# git rev-parse -q --verify a9dce6679d736cb3d612af39bab9f31f8db66f9b^{commit}
# git fetch -q -n -f git://fs.ozlabs.ibm.com/kernel/linus master
error: The last gc run reported the following. Please correct the root cause
and remove .git/gc.log.
Automatic cleanup will not be performed until the file is removed.

warning: There are too many unreachable loose objects; run 'git prune' to remove them.

# git rev-parse -q --verify a9dce6679d736cb3d612af39bab9f31f8db66f9b^{commit}
a9dce6679d736cb3d612af39bab9f31f8db66f9b
# git checkout -q -f -B kisskb a9dce6679d736cb3d612af39bab9f31f8db66f9b
# git clean -qxdf
# < git log -1
# commit a9dce6679d736cb3d612af39bab9f31f8db66f9b
# Merge: f67e3fb48912 575a0ae9744d
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Sat Mar 16 13:47:14 2019 -0700
# 
#     Merge tag 'pidfd-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
#     
#     Pull pidfd system call from Christian Brauner:
#      "This introduces the ability to use file descriptors from /proc/<pid>/
#       as stable handles on struct pid. Even if a pid is recycled the handle
#       will not change. For a start these fds can be used to send signals to
#       the processes they refer to.
#     
#       With the ability to use /proc/<pid> fds as stable handles on struct
#       pid we can fix a long-standing issue where after a process has exited
#       its pid can be reused by another process. If a caller sends a signal
#       to a reused pid it will end up signaling the wrong process.
#     
#       With this patchset we enable a variety of use cases. One obvious
#       example is that we can now safely delegate an important part of
#       process management - sending signals - to processes other than the
#       parent of a given process by sending file descriptors around via scm
#       rights and not fearing that the given process will have been recycled
#       in the meantime. It also allows for easy testing whether a given
#       process is still alive or not by sending signal 0 to a pidfd which is
#       quite handy.
#     
#       There has been some interest in this feature e.g. from systems
#       management (systemd, glibc) and container managers. I have requested
#       and gotten comments from glibc to make sure that this syscall is
#       suitable for their needs as well. In the future I expect it to take on
#       most other pid-based signal syscalls. But such features are left for
#       the future once they are needed.
#     
#       This has been sitting in linux-next for quite a while and has not
#       caused any issues. It comes with selftests which verify basic
#       functionality and also test that a recycled pid cannot be signaled via
#       a pidfd.
#     
#       Jon has written about a prior version of this patchset. It should
#       cover the basic functionality since not a lot has changed since then:
#     
#           https://lwn.net/Articles/773459/
#     
#       The commit message for the syscall itself is extensively documenting
#       the syscall, including it's functionality and extensibility"
#     
#     * tag 'pidfd-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
#       selftests: add tests for pidfd_send_signal()
#       signal: add pidfd_send_signal() syscall
# < /opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 a9dce6679d736cb3d612af39bab9f31f8db66f9b
# < make -s -j 80 ARCH=um O=/kisskb/build/linus_um-allmodconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 allmodconfig
# 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
# yes \n | make -s -j 80 ARCH=um O=/kisskb/build/linus_um-allmodconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 oldconfig
yes: standard output: Broken pipe
# make -s -j 80 ARCH=um O=/kisskb/build/linus_um-allmodconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 
/kisskb/src/arch/um/kernel/skas/uaccess.c: In function 'do_op_one_page':
/kisskb/src/arch/um/kernel/skas/uaccess.c:62:10: warning: unused variable 'buf' [-Wunused-variable]
  jmp_buf buf;
          ^
/kisskb/src/arch/um/os-Linux/umid.c: In function 'is_umdir_used':
/kisskb/src/arch/um/os-Linux/umid.c:138:2: warning: ISO C90 forbids variable length array 'file' [-Wvla]
  char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
  ^
/kisskb/src/arch/um/os-Linux/umid.c: In function 'create_pid_file':
/kisskb/src/arch/um/os-Linux/umid.c:213:2: warning: ISO C90 forbids variable length array 'file' [-Wvla]
  char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
  ^
/kisskb/src/arch/um/os-Linux/umid.c: In function 'remove_umid_dir':
/kisskb/src/arch/um/os-Linux/umid.c:388:2: warning: ISO C90 forbids variable length array 'dir' [-Wvla]
  char dir[strlen(uml_dir) + UMID_LEN + 1], err;
  ^
/kisskb/src/security/apparmor/policy_unpack.c: In function 'unpack_trans_table':
/kisskb/src/security/apparmor/policy_unpack.c:496:9: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
      str[pos] = ':';
         ^
/kisskb/src/mm/mprotect.c: In function 'change_pte_range':
/kisskb/src/mm/mprotect.c:42:20: warning: unused variable 'mm' [-Wunused-variable]
  struct mm_struct *mm = vma->vm_mm;
                    ^
/kisskb/src/drivers/i2c/i2c-core-base.c: In function 'i2c_generic_scl_recovery':
/kisskb/src/drivers/i2c/i2c-core-base.c:235:5: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
  if (ret == -EOPNOTSUPP)
     ^
/kisskb/src/lib/lz4/lz4hc_compress.c: In function 'LZ4HC_compress_generic':
/kisskb/src/lib/lz4/lz4hc_compress.c:579:1: warning: the frame size of 2144 bytes is larger than 2048 bytes [-Wframe-larger-than=]
 }
 ^
/kisskb/src/net/sunrpc/xprtsock.c: In function 'xs_read_stream_request.constprop':
/kisskb/src/net/sunrpc/xprtsock.c:529:9: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return ret < 0 ? ret : read;
         ^
/kisskb/src/net/sunrpc/xprtsock.c:525:10: warning: 'read' may be used uninitialized in this function [-Wmaybe-uninitialized]
   return read;
          ^
  LINK linux
Completed OK
# rm -rf /kisskb/build/linus_um-allmodconfig_um-x86_64
# Build took: 0:05:03.808670