2022-11-02 08:35:17

by Chen Linxuan

Subject: [PATCH] Documentation: update the description of TracerPid in procfs.rst

When the tracer of process is outside of current pid namespace, field
`TracerPid` in /proc/<pid>/status will be 0, too, just like this process
not have been traced.

This is because that function `task_pid_nr_ns` used to get the pid of
tracer will return 0 in this situation.

Co-authored-by: Yuan Haisheng <[email protected]>
Signed-off-by: Chen Linxuan <[email protected]>
---
Documentation/filesystems/proc.rst | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 898c99eae8e4..e98e0277f05e 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -245,7 +245,8 @@ It's slow but very precise.
Ngid NUMA group ID (0 if none)
Pid process id
PPid process id of the parent process
- TracerPid PID of process tracing this process (0 if not)
+ TracerPid PID of process tracing this process (0 if not, or
+ the tracer is outside of the current pid namespace)
Uid Real, effective, saved set, and file system UIDs
Gid Real, effective, saved set, and file system GIDs
FDSize number of file descriptor slots currently allocated
--
2.38.1

2022-11-15 23:08:42

by Jonathan Corbet

Subject: Re: [PATCH] Documentation: update the description of TracerPid in procfs.rst

Chen Linxuan <[email protected]> writes:

> When the tracer of process is outside of current pid namespace, field
> `TracerPid` in /proc/<pid>/status will be 0, too, just like this process
> not have been traced.
>
> This is because that function `task_pid_nr_ns` used to get the pid of
> tracer will return 0 in this situation.
>
> Co-authored-by: Yuan Haisheng <[email protected]>
> Signed-off-by: Chen Linxuan <[email protected]>
> ---
> Documentation/filesystems/proc.rst | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
> index 898c99eae8e4..e98e0277f05e 100644
> --- a/Documentation/filesystems/proc.rst
> +++ b/Documentation/filesystems/proc.rst
> @@ -245,7 +245,8 @@ It's slow but very precise.
> Ngid NUMA group ID (0 if none)
> Pid process id
> PPid process id of the parent process
> - TracerPid PID of process tracing this process (0 if not)
> + TracerPid PID of process tracing this process (0 if not, or
> + the tracer is outside of the current pid namespace)

Applied, thanks.

jon