Buildresult: linus-rand/mips-allnoconfig/mips-gcc13 built on Jul 25 2023, 13:13

kisskb

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Status:	OK
Date/Time:	Jul 25 2023, 13:13
Duration:	0:00:50.838165
Builder:	blade4b
Revision:	file: always lock position for FMODE_ATOMIC_POS (`20ea1e7d13c1b544fe67c4a8dc3943bb1ab33e6f)`
Target:	linus-rand/mips-allnoconfig/mips-gcc13
Branch:	linus-rand
Compiler:	mips-gcc13 (mips-linux-gcc (GCC) 13.1.0 / GNU ld (GNU Binutils) 2.40)
Config:	allnoconfig (download)
Log:	Download original No warnings found in log. Full Log # git rev-parse -q --verify 20ea1e7d13c1b544fe67c4a8dc3943bb1ab33e6f^{commit} # git fetch -q -n -f git://fs.ozlabs.ibm.com/kernel/linus master # git rev-parse -q --verify 20ea1e7d13c1b544fe67c4a8dc3943bb1ab33e6f^{commit} 20ea1e7d13c1b544fe67c4a8dc3943bb1ab33e6f # git checkout -q -f -B kisskb 20ea1e7d13c1b544fe67c4a8dc3943bb1ab33e6f # git clean -qxdf # < git log -1 # commit 20ea1e7d13c1b544fe67c4a8dc3943bb1ab33e6f # Author: Christian Brauner <brauner@kernel.org> # Date: Mon Jul 24 17:00:49 2023 +0200 # # file: always lock position for FMODE_ATOMIC_POS # # The pidfd_getfd() system call allows a caller with ptrace_may_access() # abilities on another process to steal a file descriptor from this # process. This system call is used by debuggers, container runtimes, # system call supervisors, networking proxies etc. So while it is a # special interest system call it is used in common tools. # # That ability ends up breaking our long-time optimization in fdget_pos(), # which "knew" that if we had exclusive access to the file descriptor # nobody else could access it, and we didn't need the lock for the file # position. # # That check for file_count(file) was always fairly subtle - it depended # on __fdget() not incrementing the file count for single-threaded # processes and thus included that as part of the rule - but it did mean # that we didn't need to take the lock in all those traditional unix # process contexts. # # So it's sad to see this go, and I'd love to have some way to re-instate # the optimization. At the same time, the lock obviously isn't ever # contended in the case we optimized, so all we were optimizing away is # the atomics and the cacheline dirtying. Let's see if anybody even # notices that the optimization is gone. # # Link: https://lore.kernel.org/linux-fsdevel/20230724-vfs-fdget_pos-v1-1-a4abfd7103f3@kernel.org/ # Fixes: 8649c322f75c ("pid: Implement pidfd_getfd syscall") # Cc: stable@kernel.org # Signed-off-by: Christian Brauner <brauner@kernel.org> # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/korg/gcc-13.1.0-nolibc/mips-linux/bin/mips-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-13.1.0-nolibc/mips-linux/bin/mips-linux-ld --version # < git log --format=%s --max-count=1 20ea1e7d13c1b544fe67c4a8dc3943bb1ab33e6f # make -s -j 24 ARCH=mips O=/kisskb/build/linus-rand_allnoconfig_mips-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/mips-linux/bin/mips-linux- allnoconfig # < make -s -j 24 ARCH=mips O=/kisskb/build/linus-rand_allnoconfig_mips-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/mips-linux/bin/mips-linux- help # make -s -j 24 ARCH=mips O=/kisskb/build/linus-rand_allnoconfig_mips-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/mips-linux/bin/mips-linux- olddefconfig # make -s -j 24 ARCH=mips O=/kisskb/build/linus-rand_allnoconfig_mips-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/mips-linux/bin/mips-linux- Completed OK # rm -rf /kisskb/build/linus-rand_allnoconfig_mips-gcc13 # Build took: 0:00:50.838165

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