v1: https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg02179.html
Changes since v1:
- Rebase on master
- Add David's Acked-by tag to the spapr patch
- Add 2 patches on QLIST_{EMPTY,REMOVE}_RCU
- Add some fixes for test-rcu-list. I wanted to be able to get no
races with ThreadSanitizer, but it still warns about two races.
I'm appending the report just in case, but I think tsan is getting
confused.
- Add RCU QSIMPLEQ and RCU QTAILQ, piggy-backing their testing
on test-rcu-list.
- Use an RCU QTAILQ instead of an RCU QLIST for the CPU list.
- Drop the patch that added the CPUState.in_list field,
since with the QTAILQ it's not necessary.
- Convert a caller in target/s390x that I missed in v1.
You can fetch this series from:
https://github.com/cota/qemu/tree/rcu-cpulist-v2
Thanks,
Emilio
---
The aforementioned TSan report:
$ make -j 12 tests/test-rcu-simpleq tests/test-rcu-list && tests/test-rcu-list
1 1
CC tests/test-rcu-simpleq.o
CC tests/test-rcu-list.o
LINK tests/test-rcu-list
LINK tests/test-rcu-simpleq
==================
WARNING: ThreadSanitizer: data race (pid=15248)
Atomic read of size 8 at 0x7b0800005600 by thread T2:
#0 __tsan_atomic64_load
../../../../gcc-8.1.0/libsanitizer/tsan/tsan_interface_atomic.cc:538
(libtsan.so.0+0x6080e)
#1 rcu_q_reader /data/src/qemu/tests/test-rcu-list.c:166
(test-rcu-list+0x9294)
#2 qemu_thread_start /data/src/qemu/util/qemu-thread-posix.c:504
(test-rcu-list+0x9af8)
Previous write of size 8 at 0x7b0800005600 by thread T3:
#0 malloc ../../../../gcc-8.1.0/libsanitizer/tsan/tsan_interceptors.cc:606
(libtsan.so.0+0x2a2f3)
#1 g_malloc <null> (libglib-2.0.so.0+0x51858)
#2 qemu_thread_start /data/src/qemu/util/qemu-thread-posix.c:504
(test-rcu-list+0x9af8)
As if synchronized via sleep:
#0 nanosleep
../../../../gcc-8.1.0/libsanitizer/tsan/tsan_interceptors.cc:366
(libtsan.so.0+0x48d20)
#1 g_usleep <null> (libglib-2.0.so.0+0x754de)
#2 qemu_thread_start /data/src/qemu/util/qemu-thread-posix.c:504
(test-rcu-list+0x9af8)
Location is heap block of size 32 at 0x7b0800005600 allocated by thread T3:
#0 malloc ../../../../gcc-8.1.0/libsanitizer/tsan/tsan_interceptors.cc:606
(libtsan.so.0+0x2a2f3)
#1 g_malloc <null> (libglib-2.0.so.0+0x51858)
#2 qemu_thread_start /data/src/qemu/util/qemu-thread-posix.c:504
(test-rcu-list+0x9af8)
Thread T2 (tid=15251, running) created by main thread at:
#0 pthread_create
../../../../gcc-8.1.0/libsanitizer/tsan/tsan_interceptors.cc:915
(libtsan.so.0+0x2af6b)
#1 qemu_thread_create /data/src/qemu/util/qemu-thread-posix.c:534
(test-rcu-list+0xadc8)
#2 create_thread /data/src/qemu/tests/test-rcu-list.c:70
(test-rcu-list+0x944f)
#3 rcu_qtest /data/src/qemu/tests/test-rcu-list.c:278 (test-rcu-list+0x95ea)
#4 main /data/src/qemu/tests/test-rcu-list.c:357 (test-rcu-list+0x893f)
Thread T3 (tid=15252, running) created by main thread at:
#0 pthread_create
../../../../gcc-8.1.0/libsanitizer/tsan/tsan_interceptors.cc:915
(libtsan.so.0+0x2af6b)
#1 qemu_thread_create /data/src/qemu/util/qemu-thread-posix.c:534
(test-rcu-list+0xadc8)
#2 create_thread /data/src/qemu/tests/test-rcu-list.c:70
(test-rcu-list+0x944f)
#3 rcu_qtest /data/src/qemu/tests/test-rcu-list.c:280 (test-rcu-list+0x9606)
#4 main /data/src/qemu/tests/test-rcu-list.c:357 (test-rcu-list+0x893f)
SUMMARY: ThreadSanitizer: data race /data/src/qemu/tests/test-rcu-list.c:166 in
rcu_q_reader
==================
==================
WARNING: ThreadSanitizer: data race (pid=15248)
Write of size 8 at 0x7b080000e880 by thread T1:
#0 free ../../../../gcc-8.1.0/libsanitizer/tsan/tsan_interceptors.cc:649
(libtsan.so.0+0x2a5ba)
#1 reclaim_list_el /data/src/qemu/tests/test-rcu-list.c:105
(test-rcu-list+0x8e66)
#2 call_rcu_thread /data/src/qemu/util/rcu.c:284 (test-rcu-list+0xbb57)
#3 qemu_thread_start /data/src/qemu/util/qemu-thread-posix.c:504
(test-rcu-list+0x9af8)
Previous atomic read of size 8 at 0x7b080000e880 by thread T2:
#0 __tsan_atomic64_load
../../../../gcc-8.1.0/libsanitizer/tsan/tsan_interface_atomic.cc:538
(libtsan.so.0+0x6080e)
#1 rcu_q_reader /data/src/qemu/tests/test-rcu-list.c:166
(test-rcu-list+0x9294)
#2 qemu_thread_start /data/src/qemu/util/qemu-thread-posix.c:504
(test-rcu-list+0x9af8)
Thread T1 (tid=15250, running) created by main thread at:
#0 pthread_create
../../../../gcc-8.1.0/libsanitizer/tsan/tsan_interceptors.cc:915
(libtsan.so.0+0x2af6b)
#1 qemu_thread_create /data/src/qemu/util/qemu-thread-posix.c:534
(test-rcu-list+0xadc8)
#2 rcu_init_complete /data/src/qemu/util/rcu.c:327 (test-rcu-list+0xb9f2)
#3 rcu_init /data/src/qemu/util/rcu.c:383 (test-rcu-list+0x89fc)
#4 __libc_csu_init <null> (test-rcu-list+0x35f9c)
Thread T2 (tid=15251, running) created by main thread at:
#0 pthread_create
../../../../gcc-8.1.0/libsanitizer/tsan/tsan_interceptors.cc:915
(libtsan.so.0+0x2af6b)
#1 qemu_thread_create /data/src/qemu/util/qemu-thread-posix.c:534
(test-rcu-list+0xadc8)
#2 create_thread /data/src/qemu/tests/test-rcu-list.c:70
(test-rcu-list+0x944f)
#3 rcu_qtest /data/src/qemu/tests/test-rcu-list.c:278 (test-rcu-list+0x95ea)
#4 main /data/src/qemu/tests/test-rcu-list.c:357 (test-rcu-list+0x893f)
SUMMARY: ThreadSanitizer: data race /data/src/qemu/tests/test-rcu-list.c:105 in
reclaim_list_el
==================
tests/test-rcu-list: 1 readers; 1 updater; nodes read: 375386, nodes removed:
78728; nodes reclaimed: 78728
ThreadSanitizer: reported 2 warnings
