On 2012-02-28 23:18, Stefan Weil wrote: > Am 17.02.2012 16:45, schrieb Jan Kiszka: >> In case we requeued a packet that was the head of a longer session >> queue, we failed to restore this ordering. Also, we did not properly >> deal with changes to Slirp::next_m. >> >> Instead of a cumbersome roll back, this fix simply avoids any changes >> until we know if the packet was actually sent. Both fixes crashes due >> to inconsistent queues and simplifies the logic. >> >> Thanks to Zhi Yong Wu who found the reason for these crashes. >> >> CC: Zhi Yong Wu <wu...@linux.vnet.ibm.com> >> CC: Fabien Chouteau <chout...@adacore.com> >> Signed-off-by: Jan Kiszka <jan.kis...@siemens.com> >> --- >> slirp/if.c | 35 +++++++++++++++++++---------------- >> 1 files changed, 19 insertions(+), 16 deletions(-) > > Latest QEMU crashed here 4 times with MIPS Malta > when I tried 'apt-get update' in the guest. See gdb output > below for details. > > I only got the crash with big endian MIPS, not with little > endian which is strange. > > After I reverted the above patch, MIPS Malta worked > again as before. > > So maybe we changed one crash against a new one.
Embarrassing.
Does this help? Specifically expired packet handling is broken.
diff --git a/slirp/if.c b/slirp/if.c
index 33f08e1..954ef1e 100644
--- a/slirp/if.c
+++ b/slirp/if.c
@@ -153,7 +153,7 @@ void if_start(Slirp *slirp)
{
uint64_t now = qemu_get_clock_ns(rt_clock);
int requeued = 0;
- bool from_batchq = false;
+ bool from_batchq;
struct mbuf *ifm, *ifqt;
DEBUG_CALL("if_start");
@@ -169,6 +169,7 @@ void if_start(Slirp *slirp)
*/
if (slirp->if_fastq.ifq_next != &slirp->if_fastq) {
ifm = slirp->if_fastq.ifq_next;
+ from_batchq = false;
} else {
/* Nothing on fastq, see if next_m is valid */
if (slirp->next_m != &slirp->if_batchq) {
@@ -176,14 +177,17 @@ void if_start(Slirp *slirp)
} else {
ifm = slirp->if_batchq.ifq_next;
}
-
from_batchq = true;
}
slirp->if_queued--;
/* Try to send packet unless it already expired */
- if (ifm->expiration_date >= now && !if_encap(slirp, ifm)) {
+ if (ifm->expiration_date < now) {
+ m_free(ifm);
+ continue;
+ }
+ if (!if_encap(slirp, ifm)) {
/* Packet is delayed due to pending ARP resolution */
requeued++;
continue;
Jan
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