On Sun, Jul 08, 2012 at 08:57:07AM +0800, Fengguang Wu wrote: > On Sat, Jul 07, 2012 at 02:54:42PM -0700, Paul E. McKenney wrote: > > On Sun, Jul 08, 2012 at 01:18:03AM +0800, wfg@xxxxxxxxxxxxxxx wrote: > > > Hi Paul, > > > > > > Kernel build failed on > > > > > > tree: git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git fixes.2012.07.06a > > > head: cfca927972e31a5b3da49bf641c525732ff3c357 > > > commit: 62fde6edf12b60fddb13a3f0a779c8be0bb7447e [12/19] rcu: Make __call_rcu() handle invocation from idle > > > config: x86_64-randconfig-tip4 (attached as .config) > > > > > > > > > kernel/built-in.o: In function `rcu_read_lock_bh_held': (.text+0x167d1): undefined reference to `rcu_is_cpu_idle' > > > kernel/built-in.o: In function `lockdep_rcu_suspicious': (.text+0x367e8): undefined reference to `rcu_is_cpu_idle' > > > kernel/built-in.o: In function `lockdep_rcu_suspicious': (.text+0x36815): undefined reference to `rcu_is_cpu_idle' > > > kernel/built-in.o: In function `css_get_next': (.text+0x40f5a): undefined reference to `rcu_is_cpu_idle' > > > drivers/built-in.o: In function `dst_link_failure': isdn_net.c:(.text+0x13950a): undefined reference to `rcu_is_cpu_idle' > > > net/built-in.o:sock.c:(.text+0x3cec): more undefined references to `rcu_is_cpu_idle' follow > > > > > > There are more similar errors in the other randconfigs. > > > > Hmmm... So you are building TINY_RCU without CONFIG_DEBUG_LOCK_ALLOC, > > but with some checking enabled. I -thought- I was testing that... > > > > But, wait. You do have CONFIG_DEBUG_LOCK_ALLOC defined. That really > > should cause rcu_is_cpu_idle() to be compiled into kernel/rcupdate.o. > > And your config builds on my system with no errors. > > I can reproduce the errors in a clean build. And I find the root cause to be > the below line in rcutiny.c: > > ==> #ifdef CONFIG_PROVE_RCU > > /* > * Test whether RCU thinks that the current CPU is idle. > */ > int rcu_is_cpu_idle(void) Ah! Fixed by d7118175 in -next, -tip, and -rcu. The bug was introduced by 9b2e4f1880 in v3.3, but apparently the commit you found was the one that actually exposed the bug. What error were you bisecting for? > > Was there perhaps another problem, maybe running out of disk space? > > Sometimes it does run out of *memory*, because I aggressively put all > .o files in tmpfs ;) In which case the make/gcc tasks are killed and > the abnormal situation is detected by grepping for "Terminated" lines > in the build log. Fair enough! ;-) Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
