Re: upstream kernel crashes

On Mon, Aug 15, 2022 at 09:45:03AM -0700, Andres Freund wrote:

Hi,

On 2022-08-15 11:40:59 -0400, Michael S. Tsirkin wrote:

quoted

OK so this gives us a quick revert as a solution for now.
Next, I would appreciate it if you just try this simple hack.
If it crashes we either have a long standing problem in virtio
code or more likely a gcp bug where it can't handle smaller
rings than what device requestes.
Thanks!

I applied the below and the problem persists.

quoted

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index f7965c5dd36b..bdd5f481570b 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c

@@ -314,6 +314,9 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 	if (!size || size > num)
 		size = num;
 
+	if (size > 1024)
+		size = 1024;
+
 	if (size & (size - 1)) {
 		dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", size);
 		return ERR_PTR(-EINVAL);

[    1.165162] virtio_net virtio1 enp0s4: renamed from eth0
[    1.177815] general protection fault, probably for non-canonical address 0xffff000000000400: 0000 [#1] PREEMPT SMP PTI
[    1.179565] CPU: 1 PID: 125 Comm: systemd-udevd Not tainted 6.0.0-rc1-bisect14-dirty #14
[    1.180785] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
[    1.182475] RIP: 0010:__kmalloc_node_track_caller+0x19e/0x380
[    1.183365] Code: 2b 04 25 28 00 00 00 0f 85 f8 01 00 00 48 83 c4 18 48 89 e8 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc 8b 4d 28 48 8b 7d 00 <48> 8b 1c 08 48 8d 4a 40 65 48 0f c7 0f 0f 94 c0 84 c0 0f 84 0b ff
[    1.186208] RSP: 0018:ffff9c470021b860 EFLAGS: 00010246
[    1.187194] RAX: ffff000000000000 RBX: 00000000000928c0 RCX: 0000000000000400
[    1.188634] RDX: 0000000000005781 RSI: 00000000000928c0 RDI: 000000000002e0f0
[    1.190177] RBP: ffff908380042c00 R08: 0000000000000600 R09: ffff908380b665e4
[    1.191256] R10: 0000000000000003 R11: 0000000000000002 R12: 00000000000928c0
[    1.192269] R13: 0000000000000740 R14: 00000000ffffffff R15: 0000000000000000
[    1.193368] FS:  00007f746702a8c0(0000) GS:ffff9084b7d00000(0000) knlGS:0000000000000000
[    1.194846] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    1.195661] CR2: 00007ffc010df980 CR3: 0000000103826005 CR4: 00000000003706e0
[    1.196912] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[    1.198216] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[    1.199367] Call Trace:
[    1.199815]  <TASK>
[    1.200138]  ? netlink_trim+0x85/0xb0
[    1.200754]  pskb_expand_head+0x92/0x340
[    1.202512]  netlink_trim+0x85/0xb0
[    1.203069]  netlink_unicast+0x54/0x390
[    1.203630]  rtnl_getlink+0x366/0x410
[    1.204155]  ? __d_alloc+0x24/0x1d0
[    1.204668]  rtnetlink_rcv_msg+0x146/0x3b0
[    1.205256]  ? _raw_spin_unlock+0xd/0x30
[    1.205867]  ? __d_add+0xf2/0x1b0
[    1.206600]  ? rtnl_calcit.isra.0+0x130/0x130
[    1.207221]  netlink_rcv_skb+0x49/0xf0
[    1.207904]  netlink_unicast+0x23a/0x390
[    1.208585]  netlink_sendmsg+0x23b/0x4b0
[    1.209203]  sock_sendmsg+0x57/0x60
[    1.210118]  __sys_sendto+0x117/0x170
[    1.210694]  ? __wake_up_common_lock+0x83/0xc0
[    1.211420]  __x64_sys_sendto+0x1b/0x30
[    1.211992]  do_syscall_64+0x37/0x90
[    1.212497]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[    1.213407] RIP: 0033:0x7f74677404e6
[    1.213973] Code: 69 0e 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 11 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 72 c3 90 41 54 48 83 ec 30 44 89 4c 24 2c 4c
[    1.217098] RSP: 002b:00007ffc010daa78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[    1.219539] RAX: ffffffffffffffda RBX: 000000000011bc98 RCX: 00007f74677404e6
[    1.220552] RDX: 0000000000000020 RSI: 0000563160679570 RDI: 0000000000000005
[    1.222378] RBP: 00005631606796b0 R08: 00007ffc010daaf0 R09: 0000000000000080
[    1.223692] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
[    1.224793] R13: 0000000000000000 R14: 0000000000000000 R15: 00005631606794b0
[    1.226228]  </TASK>
[    1.226775] Modules linked in:
[    1.227414] ---[ end trace 0000000000000000 ]---

Greetings,

Andres Freund

Okay! And just to be 100% sure, can you try the following on top of 5.19:

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 623906b4996c..6f4e54a618bc 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c

@@ -208,6 +208,9 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 		return ERR_PTR(-EINVAL);
 	}
 
+	if (num > 1024)
+		num = 1024;
+
 	info->msix_vector = msix_vec;
 
 	/* create the vring */

-- 
MST