Buildresult: linus/x86_64-defconfig/x86_64-gcc8 built on Jul 6 2023, 04:06

kisskb

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Status:	OK
Date/Time:	Jul 6 2023, 04:06
Duration:	0:05:16.850479
Builder:	ka7
Revision:	gup: make the stack expansion warning a bit more targeted (`6cd06ab12d1afdab3847e7981f301bd0404aaa5c)`
Target:	linus/x86_64-defconfig/x86_64-gcc8
Branch:	linus
Compiler:	x86_64-gcc8 (x86_64-linux-gcc (GCC) 8.5.0 / GNU ld (GNU Binutils) 2.36.1)
Config:	defconfig (download)
Log:	Download original No warnings found in log. Full Log # git gc Expanding reachable commits in commit graph: 91413 Expanding reachable commits in commit graph: 193856 Expanding reachable commits in commit graph: 297161 Expanding reachable commits in commit graph: 408828 Expanding reachable commits in commit graph: 523516 Expanding reachable commits in commit graph: 628640 Expanding reachable commits in commit graph: 748009 Expanding reachable commits in commit graph: 872304 Expanding reachable commits in commit graph: 1000121 Expanding reachable commits in commit graph: 1103772 Expanding reachable commits in commit graph: 1200517, done. Writing out commit graph in 4 passes: 60% (2928955/4802068) Writing out commit graph in 4 passes: 61% (2929262/4802068) Writing out commit graph in 4 passes: 62% (2977283/4802068) Writing out commit graph in 4 passes: 63% (3025303/4802068) Writing out commit graph in 4 passes: 64% (3073324/4802068) Writing out commit graph in 4 passes: 65% (3121345/4802068) Writing out commit graph in 4 passes: 66% (3169365/4802068) Writing out commit graph in 4 passes: 67% (3217386/4802068) Writing out commit graph in 4 passes: 68% (3265407/4802068) Writing out commit graph in 4 passes: 69% (3313427/4802068) Writing out commit graph in 4 passes: 70% (3361448/4802068) Writing out commit graph in 4 passes: 71% (3409469/4802068) Writing out commit graph in 4 passes: 72% (3457489/4802068) Writing out commit graph in 4 passes: 73% (3505510/4802068) Writing out commit graph in 4 passes: 73% (3550327/4802068) Writing out commit graph in 4 passes: 74% (3553531/4802068) Writing out commit graph in 4 passes: 75% (3601551/4802068) Writing out commit graph in 4 passes: 76% (3649572/4802068) Writing out commit graph in 4 passes: 77% (3697593/4802068) Writing out commit graph in 4 passes: 78% (3745614/4802068) Writing out commit graph in 4 passes: 79% (3793634/4802068) Writing out commit graph in 4 passes: 80% (3841655/4802068) Writing out commit graph in 4 passes: 81% (3889676/4802068) Writing out commit graph in 4 passes: 82% (3937696/4802068) Writing out commit graph in 4 passes: 83% (3985717/4802068) Writing out commit graph in 4 passes: 84% (4033738/4802068) Writing out commit graph in 4 passes: 85% (4081758/4802068) Writing out commit graph in 4 passes: 86% (4129779/4802068) Writing out commit graph in 4 passes: 87% (4177800/4802068) Writing out commit graph in 4 passes: 88% (4225820/4802068) Writing out commit graph in 4 passes: 89% (4273841/4802068) Writing out commit graph in 4 passes: 90% (4321862/4802068) Writing out commit graph in 4 passes: 91% (4369882/4802068) Writing out commit graph in 4 passes: 92% (4417903/4802068) Writing out commit graph in 4 passes: 93% (4465924/4802068) Writing out commit graph in 4 passes: 94% (4513944/4802068) Writing out commit graph in 4 passes: 95% (4561965/4802068) Writing out commit graph in 4 passes: 96% (4609986/4802068) Writing out commit graph in 4 passes: 97% (4658006/4802068) Writing out commit graph in 4 passes: 98% (4706027/4802068) Writing out commit graph in 4 passes: 99% (4754048/4802068) Writing out commit graph in 4 passes: 100% (4802068/4802068) Writing out commit graph in 4 passes: 100% (4802068/4802068), done. # git rev-parse -q --verify 6cd06ab12d1afdab3847e7981f301bd0404aaa5c^{commit} # git fetch -q -n -f git://fs.ozlabs.ibm.com/kernel/linus master # git rev-parse -q --verify 6cd06ab12d1afdab3847e7981f301bd0404aaa5c^{commit} 6cd06ab12d1afdab3847e7981f301bd0404aaa5c # git checkout -q -f -B kisskb 6cd06ab12d1afdab3847e7981f301bd0404aaa5c # git clean -qxdf # < git log -1 # commit 6cd06ab12d1afdab3847e7981f301bd0404aaa5c # Author: Linus Torvalds <torvalds@linux-foundation.org> # Date: Wed Jul 5 09:33:31 2023 -0700 # # gup: make the stack expansion warning a bit more targeted # # I added a warning about about GUP no longer expanding the stack in # commit a425ac5365f6 ("gup: add warning if some caller would seem to want # stack expansion"), but didn't really expect anybody to hit it. # # And it's true that nobody seems to have hit a _real_ case yet, but we # certainly have a number of reports of false positives. Which not only # causes extra noise in itself, but might also end up hiding any real # cases if they do exist. # # So let's tighten up the warning condition, and replace the simplistic # # vma = find_vma(mm, start); # if (vma && (start < vma->vm_start)) { # WARN_ON_ONCE(vma->vm_flags & VM_GROWSDOWN); # # with a # # vma = gup_vma_lookup(mm, start); # # helper function which works otherwise like just "vma_lookup()", but with # some heuristics for when to warn about gup no longer causing stack # expansion. # # In particular, don't just warn for "below the stack", but warn if it's # _just_ below the stack (with "just below" arbitrarily defined as 64kB, # because why not?). And rate-limit it to at most once per hour, which # means that any false positives shouldn't completely hide subsequent # reports, but we won't be flooding the logs about it either. # # The previous code triggered when some GUP user (chromium crashpad) # accessing past the end of the previous vma, for example. That has never # expanded the stack, it just causes GUP to return early, and as such we # shouldn't be warning about it. # # This is still going trigger the randomized testers, but to mitigate the # noise from that, use "dump_stack()" instead of "WARN_ON_ONCE()" to get # the kernel call chain. We'll get the relevant information, but syzbot # shouldn't get too upset about it. # # Also, don't even bother with the GROWSUP case, which would be using # different heuristics entirely, but only happens on parisc. # # Reported-by: kernel test robot <oliver.sang@intel.com> # Reported-by: John Hubbard <jhubbard@nvidia.com> # Reported-by: syzbot+6cf44e127903fdf9d929@syzkaller.appspotmail.com # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux-ld --version # < git log --format=%s --max-count=1 6cd06ab12d1afdab3847e7981f301bd0404aaa5c # make -s -j 32 ARCH=x86 O=/kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux- x86_64_defconfig # < make -s -j 32 ARCH=x86 O=/kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux- help # make -s -j 32 ARCH=x86 O=/kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux- olddefconfig # make -s -j 32 ARCH=x86 O=/kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux- Completed OK # rm -rf /kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 # Build took: 0:05:16.850479

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