Re: [PATCH] tracing: Have all levels of checks prevent recursion
From: Peter Zijlstra <peterz@infradead.org>
Date: 2021-10-15 18:29:52
Also in:
linux-riscv, live-patching, lkml
On Fri, Oct 15, 2021 at 02:20:33PM -0400, Steven Rostedt wrote:
On Fri, 15 Oct 2021 20:04:29 +0200 Peter Zijlstra [off-list ref] wrote:quoted
On Fri, Oct 15, 2021 at 01:58:06PM -0400, Steven Rostedt wrote:quoted
Something like this:I think having one copy of that in a header is better than having 3 copies. But yes, something along them lines.I was just about to ask you about this patch ;-)
Much better :-)
quoted hunk ↗ jump to hunk
diff --git a/kernel/events/internal.h b/kernel/events/internal.h index 228801e20788..c91711f20cf8 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h@@ -206,11 +206,7 @@ DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user) static inline int get_recursion_context(int *recursion) { unsigned int pc = preempt_count();
Although I think we can do without that ^ line as well :-)
- unsigned char rctx = 0; - - rctx += !!(pc & (NMI_MASK)); - rctx += !!(pc & (NMI_MASK | HARDIRQ_MASK)); - rctx += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)); + unsigned char rctx = interrupt_context_level(); if (recursion[rctx]) return -1;