -- kakuma <f-kak(a)ksh.biglobe.ne.jp>

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Re: [libvirt] Segfault in event-test.c example
by pspreadborough＠comcast.net 12 Jan '10

12 Jan '10

----- "Matthias Bolte" <matthias.bolte(a)googlemail.com> wrote: > 2010/1/10 <pspreadborough(a)comcast.net>: > > > > ----- "Matthias Bolte" <matthias.bolte(a)googlemail.com> wrote: > > > >> 2010/1/10 <pspreadborough(a)comcast.net>: > >> > > >> > Hello, > >> > > >> > I have been trying to use the domain event C code example but > >> > unfortunately it segfaults (signal 11) every time I run it: > >> > > >> > [root@Spring events-c]# ./event-test > >> > myEventAddHandleFunc:221: Add handle 5 1 0xf081a0 0x8f727f8 > >> > myEventAddHandleFunc:221: Add handle 7 1 0xf09990 0x8f727f8 > >> > myEventAddHandleFunc:221: Add handle 8 1 0xed7940 0x8f727f8 > >> > myEventAddTimeoutFunc:251: Adding Timeout -1 0xedefa0 0x8f727f8 > >> > myEventAddHandleFunc:221: Add handle 11 1 0xed7940 0x8f727f8 > >> > myEventAddTimeoutFunc:251: Adding Timeout -1 0xedefa0 0x8f727f8 > >> > main:322 :: Registering domain event cbs > >> > Segmentation fault (core dumped) > >> > > >> > Core was generated by > >> > > >> > `/root/libvirt-0.7.5/examples/domain-events/events-c/.libs/lt-event-test'. > >> > Program terminated with signal 11, Segmentation fault. > >> > [New process 21806] > >> > [New process 21822] > >> > #0 remoteDomainEventQueueFlush (timer=-1, opaque=0x8f727f8) at > >> > remote/remote_driver.c:8720 > >> > 8720 tempQueue.count = priv->domainEvents->count; > >> > (gdb) bt > >> > #0 remoteDomainEventQueueFlush (timer=-1, opaque=0x8f727f8) at > >> > remote/remote_driver.c:8720 > >> > #1 0x080490d3 in main (argc=Cannot access memory at address 0x1 > >> > ) at event-test.c:347 > >> > > >> > The stack looks corrupted so I'm doubtful that this trace if of > much > >> value. > >> > I have built > >> > and installed libvirt-0.7.5 and it and it's tools seem to be > >> operating > >> > correctly. > >> > >> I tried the event-test with libvirt-0.7.5 and QEMU/Xen and both > are > >> working as expected. No segfaults. > >> > >> Could you inspect the values of priv and priv->domainEvents in GDB > >> using 'p priv' to see if they are NULL and try to dereference them > in > >> GDB using 'p *priv' to see if they point to valid memory areas? > >> > >> Yes the backtrace looks corrupted. If there is stack/heap > corruption > >> involved valgrind may reveal it, so try to run the event-test in > >> valgrind and see if that gives any hints. > >> > >> You can also try the GIT version of libvirt. There was a invalid > free > >> call (resulting in heap corruption) in the node device code fixed > >> after the 0.7.5 release. But that should have no effect on the > >> event-test. > >> > >> Matthias > > > > Matthias, > > > > priv->domainEvents is NULL, here's the gdb output: > > This explains the segfault. The next question is, why is it NULL? > > > (gdb) p *priv > > $1 = {lock = {lock = {__data = {__lock = 1, __count = 0, __owner = > 21806, __kind = 0, __nusers = 1, {__spins = 0, __list = { > > __next = 0x0}}}, __size = > "\001\000\000\000\000\000\000\000.U\000\000\000\000\000\000\001\000\000\000\000\000\000", > > __align = 1}}, sock = 150469168, watch = 3, pid = 4, uses_tls = > 1982791681, is_secure = 1815048801, session = 0x782f6269, > > Seeing uses_tls and is_secure being large numbers and knowing that > both are used as boolean values in the code and should have values of > 0 or 1 make me think that priv points to already freed memory here. > > > type = 0x2f646e65 <Address 0x2f646e65 out of bounds>, counter = > 1684956536, localUses = 1668248365, > > hostname = 0x74656b <Address 0x74656b out of bounds>, debugLog = > 0x0, saslconn = 0x0, saslDecoded = 0x0, saslDecodedLength = 0, > > type and hostname are char pointers, but the seem to point into > nowhere, confirms that this is either freed memory or priv itself got > overwritten due to heap corruption. > > > saslDecodedOffset = 0, saslEncoded = 0x0, saslEncodedLength = 0, > saslEncodedOffset = 0, > > buffer = '\0' <repeats 68 times>, > "n\000\000\000\001\000\000\000\000\000\000\000\001\000\000\000\000\000\000\000\001\000\000\000\001\000\000\000\000\000\000\000\001\000\000\000\bQ�\b��\030\034�\b\000\000\000\000�\033�\b\001\000\000\000\002\000\000\000�\033�\b\000\000\000\000\025|�\000\a", > '\0' <repeats 11 times>, "X\000�\b", '\0' <repeats 12 times>, > "\021\000\000\000\002\000\000\000P��\b\000\000\000\000\021", '\0' > <repeats 15 times>, > "\021\000\000\0008\036�\b\f\000\000\000\020\000\000\000\021\000\000\000\a\000\000\000\b\000\000\000\t\000\000\000\021\000\000\000\002\000\000\000\230\034�\b\000\000\000\000A\000\000\000\003\000\000\000\001\000\000\000\001\000"..., > bufferLength = 0, > > bufferOffset = 0, callbackList = 0x0, domainEvents = 0x0, > eventFlushTimer = 0, domainEventDispatching = 1, wakeupSendFD = 0, > > wakeupReadFD = 0, waitDispatch = 0x0, streams = 0x0} > > > > I'll try a run with valgrind and post the results. > > > > Pete > > > > Could you test the Python version of this example found in > examples/domain-events/events-python/event-test.py? Does this work? > > Otherwise lets see if valgrind gives any hints. > > Matthias During initialization I notice that the myEventAddHandleFunc() method is called multiple times, each time with a different fd value (5,7,8 and 11). The way the code is written only the last fd value is recorded and then used in the poll() call. Is this the intended? if so why are the preceding fds ignored? myEventAddHandleFunc:223: Add handle 5 1 0xf13480 0x97b97d8 myEventAddHandleFunc:223: Add handle 7 1 0xf14c70 0x97b97d8 Allocating domainEvents:0x97c6b10 myEventAddHandleFunc:223: Add handle 8 1 0xee2940 0x97b97d8 myEventAddTimeoutFunc:260: Adding Timeout -1 0xee9fc0 0x97b97d8 Allocating domainEvents:0x97c5780 myEventAddHandleFunc:223: Add handle 11 1 0xee2940 0x97b97d8 myEventAddTimeoutFunc:260: Adding Timeout -1 0xee9fc0 0x97b97d8 main:333 :: Registering domain event cbs Regards, Pete

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[libvirt] [PATCH] Document the domain XML cache attribute for disk devices
by Matthias Bolte 11 Jan '10

11 Jan '10

--- docs/formatdomain.html.in | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-) diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index 46ab0ac..af31699 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -343,7 +343,7 @@ <pre> ... <disk type='file'> - <driver name="tap" type="aio"> + <driver name="tap" type="aio" cache="default"> <source file='/var/lib/xen/images/fv0'/> <target dev='hda' bus='ide'/> <encryption type='...'> @@ -383,7 +383,9 @@ <dd>If the hypervisor supports multiple backend drivers, then the optional <code>driver</code> element allows them to be selected. The <code>name</code> attribute is the primary backend driver name, while the optional <code>type</code> - attribute provides the sub-type. <span class="since">Since 0.1.8</span> + attribute provides the sub-type. The optional <code>cache</code> attribute + controls the cache mechanism, possible values are "default", "none", + "writethrough" and "writeback". <span class="since">Since 0.1.8</span> </dd> <dt><code>encryption</code></dt> <dd>If present, specifies how the volume is encrypted. See -- 1.6.0.4

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[libvirt] [PATCH] qemu: Fix a memory leak in qemudExtractTTYPath
by Matthias Bolte 11 Jan '10

11 Jan '10

qemudWaitForMonitor calls qemudReadLogOutput with qemudFindCharDevicePTYs as callback. qemudFindCharDevicePTYs calls qemudExtractTTYPath to assign a string to chr->data.file.path. Afterwards qemudWaitForMonitor may call qemudFindCharDevicePTYsMonitor that overwrites chr->data.file.path without freeing the old value. This results in leaking the memory allocated by qemudExtractTTYPath. Report an OOM error if the strdup in qemudFindCharDevicePTYsMonitor fails. --- src/qemu/qemu_driver.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index daa6f94..8817565 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -1433,7 +1433,13 @@ qemudFindCharDevicePTYsMonitor(virConnectPtr conn, return -1; \ } \ \ + VIR_FREE(chr->data.file.path); \ chr->data.file.path = strdup(path); \ + \ + if (chr->data.file.path == NULL) { \ + virReportOOMError(conn); \ + return -1; \ + } \ } \ } -- 1.6.0.4

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[libvirt] Just to make sure I understand the API
by Bryan Kearney 11 Jan '10

11 Jan '10

To make sure I understand the API. If I have a domain defined, but not started.. it will show up in the list returned by: virConnectListDefinedDomains but not in the list virConnectListDomains Conversely, if it is started... it will only be in the list: virConnectListDomains not in the list virConnectListDefinedDomains Is that correct? -- bk

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Re: [libvirt] Segfault in event-test.c example
by pspreadborough＠comcast.net 11 Jan '10

11 Jan '10

----- "Matthias Bolte" <matthias.bolte(a)googlemail.com> wrote: > 2010/1/10 <pspreadborough(a)comcast.net>: > > > > ----- "Matthias Bolte" <matthias.bolte(a)googlemail.com> wrote: > > > >> 2010/1/10 <pspreadborough(a)comcast.net>: > >> > > >> > Hello, > >> > > >> > I have been trying to use the domain event C code example but > >> > unfortunately it segfaults (signal 11) every time I run it: > >> > > >> > [root@Spring events-c]# ./event-test > >> > myEventAddHandleFunc:221: Add handle 5 1 0xf081a0 0x8f727f8 > >> > myEventAddHandleFunc:221: Add handle 7 1 0xf09990 0x8f727f8 > >> > myEventAddHandleFunc:221: Add handle 8 1 0xed7940 0x8f727f8 > >> > myEventAddTimeoutFunc:251: Adding Timeout -1 0xedefa0 0x8f727f8 > >> > myEventAddHandleFunc:221: Add handle 11 1 0xed7940 0x8f727f8 > >> > myEventAddTimeoutFunc:251: Adding Timeout -1 0xedefa0 0x8f727f8 > >> > main:322 :: Registering domain event cbs > >> > Segmentation fault (core dumped) > >> > > >> > Core was generated by > >> > > >> `/root/libvirt-0.7.5/examples/domain-events/events-c/.libs/lt-event-test'. > >> > Program terminated with signal 11, Segmentation fault. > >> > [New process 21806] > >> > [New process 21822] > >> > #0 remoteDomainEventQueueFlush (timer=-1, opaque=0x8f727f8) at > >> > remote/remote_driver.c:8720 > >> > 8720 tempQueue.count = priv->domainEvents->count; > >> > (gdb) bt > >> > #0 remoteDomainEventQueueFlush (timer=-1, opaque=0x8f727f8) at > >> > remote/remote_driver.c:8720 > >> > #1 0x080490d3 in main (argc=Cannot access memory at address 0x1 > >> > ) at event-test.c:347 > >> > > >> > The stack looks corrupted so I'm doubtful that this trace if of much > >> value. > >> > I have built > >> > and installed libvirt-0.7.5 and it and it's tools seem to be > >> operating > >> > correctly. > >> > >> I tried the event-test with libvirt-0.7.5 and QEMU/Xen and both are > >> working as expected. No segfaults. > >> > >> Could you inspect the values of priv and priv->domainEvents in GDB > >> using 'p priv' to see if they are NULL and try to dereference them in > >> GDB using 'p *priv' to see if they point to valid memory areas? > >> > >> Yes the backtrace looks corrupted. If there is stack/heap corruption > >> involved valgrind may reveal it, so try to run the event-test in > >> valgrind and see if that gives any hints. > >> > >> You can also try the GIT version of libvirt. There was a invalid free > >> call (resulting in heap corruption) in the node device code fixed > >> after the 0.7.5 release. But that should have no effect on the > >> event-test. > >> > >> Matthias > > > > Matthias, > > > > priv->domainEvents is NULL, here's the gdb output: > > This explains the segfault. The next question is, why is it NULL? > > > (gdb) p *priv > > $1 = {lock = {lock = {__data = {__lock = 1, __count = 0, __owner = 21806, __kind = 0, __nusers = 1, {__spins = 0, __list = { > > __next = 0x0}}}, __size = "\001\000\000\000\000\000\000\000.U\000\000\000\000\000\000\001\000\000\000\000\000\000", > > __align = 1}}, sock = 150469168, watch = 3, pid = 4, uses_tls = 1982791681, is_secure = 1815048801, session = 0x782f6269, > > Seeing uses_tls and is_secure being large numbers and knowing that > both are used as boolean values in the code and should have values of > 0 or 1 make me think that priv points to already freed memory here. > > > type = 0x2f646e65 <Address 0x2f646e65 out of bounds>, counter = 1684956536, localUses = 1668248365, > > hostname = 0x74656b <Address 0x74656b out of bounds>, debugLog = 0x0, saslconn = 0x0, saslDecoded = 0x0, saslDecodedLength = 0, > > type and hostname are char pointers, but the seem to point into > nowhere, confirms that this is either freed memory or priv itself got > overwritten due to heap corruption. > > > saslDecodedOffset = 0, saslEncoded = 0x0, saslEncodedLength = 0, saslEncodedOffset = 0, > > buffer = '\0' <repeats 68 times>, "n\000\000\000\001\000\000\000\000\000\000\000\001\000\000\000\000\000\000\000\001\000\000\000\001\000\000\000\000\000\000\000\001\000\000\000\bQ�\b��\030\034�\b\000\000\000\000�\033�\b\001\000\000\000\002\000\000\000�\033�\b\000\000\000\000\025|�\000\a", '\0' <repeats 11 times>, "X\000�\b", '\0' <repeats 12 times>, "\021\000\000\000\002\000\000\000P��\b\000\000\000\000\021", '\0' <repeats 15 times>, "\021\000\000\0008\036�\b\f\000\000\000\020\000\000\000\021\000\000\000\a\000\000\000\b\000\000\000\t\000\000\000\021\000\000\000\002\000\000\000\230\034�\b\000\000\000\000A\000\000\000\003\000\000\000\001\000\000\000\001\000"..., bufferLength = 0, > > bufferOffset = 0, callbackList = 0x0, domainEvents = 0x0, eventFlushTimer = 0, domainEventDispatching = 1, wakeupSendFD = 0, > > wakeupReadFD = 0, waitDispatch = 0x0, streams = 0x0} > > > > I'll try a run with valgrind and post the results. > > > > Pete > > > > Could you test the Python version of this example found in > examples/domain-events/events-python/event-test.py? Does this work? > > Otherwise lets see if valgrind gives any hints. > > Matthias > Matthias, I have built the latest git image and run it through valgrind, here's the valgrind output: [root@Spring .libs]# valgrind -v ./event-test xen:/// ==19881== Memcheck, a memory error detector. ==19881== Copyright (C) 2002-2006, and GNU GPL'd, by Julian Seward et al. ==19881== Using LibVEX rev 1658, a library for dynamic binary translation. ==19881== Copyright (C) 2004-2006, and GNU GPL'd, by OpenWorks LLP. ==19881== Using valgrind-3.2.1, a dynamic binary instrumentation framework. ==19881== Copyright (C) 2000-2006, and GNU GPL'd, by Julian Seward et al. ==19881== --19881-- Command line --19881-- ./event-test --19881-- xen:/// --19881-- Startup, with flags: --19881-- -v --19881-- Contents of /proc/version: --19881-- Linux version 2.6.18-164.10.1.el5xen (mockbuild(a)builder16.centos.org) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-46)) #1 SMP Thu Jan 7 21:14:48 EST 2010 --19881-- Arch and hwcaps: X86, x86-sse1-sse2 --19881-- Valgrind library directory: /usr/lib/valgrind --19881-- Reading syms from /lib/ld-2.5.so (0x163000) --19881-- Reading syms from /root/libvirt/libvirt/examples/domain-events/events-c/.libs/event-test (0x8048000) --19881-- Reading syms from /usr/lib/valgrind/x86-linux/memcheck (0x38000000) --19881-- object doesn't have a dynamic symbol table --19881-- Reading suppressions file: /usr/lib/valgrind/default.supp --19881-- REDIR: 0x178790 (index) redirected to 0x38027D0F (vgPlain_x86_linux_REDIR_FOR_index) --19881-- Reading syms from /usr/lib/valgrind/x86-linux/vgpreload_core.so (0x4001000) --19881-- Reading syms from /usr/lib/valgrind/x86-linux/vgpreload_memcheck.so (0x4003000) ==19881== WARNING: new redirection conflicts with existing -- ignoring it --19881-- new: 0x00178790 (index ) R-> 0x04006080 index --19881-- REDIR: 0x178930 (strlen) redirected to 0x4006250 (strlen) --19881-- Reading syms from /usr/local/lib/libvirt.so.0.7.5 (0x4009000) --19881-- Reading syms from /usr/lib/libxml2.so.2.6.26 (0x6254000) --19881-- object doesn't have a symbol table --19881-- Reading syms from /usr/lib/libz.so.1.2.3 (0xCD2000) --19881-- object doesn't have a symbol table --19881-- Reading syms from /lib/libm-2.5.so (0x413B000) --19881-- Reading syms from /usr/lib/libgnutls.so.13.0.6 (0x670D000) --19881-- object doesn't have a symbol table --19881-- Reading syms from /usr/lib/libgcrypt.so.11.5.2 (0x6590000) --19881-- object doesn't have a symbol table --19881-- Reading syms from /usr/lib/libsasl2.so.2.0.22 (0x6536000) --19881-- object doesn't have a symbol table --19881-- Reading syms from /usr/lib/libxenstore.so.3.0.0 (0x4162000) --19881-- object doesn't have a symbol table --19881-- Reading syms from /lib/libpthread-2.5.so (0x416A000) --19881-- Reading syms from /lib/libc-2.5.so (0x4183000) --19881-- Reading syms from /lib/libdl-2.5.so (0xCA7000) --19881-- Reading syms from /usr/lib/libgpg-error.so.0.3.0 (0xB28000) --19881-- object doesn't have a symbol table --19881-- Reading syms from /lib/libresolv-2.5.so (0x26E000) --19881-- Reading syms from /lib/libcrypt-2.5.so (0x64CE000) --19881-- REDIR: 0x41F42D0 (memset) redirected to 0x4006540 (memset) --19881-- REDIR: 0x41F47C0 (memcpy) redirected to 0x4006C20 (memcpy) --19881-- REDIR: 0x41F3430 (rindex) redirected to 0x4005F60 (rindex) --19881-- REDIR: 0x41F3090 (strlen) redirected to 0x4006230 (strlen) --19881-- REDIR: 0x41EED20 (malloc) redirected to 0x400533B (malloc) --19881-- REDIR: 0x41F2B30 (strcmp) redirected to 0x4006300 (strcmp) --19881-- REDIR: 0x41EE9E0 (calloc) redirected to 0x4004668 (calloc) --19881-- REDIR: 0x41F3DD0 (memchr) redirected to 0x4006420 (memchr) --19881-- REDIR: 0x41EC980 (free) redirected to 0x4004F55 (free) --19881-- REDIR: 0x41EF190 (realloc) redirected to 0x40053EA (realloc) ==19881== Warning: noted but unhandled ioctl 0x305000 with no size/direction hints ==19881== This could cause spurious value errors to appear. ==19881== See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing a proper wrapper. ==19881== Warning: noted but unhandled ioctl 0x305000 with no size/direction hints ==19881== This could cause spurious value errors to appear. ==19881== See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing a proper wrapper. ==19881== Warning: noted but unhandled ioctl 0x305000 with no size/direction hints ==19881== This could cause spurious value errors to appear. ==19881== See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing a proper wrapper. --19881-- REDIR: 0x41F29C0 (index) redirected to 0x4006050 (index) --19881-- REDIR: 0x41F3280 (strncmp) redirected to 0x4006290 (strncmp) --19881-- REDIR: 0x41F44C0 (stpcpy) redirected to 0x40068D0 (stpcpy) --19881-- REDIR: 0x41F3140 (strnlen) redirected to 0x4006200 (strnlen) --19881-- REDIR: 0x41F3380 (strncpy) redirected to 0x4006DA0 (strncpy) --19881-- REDIR: 0x41F2BA0 (strcpy) redirected to 0x40069B0 (strcpy) myEventAddHandleFunc:221: Add handle 5 1 0x40ad4a0 0x42d6188 myEventAddHandleFunc:221: Add handle 7 1 0x40aec90 0x42d6188 Allocating domainEvents:0x43bea68 myEventAddHandleFunc:221: Add handle 8 1 0x407c940 0x42d6188 myEventAddTimeoutFunc:251: Adding Timeout -1 0x4083fe0 0x42d6188 Allocating domainEvents:0x4e8c320 myEventAddHandleFunc:221: Add handle 11 1 0x407c940 0x42d6188 myEventAddTimeoutFunc:251: Adding Timeout -1 0x4083fe0 0x42d6188 main:322 :: Registering domain event cbs poll ==19881== Invalid read of size 4 ==19881== at 0x4084011: remoteDomainEventQueueFlush (remote_driver.c:8722) ==19881== by 0x80490C2: main (event-test.c:341) ==19881== Address 0x0 is not stack'd, malloc'd or (recently) free'd ==19881== ==19881== Process terminating with default action of signal 11 (SIGSEGV) ==19881== Access not within mapped region at address 0x0 ==19881== at 0x4084011: remoteDomainEventQueueFlush (remote_driver.c:8722) ==19881== by 0x80490C2: main (event-test.c:341) ==19881== ==19881== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 30 from 1) ==19881== ==19881== 1 errors in context 1 of 1: ==19881== Invalid read of size 4 ==19881== at 0x4084011: remoteDomainEventQueueFlush (remote_driver.c:8722) ==19881== by 0x80490C2: main (event-test.c:341) ==19881== Address 0x0 is not stack'd, malloc'd or (recently) free'd --19881-- --19881-- supp: 30 Fedora-Core-6-hack3-ld25 ==19881== ==19881== IN SUMMARY: 1 errors from 1 contexts (suppressed: 30 from 1) ==19881== ==19881== malloc/free: in use at exit: 590,340 bytes in 686 blocks. ==19881== malloc/free: 1,695 allocs, 1,009 frees, 1,700,423 bytes allocated. ==19881== ==19881== searching for pointers to 686 not-freed blocks. ==19881== checked 11,495,892 bytes. ==19881== ==19881== LEAK SUMMARY: ==19881== definitely lost: 0 bytes in 0 blocks. ==19881== possibly lost: 136 bytes in 1 blocks. ==19881== still reachable: 590,204 bytes in 685 blocks. ==19881== suppressed: 0 bytes in 0 blocks. ==19881== Reachable blocks (those to which a pointer was found) are not shown. ==19881== To see them, rerun with: --show-reachable=yes --19881-- memcheck: sanity checks: 3 cheap, 1 expensive --19881-- memcheck: auxmaps: 0 auxmap entries (0k, 0M) in use --19881-- memcheck: auxmaps: 0 searches, 0 comparisons --19881-- memcheck: SMs: n_issued = 36 (576k, 0M) --19881-- memcheck: SMs: n_deissued = 0 (0k, 0M) --19881-- memcheck: SMs: max_noaccess = 65535 (1048560k, 1023M) --19881-- memcheck: SMs: max_undefined = 0 (0k, 0M) --19881-- memcheck: SMs: max_defined = 244 (3904k, 3M) --19881-- memcheck: SMs: max_non_DSM = 36 (576k, 0M) --19881-- memcheck: max sec V bit nodes: 115 (5k, 0M) --19881-- memcheck: set_sec_vbits8 calls: 679 (new: 115, updates: 564) --19881-- memcheck: max shadow mem size: 885k, 0M --19881-- translate: fast SP updates identified: 7,064 ( 89.2%) --19881-- translate: generic_known SP updates identified: 543 ( 6.8%) --19881-- translate: generic_unknown SP updates identified: 304 ( 3.8%) --19881-- tt/tc: 13,590 tt lookups requiring 14,331 probes --19881-- tt/tc: 13,590 fast-cache updates, 3 flushes --19881-- transtab: new 6,511 (139,232 -> 2,275,366; ratio 163:10) [0 scs] --19881-- transtab: dumped 0 (0 -> ??) --19881-- transtab: discarded 8 (187 -> ??) --19881-- scheduler: 374,982 jumps (bb entries). --19881-- scheduler: 3/10,454 major/minor sched events. --19881-- sanity: 4 cheap, 1 expensive checks. --19881-- exectx: 30,011 lists, 566 contexts (avg 0 per list) --19881-- exectx: 2,732 searches, 2,171 full compares (794 per 1000) --19881-- exectx: 0 cmp2, 67 cmp4, 0 cmpAll Killed [root@Spring .libs]# I tried the python version and did have some success, but not 100% since I didn't see events for pausing the VM: [root@Spring events-python]# python event-test.py xen:/// Using uri:xen:/// myDomainEventCallback2 EVENT: Domain vm-full-1(1) Started 0 myDomainEventCallback1 EVENT: Domain vm-full-1(1) Started 0 I noticed that the the C version looks in one place for the libvirt socket and the python version in a different place, I don't know if this is significant or not? I tweaked the /etc/libvirt/libvirtd.conf file to alter the location. C: /usr/local/var/run/libvirt python: /var/run/libvirt/ Regards, Pete

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[libvirt] [PATCH] Only use pseudo-random generator for uuid if using /dev/random fails.
by Laine Stump 11 Jan '10

11 Jan '10

The original code. would only print the warning message if using /dev/random failed, but would still go ahead and call virUUIDGeneratePseudoRandomBytes in all cases anyway. --- src/util/uuid.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/src/util/uuid.c b/src/util/uuid.c index 002a64d..846581c 100644 --- a/src/util/uuid.c +++ b/src/util/uuid.c @@ -104,9 +104,9 @@ virUUIDGenerate(unsigned char *uuid) VIR_WARN(_("Falling back to pseudorandom UUID," " failed to generate random bytes: %s"), virStrerror(err, ebuf, sizeof ebuf)); + err = virUUIDGeneratePseudoRandomBytes(uuid, VIR_UUID_BUFLEN); } - - return virUUIDGeneratePseudoRandomBytes(uuid, VIR_UUID_BUFLEN); + return err; } /* Convert C from hexadecimal character to integer. */ -- 1.6.6

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[libvirt] LXC: init problem
by Robin Green 11 Jan '10

11 Jan '10

I'm trying to install Exherbo Linux in an LXC container using libvirt. I've basically succeeded, in that I can "virsh console" in and start sshd, but I haven't managed to boot it starting from /sbin/init rather than /bin/bash. If I have the following (I probably should have modified the uuid and the mac address from the standard example, but that's not relevant): <domain type='lxc'> <name>exherbo</name> <uuid>a4047015-171c-ae56-bc1e-57102d4b86bf</uuid> <memory>1000000</memory> <currentMemory>1000000</currentMemory> <vcpu>2</vcpu> <os> <type arch='i686'>exe</type> <init>/sbin/init</init> </os> <clock offset='utc'/> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>destroy</on_crash> <devices> <emulator>/usr/libexec/libvirt_lxc</emulator> <filesystem type='mount'> <source dir='/home/greenrd/exherbo'/> <target dir='/'/> </filesystem> <interface type='network'> <mac address='52:54:00:56:64:42'/> <source network='default'/> <target dev='veth0'/> </interface> <console type='pty'> <target port='0'/> </console> </devices> </domain> and do virsh --connect lxc:/// start exherbo && virsh --connect lxc:/// console exherbo nothing appears - then if I press Enter, the container dies. In pstree all I see that's relevant is: ├─libvirt_lxc───libvirt_lxc so it looks like init dies. If I run init in gdb in the container I just get: Starting program: /sbin/init Usage: init 0123456SsQqAaBbCcUu Program exited with code 01. so I suppose it could be wanting a runlevel as argument. I'm guessing though that /sbin/init is running in a different mode - telinit mode - as its PID is not 1. Is there any way to get an instant console from the virsh start command, so I can see what's going on? -- Robin

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