Messages in this thread | | | Date | Tue, 31 May 2016 19:34:13 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [RFC PATCH 1/2] rcu: sysctl: Panic on RCU Stall |
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On Tue, May 31, 2016 at 07:49:41PM -0300, Daniel Bristot de Oliveira wrote: > On 05/31/2016 04:23 PM, Josh Triplett wrote: > > Hi Josh, > > > Sorry, realized something else a moment after sending: I don't think > > this will build if you use the tiny RCU implementation. That > > implementation *does* support tracing, and if you enable tracing, > > you'll have CONFIG_RCU_STALL_COMMON=y, but you won't build tree.c where > > the variable definition lives. So, the sysctl code will reference a > > variable that doesn't exist. > > Good catch! > > [root@f23 linux]# egrep '(TINY_RCU|RCU_TRACE)' .config > CONFIG_TINY_RCU=y > # CONFIG_TREE_RCU_TRACE is not set > CONFIG_RCU_TRACE=y > [root@f23 linux]# make > ... > kernel/built-in.o:(.data+0x4688): undefined reference to `sysctl_panic_on_rcu_stall' > Makefile:937: recipe for target 'vmlinux' failed > make: *** [vmlinux] Error 1 > > > How about this change in the condition: > -#ifdef CONFIG_RCU_STALL_COMMON > +#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU)
Looks plausible to me. But what I would trust quite a bit more than my own opinion would be successful builds for all three configurations. ;-)
Thanx, Paul
> It worked fine here, but I may be missing something, so I better > check with the experts :-). > > Thanks for reviewing the patch set! > > -- Daniel >
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