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Re: [Qemu-devel] [PATCH v2] dump-guest-memory.py: fix "You can't do that
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-devel] [PATCH v2] dump-guest-memory.py: fix "You can't do that without a process to debug" |
Date: |
Tue, 12 Dec 2017 18:32:30 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 |
On 12/12/17 18:22, Marc-André Lureau wrote:
> If the script is run with a core (no running process), it produces an
> error:
>
> (gdb) dump-guest-memory /tmp/vmcore X86_64
> guest RAM blocks:
> target_start target_end host_addr message count
> ---------------- ---------------- ---------------- ------- -----
> 0000000000000000 00000000000a0000 00007f7935800000 added 1
> 00000000000a0000 00000000000b0000 00007f7934200000 added 2
> 00000000000c0000 00000000000ca000 00007f79358c0000 added 3
> 00000000000ca000 00000000000cd000 00007f79358ca000 joined 3
> 00000000000cd000 00000000000e8000 00007f79358cd000 joined 3
> 00000000000e8000 00000000000f0000 00007f79358e8000 joined 3
> 00000000000f0000 0000000000100000 00007f79358f0000 joined 3
> 0000000000100000 0000000080000000 00007f7935900000 joined 3
> 00000000fd000000 00000000fe000000 00007f7934200000 added 4
> 00000000fffc0000 0000000100000000 00007f7935600000 added 5
> Python Exception <class 'gdb.error'> You can't do that without a process to
> debug.:
> Error occurred in Python command: You can't do that without a process
> to debug.
>
> Replace the object_resolve_path_type() function call call with a
> local volatile variable.
Patch looks great and the above is fine with me too -- I just note we
have "call call", which could be improved. But, I don't insist.
Reviewed-by: Laszlo Ersek <address@hidden>
Thanks!
Laszlo
>
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
>
> v2:
> - use a vmcoreinfo_realize() local volatile variable
> - tweak commit message
>
> scripts/dump-guest-memory.py | 3 +--
> hw/misc/vmcoreinfo.c | 3 +++
> 2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/dump-guest-memory.py b/scripts/dump-guest-memory.py
> index 1af26c1a45..09bec92b50 100644
> --- a/scripts/dump-guest-memory.py
> +++ b/scripts/dump-guest-memory.py
> @@ -546,8 +546,7 @@ shape and this command should mostly work."""
> return None
>
> def add_vmcoreinfo(self):
> - vmci = '(VMCoreInfoState *)' + \
> - 'object_resolve_path_type("", "vmcoreinfo", 0)'
> + vmci = 'vmcoreinfo_realize::vmcoreinfo_state'
> if not gdb.parse_and_eval("%s" % vmci) \
> or not gdb.parse_and_eval("(%s)->has_vmcoreinfo" % vmci):
> return
> diff --git a/hw/misc/vmcoreinfo.c b/hw/misc/vmcoreinfo.c
> index 31db57ab44..a2805527cb 100644
> --- a/hw/misc/vmcoreinfo.c
> +++ b/hw/misc/vmcoreinfo.c
> @@ -35,6 +35,8 @@ static void vmcoreinfo_realize(DeviceState *dev, Error
> **errp)
> {
> VMCoreInfoState *s = VMCOREINFO(dev);
> FWCfgState *fw_cfg = fw_cfg_find();
> + /* for gdb script dump-guest-memory.py */
> + static VMCoreInfoState * volatile vmcoreinfo_state G_GNUC_UNUSED;
>
> /* Given that this function is executing, there is at least one
> VMCOREINFO
> * device. Check if there are several.
> @@ -56,6 +58,7 @@ static void vmcoreinfo_realize(DeviceState *dev, Error
> **errp)
> &s->vmcoreinfo, sizeof(s->vmcoreinfo), false);
>
> qemu_register_reset(vmcoreinfo_reset, dev);
> + vmcoreinfo_state = s;
> }
>
> static const VMStateDescription vmstate_vmcoreinfo = {
>