[dramforever@live.com: [PATCH] man/man5/proc_pid.5: Clarify which user namespace affects permissions]

[dramforever@live.com: [PATCH] man/man5/proc_pid.5: Clarify which user namespace affects permissions]

[Alejandro Colomar]

[-- Attachment #1: Type: text/plain, Size: 2212 bytes --]

Hi Vivian,

Can you please confirm this is you?  I received this patch from an
address that doesn't match the one I see in your kernel commits, and
when I replied to <dramforever@live.com>, the message bounced.  I'm just
checking.  See patch from the @live.com address below.


Have a lovely night!
Alex

----- Forwarded message from Vivian Wang <dramforever@live.com> -----

Date: Mon, 16 Mar 2026 22:07:52 +0800
From: Vivian Wang <dramforever@live.com>
To: Alejandro Colomar <alx@kernel.org>
Cc: linux-man@vger.kernel.org, Michael Kerrisk <mtk.manpages@gmail.com>
Subject: [PATCH] man/man5/proc_pid.5: Clarify which user namespace affects
 permissions
Message-ID: <OSCPR01MB134682A1A80B8C9FB71CBA64DC640A@OSCPR01MB13468.jpnprd01.prod.outlook.com>
User-Agent: Mozilla Thunderbird

A more careful reading of fs/proc/base.c (since v4.11, as of v7.0-rc1)
reveals that it is not task->cred->user_ns that is checked, but
task->mm->user_ns, which is set during execve(2) (and copied over in
fork(2) and so on) [1], and is the correct user namespace to check for
ptrace-related purposes. Clarify the relevant text.

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bfedb589252c01fa505ac9f6f2a3d5d68d707ef4

Fixes: ae636827 ("proc.5: Fix description of /proc/PID/* ownership to account for user namespaces")
Signed-off-by: Vivian Wang <dramforever@live.com>
---
 man/man5/proc_pid.5 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/man/man5/proc_pid.5 b/man/man5/proc_pid.5
index eac97fa1d..2fe35bd09 100644
--- a/man/man5/proc_pid.5
+++ b/man/man5/proc_pid.5
@@ -30,7 +30,9 @@ Before Linux 4.11,
 meant the "global" root user ID and group ID
 (i.e., UID 0 and GID 0 in the initial user namespace).
 Since Linux 4.11,
-if the process is in a noninitial user namespace that has a
+if when the last time the process called
+.BR execve (2),
+it was in a noninitial user namespace that has a
 valid mapping for user (group) ID 0 inside the namespace, then
 the user (group) ownership of the files under
 .IR /proc/ pid
-- 
2.53.0



----- End forwarded message -----

-- 
<https://www.alejandro-colomar.es>

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

Re: [dramforever@live.com: [PATCH] man/man5/proc_pid.5: Clarify which user namespace affects permissions]

[Vivian Wang]

On 3/18/26 08:56, Alejandro Colomar wrote:

> Hi Vivian,
>
> Can you please confirm this is you?  I received this patch from an
> address that doesn't match the one I see in your kernel commits, and
> when I replied to <dramforever@live.com>, the message bounced.  I'm just
> checking.  See patch from the @live.com address below.

Hi, Alejandro,

This is me.

Apologies for the confusion. My idea was to use my personal email
(dramforever@live.com) for dayjob-related stuff, and employer email
(@iscas.ac.cn) for work-related stuff.

I've started signing off as "Vivian Wang <dramforever@live.com>" in
OpenSBI first, before being employed at ISCAS (see [1], firstly done in
[2] after someone complained about me just signing off as "dramforever
<dramforever@live.com>"). In June 2025 I was hired by ISCAS and started
doing primarily kernel work, which was probably where you saw this.

I did not realize that apparently kernel.org mail bounces on my free
Outlook email - I wasn't even getting it in my spam box. Unfortunately I
don't think I have much control over the behavior of Microsoft's Outlook
servers.

Next time I will use a different personal address - with a reply from my
apparently more well known @iscas.ac.cn address vouching for its
authenticity, to avoid confusion.

[1]: https://lore.kernel.org/opensbi/?q=f%3A%22Vivian+Wang+%3Cdramforever%22
[2]: https://lore.kernel.org/opensbi/TYYP286MB1439C5C64BCF8E9DB7883772C69F9@TYYP286MB1439.JPNP286.PROD.OUTLOOK.COM/

>
> Have a lovely night!
> Alex

Thank you.

Vivian "dramforever" Wang

Re: [dramforever@live.com: [PATCH] man/man5/proc_pid.5: Clarify which user namespace affects permissions]

[Alejandro Colomar]

[-- Attachment #1: Type: text/plain, Size: 2000 bytes --]

Hi Vivian,

On 2026-03-18T09:43:07+0800, Vivian Wang wrote:
> On 3/18/26 08:56, Alejandro Colomar wrote:
> 
> > Hi Vivian,
> >
> > Can you please confirm this is you?  I received this patch from an
> > address that doesn't match the one I see in your kernel commits, and
> > when I replied to <dramforever@live.com>, the message bounced.  I'm just
> > checking.  See patch from the @live.com address below.
> 
> Hi, Alejandro,
> 
> This is me.

Thanks for confirming!  :)

> Apologies for the confusion. My idea was to use my personal email
> (dramforever@live.com) for dayjob-related stuff, and employer email
> (@iscas.ac.cn) for work-related stuff.
> 
> I've started signing off as "Vivian Wang <dramforever@live.com>" in
> OpenSBI first, before being employed at ISCAS (see [1], firstly done in
> [2] after someone complained about me just signing off as "dramforever
> <dramforever@live.com>"). In June 2025 I was hired by ISCAS and started
> doing primarily kernel work, which was probably where you saw this.
> 
> I did not realize that apparently kernel.org mail bounces on my free
> Outlook email - I wasn't even getting it in my spam box. Unfortunately I
> don't think I have much control over the behavior of Microsoft's Outlook
> servers.
> 
> Next time I will use a different personal address - with a reply from my
> apparently more well known @iscas.ac.cn address vouching for its
> authenticity, to avoid confusion.

No problem; I'm fine with your personal address.  (At least, if it
didn't bounce; that's a problem.)

So, I was saying I have applied the patch.  Thanks!  :-)

> 
> [1]: https://lore.kernel.org/opensbi/?q=f%3A%22Vivian+Wang+%3Cdramforever%22
> [2]: https://lore.kernel.org/opensbi/TYYP286MB1439C5C64BCF8E9DB7883772C69F9@TYYP286MB1439.JPNP286.PROD.OUTLOOK.COM/
> 
> >
> > Have a lovely night!
> > Alex
> 
> Thank you.
> 
> Vivian "dramforever" Wang

:)

Cheers,
Alex

-- 
<https://www.alejandro-colomar.es>

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]