Re: Random guest crashes since 5c34d002dcc7 ("virtio_pci: use shared interrupts for virtqueues")

[Michael S. Tsirkin]

On Sat, Apr 08, 2017 at 07:01:34AM +0200, Mike Galbraith wrote:
> On Fri, 2017-04-07 at 21:56 +0300, Michael S. Tsirkin wrote:
> 
> > OK. test3 and test4 are now pushed: test3 should fix your hang,
> > test4 is trying to fix a crash reported independently.
> 
> test3 does not fix the post hibernate hang business that I can easily
> reproduce, those are NFS, and at least as old as 4.4.  Host/guest,
> dunno, put 4.4 on both, guest hangs intermittently.

OK so IIUC you agree it's a good idea to send test4 to Linus, right?
Hybernation's still broken but that's not a regression.

> [<ffffffffa039a550>] __rpc_wait_for_completion_task+0x30/0x30 [sunrpc]
> [<ffffffffa039a56e>] rpc_wait_bit_killable+0x1e/0xb0 [sunrpc]
> [<ffffffffa039a550>] __rpc_wait_for_completion_task+0x30/0x30 [sunrpc]
> [<ffffffff810c6450>] autoremove_wake_function+0x50/0x50
> [<ffffffffa038f670>] call_decode+0x850/0x850 [sunrpc]
> [<ffffffffa038f670>] call_decode+0x850/0x850 [sunrpc]
> [<ffffffffa039b17e>] __rpc_execute+0x14e/0x440 [sunrpc]
> [<ffffffff810f7d35>] ktime_get+0x35/0xa0
> [<ffffffffa0390900>] rpc_run_task+0x120/0x170 [sunrpc]
> [<ffffffffa064a1c6>] nfs4_call_sync_sequence+0x56/0x80 [nfsv4]
> [<ffffffffa064acd0>] _nfs4_proc_getattr+0xb0/0xc0 [nfsv4]
> [<ffffffff8123f8b2>] path_lookupat+0xd2/0x100
> [<ffffffffa0655d9c>] nfs4_proc_getattr+0x5c/0xe0 [nfsv4]
> [<ffffffffa0612120>] __nfs_revalidate_inode+0xa0/0x300 [nfs]
> [<ffffffffa0612485>] nfs_getattr+0x95/0x250 [nfs]
> [<ffffffff812365eb>] vfs_statx+0x7b/0xc0
> [<ffffffff81236a60>] SYSC_newstat+0x20/0x40
> [<ffffffff81687177>] entry_SYSCALL_64_fastpath+0x1a/0xa9
> [<ffffffffffffffff>] 0xffffffffffffffff
> 
> I noted no _other_ misbehavior in either kernel, w/wo threadirqs.
> 
> 	-Mike

Interesting. I would guess virtio net does not complete some
packets. So you were unable to find an old guest where this
works fine?

-- 
MST