1050026 - b2g-info and get_about_memory.py fail if Nuwa process doesn't rename itself

Status: RESOLVED FIXED

(Core :: DOM: Content Processes, defect)

Description

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

A spin off from bug 1048024 comment 41.

dhylands is working on a patch.

Comment 1

[Dave Hylands [:dhylands]]

I'm actually working on a patch to make b2g-info and get_about_memory not care whether the process is named Nuwa or not.

It looks at the pid, ppid, and the executable name to figure out which are child and master processes.

Comment 2

[Dave Hylands [:dhylands]]

Attachment: PR for get_about_memory.py

Comment 3

[Dave Hylands [:dhylands]]

Attachment: PR for b2g-info

Comment 4

[Ting-Yu Chou [:ting] (away)]

Comment on attachment 8469041 [details] [review]
PR for get_about_memory.py

This is for get_about_memory.py actually, there're two minor comments.

Comment 5

[Ting-Yu Chou [:ting] (away)]

Comment on attachment 8469042 [details] [review]
PR for b2g-info

r=me after double check getuid() is needed, and the side effect from b2g_processes() is acceptable.

Comment 6

[Ting-Yu Chou [:ting] (away)]

Dave, thank you for such a quick response. But I guess we still need to know why Nuwa is not renaming itself? I couldn't repro on my Flame though.

Comment 7

[Dave Hylands [:dhylands]]

https://github.com/mozilla-b2g/gonk-misc/commit/6822004d07064ea3ebbc0c94cd2e15be6a02069d
https://github.com/mozilla-b2g/B2G/commit/a5411c63509332d35a1566e10a9f40d8752fd32a

With these commits, b2g-info and get_about_memory.py should both work even when the Nuwa process doesn't get renamed.

I'm still seeing the Nuwa process showing with the name b2g:

> 2563 >adb shell b2g-ps
> APPLICATION    SEC USER     PID   PPID  VSIZE  RSS     WCHAN    PC         NAME
> b2g              0 root      306   1     170820 84144 ffffffff 00000000 S /system/b2g/b2g
> b2g              0 root      457   306   55680  5536  ffffffff 00000000 S /system/b2g/b2g
> Built-in Keyboa  2 u0_a943   943   306   88824  33688 ffffffff 00000000 S /system/b2g/plugin-container
> Homescreen       2 u0_a945   945   306   85348  38480 ffffffff 00000000 S /system/b2g/plugin-container

Comment 8

[Ting-Yu Chou [:ting] (away)]

I just read your updated b2g_processes() to address the side effect, and found a problem.

If you run |adb shell b2g-info -m|, main_process() will go through the for loop twice and complain there are two b2g main process which are the same pid. It's because main_process() is reentrant when m_main_process hasn't been set.

The same problem happens when you do a |adb shell b2g-info -p| or |adb shell b2g-info -c|.

Comment 9

[Dave Hylands [:dhylands]]

Attachment: PR for b2g-info (part 2)

Addresses the reentrancy problem.

Comment 10

[Dave Hylands [:dhylands]]

Comment on attachment 8469292 [details] [review]
PR for b2g-info (part 2)

I'll put tchou down to review unless I can find somebody else sooner.

Comment 11

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

Comment on attachment 8469292 [details] [review]
PR for b2g-info (part 2)

r=me

Comment 12

[Dave Hylands [:dhylands]]

https://github.com/mozilla-b2g/gonk-misc/commit/b0b5df8c194be48fc8a2f8d1c4310c36388eec9e