Buildresult: linus/arm64-allmodconfig/arm64-gcc8 built on Jun 4 2019, 21:29

kisskb

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Status:	OK
Date/Time:	Jun 4 2019, 21:29
Duration:	0:12:02.305590
Builder:	ka4
Revision:	rcu: locking and unlocking need to always be at least barriers (`66be4e66a7f422128748e3c3ef6ee72b20a6197b)`
Target:	linus/arm64-allmodconfig/arm64-gcc8
Branch:	linus
Compiler:	arm64-gcc8 (aarch64-linux-gcc (GCC) 8.1.0 / GNU ld (GNU Binutils) 2.30)
Config:	allmodconfig (download)
Log:	Download original Possible warnings (9) fs/btrfs/props.c:389:4: warning: 'num_bytes' may be used uninitialized in this function [-Wmaybe-uninitialized] drivers/hwtracing/intel_th/msu.c:783:21: warning: unused variable 'i' [-Wunused-variable] drivers/hwtracing/intel_th/msu.c:863:6: warning: unused variable 'i' [-Wunused-variable] warning: same module names found: warning: same module names found: warning: same module names found: warning: same module names found: warning: same module names found: warning: same module names found: Full Log # git rev-parse -q --verify 66be4e66a7f422128748e3c3ef6ee72b20a6197b^{commit} 66be4e66a7f422128748e3c3ef6ee72b20a6197b already have revision, skipping fetch # git checkout -q -f -B kisskb 66be4e66a7f422128748e3c3ef6ee72b20a6197b # git clean -qxdf # < git log -1 # commit 66be4e66a7f422128748e3c3ef6ee72b20a6197b # Author: Linus Torvalds <torvalds@linux-foundation.org> # Date: Mon Jun 3 13:26:20 2019 -0700 # # rcu: locking and unlocking need to always be at least barriers # # Herbert Xu pointed out that commit bb73c52bad36 ("rcu: Don't disable # preemption for Tiny and Tree RCU readers") was incorrect in making the # preempt_disable/enable() be conditional on CONFIG_PREEMPT_COUNT. # # If CONFIG_PREEMPT_COUNT isn't enabled, the preemption enable/disable is # a no-op, but still is a compiler barrier. # # And RCU locking still _needs_ that compiler barrier. # # It is simply fundamentally not true that RCU locking would be a complete # no-op: we still need to guarantee (for example) that things that can # trap and cause preemption cannot migrate into the RCU locked region. # # The way we do that is by making it a barrier. # # See for example commit 386afc91144b ("spinlocks and preemption points # need to be at least compiler barriers") from back in 2013 that had # similar issues with spinlocks that become no-ops on UP: they must still # constrain the compiler from moving other operations into the critical # region. # # Now, it is true that a lot of RCU operations already use READ_ONCE() and # WRITE_ONCE() (which in practice likely would never be re-ordered wrt # anything remotely interesting), but it is also true that that is not # globally the case, and that it's not even necessarily always possible # (ie bitfields etc). # # Reported-by: Herbert Xu <herbert@gondor.apana.org.au> # Fixes: bb73c52bad36 ("rcu: Don't disable preemption for Tiny and Tree RCU readers") # Cc: stable@kernel.org # Cc: Boqun Feng <boqun.feng@gmail.com> # Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/aarch64-linux/bin/aarch64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/aarch64-linux/bin/aarch64-linux-ld --version # < git log --format=%s --max-count=1 66be4e66a7f422128748e3c3ef6ee72b20a6197b # < make -s -j 120 ARCH=arm64 O=/kisskb/build/linus_arm64-allmodconfig_arm64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/aarch64-linux/bin/aarch64-linux- allmodconfig # make -s -j 120 ARCH=arm64 O=/kisskb/build/linus_arm64-allmodconfig_arm64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/aarch64-linux/bin/aarch64-linux- /kisskb/src/fs/btrfs/props.c: In function 'inherit_props': /kisskb/src/fs/btrfs/props.c:389:4: warning: 'num_bytes' may be used uninitialized in this function [-Wmaybe-uninitialized] btrfs_block_rsv_release(fs_info, trans->block_rsv, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ num_bytes); ~~~~~~~~~~ /kisskb/src/drivers/hwtracing/intel_th/msu.c: In function 'msc_buffer_win_alloc': /kisskb/src/drivers/hwtracing/intel_th/msu.c:783:21: warning: unused variable 'i' [-Wunused-variable] int ret = -ENOMEM, i; ^ /kisskb/src/drivers/hwtracing/intel_th/msu.c: In function 'msc_buffer_win_free': /kisskb/src/drivers/hwtracing/intel_th/msu.c:863:6: warning: unused variable 'i' [-Wunused-variable] int i; ^ warning: same module names found: drivers/regulator/88pm800.ko drivers/mfd/88pm800.ko warning: same module names found: drivers/gpu/drm/bridge/adv7511/adv7511.ko drivers/media/i2c/adv7511.ko warning: same module names found: drivers/net/phy/asix.ko drivers/net/usb/asix.ko warning: same module names found: fs/coda/coda.ko drivers/media/platform/coda/coda.ko warning: same module names found: drivers/video/fbdev/mxsfb.ko drivers/gpu/drm/mxsfb/mxsfb.ko warning: same module names found: drivers/net/phy/realtek.ko drivers/net/dsa/realtek.ko Completed OK # rm -rf /kisskb/build/linus_arm64-allmodconfig_arm64-gcc8 # Build took: 0:12:02.305590

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