(+ linux-next)
Hi Michael,
Dragos reported below oops for which I have a fix at hand (having it
fully tested), ready to be posted to linux-next. Please let me know if
you want me to respin the original patch series, or you would think it'd
be fine to fix it on top.
On 10/23/2023 11:59 AM, Dragos Tatulea wrote:
On Sat, 2023-10-21 at 02:25 -0700, Si-Wei Liu wrote:
Using .compat_reset op from the previous patch, the buggy .reset
behaviour can be kept as-is on older userspace apps, which don't ack the
IOTLB_PERSIST backend feature. As this compatibility quirk is limited to
those drivers that used to be buggy in the past, it won't affect change
the behaviour or affect ABI on the setups with API compliant driver.
The separation of .compat_reset from the regular .reset allows
vhost-vdpa able to know which driver had broken behaviour before, so it
can apply the corresponding compatibility quirk to the individual driver
whenever needed. Compared to overloading the existing .reset with
flags, .compat_reset won't cause any extra burden to the implementation
of every compliant driver.
Signed-off-by: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
---
drivers/vhost/vdpa.c | 17 +++++++++++++----
drivers/virtio/virtio_vdpa.c | 2 +-
include/linux/vdpa.h | 7 +++++--
3 files changed, 19 insertions(+), 7 deletions(-)
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index acc7c74ba7d6..9ce40003793b 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -227,13 +227,22 @@ static void vhost_vdpa_unsetup_vq_irq(struct vhost_vdpa
*v, u16 qid)
irq_bypass_unregister_producer(&vq->call_ctx.producer);
}
-static int vhost_vdpa_reset(struct vhost_vdpa *v)
+static int _compat_vdpa_reset(struct vhost_vdpa *v)
{
struct vdpa_device *vdpa = v->vdpa;
+ u32 flags = 0;
- v->in_batch = 0;
+ flags |= !vhost_backend_has_feature(v->vdev.vqs[0],
+ VHOST_BACKEND_F_IOTLB_PERSIST) ?
+ VDPA_RESET_F_CLEAN_MAP : 0;
Hi Si-Wei,
I am getting a Oops due to the vqs not being initialized here. Here's how it it
looks like:
[ 37.817075] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 37.817674] #PF: supervisor read access in kernel mode
[ 37.818150] #PF: error_code(0x0000) - not-present page
[ 37.818615] PGD 0 P4D 0
[ 37.818893] Oops: 0000 [#1] SMP
[ 37.819223] CPU: 3 PID: 1727 Comm: qemu-system-x86 Not tainted 6.6.0-rc6+ #2
[ 37.819829] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-
1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[ 37.820791] RIP: 0010:_compat_vdpa_reset+0x47/0xc0 [vhost_vdpa]
[ 37.821316] Code: c7 c7 fb 12 56 a0 4c 8d a5 b8 02 00 00 48 89 ea e8 7e b8 c4
e0 48 8b 43 28 48 89 ee 48 c7 c7 19 13 56 a0 4c 8b ad b0 02 00 00 <48> 8b 00 49
8b 95 d8 00 00 00 48 8b 80 88 45 00 00 48 c1 e8 08 48
[ 37.822811] RSP: 0018:ffff8881063c3c38 EFLAGS: 00010246
[ 37.823285] RAX: 0000000000000000 RBX: ffff8881074eb800 RCX: 0000000000000000
[ 37.823893] RDX: 0000000000000000 RSI: ffff888103ab4000 RDI: ffffffffa0561319
[ 37.824506] RBP: ffff888103ab4000 R08: 00000000ffffdfff R09: 0000000000000001
[ 37.825116] R10: 0000000000000003 R11: ffff88887fecbac0 R12: ffff888103ab42b8
[ 37.825721] R13: ffff888106dbe850 R14: 0000000000000003 R15: ffff8881074ebc18
[ 37.826326] FS: 00007f02fba6ef00(0000) GS:ffff88885f8c0000(0000)
knlGS:0000000000000000
[ 37.827035] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 37.827552] CR2: 0000000000000000 CR3: 00000001325e5003 CR4: 0000000000372ea0
[ 37.828162] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 37.828772] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 37.829381] Call Trace:
[ 37.829660] <TASK>
[ 37.829911] ? __die+0x1f/0x60
[ 37.830234] ? page_fault_oops+0x14c/0x3b0
[ 37.830623] ? exc_page_fault+0x74/0x140
[ 37.830999] ? asm_exc_page_fault+0x22/0x30
[ 37.831402] ? _compat_vdpa_reset+0x47/0xc0 [vhost_vdpa]
[ 37.831888] ? _compat_vdpa_reset+0x32/0xc0 [vhost_vdpa]
[ 37.832366] vhost_vdpa_open+0x55/0x270 [vhost_vdpa]
[ 37.832821] ? sb_init_dio_done_wq+0x50/0x50
[ 37.833225] chrdev_open+0xc0/0x210
[ 37.833582] ? __unregister_chrdev+0x50/0x50
[ 37.833990] do_dentry_open+0x1fc/0x4f0
[ 37.834363] path_openat+0xc2d/0xf20
[ 37.834721] do_filp_open+0xb4/0x160
[ 37.835082] ? kmem_cache_alloc+0x3c/0x490
[ 37.835474] do_sys_openat2+0x8d/0xc0
[ 37.835834] __x64_sys_openat+0x6a/0xa0
[ 37.836208] do_syscall_64+0x3c/0x80
[ 37.836564] entry_SYSCALL_64_after_hwframe+0x46/0xb0
[ 37.837021] RIP: 0033:0x7f02fcc2c085
[ 37.837378] Code: 8b 55 d0 48 89 45 b0 75 a0 44 89 55 9c e8 63 7d f8 ff 44 8b
55 9c 89 da 4c 89 e6 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0
ff ff 77 33 44 89 c7 89 45 9c e8 b8 7d f8 ff 8b 45 9c
[ 37.838891] RSP: 002b:00007ffdea3c8cc0 EFLAGS: 00000293 ORIG_RAX:
0000000000000101
[ 37.839571] RAX: ffffffffffffffda RBX: 0000000000080002 RCX: 00007f02fcc2c085
[ 37.840179] RDX: 0000000000080002 RSI: 000055e439b5fa40 RDI: 00000000ffffff9c
[ 37.840785] RBP: 00007ffdea3c8d30 R08: 0000000000000000 R09: 00007ffdea3c8df8
[ 37.841396] R10: 0000000000000000 R11: 0000000000000293 R12: 000055e439b5fa40
[ 37.842014] R13: 0000000000000000 R14: 000055e43792fd00 R15: 0000000000000000
[ 37.842626] </TASK>
[ 37.842884] Modules linked in: vhost_vdpa vhost mlx5_vdpa vringh vhost_iotlb
vdpa mlx5_ib mlx5_core xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink
iptable_nat nf_nat xt_addrtype br_netfilter rpcrdma rdma_ucm ib_iser libiscsi
scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm ib_uverbs ib_core
overlay zram zsmalloc fuse [last unloaded: mlx5_core]
[ 37.845437] CR2: 0000000000000000
[ 37.845778] ---[ end trace 0000000000000000 ]---
[ 37.846205] RIP: 0010:_compat_vdpa_reset+0x47/0xc0 [vhost_vdpa]
[ 37.846730] Code: c7 c7 fb 12 56 a0 4c 8d a5 b8 02 00 00 48 89 ea e8 7e b8 c4
e0 48 8b 43 28 48 89 ee 48 c7 c7 19 13 56 a0 4c 8b ad b0 02 00 00 <48> 8b 00 49
8b 95 d8 00 00 00 48 8b 80 88 45 00 00 48 c1 e8 08 48
[ 37.848240] RSP: 0018:ffff8881063c3c38 EFLAGS: 00010246
[ 37.848711] RAX: 0000000000000000 RBX: ffff8881074eb800 RCX: 0000000000000000
[ 37.849319] RDX: 0000000000000000 RSI: ffff888103ab4000 RDI: ffffffffa0561319
[ 37.849924] RBP: ffff888103ab4000 R08: 00000000ffffdfff R09: 0000000000000001
[ 37.850531] R10: 0000000000000003 R11: ffff88887fecbac0 R12: ffff888103ab42b8
[ 37.851136] R13: ffff888106dbe850 R14: 0000000000000003 R15: ffff8881074ebc18
[ 37.851741] FS: 00007f02fba6ef00(0000) GS:ffff88885f8c0000(0000)
knlGS:0000000000000000
[ 37.852464] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 37.852975] CR2: 0000000000000000 CR3: 00000001325e5003 CR4: 0000000000372ea0
[ 37.853585] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 37.854192] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 37.854797] note: qemu-system-x86[1727] exited with irqs disabled
Looks like the patches are already in linux-next so I guess we'll need a fix for
this.
To Dragos: thanks for your report, I will add your Reported-by from here.
Thanks,
-Siwei
Thanks,
Dragos
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