blob: 10ee97b31c756b8b7071e798c1a66dbd263e47df [file] [log] [blame]
From a80b4e33952be0209ba984df1ff7464a72c353ad Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Date: Thu, 18 Jan 2018 15:42:09 -0500
Subject: [PATCH 1752/1795] ring-buffer: Fix duplicate results in mapping
context to bits in recursive lock
In bringing back the context checks, the code checks first if its normal
(non-interrupt) context, and then for NMI then IRQ then softirq. The final
check is redundant. Since the if branch is only hit if the context is one of
NMI, IRQ, or SOFTIRQ, if it's not NMI or IRQ there's no reason to check if
it is SOFTIRQ. The current code returns the same result even if its not a
SOFTIRQ. Which is confusing.
pc & SOFTIRQ_OFFSET ? 2 : RB_CTX_SOFTIRQ
Is redundant as RB_CTX_SOFTIRQ *is* 2!
Fixes: a0e3a18f4baf ("ring-buffer: Bring back context level recursive checks")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
(cherry picked from commit 0164e0d7e803af3ee1c63770978c728f8778ad01)
Signed-off-by: Hirotaka MOTAI <Motai.Hirotaka@aj.MitsubishiElectric.co.jp>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
kernel/trace/ring_buffer.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 5c4dc1c18519..e3769d3c9bca 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2590,8 +2590,7 @@ trace_recursive_lock(struct ring_buffer_per_cpu *cpu_buffer)
bit = RB_CTX_NORMAL;
else
bit = pc & NMI_MASK ? RB_CTX_NMI :
- pc & HARDIRQ_MASK ? RB_CTX_IRQ :
- pc & SOFTIRQ_OFFSET ? 2 : RB_CTX_SOFTIRQ;
+ pc & HARDIRQ_MASK ? RB_CTX_IRQ : RB_CTX_SOFTIRQ;
if (unlikely(val & (1 << bit)))
return 1;
--
2.19.0