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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2018-01-18 15:42:09 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-01-18 15:45:48 -0500
commit0164e0d7e803af3ee1c63770978c728f8778ad01 (patch)
tree0bcf3a618d4d36a1efc6458456f579783b17d19e
parent68e76e034b6b1c1ce2eece1ab8ae4008e14be470 (diff)
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>
-rw-r--r--kernel/trace/ring_buffer.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 0cddf60186da..5af2842dea96 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2579,8 +2579,7 @@ 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;