# git rev-parse -q --verify 1562551aec8bb15974c69ee79b8da8cc688e7340^{commit}
1562551aec8bb15974c69ee79b8da8cc688e7340
already have revision, skipping fetch
# git checkout -q -f -B kisskb 1562551aec8bb15974c69ee79b8da8cc688e7340
# git clean -qxdf
# < git log -1
# commit 1562551aec8bb15974c69ee79b8da8cc688e7340
# Author: Michael Ellerman <mpe@ellerman.id.au>
# Date:   Fri Dec 16 12:43:12 2022 +1100
# 
#     powerpc/code-patching: Fix oops with DEBUG_VM enabled
#     
#     Nathan reported that the new per-cpu mm patching oopses if DEBUG_VM is
#     enabled:
#     
#       ------------[ cut here ]------------
#       kernel BUG at arch/powerpc/mm/pgtable.c:333!
#       Oops: Exception in kernel mode, sig: 5 [#1]
#       LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
#       Modules linked in:
#       CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.1.0-rc2+ #1
#       Hardware name: IBM PowerNV (emulated by qemu) POWER9 0x4e1200 opal:v7.0 PowerNV
#       ...
#       NIP assert_pte_locked+0x180/0x1a0
#       LR  assert_pte_locked+0x170/0x1a0
#       Call Trace:
#         0x60000000 (unreliable)
#         patch_instruction+0x618/0x6d0
#         arch_prepare_kprobe+0xfc/0x2d0
#         register_kprobe+0x520/0x7c0
#         arch_init_kprobes+0x28/0x3c
#         init_kprobes+0x108/0x184
#         do_one_initcall+0x60/0x2e0
#         kernel_init_freeable+0x1f0/0x3e0
#         kernel_init+0x34/0x1d0
#         ret_from_kernel_thread+0x5c/0x64
#     
#     Caused by the assert_spin_locked() failing in assert_pte_locked(). The
#     assert fails because we have unlocked the PTE in text_area_cpu_up_mm().
#     
#     Instead leave the PTE locked and only unlock it when we tear down the
#     patching_mm for the CPU. That avoids the assert failing, and nothing
#     else should be using the PTE so leaving it locked is arguably more
#     correct.
#     
#     Fixes: c28c15b6d28a ("powerpc/code-patching: Use temporary mm for Radix MMU")
#     Reported-by: Nathan Chancellor <nathan@kernel.org>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 1562551aec8bb15974c69ee79b8da8cc688e7340
# < make -s -j 32 ARCH=x86 O=/kisskb/build/powerpc-next_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux-  x86_64_defconfig
# < make -s -j 32 ARCH=x86 O=/kisskb/build/powerpc-next_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux-  help
# make -s -j 32 ARCH=x86 O=/kisskb/build/powerpc-next_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux-  olddefconfig
# make -s -j 32 ARCH=x86 O=/kisskb/build/powerpc-next_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux-  
Completed OK
# rm -rf /kisskb/build/powerpc-next_x86_64_defconfig_x86_64-gcc8
# Build took: 0:01:54.960131