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authorSteven Rostedt <rostedt@goodmis.org>2025-04-02 10:49:04 -0400
committerSteven Rostedt (Google) <rostedt@goodmis.org>2025-04-02 11:02:26 -0400
commitc44a14f216f45d8bf1634b52854a699d7090f1e8 (patch)
tree0665d4830496b4476a8c97b0407b4d5c03a34737 /Documentation
parent028a58ec154257e618c27fb0eba8d9e30379bc3d (diff)
tracing: Enforce the persistent ring buffer to be page aligned
Enforce that the address and the size of the memory used by the persistent ring buffer is page aligned. Also update the documentation to reflect this requirement. Link: https://lore.kernel.org/all/CAHk-=whUOfVucfJRt7E0AH+GV41ELmS4wJqxHDnui6Giddfkzw@mail.gmail.com/ 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> Cc: Vincent Donnefort <vdonnefort@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mike Rapoport <rppt@kernel.org> Cc: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/20250402144953.412882844@goodmis.org Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt2
-rw-r--r--Documentation/trace/debugging.rst2
2 files changed, 4 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index fb8752b42ec8..71861643ef14 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -7241,6 +7241,8 @@
This is just one of many ways that can clear memory. Make sure your system
keeps the content of memory across reboots before relying on this option.
+ NB: Both the mapped address and size must be page aligned for the architecture.
+
See also Documentation/trace/debugging.rst
diff --git a/Documentation/trace/debugging.rst b/Documentation/trace/debugging.rst
index 54fb16239d70..d54bc500af80 100644
--- a/Documentation/trace/debugging.rst
+++ b/Documentation/trace/debugging.rst
@@ -136,6 +136,8 @@ kernel, so only the same kernel is guaranteed to work if the mapping is
preserved. Switching to a different kernel version may find a different
layout and mark the buffer as invalid.
+NB: Both the mapped address and size must be page aligned for the architecture.
+
Using trace_printk() in the boot instance
-----------------------------------------
By default, the content of trace_printk() goes into the top level tracing