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  1. 05 May, 2024 36 commits
  3. 04 May, 2024 4 commits
    • Steven Rostedt (Google)'s avatar
      eventfs: Have "events" directory get permissions from its parent · d57cf30c
      Steven Rostedt (Google) authored 
      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: 8186fff7 ("tracefs/eventfs: Use root and instance inodes as default ownership")
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
      d57cf30c
    • Steven Rostedt (Google)'s avatar
      eventfs: Do not treat events directory different than other directories · 22e61e15
      Steven Rostedt (Google) authored 
      Treat the events directory the same as other directories when it comes to
permissions. The events directory was considered different because it's
dentry is persistent, whereas the other directory dentries are created
when accessed. But the way tracefs now does its ownership by using the
root dentry's permissions as the default permissions, the events directory
can get out of sync when a remount is performed setting the group and user
permissions.

Remove the special case for the events directory on setting the
attributes. This allows the updates caused by remount to work properly as
well as simplifies the code.

Link: https://lore.kernel.org/linux-trace-kernel/20240502200906.002923579@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: 8186fff7 ("tracefs/eventfs: Use root and instance inodes as default ownership")
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
      22e61e15
    • Steven Rostedt (Google)'s avatar
      eventfs: Do not differentiate the toplevel events directory · d53891d3
      Steven Rostedt (Google) authored 
      The toplevel events directory is really no different than the events
directory of instances. Having the two be different caused
inconsistencies and made it harder to fix the permissions bugs.

Make all events directories act the same.

Link: https://lore.kernel.org/linux-trace-kernel/20240502200905.846448710@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: 8186fff7 ("tracefs/eventfs: Use root and instance inodes as default ownership")
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
      d53891d3
    • Steven Rostedt (Google)'s avatar
      tracefs: Still use mount point as default permissions for instances · 6599bd55
      Steven Rostedt (Google) authored 
      If the instances directory's permissions were never change, then have it
and its children use the mount point permissions as the default.

Currently, the permissions of instance directories are determined by the
instance directory's permissions itself. But if the tracefs file system is
remounted and changes the permissions, the instance directory and its
children should use the new permission.

But because both the instance directory and its children use the instance
directory's inode for permissions, it misses the update.

To demonstrate this:

  # cd /sys/kernel/tracing/
  # mkdir instances/foo
  # ls -ld instances/foo
 drwxr-x--- 5 root root 0 May  1 19:07 instances/foo
  # ls -ld instances
 drwxr-x--- 3 root root 0 May  1 18:57 instances
  # ls -ld current_tracer
 -rw-r----- 1 root root 0 May  1 18:57 current_tracer

  # mount -o remount,gid=1002 .
  # ls -ld instances
 drwxr-x--- 3 root root 0 May  1 18:57 instances
  # ls -ld instances/foo/
 drwxr-x--- 5 root root 0 May  1 19:07 instances/foo/
  # ls -ld current_tracer
 -rw-r----- 1 root lkp 0 May  1 18:57 current_tracer

Notice that changing the group id to that of "lkp" did not affect the
instances directory nor its children. It should have been:

  # ls -ld current_tracer
 -rw-r----- 1 root root 0 May  1 19:19 current_tracer
  # ls -ld instances/foo/
 drwxr-x--- 5 root root 0 May  1 19:25 instances/foo/
  # ls -ld instances
 drwxr-x--- 3 root root 0 May  1 19:19 instances

  # mount -o remount,gid=1002 .
  # ls -ld current_tracer
 -rw-r----- 1 root lkp 0 May  1 19:19 current_tracer
  # ls -ld instances
 drwxr-x--- 3 root lkp 0 May  1 19:19 instances
  # ls -ld instances/foo/
 drwxr-x--- 5 root lkp 0 May  1 19:25 instances/foo/

Where all files were updated by the remount gid update.

Link: https://lore.kernel.org/linux-trace-kernel/20240502200905.686838327@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: 8186fff7 ("tracefs/eventfs: Use root and instance inodes as default ownership")
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
      6599bd55
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