From: Paolo Bonzini <pbonzini@redhat.com>
To: Liang Li <liang.z.li@intel.com>, qemu-devel@nongnu.org
Cc: peter.crosthwaite@xilinx.com, xen-devel@lists.xensource.com,
stefano.stabellini@eu.citrix.com, kevin.tian@intel.com,
yang.z.zhang@intel.com, robert.hu@intel.com
Subject: Re: [Qemu-devel] [PATCH] xen-pt: Fix bug cause PCI devices re-attach failed
Date: Mon, 13 Apr 2015 16:28:03 +0200 [thread overview]
Message-ID: <552BD273.9060105@redhat.com> (raw)
In-Reply-To: <1428934370-29695-1-git-send-email-liang.z.li@intel.com>
On 13/04/2015 16:12, Liang Li wrote:
> 2. Do the attach and detach operation with a time interval. eg. 10s.
>
> The error message will not disappear if retry, in this case, it's
> a bug.
>
> In the 'xen_pt_region_add' and 'xen_pt_region_del', we should only care
> about the 'xen-pci-pt-*' memory region, this can avoid the region's
> reference count is not equal with the dereference count when the
> device is detached and prevent the device's related QemuOpts object from
> being released properly, and then trigger the bug when the device is
> re-attached.
This doesn't explain _which_ region is causing the bug and how.
Assuming this is the right fix, should you instead move the
memory_region_ref/unref pair from xen_pt_region_add/del after this
conditional:
if (bar == -1 && (!s->msix || &s->msix->mmio != mr)) {
return;
}
in xen_pt_region_update?
Paolo
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com>
To: Liang Li <liang.z.li@intel.com>, qemu-devel@nongnu.org
Cc: peter.crosthwaite@xilinx.com, xen-devel@lists.xensource.com,
stefano.stabellini@eu.citrix.com, kevin.tian@intel.com,
yang.z.zhang@intel.com, robert.hu@intel.com
Subject: Re: [PATCH] xen-pt: Fix bug cause PCI devices re-attach failed
Date: Mon, 13 Apr 2015 16:28:03 +0200 [thread overview]
Message-ID: <552BD273.9060105@redhat.com> (raw)
In-Reply-To: <1428934370-29695-1-git-send-email-liang.z.li@intel.com>
On 13/04/2015 16:12, Liang Li wrote:
> 2. Do the attach and detach operation with a time interval. eg. 10s.
>
> The error message will not disappear if retry, in this case, it's
> a bug.
>
> In the 'xen_pt_region_add' and 'xen_pt_region_del', we should only care
> about the 'xen-pci-pt-*' memory region, this can avoid the region's
> reference count is not equal with the dereference count when the
> device is detached and prevent the device's related QemuOpts object from
> being released properly, and then trigger the bug when the device is
> re-attached.
This doesn't explain _which_ region is causing the bug and how.
Assuming this is the right fix, should you instead move the
memory_region_ref/unref pair from xen_pt_region_add/del after this
conditional:
if (bar == -1 && (!s->msix || &s->msix->mmio != mr)) {
return;
}
in xen_pt_region_update?
Paolo
next prev parent reply other threads:[~2015-04-13 14:28 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-13 14:12 [Qemu-devel] [PATCH] xen-pt: Fix bug cause PCI devices re-attach failed Liang Li
2015-04-13 14:12 ` Liang Li
2015-04-13 14:28 ` Paolo Bonzini [this message]
2015-04-13 14:28 ` Paolo Bonzini
2015-04-15 14:14 ` [Qemu-devel] " Li, Liang Z
2015-04-15 14:14 ` Li, Liang Z
2015-04-15 14:16 ` [Qemu-devel] " Paolo Bonzini
2015-04-15 14:16 ` Paolo Bonzini
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