# git rev-parse -q --verify 574823bfab82d9d8fa47f422778043fbb4b4f50e^{commit} 574823bfab82d9d8fa47f422778043fbb4b4f50e already have revision, skipping fetch # git checkout -q -f -B kisskb 574823bfab82d9d8fa47f422778043fbb4b4f50e # git clean -qxdf # < git log -1 # commit 574823bfab82d9d8fa47f422778043fbb4b4f50e # Author: Linus Torvalds # Date: Sat Jan 5 17:50:59 2019 -0800 # # Change mincore() to count "mapped" pages rather than "cached" pages # # The semantics of what "in core" means for the mincore() system call are # somewhat unclear, but Linux has always (since 2.3.52, which is when # mincore() was initially done) treated it as "page is available in page # cache" rather than "page is mapped in the mapping". # # The problem with that traditional semantic is that it exposes a lot of # system cache state that it really probably shouldn't, and that users # shouldn't really even care about. # # So let's try to avoid that information leak by simply changing the # semantics to be that mincore() counts actual mapped pages, not pages # that might be cheaply mapped if they were faulted (note the "might be" # part of the old semantics: being in the cache doesn't actually guarantee # that you can access them without IO anyway, since things like network # filesystems may have to revalidate the cache before use). # # In many ways the old semantics were somewhat insane even aside from the # information leak issue. From the very beginning (and that beginning is # a long time ago: 2.3.52 was released in March 2000, I think), the code # had a comment saying # # Later we can get more picky about what "in core" means precisely. # # and this is that "later". Admittedly it is much later than is really # comfortable. # # NOTE! This is a real semantic change, and it is for example known to # change the output of "fincore", since that program literally does a # mmmap without populating it, and then doing "mincore()" on that mapping # that doesn't actually have any pages in it. # # I'm hoping that nobody actually has any workflow that cares, and the # info leak is real. # # We may have to do something different if it turns out that people have # valid reasons to want the old semantics, and if we can limit the # information leak sanely. # # Cc: Kevin Easton # Cc: Jiri Kosina # Cc: Masatake YAMATO # Cc: Andrew Morton # Cc: Greg KH # Cc: Peter Zijlstra # Cc: Michal Hocko # Signed-off-by: Linus Torvalds # < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version # < git log --format=%s --max-count=1 574823bfab82d9d8fa47f422778043fbb4b4f50e # < make -s -j 120 ARCH=powerpc O=/kisskb/build/linus-rand_powerpc-randconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- randconfig KCONFIG_SEED=0x11896AE0 # 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 # yes \n | make -s -j 120 ARCH=powerpc O=/kisskb/build/linus-rand_powerpc-randconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- oldconfig yes: standard output: Broken pipe # make -s -j 120 ARCH=powerpc O=/kisskb/build/linus-rand_powerpc-randconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- /kisskb/src/arch/powerpc/kernel/exceptions-64e.S: Assembler messages: /kisskb/src/arch/powerpc/kernel/exceptions-64e.S:587: Error: unrecognized opcode: `mc_btb_flush' make[3]: *** [/kisskb/src/scripts/Makefile.build:367: arch/powerpc/kernel/exceptions-64e.o] Error 1 make[3]: *** Waiting for unfinished jobs.... make[2]: *** [/kisskb/src/scripts/Makefile.build:492: arch/powerpc/kernel] Error 2 make[1]: *** [/kisskb/src/Makefile:1049: arch/powerpc] Error 2 make[1]: *** Waiting for unfinished jobs.... In file included from /kisskb/src/drivers/net/ethernet/aurora/nb8800.c:40:0: /kisskb/src/drivers/net/ethernet/aurora/nb8800.h:92:0: warning: "TCR_DIE" redefined #define TCR_DIE BIT(7) ^ In file included from /kisskb/src/arch/powerpc/include/asm/reg.h:21:0, from /kisskb/src/arch/powerpc/include/asm/processor.h:13, from /kisskb/src/arch/powerpc/include/asm/thread_info.h:28, from /kisskb/src/include/linux/thread_info.h:38, from /kisskb/src/include/asm-generic/preempt.h:5, from ./arch/powerpc/include/generated/asm/preempt.h:1, from /kisskb/src/include/linux/preempt.h:78, from /kisskb/src/include/linux/spinlock.h:51, from /kisskb/src/include/linux/seqlock.h:36, from /kisskb/src/include/linux/time.h:6, from /kisskb/src/include/linux/stat.h:19, from /kisskb/src/include/linux/module.h:10, from /kisskb/src/drivers/net/ethernet/aurora/nb8800.c:23: /kisskb/src/arch/powerpc/include/asm/reg_booke.h:554:0: note: this is the location of the previous definition #define TCR_DIE TCR_PIE /* DEC Interrupt Enable */ ^ make: *** [Makefile:152: sub-make] Error 2 Command 'make -s -j 120 ARCH=powerpc O=/kisskb/build/linus-rand_powerpc-randconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- ' returned non-zero exit status 2 # rm -rf /kisskb/build/linus-rand_powerpc-randconfig_powerpc-gcc5 # Build took: 0:00:49.326281