On Fri, Mar 05, 2010 at 11:20:38PM -0500, Laine Stump wrote:

doTunnelSendAll function (used by QEMU migration) uses a 64k buffer on the stack, which could be problematic. This patch replaces that with a buffer from the heap.

While in the neighborhood, this patch also improves error reporting in the case that saferead fails - previously, virStreamAbort() was called (resetting errno) before reporting the error. It's been changed to report the error first. ---

Eric noticed that I was inconsistent in the ordering of cleanup vs. error reporting, so I fixed that in this version.

src/qemu/qemu_driver.c | 18 +++++++++++++++--- 1 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index bb3edde..5a18938 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -8399,19 +8399,28 @@ cleanup: }

+#define TUNNEL_SEND_BUF_SIZE 65536 + static int doTunnelSendAll(virStreamPtr st, int sock) { - char buffer[65536]; - int nbytes = sizeof(buffer); + char *buffer; + int nbytes = TUNNEL_SEND_BUF_SIZE; + + if (VIR_ALLOC_N(buffer, TUNNEL_SEND_BUF_SIZE) < 0) { + virReportOOMError(); + virStreamAbort(st); + return -1; + }

/* XXX should honour the 'resource' parameter here */ for (;;) { nbytes = saferead(sock, buffer, nbytes); if (nbytes < 0) { - virStreamAbort(st); virReportSystemError(errno, "%s", _("tunnelled migration failed to read from qemu")); + virStreamAbort(st); + VIR_FREE(buffer); return -1; } else if (nbytes == 0) @@ -8421,10 +8430,13 @@ static int doTunnelSendAll(virStreamPtr st, if (virStreamSend(st, buffer, nbytes) < 0) { qemuReportError(VIR_ERR_OPERATION_FAILED, "%s", _("Failed to write migration data to remote libvirtd")); + VIR_FREE(buffer); return -1; } }

+ VIR_FREE(buffer); + if (virStreamFinish(st) < 0) /* virStreamFinish set the error for us */ return -1;

ACK, this needed fixing ! Pushed, thanks ! Daniel -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel@veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/