Buildresult: linus/um-allyesconfig/um-x86_64-gcc12 built on Jul 6 2023, 05:58

kisskb

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Status:	OK
Date/Time:	Jul 6 2023, 05:58
Duration:	0:17:03.383638
Builder:	ka7
Revision:	gup: make the stack expansion warning a bit more targeted (`6cd06ab12d1afdab3847e7981f301bd0404aaa5c)`
Target:	linus/um-allyesconfig/um-x86_64-gcc12
Branch:	linus
Compiler:	um-x86_64-gcc12 (x86_64-linux-gcc.br_real (Buildroot 2021.11-4428-g6b6741b) 12.2.0 / GNU ld (GNU Binutils) 2.39)
Config:	allyesconfig (download)
Log:	Download original Possible warnings (4) .config:12997:warning: override: reassigning to symbol GCC_PLUGIN_LATENT_ENTROPY .config:13001:warning: override: reassigning to symbol UML_NET_ETHERTAP .config:13003:warning: override: reassigning to symbol UML_NET_SLIP .config:13008:warning: override: reassigning to symbol UML_NET_SLIRP Full Log # git rev-parse -q --verify 6cd06ab12d1afdab3847e7981f301bd0404aaa5c^{commit} 6cd06ab12d1afdab3847e7981f301bd0404aaa5c already have revision, skipping fetch # 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/x86-64--glibc--bleeding-edge-2022.08-1/bin/x86_64-linux-gcc --version # < /opt/cross/kisskb/x86-64--glibc--bleeding-edge-2022.08-1/bin/x86_64-linux-ld --version # < git log --format=%s --max-count=1 6cd06ab12d1afdab3847e7981f301bd0404aaa5c # make -s -j 32 ARCH=um O=/kisskb/build/linus_allyesconfig_um-x86_64-gcc12 CROSS_COMPILE=/opt/cross/kisskb/x86-64--glibc--bleeding-edge-2022.08-1/bin/x86_64-linux- SUBARCH=x86_64 allyesconfig # Added to kconfig CONFIG_STANDALONE=y # Added to kconfig CONFIG_KCOV=n # Added to kconfig CONFIG_GCC_PLUGINS=n # Added to kconfig CONFIG_GCC_PLUGIN_CYC_COMPLEXITY=n # Added to kconfig CONFIG_GCC_PLUGIN_SANCOV=n # Added to kconfig CONFIG_GCC_PLUGIN_LATENT_ENTROPY=n # Added to kconfig CONFIG_GCC_PLUGIN_STRUCTLEAK=n # Added to kconfig CONFIG_GCC_PLUGIN_RANDSTRUCT=n # Added to kconfig CONFIG_UML_NET=n # Added to kconfig CONFIG_UML_NET_ETHERTAP=n # Added to kconfig CONFIG_UML_NET_TUNTAP=n # Added to kconfig CONFIG_UML_NET_SLIP=n # Added to kconfig CONFIG_UML_NET_DAEMON=n # Added to kconfig CONFIG_UML_NET_VDE=n # Added to kconfig CONFIG_UML_NET_MCAST=n # Added to kconfig CONFIG_UML_NET_PCAP=n # Added to kconfig CONFIG_UML_NET_SLIRP=n # Added to kconfig CONFIG_GCOV_KERNEL=n # Added to kconfig CONFIG_DEBUG_INFO_BTF=n # Added to kconfig CONFIG_BPF_PRELOAD=n # Added to kconfig CONFIG_SPI_STM32_QSPI=n # < make -s -j 32 ARCH=um O=/kisskb/build/linus_allyesconfig_um-x86_64-gcc12 CROSS_COMPILE=/opt/cross/kisskb/x86-64--glibc--bleeding-edge-2022.08-1/bin/x86_64-linux- SUBARCH=x86_64 help # make -s -j 32 ARCH=um O=/kisskb/build/linus_allyesconfig_um-x86_64-gcc12 CROSS_COMPILE=/opt/cross/kisskb/x86-64--glibc--bleeding-edge-2022.08-1/bin/x86_64-linux- SUBARCH=x86_64 olddefconfig .config:12997:warning: override: reassigning to symbol GCC_PLUGIN_LATENT_ENTROPY .config:13001:warning: override: reassigning to symbol UML_NET_ETHERTAP .config:13003:warning: override: reassigning to symbol UML_NET_SLIP .config:13008:warning: override: reassigning to symbol UML_NET_SLIRP # make -s -j 32 ARCH=um O=/kisskb/build/linus_allyesconfig_um-x86_64-gcc12 CROSS_COMPILE=/opt/cross/kisskb/x86-64--glibc--bleeding-edge-2022.08-1/bin/x86_64-linux- SUBARCH=x86_64 LINK linux Completed OK # rm -rf /kisskb/build/linus_allyesconfig_um-x86_64-gcc12 # Build took: 0:17:03.383638

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