On Mon, Mar 25, 2024 at 4:44 PM Igor Raits <igor@xxxxxxxxxxxx> wrote: > > Hello, > > On Fri, Mar 22, 2024 at 12:19 PM Igor Raits <igor@xxxxxxxxxxxx> wrote: > > > > Hi Jason, > > > > On Fri, Mar 22, 2024 at 9:39 AM Igor Raits <igor@xxxxxxxxxxxx> wrote: > > > > > > Hi Jason, > > > > > > On Fri, Mar 22, 2024 at 6:31 AM Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > > > > > > On Thu, Mar 21, 2024 at 5:44 PM Igor Raits <igor@xxxxxxxxxxxx> wrote: > > > > > > > > > > Hello Jason & others, > > > > > > > > > > On Wed, Mar 20, 2024 at 10:33 AM Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > > > > > > > > > > On Tue, Mar 19, 2024 at 9:15 PM Igor Raits <igor@xxxxxxxxxxxx> wrote: > > > > > > > > > > > > > > Hello Stefan, > > > > > > > > > > > > > > On Tue, Mar 19, 2024 at 2:12 PM Stefan Hajnoczi <stefanha@xxxxxxxxxx> wrote: > > > > > > > > > > > > > > > > On Tue, Mar 19, 2024 at 10:00:08AM +0100, Igor Raits wrote: > > > > > > > > > Hello, > > > > > > > > > > > > > > > > > > We have started to observe kernel crashes on 6.7.y kernels (atm we > > > > > > > > > have hit the issue 5 times on 6.7.5 and 6.7.10). On 6.6.9 where we > > > > > > > > > have nodes of cluster it looks stable. Please see stacktrace below. If > > > > > > > > > you need more information please let me know. > > > > > > > > > > > > > > > > > > We do not have a consistent reproducer but when we put some bigger > > > > > > > > > network load on a VM, the hypervisor's kernel crashes. > > > > > > > > > > > > > > > > > > Help is much appreciated! We are happy to test any patches. > > > > > > > > > > > > > > > > CCing Michael Tsirkin and Jason Wang for vhost_net. > > > > > > > > > > > > > > > > > > > > > > > > > > [62254.167584] stack segment: 0000 [#1] PREEMPT SMP NOPTI > > > > > > > > > [62254.173450] CPU: 63 PID: 11939 Comm: vhost-11890 Tainted: G > > > > > > > > > E 6.7.10-1.gdc.el9.x86_64 #1 > > > > > > > > > > > > > > > > Are there any patches in this kernel? > > > > > > > > > > > > > > Only one, unrelated to this part. Removal of pr_err("EEVDF scheduling > > > > > > > fail, picking leftmost\n"); line (reported somewhere few months ago > > > > > > > and it was suggested workaround until proper solution comes). > > > > > > > > > > > > Btw, a bisection would help as well. > > > > > > > > > > In the end it seems like we don't really have "stable" setup, so > > > > > bisection looks to be useless but we did find few things meantime: > > > > > > > > > > 1. On 6.6.9 it crashes either with unexpected GSO type or usercopy: > > > > > Kernel memory exposure attempt detected from SLUB object > > > > > 'skbuff_head_cache' > > > > > > > > Do you have a full calltrace for this? > > > > > > I have shared it in one of the messages in this thread. > > > https://marc.info/?l=linux-virtualization&m=171085443512001&w=2 > > > > > > > > 2. On 6.7.5, 6.7.10 and 6.8.1 it crashes with RIP: > > > > > 0010:skb_release_data+0xb8/0x1e0 > > > > > > > > And for this? > > > > > > https://marc.info/?l=linux-netdev&m=171083870801761&w=2 > > > > > > > > 3. It does NOT crash on 6.8.1 when VM does not have multi-queue setup > > > > > > > > > > Looks like the multi-queue setup (we have 2 interfaces × 3 virtio > > > > > queues for each) is causing problems as if we set only one queue for > > > > > each interface the issue is gone. > > > > > Maybe there is some race condition in __pfx_vhost_task_fn+0x10/0x10 or > > > > > somewhere around? > > > > > > > > I can't tell now, but it seems not because if we have 3 queue pairs we > > > > will have 3 vhost threads. > > > > > > > > > We have noticed that there are 3 of such functions > > > > > in the stacktrace that gave us hints about what we could try… > > > > > > > > Let's try to enable SLUB_DEBUG and KASAN to see if we can get > > > > something interesting. > > > > > > We were able to reproduce it even with 1 vhost queue... And now we > > > have slub_debug + kasan so I hopefully have more useful data for you > > > now. > > > I have attached it for better readability. > > > > Looks like we have found a "stable" kernel and that is 6.1.32. The > > 6.3.y is broken and we are testing 6.2.y now. > > My guess it would be related to virtio/vsock: replace virtio_vsock_pkt > > with sk_buff that was done around that time but we are going to test, > > bisect and let you know more. > > So we have been trying to bisect it but it is basically impossible for > us to do so as the ICE driver was quite broken for most of the release > cycle so we have no networking on 99% of the builds and we can't test > such a setup. > More specifically, the bug was introduced between 6.2 and 6.3 but we > could not get much further. The last good commit we were able to test > was f18f9845f2f10d3d1fc63e4ad16ee52d2d9292fa and then after 20 commits > where we had no networking we gave up. > > If you have some suspicious commit(s) we could revert - happy to test. Here is the is for the change since f18f9845f2f10d3d1fc63e4ad16ee52d2d9292fa: cbfbfe3aee71 tun: prevent negative ifindex b2f8323364ab tun: add __exit annotations to module exit func tun_cleanup() 6231e47b6fad tun: avoid high-order page allocation for packet header 4d016ae42efb Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 59eeb2329405 drivers: net: prevent tun_build_skb() to exceed the packet size limit 35b1b1fd9638 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net ce7c7fef1473 net: tun: change tun_alloc_skb() to allow bigger paged allocations 9bc3047374d5 net: tun_chr_open(): set sk_uid from current_fsuid() 82b2bc279467 tun: Fix memory leak for detached NAPI queue. 6e98b09da931 Merge tag 'net-next-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next de4f5fed3f23 iov_iter: add iter_iovec() helper 438b406055cd tun: flag the device as supporting FMODE_NOWAIT de4287336794 Daniel Borkmann says: a096ccca6e50 tun: tun_chr_open(): correctly initialize socket uid 66c0e13ad236 drivers: net: turn on XDP features The commit that touches the datapath are: 6231e47b6fad tun: avoid high-order page allocation for packet header 59eeb2329405 drivers: net: prevent tun_build_skb() to exceed the packet size limit ce7c7fef1473 net: tun: change tun_alloc_skb() to allow bigger paged allocations 82b2bc279467 tun: Fix memory leak for detached NAPI queue. de4f5fed3f23 iov_iter: add iter_iovec() helper I assume you didn't use NAPI mode, so 82b2bc279467 tun: Fix memory leak for detached NAPI queue doesn't make sense for us. The rest might be the bad commit if it is caused by a change of tun itself. btw I vaguely remember KASAN will report who did the allocation and who did the free. But it seems not in your KASAN log. Thanks > > Thanks again. >