From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Don Slutz <dslutz@verizon.com>, xen-devel@lists.xen.org
Cc: Keir Fraser <keir@xen.org>,
Ian Campbell <ian.campbell@citrix.com>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
George Dunlap <george.dunlap@eu.citrix.com>,
Tim Deegan <tim@xen.org>, Ian Jackson <ian.jackson@eu.citrix.com>,
Jan Beulich <jbeulich@suse.com>
Subject: Re: [BUGFIX][PATCH v2 2/5] dbg_rw_guest_mem: need to call put_gfn in error path.
Date: Wed, 8 Jan 2014 01:15:40 +0000 [thread overview]
Message-ID: <52CCA6BC.5080406@citrix.com> (raw)
In-Reply-To: <52CCA496.80008@terremark.com>
On 08/01/2014 01:06, Don Slutz wrote:
> On 01/07/14 19:55, Andrew Cooper wrote:
>> On 08/01/2014 00:25, Don Slutz wrote:
>>> Using a 1G hvm domU (in grub) and gdbsx:
>>>
>>> (gdb) set arch i8086
>>> warning: A handler for the OS ABI "GNU/Linux" is not built into this
>>> configuration
>>> of GDB. Attempting to continue with the default i8086 settings.
>>>
>>> The target architecture is assumed to be i8086
>>> (gdb) target remote localhost:9999
>>> Remote debugging using localhost:9999
>>> Remote debugging from host 127.0.0.1
>>> 0x0000d475 in ?? ()
>>> (gdb) x/1xh 0x6ae9168b
>>>
>>> Will reproduce this bug.
>>>
>>> With a debug=y build you will get:
>>>
>>> Assertion '!preempt_count()' failed at preempt.c:37
>>>
>>> For a debug=n build you will get a dom0 VCPU hung (at some point) in:
>>>
>>> [ffff82c4c0126eec] _write_lock+0x3c/0x50
>>> ffff82c4c01e43a0 __get_gfn_type_access+0x150/0x230
>>> ffff82c4c0158885 dbg_rw_mem+0x115/0x360
>>> ffff82c4c0158fc8 arch_do_domctl+0x4b8/0x22f0
>>> ffff82c4c01709ed get_page+0x2d/0x100
>>> ffff82c4c01031aa do_domctl+0x2ba/0x11e0
>>> ffff82c4c0179662 do_mmuext_op+0x8d2/0x1b20
>>> ffff82c4c0183598 __update_vcpu_system_time+0x288/0x340
>>> ffff82c4c015c719 continue_nonidle_domain+0x9/0x30
>>> ffff82c4c012938b add_entry+0x4b/0xb0
>>> ffff82c4c02223f9 syscall_enter+0xa9/0xae
>>>
>>> And gdb output:
>>>
>>> (gdb) x/1xh 0x6ae9168b
>>> 0x6ae9168b: 0x3024
>>> (gdb) x/1xh 0x6ae9168b
>>> 0x6ae9168b: Ignoring packet error, continuing...
>>> Reply contains invalid hex digit 116
>>>
>>> The 1st one worked because the p2m.lock is recursive and the PCPU
>>> had not yet changed.
>>>
>>> crash reports (for example):
>>>
>>> crash> mm_rwlock_t 0xffff83083f913010
>>> struct mm_rwlock_t {
>>> lock = {
>>> raw = {
>>> lock = 2147483647
>>> },
>>> debug = {<No data fields>}
>>> },
>>> unlock_level = 0,
>>> recurse_count = 1,
>>> locker = 1,
>>> locker_function = 0xffff82c4c022c640 <__func__.13514>
>>> "__get_gfn_type_access"
>>> }
>>>
>>> Signed-off-by: Don Slutz <dslutz@verizon.com>
>> Technically this should include by Signed-off-by: Andrew Cooper
>> <andrew.cooper3@citrix.com> tag (being the author of the code) as well
>> as your own (being the discoverer of the bug and author of the commit
>> message), but I notice I accidentally omitted it from the original email
>> thread, so my apologies.
>
> I was not sure if I should have added it without you adding it... So I
> went without.
That is fair enough - it was my mistake to start with so no worries.
>
>
>> It should probably also include your Tested-by: tag
>
> That is fine with me. Should I make a v3 of just this with both tags?
>
> -Don Slutz
Depends whether the committers are happy accumulating tags and whether
there is further comment/changes required for the patch.
As a rule of thumb, I would say "no for now" with a "accumulate if a new
v3 is needed" or "a committer asks you to accumulate".
~Andrew
next prev parent reply other threads:[~2014-01-08 1:15 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-08 0:25 [BUGFIX][PATCH v2 0/5] gdbsx: fix 3 bugs Don Slutz
2014-01-08 0:25 ` [PATCH v2 1/5] Add Emacs local variables to source files Don Slutz
2014-01-08 1:16 ` Mukesh Rathor
2014-01-08 1:27 ` Andrew Cooper
2014-01-08 9:51 ` Ian Campbell
2014-01-08 15:58 ` Ian Campbell
2014-01-08 0:25 ` [BUGFIX][PATCH v2 2/5] dbg_rw_guest_mem: need to call put_gfn in error path Don Slutz
2014-01-08 0:55 ` Andrew Cooper
2014-01-08 1:06 ` Don Slutz
2014-01-08 1:15 ` Andrew Cooper [this message]
2014-01-08 1:14 ` Mukesh Rathor
2014-01-08 1:44 ` Mukesh Rathor
2014-01-08 2:30 ` Andrew Cooper
2014-01-08 2:44 ` Mukesh Rathor
2014-01-08 10:40 ` Ian Campbell
2014-01-08 14:01 ` Don Slutz
2014-01-08 8:36 ` Jan Beulich
2014-01-08 13:48 ` Don Slutz
2014-01-08 0:25 ` [PATCH v2 3/5] dbg_rw_guest_mem: Conditionally enable debug log output Don Slutz
2014-01-08 1:38 ` Mukesh Rathor
2014-01-08 10:38 ` Ian Campbell
2014-01-08 14:28 ` Don Slutz
2014-01-08 16:47 ` Ian Campbell
2014-01-08 17:04 ` Tim Deegan
2014-01-08 17:44 ` Ian Campbell
2014-01-08 18:10 ` Tim Deegan
2014-01-09 8:41 ` Ian Campbell
2014-01-09 10:32 ` Tim Deegan
2014-01-09 0:38 ` Mukesh Rathor
2014-01-09 9:59 ` Ian Campbell
2014-01-09 16:08 ` Don Slutz
2014-01-09 16:30 ` Jan Beulich
2014-01-09 17:56 ` Don Slutz
2014-01-10 17:13 ` Ian Campbell
2014-01-10 21:15 ` Don Slutz
2014-01-10 22:08 ` [PATCH v3 " Don Slutz
2014-01-10 1:54 ` [PATCH v2 " Mukesh Rathor
2014-01-08 0:25 ` [BUGFIX][PATCH v2 4/5] xg_read_mem: Report on error Don Slutz
2014-01-08 1:16 ` Mukesh Rathor
2014-01-08 0:25 ` [BUGFIX][PATCH v2 5/5] xg_main: If XEN_DOMCTL_gdbsx_guestmemio fails then force error Don Slutz
2014-01-08 1:11 ` Mukesh Rathor
2014-01-08 10:35 ` Ian Campbell
2014-01-08 14:39 ` Don Slutz
2014-01-08 8:28 ` [BUGFIX][PATCH v2 0/5] gdbsx: fix 3 bugs Jan Beulich
2014-01-08 14:43 ` Don Slutz
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