systemtap: not to use spin_unlock_wait anymore

[gowrishankarm]

cde:info Mirrored with LTC bug https://bugzilla.linux.ibm.com/show_bug.cgi?id=160774 </cde:info>

Systemtap (3.1-5.dev.git39b62b4) seems to be broken in current hostos devel (4.14 rc4 kernel) for a reason that it refers to calling spin_unlock_wait() which is no more in kernel as in its commit d3a024a

  locking: Remove spin_unlock_wait() generic definitions 

  There is no agreed-upon definition of spin_unlock_wait()'s semantics,
  and it appears that all callers could do just as well with a lock/unlock
  pair.  This commit therefore removes spin_unlock_wait() and related
  definitions from core code. 

Hence, executing systemtap ends up with below error:

~]# stap -v -e 'probe vfs.read {exit()}' 
Pass 1: parsed user script and 490 library scripts using 174720virt/57280res/7744shr/47296data kb, in 640usr/20sys/653real ms.
Pass 2: analyzed script: 1 probe, 1 function, 7 embeds, 0 globals using 325248virt/209920res/9792shr/197824data kb, in 3170usr/700sys/3885real ms.
Pass 3: translated to C into "/tmp/staptlhTut/stap_83fd83b4a24b54380d462a6bd5886728_2819_src.c" using 325248virt/210112res/9984shr/197824data kb, in 30usr/150sys/187real ms.
In file included from /usr/share/systemtap/runtime/stp_utrace.c:30:0,
                 from /usr/share/systemtap/runtime/linux/task_finder2.c:4,
                 from /usr/share/systemtap/runtime/linux/task_finder.c:17,
                 from /usr/share/systemtap/runtime/linux/runtime.h:222,
                 from /usr/share/systemtap/runtime/runtime.h:26,
                 from /tmp/staptlhTut/stap_83fd83b4a24b54380d462a6bd5886728_2819_src.c:25:
/usr/share/systemtap/runtime/stp_helper_lock.h: In function ‘stp_spin_unlock_wait’:
/usr/share/systemtap/runtime/stp_helper_lock.h:60:1: error: implicit declaration of function ‘spin_unlock_wait’ [-Werror=implicit-function-declaration]
 static inline void stp_spin_unlock_wait(spinlock_t *lock) { spin_unlock_wait(lock); }
 ^
cc1: all warnings being treated as errors
make[1]: *** [/tmp/staptlhTut/stap_83fd83b4a24b54380d462a6bd5886728_2819_src.o] Error 1
make: *** [_module_/tmp/staptlhTut] Error 2
WARNING: kbuild exited with status: 2
Pass 4: compiled C into "stap_83fd83b4a24b54380d462a6bd5886728_2819.ko" in 14550usr/1330sys/15774real ms.
Pass 4: compilation failed.  [man error::pass4]

Upstream systemtap fix to getrid of spin_unlock_wait:

https://sourceware.org/git/gitweb.cgi?p=systemtap.git;a=commit;f=runtime/stp_utrace.c;h=0643ca2b7fd8cb6407aa84f41d26a71d2f2f8e90

Applied fix locally With that,

~]# stap -v -e 'probe oneshot { println("hello world") }'
Pass 1: parsed user script and 490 library scripts using 174720virt/57280res/7744shr/47296data kb, in 630usr/20sys/652real ms.
Pass 2: analyzed script: 1 probe, 1 function, 0 embeds, 0 globals using 175488virt/57280res/7744shr/48064data kb, in 10usr/0sys/10real ms.
Pass 3: using cached /root/.systemtap/cache/56/stap_56041bf7d0574051b4814be457798d87_1190.c
Pass 4: using cached /root/.systemtap/cache/56/stap_56041bf7d0574051b4814be457798d87_1190.ko
Pass 5: starting run.
ERROR: module version mismatch (#1 SMP Thu Oct 26 22:52:08 -02 2017 vs #1 SMP Tue Oct 24 00:46:42 UTC 2017), release 4.14.0-1.rc4.dev.gitb27fc5c.el7.centos.ppc64le
WARNING: /usr/bin/staprun exited with status: 1
Pass 5: run completed in 10usr/50sys/332real ms.
Pass 5: run failed.  [man error::pass5]

Tried wiping out ~/.systemtap/cache/ but did not help. So, matched /usr/src/kernels/.../include/generated/compile.h, for stap and it worked (just a workaround to avoid recompiling stap).

~]# stap -v -e 'probe oneshot { println("hello world") }'
Pass 1: parsed user script and 490 library scripts using 174720virt/57216res/7744shr/47296data kb, in 630usr/20sys/653real ms.
Pass 2: analyzed script: 1 probe, 1 function, 0 embeds, 0 globals using 175488virt/57216res/7744shr/48064data kb, in 0usr/0sys/10real ms.
Pass 3: translated to C into "/tmp/stapG4SOWi/stap_56041bf7d0574051b4814be457798d87_1190_src.c" using 175616virt/59648res/9280shr/48192data kb, in 0usr/0sys/0real ms.
Pass 4: compiled C into "stap_56041bf7d0574051b4814be457798d87_1190.ko" in 2850usr/510sys/3250real ms.
Pass 5: starting run.
hello world
Pass 5: run completed in 20usr/70sys/809real ms.

Please include mentioned patch for systemtap to work.

[mopsfelder]

I confirm that systemtap-3.2-1.dev.git4051c70.el7.centos.ppc64le is working fine with kernel-4.14.0-2.rc8.dev.gitcc4bf22.el7.centos.ppc64le. This issue can be closed.

# stap -v -e 'probe oneshot { println("hello world") }'
Pass 1: parsed user script and 493 library scripts using 175936virt/58432res/7744shr/48448data kb, in 480usr/30sys/577real ms.
Pass 2: analyzed script: 1 probe, 1 function, 0 embeds, 0 globals using 176704virt/58432res/7744shr/49216data kb, in 10usr/0sys/29real ms.
Pass 3: translated to C into "/tmp/stapd8B9HA/stap_af87a4f97e038c002464edfc6be6e231_1194_src.c" using 176832virt/60928res/9344shr/49344data kb, in 0usr/0sys/1real ms.
Pass 4: compiled C into "stap_af87a4f97e038c002464edfc6be6e231_1194.ko" in 16920usr/1440sys/18798real ms.
Pass 5: starting run.
hello world
Pass 5: run completed in 10usr/60sys/783real ms.

# echo $?
0

# rpm -q systemtap kernel
systemtap-3.2-1.dev.git4051c70.el7.centos.ppc64le
kernel-4.14.0-2.rc8.dev.gitcc4bf22.el7.centos.ppc64le