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Message-ID: <20250102220238.225015816@goodmis.org>
Date: Thu, 02 Jan 2025 17:02:38 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org
Cc: Masami Hiramatsu <mhiramat@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [for-linus][PATCH 0/2] ftrace: Fixes for v6.13
Fixes for ftrace in v6.13:
- Add needed READ_ONCE() around access to the fgraph array element
The updates to the fgraph array can happen when callbacks are registered
and unregistered. The __ftrace_return_to_handler() can handle reading
either the old value or the new value. But once it reads that value
it must stay consistent otherwise the check that looks to see if the
value is a stub may show false, but if the compiler decides to re-read
after that check, it can be true which can cause the code to crash
later on.
- Make function profiler use the top level ops for filtering again
When function graph became available for instances, its filter ops became
independent from the top level set_ftrace_filter. In the process the
function profiler received its own filter ops as well. But the function
profiler uses the top level set_ftrace_filter file and does not have one
of its own. In giving it its own filter ops, it lost any user interface
it once had. Make it use the top level set_ftrace_filter file again.
This fixes a regression.
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