From: Steven Rostedt (VMware) Date: Thu, 18 Jan 2018 20:42:09 +0000 (-0500) Subject: ring-buffer: Fix duplicate results in mapping context to bits in recursive lock X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0164e0d7e803af3ee1c63770978c728f8778ad01;p=linux.git 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) --- diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 0cddf60186da0..5af2842dea962 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;