Buildresult: linus/i386-allnoconfig/i386-gcc4.6 built on Jan 7 2019, 11:12

kisskb

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Status:	OK
Date/Time:	Jan 7 2019, 11:12
Duration:	0:00:15.894168
Builder:	ka4
Revision:	Change mincore() to count "mapped" pages rather than "cached" pages (`574823bfab82d9d8fa47f422778043fbb4b4f50e)`
Target:	linus/i386-allnoconfig/i386-gcc4.6
Branch:	linus
Compiler:	i386-gcc4.6 (i386-linux-gcc (GCC) 4.6.3 / GNU ld (GNU Binutils) 2.22)
Config:	allnoconfig (download)
Log:	Download original Possible warnings (2) kernel/printk/printk.c:186:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized] arch/x86/kernel/e820.c:650:16: warning: 'gapstart' may be used uninitialized in this function [-Wuninitialized] Full Log # 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 <torvalds@linux-foundation.org> # 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 <kevin@guarana.org> # Cc: Jiri Kosina <jikos@kernel.org> # Cc: Masatake YAMATO <yamato@redhat.com> # Cc: Andrew Morton <akpm@linux-foundation.org> # Cc: Greg KH <gregkh@linuxfoundation.org> # Cc: Peter Zijlstra <peterz@infradead.org> # Cc: Michal Hocko <mhocko@suse.com> # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux-gcc --version # < /opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux-ld --version # < git log --format=%s --max-count=1 574823bfab82d9d8fa47f422778043fbb4b4f50e # < make -s -j 10 ARCH=i386 O=/kisskb/build/linus_i386-allnoconfig_i386 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux- allnoconfig # make -s -j 10 ARCH=i386 O=/kisskb/build/linus_i386-allnoconfig_i386 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux- /kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl': /kisskb/src/kernel/printk/printk.c:186:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/arch/x86/kernel/e820.c: In function 'e820__setup_pci_gap': /kisskb/src/arch/x86/kernel/e820.c:650:16: warning: 'gapstart' may be used uninitialized in this function [-Wuninitialized] Completed OK # rm -rf /kisskb/build/linus_i386-allnoconfig_i386 # Build took: 0:00:15.894168

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