From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
linux-arch@vger.kernel.org,
Joel Fernandes <joel@joelfernandes.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Andy Lutomirski <luto@kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
stable@kernel.org
Subject: [for-next][PATCH 17/18] function_graph: Reverse the order of pushing the ret_stack and the callback
Date: Wed, 21 Nov 2018 19:28:18 -0500 [thread overview]
Message-ID: <20181122003333.880108256@goodmis.org> (raw)
In-Reply-To: 20181122002801.501220343@goodmis.org
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
The function graph profiler uses the ret_stack to store the "subtime" and
reuse it by nested functions and also on the return. But the current logic
has the profiler callback called before the ret_stack is updated, and it is
just modifying the ret_stack that will later be allocated (it's just lucky
that the "subtime" is not touched when it is allocated).
This could also cause a crash if we are at the end of the ret_stack when
this happens.
By reversing the order of the allocating the ret_stack and then calling the
callbacks attached to a function being traced, the ret_stack entry is no
longer used before it is allocated.
Cc: stable@kernel.org
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace_functions_graph.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 4f0d72ae6362..2561460d7baf 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -188,15 +188,17 @@ int function_graph_enter(unsigned long ret, unsigned long func,
trace.func = func;
trace.depth = ++current->curr_ret_depth;
- /* Only trace if the calling function expects to */
- if (!ftrace_graph_entry(&trace))
- goto out;
-
if (ftrace_push_return_trace(ret, func,
frame_pointer, retp))
goto out;
+ /* Only trace if the calling function expects to */
+ if (!ftrace_graph_entry(&trace))
+ goto out_ret;
+
return 0;
+ out_ret:
+ current->curr_ret_stack--;
out:
current->curr_ret_depth--;
return -EBUSY;
--
2.19.1
next prev parent reply other threads:[~2018-11-22 0:34 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-22 0:28 [for-next][PATCH 00/18] function_graph: Add separate depth counter to prevent trace corruption Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 01/18] function_graph: Create function_graph_enter() to consolidate architecture code Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 02/18] x86/function_graph: Simplify with function_graph_entry() Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 03/18] ARM: function_graph: " Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 04/18] arm64: " Steven Rostedt
2018-11-27 18:07 ` Will Deacon
2018-11-27 18:26 ` Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 05/18] microblaze: " Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 06/18] MIPS: " Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 07/18] nds32: " Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 08/18] parisc: " Steven Rostedt
[not found] ` <20181123073033.2083020863@mail.kernel.org>
2018-11-23 9:06 ` Helge Deller
2018-11-23 17:12 ` Steven Rostedt
2018-11-23 18:34 ` Sasha Levin
2018-11-23 19:26 ` Steven Rostedt
2018-11-23 20:00 ` Sasha Levin
2018-11-24 18:46 ` Steven Rostedt
2018-12-03 14:54 ` Sasha Levin
2018-11-22 0:28 ` [for-next][PATCH 09/18] powerpc/function_graph: " Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 10/18] riscv/function_graph: " Steven Rostedt
2018-11-26 16:47 ` Palmer Dabbelt
2018-11-22 0:28 ` [for-next][PATCH 11/18] s390/function_graph: " Steven Rostedt
2018-11-22 6:43 ` Martin Schwidefsky
2018-11-23 17:15 ` Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 12/18] sh/function_graph: " Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 13/18] sparc/function_graph: " Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 14/18] function_graph: Make ftrace_push_return_trace() static Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 15/18] function_graph: Use new curr_ret_depth to manage depth instead of curr_ret_stack Steven Rostedt
2018-11-22 10:03 ` Peter Zijlstra
2018-11-23 14:14 ` Steven Rostedt
2018-11-22 0:28 ` [for-next][PATCH 16/18] function_graph: Move return callback before update " Steven Rostedt
2018-11-22 0:28 ` Steven Rostedt [this message]
2018-11-22 0:28 ` [for-next][PATCH 18/18] function_graph: Have profiler use curr_ret_stack and not depth Steven Rostedt
2018-11-26 5:15 ` [for-next][PATCH 00/18] function_graph: Add separate depth counter to prevent trace corruption Masami Hiramatsu
2018-11-28 20:39 ` Joe Lawrence
2018-11-28 21:00 ` Steven Rostedt
2018-11-29 3:29 ` Steven Rostedt
2018-11-29 4:24 ` Steven Rostedt
2018-11-29 15:08 ` Joe Lawrence
2018-11-29 16:17 ` Steven Rostedt
2018-11-29 16:32 ` Joe Lawrence
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