# git rev-parse -q --verify a68a0262abdaa251e12c53715f48e698a18ef402^{commit}
a68a0262abdaa251e12c53715f48e698a18ef402
already have revision, skipping fetch
# git checkout -q -f -B kisskb a68a0262abdaa251e12c53715f48e698a18ef402
# git clean -qxdf
# < git log -1
# commit a68a0262abdaa251e12c53715f48e698a18ef402
# Author: Minchan Kim <minchan@kernel.org>
# Date:   Tue Dec 8 20:57:18 2020 -0800
# 
#     mm/madvise: remove racy mm ownership check
#     
#     Jann spotted the security hole due to race of mm ownership check.
#     
#     If the task is sharing the mm_struct but goes through execve() before
#     mm_access(), it could skip process_madvise_behavior_valid check.  That
#     makes *any advice hint* to reach into the remote process.
#     
#     This patch removes the mm ownership check.  With it, it will lose the
#     ability that local process could give *any* advice hint with vector
#     interface for some reason (e.g., performance).  Since there is no
#     concrete example in upstream yet, it would be better to remove the
#     abiliity at this moment and need to review when such new advice comes
#     up.
#     
#     Fixes: ecb8ac8b1f14 ("mm/madvise: introduce process_madvise() syscall: an external memory hinting API")
#     Reported-by: Jann Horn <jannh@google.com>
#     Suggested-by: Jann Horn <jannh@google.com>
#     Signed-off-by: Minchan Kim <minchan@kernel.org>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/m68k-linux/bin/m68k-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/m68k-linux/bin/m68k-linux-ld --version
# < git log --format=%s --max-count=1 a68a0262abdaa251e12c53715f48e698a18ef402
# < make -s -j 24 ARCH=m68k O=/kisskb/build/linus_sun3_defconfig_m68k-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/m68k-linux/bin/m68k-linux-  sun3_defconfig

WARNING: unmet direct dependencies detected for NEED_MULTIPLE_NODES
  Depends on [n]: DISCONTIGMEM [=n] || NUMA
  Selected by [y]:
  - SINGLE_MEMORY_CHUNK [=y] && MMU [=y]

WARNING: unmet direct dependencies detected for NEED_MULTIPLE_NODES
  Depends on [n]: DISCONTIGMEM [=n] || NUMA
  Selected by [y]:
  - SINGLE_MEMORY_CHUNK [=y] && MMU [=y]
# < make -s -j 24 ARCH=m68k O=/kisskb/build/linus_sun3_defconfig_m68k-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/m68k-linux/bin/m68k-linux-  help
# make -s -j 24 ARCH=m68k O=/kisskb/build/linus_sun3_defconfig_m68k-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/m68k-linux/bin/m68k-linux-  olddefconfig

WARNING: unmet direct dependencies detected for NEED_MULTIPLE_NODES
  Depends on [n]: DISCONTIGMEM [=n] || NUMA
  Selected by [y]:
  - SINGLE_MEMORY_CHUNK [=y] && MMU [=y]

WARNING: unmet direct dependencies detected for NEED_MULTIPLE_NODES
  Depends on [n]: DISCONTIGMEM [=n] || NUMA
  Selected by [y]:
  - SINGLE_MEMORY_CHUNK [=y] && MMU [=y]
# make -s -j 24 ARCH=m68k O=/kisskb/build/linus_sun3_defconfig_m68k-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/m68k-linux/bin/m68k-linux-  
In file included from /kisskb/src/kernel/rcu/update.c:578:
/kisskb/src/kernel/rcu/tasks.h:710:13: warning: 'show_rcu_tasks_rude_gp_kthread' defined but not used [-Wunused-function]
 static void show_rcu_tasks_rude_gp_kthread(void) {}
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /kisskb/src/arch/m68k/include/asm/atomic.h:7,
                 from /kisskb/src/include/linux/atomic.h:7,
                 from /kisskb/src/include/linux/cpumask.h:13,
                 from /kisskb/src/include/linux/smp.h:13,
                 from /kisskb/src/include/linux/lockdep.h:14,
                 from /kisskb/src/include/linux/spinlock.h:59,
                 from /kisskb/src/include/linux/wait.h:9,
                 from /kisskb/src/include/linux/wait_bit.h:8,
                 from /kisskb/src/include/linux/fs.h:6,
                 from /kisskb/src/fs/ocfs2/file.c:13:
/kisskb/src/fs/ocfs2/file.c: In function 'ocfs2_file_write_iter':
/kisskb/src/arch/m68k/include/asm/cmpxchg.h:79:22: warning: value computed is not used [-Wunused-value]
 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
                     ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/kisskb/src/fs/ocfs2/file.c:2419:3: note: in expansion of macro 'xchg'
   xchg(&iocb->ki_complete, saved_ki_complete);
   ^~~~
Completed OK
# rm -rf /kisskb/build/linus_sun3_defconfig_m68k-gcc8
# Build took: 0:02:30.300123