Buildresult: linus/i386-allnoconfig/i386-gcc4.6 built on Aug 2 2018, 08:53

kisskb

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Status:	OK
Date/Time:	Aug 2 2018, 08:53
Duration:	0:00:19.312379
Builder:	ka4
Revision:	mm: do not initialize TLB stack vma's with vma_init() (`8b11ec1b5ffb54f71cb5a5e5c8c4d36e5d113085)`
Target:	linus/i386-allnoconfig/i386-gcc4.6
Branch:	linus
Compiler:	i386-gcc4.6 (i386-linux-gcc (GCC) 4.6.3)
Config:	allnoconfig (download)
Log:	Download original Possible warnings (2) kernel/printk/printk.c:183:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized] arch/x86/kernel/e820.c:651:16: warning: 'gapstart' may be used uninitialized in this function [-Wuninitialized] Full Log # git rev-parse -q --verify 8b11ec1b5ffb54f71cb5a5e5c8c4d36e5d113085^{commit} 8b11ec1b5ffb54f71cb5a5e5c8c4d36e5d113085 already have revision, skipping fetch # git checkout -q -f -B kisskb 8b11ec1b5ffb54f71cb5a5e5c8c4d36e5d113085 # git clean -qxdf # < git log -1 # commit 8b11ec1b5ffb54f71cb5a5e5c8c4d36e5d113085 # Author: Linus Torvalds <torvalds@linux-foundation.org> # Date: Wed Aug 1 13:43:38 2018 -0700 # # mm: do not initialize TLB stack vma's with vma_init() # # Commit 2c4541e24c55 ("mm: use vma_init() to initialize VMAs on stack and # data segments") tried to initialize various left-over ad-hoc vma's # "properly", but actually made things worse for the temporary vma's used # for TLB flushing. # # vma_init() doesn't actually initialize all of the vma, just a few # fields, so doing something like # # - struct vm_area_struct vma = { .vm_mm = tlb->mm, }; # + struct vm_area_struct vma; # + # + vma_init(&vma, tlb->mm); # # was actually very bad: instead of having a nicely initialized vma with # every field but "vm_mm" zeroed, you'd have an entirely uninitialized vma # with only a couple of fields initialized. And they weren't even fields # that the code in question mostly cared about. # # The flush_tlb_range() function takes a "struct vma" rather than a # "struct mm_struct", because a few architectures actually care about what # kind of range it is - being able to only do an ITLB flush if it's a # range that doesn't have data accesses enabled, for example. And all the # normal users already have the vma for doing the range invalidation. # # But a few people want to call flush_tlb_range() with a range they just # made up, so they also end up using a made-up vma. x86 just has a # special "flush_tlb_mm_range()" function for this, but other # architectures (arm and ia64) do the "use fake vma" thing instead, and # thus got caught up in the vma_init() changes. # # At the same time, the TLB flushing code really doesn't care about most # other fields in the vma, so vma_init() is just unnecessary and # pointless. # # This fixes things by having an explicit "this is just an initializer for # the TLB flush" initializer macro, which is used by the arm/arm64/ia64 # people who mis-use this interface with just a dummy vma. # # Fixes: 2c4541e24c55 ("mm: use vma_init() to initialize VMAs on stack and data segments") # Cc: Dmitry Vyukov <dvyukov@google.com> # Cc: Oleg Nesterov <oleg@redhat.com> # Cc: Andrea Arcangeli <aarcange@redhat.com> # Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> # Cc: Andrew Morton <akpm@linux-foundation.org> # Cc: John Stultz <john.stultz@linaro.org> # Cc: Hugh Dickins <hughd@google.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 # < git log --format=%s --max-count=1 8b11ec1b5ffb54f71cb5a5e5c8c4d36e5d113085 # < 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:183:16: 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:651:16: warning: 'gapstart' may be used uninitialized in this function [-Wuninitialized] Completed OK # rm -rf /kisskb/build/linus_i386-allnoconfig_i386 # Build took: 0:00:19.312379

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