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Currently, non-privileged user could only use uprobe with
kernel.perf_event_paranoid = -1
However, setting perf_event_paranoid to -1 leaks other users' processes to
non-privileged uprobes.
To introduce proper permission control of uprobes, we are building the
following system:
A daemon with CAP_SYS_ADMIN is in charge to create uprobes via tracefs;
Users asks the daemon to create uprobes;
Then user can attach uprobe only to processes owned by the user.
This patch allows non-privileged user to attach uprobe to processes owned
by the user.
The following example shows how to use uprobe with non-privileged user.
This is based on Brendan's blog post [1]
1. Create uprobe with root:
sudo perf probe -x 'readline%return +0($retval):string'
2. Then non-root user can use the uprobe as:
perf record -vvv -e probe_bash:readline__return -p <pid> sleep 20
perf script
[1] http://www.brendangregg.com/blog/2015-06-28/linux-ftrace-uprobe.html
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <kernel-team@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190507161545.788381-1-songliubraving@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.