# git rev-parse -q --verify 2f87d0916ce0d2925cedbc9e8f5d6291ba2ac7b2^{commit}
# git fetch -q -n -f git://fs.ozlabs.ibm.com/kernel/linus master
# git rev-parse -q --verify 2f87d0916ce0d2925cedbc9e8f5d6291ba2ac7b2^{commit}
2f87d0916ce0d2925cedbc9e8f5d6291ba2ac7b2
# git checkout -q -f -B kisskb 2f87d0916ce0d2925cedbc9e8f5d6291ba2ac7b2
# git clean -qxdf
# < git log -1
# commit 2f87d0916ce0d2925cedbc9e8f5d6291ba2ac7b2
# Merge: bdc727651223 09661f75e75c
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Tue Oct 15 11:18:44 2024 -0700
# 
#     Merge tag 'trace-ringbuffer-v6.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
#     
#     Pull ring-buffer fixes from Steven Rostedt:
#     
#      - Fix ref counter of buffers assigned at boot up
#     
#        A tracing instance can be created from the kernel command line. If it
#        maps to memory, it is considered permanent and should not be deleted,
#        or bad things can happen. If it is not mapped to memory, then the
#        user is fine to delete it via rmdir from the instances directory. But
#        the ref counts assumed 0 was free to remove and greater than zero was
#        not. But this was not the case. When an instance is created, it
#        should have the reference of 1, and if it should not be removed, it
#        must be greater than 1. The boot up code set normal instances with a
#        ref count of 0, which could get removed if something accessed it and
#        then released it. And memory mapped instances had a ref count of 1
#        which meant it could be deleted, and bad things happen. Keep normal
#        instances ref count as 1, and set memory mapped instances ref count
#        to 2.
#     
#      - Protect sub buffer size (order) updates from other modifications
#     
#        When a ring buffer is changing the size of its sub-buffers, no other
#        operations should be performed on the ring buffer. That includes
#        reading it. But the locking only grabbed the buffer->mutex that keeps
#        some operations from touching the ring buffer. It also must hold the
#        cpu_buffer->reader_lock as well when updates happen as other paths
#        use that to do some operations on the ring buffer.
#     
#     * tag 'trace-ringbuffer-v6.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
#       ring-buffer: Fix reader locking when changing the sub buffer order
#       ring-buffer: Fix refcount setting of boot mapped buffers
# < /opt/cross/kisskb/korg/gcc-13.1.0-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-13.1.0-nolibc/x86_64-linux/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 2f87d0916ce0d2925cedbc9e8f5d6291ba2ac7b2
# make -s -j 40 ARCH=x86_64 O=/kisskb/build/linus_defconfig_x86_64-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/x86_64-linux/bin/x86_64-linux-  defconfig
# < make -s -j 40 ARCH=x86_64 O=/kisskb/build/linus_defconfig_x86_64-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/x86_64-linux/bin/x86_64-linux-  help
# make -s -j 40 ARCH=x86_64 O=/kisskb/build/linus_defconfig_x86_64-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/x86_64-linux/bin/x86_64-linux-  olddefconfig
# make -s -j 40 ARCH=x86_64 O=/kisskb/build/linus_defconfig_x86_64-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/x86_64-linux/bin/x86_64-linux-  
Completed OK
# rm -rf /kisskb/build/linus_defconfig_x86_64-gcc13
# Build took: 0:01:46.144420