# 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/sh4-linux/bin/sh4-linux-gcc --version
# < git log --format=%s --max-count=1 44960f2a7b63e224b1091b3e1d6f60e0cdf4be0c
# < make -s -j 80 ARCH=sh O=/kisskb/build/linus_sh7785lcr_32bit_defconfig_sh4 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/sh4-linux/bin/sh4-linux-  sh7785lcr_32bit_defconfig
# make -s -j 80 ARCH=sh O=/kisskb/build/linus_sh7785lcr_32bit_defconfig_sh4 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/sh4-linux/bin/sh4-linux-  
  Generating include/generated/machtypes.h
<stdin>:1317:2: warning: #warning syscall pkey_mprotect not implemented [-Wcpp]
<stdin>:1320:2: warning: #warning syscall pkey_alloc not implemented [-Wcpp]
<stdin>:1323:2: warning: #warning syscall pkey_free not implemented [-Wcpp]
<stdin>:1326:2: warning: #warning syscall statx not implemented [-Wcpp]
<stdin>:1332:2: warning: #warning syscall io_pgetevents not implemented [-Wcpp]
<stdin>:1335:2: warning: #warning syscall rseq not implemented [-Wcpp]
/kisskb/src/arch/sh/kernel/cpu/sh4/../sh3/../../entry-common.S: Assembler messages:
/kisskb/src/arch/sh/kernel/cpu/sh4/../sh3/../../entry-common.S:389: Warning: overflow in branch to syscall_exit_work; converted into longer instruction sequence
/kisskb/src/arch/sh/kernel/cpu/sh4/../sh3/../../entry-common.S:392: Warning: overflow in branch to syscall_exit_work; converted into longer instruction sequence
/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/kernel/rcu/srcutree.c: In function 'init_srcu_struct_fields':
/kisskb/src/kernel/rcu/srcutree.c:127:33: warning: 'levelspread[<U2280>]' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/rcu/srcutree.c:94:6: note: 'levelspread[<U2280>]' was declared here
/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/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/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/drivers/sh/clk/cpg.c: In function 'r8':
/kisskb/src/drivers/sh/clk/cpg.c:41:2: warning: passing argument 1 of 'ioread8' discards 'const' qualifier from pointer target type [enabled by default]
/kisskb/src/include/asm-generic/iomap.h:29:21: note: expected 'void *' but argument is of type 'const void *'
/kisskb/src/drivers/sh/clk/cpg.c: In function 'r16':
/kisskb/src/drivers/sh/clk/cpg.c:46:2: warning: passing argument 1 of 'ioread16' discards 'const' qualifier from pointer target type [enabled by default]
/kisskb/src/include/asm-generic/iomap.h:30:21: note: expected 'void *' but argument is of type 'const void *'
/kisskb/src/drivers/sh/clk/cpg.c: In function 'r32':
/kisskb/src/drivers/sh/clk/cpg.c:51:2: warning: passing argument 1 of 'ioread32' discards 'const' qualifier from pointer target type [enabled by default]
/kisskb/src/include/asm-generic/iomap.h:32:21: note: expected 'void *' but argument is of type 'const void *'
Image Name:   Linux-4.18.0-rc7-g44960f2
Created:      Thu Aug  2 05:52:37 2018
Image Type:   SuperH Linux Kernel Image (gzip compressed)
Data Size:    4077340 Bytes = 3981.78 kB = 3.89 MB
Load Address: 80001000
Entry Point:  80002000
  Image arch/sh/boot/uImage is ready
Completed OK
# rm -rf /kisskb/build/linus_sh7785lcr_32bit_defconfig_sh4
# Build took: 0:01:01.352110