51a2049a2c
[ Upstream commit d57cf30c4c07837799edec949102b0adf58bae79 ] The events directory gets its permissions from the root inode. But this can cause an inconsistency if the instances directory changes its permissions, as the permissions of the created directories under it should inherit the permissions of the instances directory when directories under it are created. Currently the behavior is: # cd /sys/kernel/tracing # chgrp 1002 instances # mkdir instances/foo # ls -l instances/foo [..] -r--r----- 1 root lkp 0 May 1 18:55 buffer_total_size_kb -rw-r----- 1 root lkp 0 May 1 18:55 current_tracer -rw-r----- 1 root lkp 0 May 1 18:55 error_log drwxr-xr-x 1 root root 0 May 1 18:55 events --w------- 1 root lkp 0 May 1 18:55 free_buffer drwxr-x--- 2 root lkp 0 May 1 18:55 options drwxr-x--- 10 root lkp 0 May 1 18:55 per_cpu -rw-r----- 1 root lkp 0 May 1 18:55 set_event All the files and directories under "foo" has the "lkp" group except the "events" directory. That's because its getting its default value from the mount point instead of its parent. Have the "events" directory make its default value based on its parent's permissions. That now gives: # ls -l instances/foo [..] -rw-r----- 1 root lkp 0 May 1 21:16 buffer_subbuf_size_kb -r--r----- 1 root lkp 0 May 1 21:16 buffer_total_size_kb -rw-r----- 1 root lkp 0 May 1 21:16 current_tracer -rw-r----- 1 root lkp 0 May 1 21:16 error_log drwxr-xr-x 1 root lkp 0 May 1 21:16 events --w------- 1 root lkp 0 May 1 21:16 free_buffer drwxr-x--- 2 root lkp 0 May 1 21:16 options drwxr-x--- 10 root lkp 0 May 1 21:16 per_cpu -rw-r----- 1 root lkp 0 May 1 21:16 set_event Link: https://lore.kernel.org/linux-trace-kernel/20240502200906.161887248@goodmis.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: 8186fff7ab649 ("tracefs/eventfs: Use root and instance inodes as default ownership") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@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.