Messages in this thread |  | | Subject | Re: 5.13-rt1 + KVM = WARNING: at fs/eventfd.c:74 eventfd_signal() | From | Jason Wang <> | Date | Wed, 14 Jul 2021 17:23:02 +0800 |
| |
在 2021/7/14 下午4:10, Paolo Bonzini 写道: > On 14/07/21 10:01, Daniel Bristot de Oliveira wrote: >> Hey >> >> I use kvm-vm for regular development, and while using the kernel-rt >> v5.13-rt1 >> (the latest) on the host, and a regular kernel on the guest, after a >> while, >> this happens: >> >> [ 1723.404979] ------------[ cut here ]------------ >> [ 1723.404981] WARNING: CPU: 12 PID: 2554 at fs/eventfd.c:74 >> eventfd_signal+0x7e/0x90 > >> [ 1723.405055] RIP: 0010:eventfd_signal+0x7e/0x90 >> [ 1723.405059] Code: 01 00 00 00 be 03 00 00 00 4c 89 ef e8 5b ec d9 >> ff 65 ff 0d e4 34 c9 5a 4c 89 ef e8 ec a8 86 00 4c 89 e0 5b 5d 41 5c >> 41 5d c3 <0f> 0b 45 31 e4 5b 5d 4c 89 e0 41 5c 41 5d c3 0f 1f 00 0f >> 1f 44 00 >> [ 1723.405078] vhost_tx_batch.constprop.0+0x7d/0xc0 [vhost_net] >> [ 1723.405083] handle_tx_copy+0x15b/0x5c0 [vhost_net] >> [ 1723.405088] ? __vhost_add_used_n+0x200/0x200 [vhost] >> [ 1723.405092] handle_tx+0xa5/0xe0 [vhost_net] >> [ 1723.405095] vhost_worker+0x93/0xd0 [vhost] >> [ 1723.405099] kthread+0x186/0x1a0 >> [ 1723.405103] ? __kthread_parkme+0xa0/0xa0 >> [ 1723.405105] ret_from_fork+0x22/0x30 >> [ 1723.405110] ---[ end trace 0000000000000002 ]--- > > The WARN has this comment above: > > /* > * Deadlock or stack overflow issues can happen if we recurse > here > * through waitqueue wakeup handlers. If the caller users > potentially > * nested waitqueues with custom wakeup handlers, then it should > * check eventfd_signal_count() before calling this function. If > * it returns true, the eventfd_signal() call should be > deferred to a > * safe context. > */ > > This was added in 2020, so it's unlikely to be the direct cause of the > change. What is a known-good version for the host? > > Since it is not KVM stuff, I'm CCing Michael and Jason. > > Paolo >
I think this can be probably fixed here:
https://lore.kernel.org/lkml/20210618084412.18257-1-zhe.he@windriver.com/
Thanks
|  |