# git rev-parse -q --verify 44960f2a7b63e224b1091b3e1d6f60e0cdf4be0c^{commit}
44960f2a7b63e224b1091b3e1d6f60e0cdf4be0c
already have revision, skipping fetch
# git checkout -q -f -B kisskb 44960f2a7b63e224b1091b3e1d6f60e0cdf4be0c
# git clean -qxdf
# < git log -1
# commit 44960f2a7b63e224b1091b3e1d6f60e0cdf4be0c
# Author: John Stultz <john.stultz@linaro.org>
# Date:   Tue Jul 31 10:17:04 2018 -0700
# 
#     staging: ashmem: Fix SIGBUS crash when traversing mmaped ashmem pages
#     
#     Amit Pundir and Youling in parallel reported crashes with recent
#     mainline kernels running Android:
#     
#       F DEBUG   : *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
#       F DEBUG   : Build fingerprint: 'Android/db410c32_only/db410c32_only:Q/OC-MR1/102:userdebug/test-key
#       F DEBUG   : Revision: '0'
#       F DEBUG   : ABI: 'arm'
#       F DEBUG   : pid: 2261, tid: 2261, name: zygote  >>> zygote <<<
#       F DEBUG   : signal 7 (SIGBUS), code 2 (BUS_ADRERR), fault addr 0xec00008
#       ... <snip> ...
#       F DEBUG   : backtrace:
#       F DEBUG   :     #00 pc 00001c04  /system/lib/libc.so (memset+48)
#       F DEBUG   :     #01 pc 0010c513  /system/lib/libart.so (create_mspace_with_base+82)
#       F DEBUG   :     #02 pc 0015c601  /system/lib/libart.so (art::gc::space::DlMallocSpace::CreateMspace(void*, unsigned int, unsigned int)+40)
#       F DEBUG   :     #03 pc 0015c3ed  /system/lib/libart.so (art::gc::space::DlMallocSpace::CreateFromMemMap(art::MemMap*, std::__1::basic_string<char, std::__ 1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int, unsigned int, unsigned int, unsigned int, bool)+36)
#       ...
#     
#     This was bisected back to commit bfd40eaff5ab ("mm: fix
#     vma_is_anonymous() false-positives").
#     
#     create_mspace_with_base() in the trace above, utilizes ashmem, and with
#     ashmem, for shared mappings we use shmem_zero_setup(), which sets the
#     vma->vm_ops to &shmem_vm_ops.  But for private ashmem mappings nothing
#     sets the vma->vm_ops.
#     
#     Looking at the problematic patch, it seems to add a requirement that one
#     call vma_set_anonymous() on a vma, otherwise the dummy_vm_ops will be
#     used.  Using the dummy_vm_ops seem to triggger SIGBUS when traversing
#     unmapped pages.
#     
#     Thus, this patch adds a call to vma_set_anonymous() for ashmem private
#     mappings and seems to avoid the reported problem.
#     
#     Fixes: bfd40eaff5ab ("mm: fix vma_is_anonymous() false-positives")
#     Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
#     Cc: Andrew Morton <akpm@linux-foundation.org>
#     Cc: Dmitry Vyukov <dvyukov@google.com>
#     Cc: Oleg Nesterov <oleg@redhat.com>
#     Cc: Andrea Arcangeli <aarcange@redhat.com>
#     Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
#     Cc: Hugh Dickins <hughd@google.com>
#     Cc: Joel Fernandes <joelaf@google.com>
#     Cc: Colin Cross <ccross@google.com>
#     Cc: Matthew Wilcox <willy@infradead.org>
#     Reported-by: Amit Pundir <amit.pundir@linaro.org>
#     Reported-by: Youling 257 <youling257@gmail.com>
#     Signed-off-by: John Stultz <john.stultz@linaro.org>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-gcc --version
# < git log --format=%s --max-count=1 44960f2a7b63e224b1091b3e1d6f60e0cdf4be0c
# < make -s -j 80 ARCH=powerpc O=/kisskb/build/linus_corenet32_smp_defconfig_powerpc CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  corenet32_smp_defconfig
# make -s -j 80 ARCH=powerpc O=/kisskb/build/linus_corenet32_smp_defconfig_powerpc CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  
/kisskb/src/kernel/cgroup/cgroup-v1.c: In function 'cgroup1_mount':
/kisskb/src/kernel/cgroup/cgroup-v1.c:1256:20: warning: 'root' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:183:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/base/regmap/regmap.c: In function 'regmap_raw_read':
/kisskb/src/drivers/base/regmap/regmap.c:2497:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/base/regmap/regmap.c: In function '_regmap_raw_write':
/kisskb/src/drivers/base/regmap/regmap.c:1819:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/mm/hugetlb.c: In function 'alloc_pool_huge_page':
/kisskb/src/mm/hugetlb.c:1433:5: warning: 'page' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/tty/serial/8250/8250_core.c: In function 'univ8250_release_irq':
/kisskb/src/drivers/tty/serial/8250/8250_core.c:251:18: warning: 'i' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/tty/serial/8250/8250_core.c:231:19: note: 'i' was declared here
/kisskb/src/fs/proc/inode.c: In function 'proc_reg_open':
/kisskb/src/include/linux/list.h:65:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c:339:21: note: 'pdeo' was declared here
/kisskb/src/fs/udf/unicode.c: In function 'udf_name_conv_char':
/kisskb/src/fs/udf/unicode.c:132:8: warning: 'c' may be used uninitialized in this function [-Wuninitialized]
INFO: Uncompressed kernel (size 0xc3afe0) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0xd00000)
Image Name:   Linux-4.18.0-rc7-g44960f2
Created:      Thu Aug  2 05:18:32 2018
Image Type:   PowerPC Linux Kernel Image (gzip compressed)
Data Size:    5801463 Bytes = 5665.49 kB = 5.53 MB
Load Address: 00000000
Entry Point:  00000000
Completed OK
# rm -rf /kisskb/build/linus_corenet32_smp_defconfig_powerpc
# Build took: 0:01:41.102633