# git rev-parse -q --verify c7dee506ec3450717e84518ab3a6a3f2ce755cf6^{commit} c7dee506ec3450717e84518ab3a6a3f2ce755cf6 already have revision, skipping fetch # git checkout -q -f -B kisskb c7dee506ec3450717e84518ab3a6a3f2ce755cf6 # git clean -qxdf # < git log -1 # commit c7dee506ec3450717e84518ab3a6a3f2ce755cf6 # Author: Michael Ellerman # Date: Tue Aug 31 23:41:15 2021 +1000 # # powerpc/ptdump: Fix generic ptdump for 64-bit # # Since the conversion to generic ptdump we see crashes on 64-bit: # # BUG: Unable to handle kernel data access on read at 0xc0eeff7f00000000 # Faulting instruction address: 0xc00000000045e5fc # Oops: Kernel access of bad area, sig: 11 [#1] # ... # NIP __walk_page_range+0x2bc/0xce0 # LR __walk_page_range+0x240/0xce0 # Call Trace: # __walk_page_range+0x240/0xce0 (unreliable) # walk_page_range_novma+0x74/0xb0 # ptdump_walk_pgd+0x98/0x170 # ptdump_check_wx+0x88/0xd0 # mark_rodata_ro+0x48/0x80 # kernel_init+0x74/0x1a0 # ret_from_kernel_thread+0x5c/0x64 # # What's happening is that have walked off the end of the kernel page # tables, and started dereferencing junk values. # # That happens because we initialised the ptdump_range to span all the way # up to 0xffffffffffffffff: # # static struct ptdump_range ptdump_range[] __ro_after_init = { # {TASK_SIZE_MAX, ~0UL}, # # But the kernel page tables don't span that far. So on 64-bit set the end # of the range to be the address immediately past the end of the kernel # page tables, to limit the page table walk to valid addresses. # # Fixes: e084728393a5 ("powerpc/ptdump: Convert powerpc to GENERIC_PTDUMP") # Reported-by: Nathan Chancellor # Signed-off-by: Michael Ellerman # < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version # < git log --format=%s --max-count=1 c7dee506ec3450717e84518ab3a6a3f2ce755cf6 # < make -s -j 24 ARCH=powerpc O=/kisskb/build/powerpc-next_corenet64_smp_defconfig+KVM_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- corenet64_smp_defconfig # Added to kconfig CONFIG_KVM_E500MC=y # Added to kconfig CONFIG_VIRTUALIZATION=y # Added to kconfig CONFIG_KVM_MPIC=y # < make -s -j 24 ARCH=powerpc O=/kisskb/build/powerpc-next_corenet64_smp_defconfig+KVM_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- help # make -s -j 24 ARCH=powerpc O=/kisskb/build/powerpc-next_corenet64_smp_defconfig+KVM_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- olddefconfig .config:4265:warning: override: reassigning to symbol VIRTUALIZATION # make -s -j 24 ARCH=powerpc O=/kisskb/build/powerpc-next_corenet64_smp_defconfig+KVM_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- Completed OK # rm -rf /kisskb/build/powerpc-next_corenet64_smp_defconfig+KVM_powerpc-gcc5 # Build took: 0:03:09.904981