Buildresult: linus-rand/powerpc-randconfig/powerpc-gcc9 built on Jul 31 2021, 09:48

kisskb

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Status:	Failed
Date/Time:	Jul 31 2021, 09:48
Duration:	0:00:24.085125
Builder:	ka3
Revision:	pipe: make pipe writes always wake up readers (`3a34b13a88caeb2800ab44a4918f230041b37dd9)`
Target:	linus-rand/powerpc-randconfig/powerpc-gcc9
Branch:	linus-rand
Compiler:	powerpc-gcc9 (powerpc64-linux-gcc (GCC) 9.2.0 / GNU ld (GNU Binutils) 2.32)
Config:	randconfig (download)
Log:	Download original Possible errors scripts/mod/empty.c:1: internal compiler error: Segmentation fault make[2]: * [scripts/Makefile.build:271: scripts/mod/empty.o] Error 1 make[1]: * [Makefile:1212: prepare0] Error 2 make: *** [Makefile:220: __sub-make] Error 2 Possible warnings (5) .config:3566:warning: override: reassigning to symbol STANDALONE .config:3571:warning: override: reassigning to symbol PPC_DISABLE_WERROR .config:3573:warning: override: reassigning to symbol PREVENT_FIRMWARE_BUILD .config:3575:warning: override: reassigning to symbol GCC_PLUGINS .config:3577:warning: override: reassigning to symbol TRIM_UNUSED_KSYMS Full Log # git rev-parse -q --verify 3a34b13a88caeb2800ab44a4918f230041b37dd9^{commit} # git fetch -q -n -f git://fs.ozlabs.ibm.com/kernel/linus master # git rev-parse -q --verify 3a34b13a88caeb2800ab44a4918f230041b37dd9^{commit} 3a34b13a88caeb2800ab44a4918f230041b37dd9 # git checkout -q -f -B kisskb 3a34b13a88caeb2800ab44a4918f230041b37dd9 # git clean -qxdf # < git log -1 # commit 3a34b13a88caeb2800ab44a4918f230041b37dd9 # Author: Linus Torvalds <torvalds@linux-foundation.org> # Date: Fri Jul 30 15:42:34 2021 -0700 # # pipe: make pipe writes always wake up readers # # Since commit 1b6b26ae7053 ("pipe: fix and clarify pipe write wakeup # logic") we have sanitized the pipe write logic, and would only try to # wake up readers if they needed it. # # In particular, if the pipe already had data in it before the write, # there was no point in trying to wake up a reader, since any existing # readers must have been aware of the pre-existing data already. Doing # extraneous wakeups will only cause potential thundering herd problems. # # However, it turns out that some Android libraries have misused the EPOLL # interface, and expected "edge triggered" be to "any new write will # trigger it". Even if there was no edge in sight. # # Quoting Sandeep Patil: # "The commit 1b6b26ae7053 ('pipe: fix and clarify pipe write wakeup # logic') changed pipe write logic to wakeup readers only if the pipe # was empty at the time of write. However, there are libraries that # relied upon the older behavior for notification scheme similar to # what's described in [1] # # One such library 'realm-core'[2] is used by numerous Android # applications. The library uses a similar notification mechanism as GNU # Make but it never drains the pipe until it is full. When Android moved # to v5.10 kernel, all applications using this library stopped working. # # The library has since been fixed[3] but it will be a while before all # applications incorporate the updated library" # # Our regression rule for the kernel is that if applications break from # new behavior, it's a regression, even if it was because the application # did something patently wrong. Also note the original report [4] by # Michal Kerrisk about a test for this epoll behavior - but at that point # we didn't know of any actual broken use case. # # So add the extraneous wakeup, to approximate the old behavior. # # [ I say "approximate", because the exact old behavior was to do a wakeup # not for each write(), but for each pipe buffer chunk that was filled # in. The behavior introduced by this change is not that - this is just # "every write will cause a wakeup, whether necessary or not", which # seems to be sufficient for the broken library use. ] # # It's worth noting that this adds the extraneous wakeup only for the # write side, while the read side still considers the "edge" to be purely # about reading enough from the pipe to allow further writes. # # See commit f467a6a66419 ("pipe: fix and clarify pipe read wakeup logic") # for the pipe read case, which remains that "only wake up if the pipe was # full, and we read something from it". # # Link: https://lore.kernel.org/lkml/CAHk-=wjeG0q1vgzu4iJhW5juPkTsjTYmiqiMUYAebWW+0bam6w@mail.gmail.com/ [1] # Link: https://github.com/realm/realm-core [2] # Link: https://github.com/realm/realm-core/issues/4666 [3] # Link: https://lore.kernel.org/lkml/CAKgNAkjMBGeAwF=2MKK758BhxvW58wYTgYKB2V-gY1PwXxrH+Q@mail.gmail.com/ [4] # Link: https://lore.kernel.org/lkml/20210729222635.2937453-1-sspatil@android.com/ # Reported-by: Sandeep Patil <sspatil@android.com> # Cc: Michael Kerrisk <mtk.manpages@gmail.com> # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version # < git log --format=%s --max-count=1 3a34b13a88caeb2800ab44a4918f230041b37dd9 # < make -s -j 80 ARCH=powerpc O=/kisskb/build/linus-rand_powerpc-randconfig_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- randconfig # Added to kconfig CONFIG_STANDALONE=y # Added to kconfig CONFIG_BUILD_DOCSRC=n # Added to kconfig CONFIG_MODULE_SIG=n # Added to kconfig CONFIG_CPU_BIG_ENDIAN=y # Added to kconfig CONFIG_PPC64=y # Added to kconfig CONFIG_PPC_DISABLE_WERROR=y # Added to kconfig CONFIG_SECTION_MISMATCH_WARN_ONLY=y # Added to kconfig CONFIG_PREVENT_FIRMWARE_BUILD=y # Added to kconfig CONFIG_CC_STACKPROTECTOR_STRONG=n # Added to kconfig CONFIG_GCC_PLUGINS=n # Added to kconfig CONFIG_LD_HEAD_STUB_CATCH=y # Added to kconfig CONFIG_TRIM_UNUSED_KSYMS=n # Added to kconfig CONFIG_UBSAN=n # < make -s -j 80 ARCH=powerpc O=/kisskb/build/linus-rand_powerpc-randconfig_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- help # make -s -j 80 ARCH=powerpc O=/kisskb/build/linus-rand_powerpc-randconfig_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- olddefconfig .config:3566:warning: override: reassigning to symbol STANDALONE .config:3571:warning: override: reassigning to symbol PPC_DISABLE_WERROR .config:3573:warning: override: reassigning to symbol PREVENT_FIRMWARE_BUILD .config:3575:warning: override: reassigning to symbol GCC_PLUGINS .config:3577:warning: override: reassigning to symbol TRIM_UNUSED_KSYMS # make -s -j 80 ARCH=powerpc O=/kisskb/build/linus-rand_powerpc-randconfig_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- /kisskb/src/scripts/mod/empty.c:1: internal compiler error: Segmentation fault 1 \| /* empty file to figure out endianness / word size / \| Please submit a full bug report, with preprocessed source if appropriate. See <https://gcc.gnu.org/bugs/> for instructions. make[2]: [/kisskb/src/scripts/Makefile.build:271: scripts/mod/empty.o] Error 1 make[2]: * Waiting for unfinished jobs.... make[1]: * [/kisskb/src/Makefile:1212: prepare0] Error 2 make[1]: * Waiting for unfinished jobs.... make: *** [Makefile:220: __sub-make] Error 2 Command 'make -s -j 80 ARCH=powerpc O=/kisskb/build/linus-rand_powerpc-randconfig_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- ' returned non-zero exit status 2 # rm -rf /kisskb/build/linus-rand_powerpc-randconfig_powerpc-gcc9 # Build took: 0:00:24.085125

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