# git rev-parse -q --verify 2accfdb7eff65f390c4308b0e9cb7c3fe48ad63c^{commit}
# git fetch -q -n -f git://fs.ozlabs.ibm.com/kernel/linus master
# git rev-parse -q --verify 2accfdb7eff65f390c4308b0e9cb7c3fe48ad63c^{commit}
2accfdb7eff65f390c4308b0e9cb7c3fe48ad63c
# git checkout -q -f -B kisskb 2accfdb7eff65f390c4308b0e9cb7c3fe48ad63c
# git clean -qxdf
# < git log -1
# commit 2accfdb7eff65f390c4308b0e9cb7c3fe48ad63c
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Mon Jul 29 10:58:28 2024 -0700
# 
#     profiling: attempt to remove per-cpu profile flip buffer
#     
#     This is the really old legacy kernel profiling code, which has long
#     since been obviated by "real profiling" (ie 'prof' and company), and
#     mainly remains as a source of syzbot reports.
#     
#     There are anecdotal reports that people still use it for boot-time
#     profiling, but it's unlikely that such use would care about the old NUMA
#     optimizations in this code from 2004 (commit ad02973d42: "profile: 512x
#     Altix timer interrupt livelock fix" in the BK import archive at [1])
#     
#     So in order to head off future syzbot reports, let's try to simplify
#     this code and get rid of the per-cpu profile buffers that are quite a
#     large portion of the complexity footprint of this thing (including CPU
#     hotplug callbacks etc).
#     
#     It's unlikely anybody will actually notice, or possibly, as Thomas put
#     it: "Only people who indulge in nostalgia will notice :)".
#     
#     That said, if it turns out that this code is actually actively used by
#     somebody, we can always revert this removal.  Thus the "attempt" in the
#     summary line.
#     
#     [ Note: in a small nod to "the profiling code can cause NUMA problems",
#       this also removes the "increment the last entry in the profiling array
#       on any unknown hits" logic. That would account any program counter in
#       a module to that single counter location, and might exacerbate any
#       NUMA cacheline bouncing issues ]
#     
#     Link: https://lore.kernel.org/all/CAHk-=wgs52BxT4Zjmjz8aNvHWKxf5_ThBY4bYL1Y6CTaNL2dTw@mail.gmail.com/
#     Link:  https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git [1]
#     Cc: Thomas Gleixner <tglx@linutronix.de>
#     Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-13.1.0-nolibc/sparc64-linux/bin/sparc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-13.1.0-nolibc/sparc64-linux/bin/sparc64-linux-ld --version
# < git log --format=%s --max-count=1 2accfdb7eff65f390c4308b0e9cb7c3fe48ad63c
# make -s -j 24 ARCH=sparc64 O=/kisskb/build/linus_allmodconfig_sparc64-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/sparc64-linux/bin/sparc64-linux-  allmodconfig
# < make -s -j 24 ARCH=sparc64 O=/kisskb/build/linus_allmodconfig_sparc64-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/sparc64-linux/bin/sparc64-linux-  help
# make -s -j 24 ARCH=sparc64 O=/kisskb/build/linus_allmodconfig_sparc64-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/sparc64-linux/bin/sparc64-linux-  olddefconfig
# make -s -j 24 ARCH=sparc64 O=/kisskb/build/linus_allmodconfig_sparc64-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/sparc64-linux/bin/sparc64-linux-  
<stdin>:1519:2: warning: #warning syscall clone3 not implemented [-Wcpp]
/kisskb/src/arch/sparc/vdso/vclock_gettime.c:254:1: error: no previous prototype for '__vdso_clock_gettime' [-Werror=missing-prototypes]
  254 | __vdso_clock_gettime(clockid_t clock, struct __kernel_old_timespec *ts)
      | ^~~~~~~~~~~~~~~~~~~~
/kisskb/src/arch/sparc/vdso/vclock_gettime.c:282:1: error: no previous prototype for '__vdso_clock_gettime_stick' [-Werror=missing-prototypes]
  282 | __vdso_clock_gettime_stick(clockid_t clock, struct __kernel_old_timespec *ts)
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~
/kisskb/src/arch/sparc/vdso/vclock_gettime.c:307:1: error: no previous prototype for '__vdso_gettimeofday' [-Werror=missing-prototypes]
  307 | __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
      | ^~~~~~~~~~~~~~~~~~~
/kisskb/src/arch/sparc/vdso/vclock_gettime.c:343:1: error: no previous prototype for '__vdso_gettimeofday_stick' [-Werror=missing-prototypes]
  343 | __vdso_gettimeofday_stick(struct __kernel_old_timeval *tv, struct timezone *tz)
      | ^~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
make[5]: *** [/kisskb/src/scripts/Makefile.build:244: arch/sparc/vdso/vclock_gettime.o] Error 1
make[4]: *** [/kisskb/src/scripts/Makefile.build:485: arch/sparc/vdso] Error 2
make[4]: *** Waiting for unfinished jobs....
make[3]: *** [/kisskb/src/scripts/Makefile.build:485: arch/sparc] Error 2
make[3]: *** Waiting for unfinished jobs....
/kisskb/src/kernel/fork.c: In function '__do_sys_clone3':
/kisskb/src/kernel/fork.c:3072:2: error: #warning clone3() entry point is missing, please fix [-Werror=cpp]
 3072 | #warning clone3() entry point is missing, please fix
      |  ^~~~~~~
cc1: all warnings being treated as errors
make[4]: *** [/kisskb/src/scripts/Makefile.build:244: kernel/fork.o] Error 1
make[4]: *** Waiting for unfinished jobs....
make[3]: *** [/kisskb/src/scripts/Makefile.build:485: kernel] Error 2
make[2]: *** [/kisskb/src/Makefile:1925: .] Error 2
make[1]: *** [/kisskb/src/Makefile:224: __sub-make] Error 2
make: *** [Makefile:224: __sub-make] Error 2
Command 'make -s -j 24 ARCH=sparc64 O=/kisskb/build/linus_allmodconfig_sparc64-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/sparc64-linux/bin/sparc64-linux-  ' returned non-zero exit status 2.
# rm -rf /kisskb/build/linus_allmodconfig_sparc64-gcc13
# Build took: 0:37:45.369503