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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-11-06 03:32:46 +0100 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-11-06 14:42:26 +0100 |
| commit | 773c16705058e9be7b0f4ce124e89cd231c120a2 (patch) | |
| tree | 30bbb7933a0b1bc835d64cd6d61ca8e9b87f8eb7 /Documentation | |
| parent | ftrace: Reverse what the RECURSION flag means in the ftrace_ops (diff) | |
| download | linux-773c16705058e9be7b0f4ce124e89cd231c120a2.tar.xz linux-773c16705058e9be7b0f4ce124e89cd231c120a2.zip | |
ftrace: Add recording of functions that caused recursion
This adds CONFIG_FTRACE_RECORD_RECURSION that will record to a file
"recursed_functions" all the functions that caused recursion while a
callback to the function tracer was running.
Link: https://lkml.kernel.org/r/20201106023548.102375687@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Guo Ren <guoren@kernel.org>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-csky@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: live-patching@vger.kernel.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/trace/ftrace-uses.rst | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/Documentation/trace/ftrace-uses.rst b/Documentation/trace/ftrace-uses.rst index 86cd14b8e126..5981d5691745 100644 --- a/Documentation/trace/ftrace-uses.rst +++ b/Documentation/trace/ftrace-uses.rst @@ -118,7 +118,7 @@ can help in this regard. If you start your code with: int bit; - bit = ftrace_test_recursion_trylock(); + bit = ftrace_test_recursion_trylock(ip, parent_ip); if (bit < 0) return; @@ -130,7 +130,9 @@ The code in between will be safe to use, even if it ends up calling a function that the callback is tracing. Note, on success, ftrace_test_recursion_trylock() will disable preemption, and the ftrace_test_recursion_unlock() will enable it again (if it was previously -enabled). +enabled). The instruction pointer (ip) and its parent (parent_ip) is passed to +ftrace_test_recursion_trylock() to record where the recursion happened +(if CONFIG_FTRACE_RECORD_RECURSION is set). Alternatively, if the FTRACE_OPS_FL_RECURSION flag is set on the ftrace_ops (as explained below), then a helper trampoline will be used to test |