On 2016/11/10 at 10:45, Dave Young wrote:
> On 11/09/16 at 06:34pm, Xunlei Pang wrote:
>> On 2016/11/09 at 16:33, Dave Young wrote:
>>> Hi, Xunlei
>>> On 11/07/16 at 01:34pm, Xunlei Pang wrote:
>>>> Extend "rd.memdebug" to "4", and "make_trace_mem" to "4+:komem".
>>>> Add new "cleanup_trace_mem" to cleanup the trace if active.
>>>>
>>>> Signed-off-by: Xunlei Pang <xlpang@xxxxxxxxxx>
>>>> ---
>>>> modules.d/98dracut-systemd/dracut-cmdline.sh | 2 +-
>>>> modules.d/98dracut-systemd/dracut-pre-mount.sh | 2 +-
>>>> modules.d/98dracut-systemd/dracut-pre-pivot.sh | 3 ++-
>>>> modules.d/98dracut-systemd/dracut-pre-trigger.sh | 2 +-
>>>> modules.d/99base/dracut-lib.sh | 13 ++++++++++++-
>>>> modules.d/99base/init.sh | 9 +++++----
>>>> modules.d/99base/module-setup.sh | 1 +
>>>> 7 files changed, 23 insertions(+), 9 deletions(-)
>>>>
>>>> diff --git a/modules.d/98dracut-systemd/dracut-cmdline.sh b/modules.d/98dracut-systemd/dracut-cmdline.sh
>>>> index 6c6ee02..bff9435 100755
>>>> --- a/modules.d/98dracut-systemd/dracut-cmdline.sh
>>>> +++ b/modules.d/98dracut-systemd/dracut-cmdline.sh
>>>> @@ -42,7 +42,7 @@ export root
>>>> export rflags
>>>> export fstype
>>>>
>>>> -make_trace_mem "hook cmdline" '1+:mem' '1+:iomem' '3+:slab'
>>>> +make_trace_mem "hook cmdline" '1+:mem' '1+:iomem' '3+:slab' '4+:komem'
>>>> # run scriptlets to parse the command line
>>>> getarg 'rd.break=cmdline' -d 'rdbreak=cmdline' && emergency_shell -n cmdline "Break before cmdline"
>>>> source_hook cmdline
>>>> diff --git a/modules.d/98dracut-systemd/dracut-pre-mount.sh b/modules.d/98dracut-systemd/dracut-pre-mount.sh
>>>> index ae51128..a3b9d29 100755
>>>> --- a/modules.d/98dracut-systemd/dracut-pre-mount.sh
>>>> +++ b/modules.d/98dracut-systemd/dracut-pre-mount.sh
>>>> @@ -8,7 +8,7 @@ type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh
>>>>
>>>> source_conf /etc/conf.d
>>>>
>>>> -make_trace_mem "hook pre-mount" '1:shortmem' '2+:mem' '3+:slab'
>>>> +make_trace_mem "hook pre-mount" '1:shortmem' '2+:mem' '3+:slab' '4+:komem'
>>>> # pre pivot scripts are sourced just before we doing cleanup and switch over
>>>> # to the new root.
>>>> getarg 'rd.break=pre-mount' 'rdbreak=pre-mount' && emergency_shell -n pre-mount "Break pre-mount"
>>>> diff --git a/modules.d/98dracut-systemd/dracut-pre-pivot.sh b/modules.d/98dracut-systemd/dracut-pre-pivot.sh
>>>> index cc70e3c..dc9a250 100755
>>>> --- a/modules.d/98dracut-systemd/dracut-pre-pivot.sh
>>>> +++ b/modules.d/98dracut-systemd/dracut-pre-pivot.sh
>>>> @@ -8,12 +8,13 @@ type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh
>>>>
>>>> source_conf /etc/conf.d
>>>>
>>>> -make_trace_mem "hook pre-pivot" '1:shortmem' '2+:mem' '3+:slab'
>>>> +make_trace_mem "hook pre-pivot" '1:shortmem' '2+:mem' '3+:slab' '4+:komem'
>>>> # pre pivot scripts are sourced just before we doing cleanup and switch over
>>>> # to the new root.
>>>> getarg 'rd.break=pre-pivot' 'rdbreak=pre-pivot' && emergency_shell -n pre-pivot "Break pre-pivot"
>>>> source_hook pre-pivot
>>>>
>>>> +cleanup_trace_mem
>>>> # pre pivot cleanup scripts are sourced just before we switch over to the new root.
>>>> getarg 'rd.break=cleanup' 'rdbreak=cleanup' && emergency_shell -n cleanup "Break cleanup"
>>>> source_hook cleanup
>>>> diff --git a/modules.d/98dracut-systemd/dracut-pre-trigger.sh b/modules.d/98dracut-systemd/dracut-pre-trigger.sh
>>>> index ac1ec36..7cd821e 100755
>>>> --- a/modules.d/98dracut-systemd/dracut-pre-trigger.sh
>>>> +++ b/modules.d/98dracut-systemd/dracut-pre-trigger.sh
>>>> @@ -8,7 +8,7 @@ type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh
>>>>
>>>> source_conf /etc/conf.d
>>>>
>>>> -make_trace_mem "hook pre-trigger" "1:shortmem" "2+:mem" "3+:slab"
>>>> +make_trace_mem "hook pre-trigger" '1:shortmem' '2+:mem' '3+:slab' '4+:komem'
>>>>
>>>> source_hook pre-trigger
>>>>
>>>> diff --git a/modules.d/99base/dracut-lib.sh b/modules.d/99base/dracut-lib.sh
>>>> index 060b3fe..2a29bbc 100755
>>>> --- a/modules.d/99base/dracut-lib.sh
>>>> +++ b/modules.d/99base/dracut-lib.sh
>>>> @@ -1206,12 +1206,20 @@ are_lists_eq() {
>>>>
>>>> setmemdebug() {
>>>> if [ -z "$DEBUG_MEM_LEVEL" ]; then
>>>> - export DEBUG_MEM_LEVEL=$(getargnum 0 0 3 rd.memdebug)
>>>> + export DEBUG_MEM_LEVEL=$(getargnum 0 0 4 rd.memdebug)
>>>> fi
>>>> }
>>>>
>>>> setmemdebug
>>>>
>>>> +cleanup_trace_mem()
>>>> +{
>>>> + # tracekomem based on kernel trace needs cleanup after use.
>>>> + if [[ $DEBUG_MEM_LEVEL -eq 4 ]]; then
>>> It does not work if out of tree modules add it to DEBUG_MEM_LEVEL <
>>> 4, sounds bad to hard code it. It seems good to do the cleanup without
>>> the check.
>> Hi Dave,
>>
>> I can't understand why out of tree modules would do this, however we can't
>> guarantee that even after removing the hard code condition. Let's say, out of
>> tree modules use it at the very beginning and disable it quite after pre-pivot
>> with no "rd.memdebug", then the trace will be disabled at pre-pivot which will
>> cause confusion(or unnoticed data loss) for the out of tree modules.
> It should be a corner case, but use a fixed DEBUG_MEM_LEVEL sounds
> still not good, we designed the DEBUG_MEM_LEVEL but the design does not
> limit each facility to force connect to one of the levels.
Hi Dave,
Maybe I didn't quite catch what you meant.
The current implementation only uses level 4 for komem using '4+:komem', do you mean
some out of tree module adds something like: make_trace_mem '2+: komem'? If so, it contradicts
the "rd.memdebug" manpage described in PATCH3/3.
>
> But I have no strong opinion, I can live with it..
>
>>> There is another concern, if someone manually enables tracing in kernel
>>> cmdline then we should not cleanup, maybe we can print a warning msg
>>> and do not do our tracing at all.
>>>
>>> For cleanup and prepare ideally we can do something like make_trace_mem,
>>> like prepare_trace_mem and cleanup_trace_mem, for each facility if there
>>> is a prepare/cleanup function then call it. But for the time being it
>>> may not worth to add the complexity. What do you think?
>> Because the script does cleanup iff is_trace_ready() returns true when
>> both tracing is on and the events match, I think it is safe enough that
>> we don't need to worry about the wrong cleanup if we really want to do this:
>> is_trace_ready() {
>> local trace_base want_events current_events
>>
>> trace_base=$(get_trace_base)
>> ! [[ -f "$trace_base/tracing/trace" ]] && return 1
>>
>> [[ $(cat $trace_base/tracing/tracing_on) = 0 ]] && return 1
>>
>> # Also check if trace events were properly setup.
>> want_events=$(get_want_events)
>> current_events=$(echo $(cat $trace_base/tracing/set_event))
>> [[ "$current_events" != "$want_events" ]] && return 1
>>
>> return 0
>> }
> Dracut is used more in normal boot than kdump, if one enabled trace in
> grub and the events happen to be same, but we disabled it user will be
> not happy.
Yes, as long as they don't specify "rd.memdebug=4", the current implementation
isn't problematic.
If people use "rd.memdebug=4", they should be aware what they are doing to trace,
also enabling the same events (module_load, module_put and alloc_pages) only is rare.
Regards,
Xunlei
>
>> Regards,
>> Xunlei
>>
>>>> + tracekomem --cleanup
>>>> + fi
>>>> +}
>>>> +
>>>> # parameters: msg [trace_level:trace]...
>>>> make_trace_mem()
>>>> {
>>>> @@ -1296,6 +1304,9 @@ show_memstats()
>>>> iomem)
>>>> cat /proc/iomem
>>>> ;;
>>>> + komem)
>>>> + tracekomem
>>>> + ;;
>>>> esac
>>>> }
>>>>
>>>> diff --git a/modules.d/99base/init.sh b/modules.d/99base/init.sh
>>>> index a563393..e4f7cff 100755
>>>> --- a/modules.d/99base/init.sh
>>>> +++ b/modules.d/99base/init.sh
>>>> @@ -131,7 +131,7 @@ if ! getargbool 1 'rd.hostonly'; then
>>>> fi
>>>>
>>>> # run scriptlets to parse the command line
>>>> -make_trace_mem "hook cmdline" '1+:mem' '1+:iomem' '3+:slab'
>>>> +make_trace_mem "hook cmdline" '1+:mem' '1+:iomem' '3+:slab' '4+:komem'
>>>> getarg 'rd.break=cmdline' -d 'rdbreak=cmdline' && emergency_shell -n cmdline "Break before cmdline"
>>>> source_hook cmdline
>>>>
>>>> @@ -160,7 +160,7 @@ fi
>>>>
>>>> udevproperty "hookdir=$hookdir"
>>>>
>>>> -make_trace_mem "hook pre-trigger" '1:shortmem' '2+:mem' '3+:slab'
>>>> +make_trace_mem "hook pre-trigger" '1:shortmem' '2+:mem' '3+:slab' '4+:komem'
>>>> getarg 'rd.break=pre-trigger' -d 'rdbreak=pre-trigger' && emergency_shell -n pre-trigger "Break before pre-trigger"
>>>> source_hook pre-trigger
>>>>
>>>> @@ -230,7 +230,7 @@ unset RDRETRY
>>>>
>>>> # pre-mount happens before we try to mount the root filesystem,
>>>> # and happens once.
>>>> -make_trace_mem "hook pre-mount" '1:shortmem' '2+:mem' '3+:slab'
>>>> +make_trace_mem "hook pre-mount" '1:shortmem' '2+:mem' '3+:slab' '4+:komem'
>>>> getarg 'rd.break=pre-mount' -d 'rdbreak=pre-mount' && emergency_shell -n pre-mount "Break pre-mount"
>>>> source_hook pre-mount
>>>>
>>>> @@ -266,11 +266,12 @@ done
>>>>
>>>> # pre pivot scripts are sourced just before we doing cleanup and switch over
>>>> # to the new root.
>>>> -make_trace_mem "hook pre-pivot" '1:shortmem' '2+:mem' '3+:slab'
>>>> +make_trace_mem "hook pre-pivot" '1:shortmem' '2+:mem' '3+:slab' '4+:komem'
>>>> getarg 'rd.break=pre-pivot' -d 'rdbreak=pre-pivot' && emergency_shell -n pre-pivot "Break pre-pivot"
>>>> source_hook pre-pivot
>>>>
>>>> make_trace_mem "hook cleanup" '1:shortmem' '2+:mem' '3+:slab'
>>>> +cleanup_trace_mem
>>>> # pre pivot cleanup scripts are sourced just before we switch over to the new root.
>>>> getarg 'rd.break=cleanup' -d 'rdbreak=cleanup' && emergency_shell -n cleanup "Break cleanup"
>>>> source_hook cleanup
>>>> diff --git a/modules.d/99base/module-setup.sh b/modules.d/99base/module-setup.sh
>>>> index b03772e..a1569b1 100755
>>>> --- a/modules.d/99base/module-setup.sh
>>>> +++ b/modules.d/99base/module-setup.sh
>>>> @@ -35,6 +35,7 @@ install() {
>>>> inst_script "$moddir/initqueue.sh" "/sbin/initqueue"
>>>> inst_script "$moddir/loginit.sh" "/sbin/loginit"
>>>> inst_script "$moddir/rdsosreport.sh" "/sbin/rdsosreport"
>>>> + inst_script "$moddir/memtrace-ko.sh" "/sbin/tracekomem"
>>>>
>>>> [ -e "${initdir}/lib" ] || mkdir -m 0755 -p ${initdir}/lib
>>>> mkdir -m 0755 -p ${initdir}/lib/dracut
>>>> --
>>>> 1.8.3.1
>>>>
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>>> Thanks
>>> Dave
>>> --
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> Thanks
> Dave
> --
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