# git rev-parse -q --verify 348c71344111d7a48892e3e52264ff11956fc196^{commit}
348c71344111d7a48892e3e52264ff11956fc196
already have revision, skipping fetch
# git checkout -q -f -B kisskb 348c71344111d7a48892e3e52264ff11956fc196
# git clean -qxdf
# < git log -1
# commit 348c71344111d7a48892e3e52264ff11956fc196
# Author: Kajol Jain <kjain@linux.ibm.com>
# Date:   Thu May 5 21:04:51 2022 +0530
# 
#     powerpc/papr_scm: Fix buffer overflow issue with CONFIG_FORTIFY_SOURCE
#     
#     With CONFIG_FORTIFY_SOURCE enabled, string functions will also perform
#     dynamic checks for string size which can panic the kernel, like incase
#     of overflow detection.
#     
#     In papr_scm, papr_scm_pmu_check_events function uses stat->stat_id with
#     string operations, to populate the nvdimm_events_map array. Since
#     stat_id variable is not NULL terminated, the kernel panics with
#     CONFIG_FORTIFY_SOURCE enabled at boot time.
#     
#     Below are the logs of kernel panic:
#     
#       detected buffer overflow in __fortify_strlen
#       ------------[ cut here ]------------
#       kernel BUG at lib/string_helpers.c:980!
#       Oops: Exception in kernel mode, sig: 5 [#1]
#       NIP [c00000000077dad0] fortify_panic+0x28/0x38
#       LR [c00000000077dacc] fortify_panic+0x24/0x38
#       Call Trace:
#       [c0000022d77836e0] [c00000000077dacc] fortify_panic+0x24/0x38 (unreliable)
#       [c00800000deb2660] papr_scm_pmu_check_events.constprop.0+0x118/0x220 [papr_scm]
#       [c00800000deb2cb0] papr_scm_probe+0x288/0x62c [papr_scm]
#       [c0000000009b46a8] platform_probe+0x98/0x150
#     
#     Fix this issue by using kmemdup_nul() to copy the content of
#     stat->stat_id directly to the nvdimm_events_map array.
#     
#     mpe: stat->stat_id comes from the hypervisor, not userspace, so there is
#     no security exposure.
#     
#     Fixes: 4c08d4bbc089 ("powerpc/papr_scm: Add perf interface support")
#     Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20220505153451.35503-1-kjain@linux.ibm.com
# < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 348c71344111d7a48892e3e52264ff11956fc196
# < make -s -j 24 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64le_defconfig+NO_KVM_powerpc-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  ppc64le_defconfig
# Added to kconfig CONFIG_KVM_BOOK3S_64=n
# Added to kconfig CONFIG_KVM=n
# < make -s -j 24 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64le_defconfig+NO_KVM_powerpc-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  help
# make -s -j 24 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64le_defconfig+NO_KVM_powerpc-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  olddefconfig
# make -s -j 24 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64le_defconfig+NO_KVM_powerpc-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_ppc64le_defconfig+NO_KVM_powerpc-gcc11
# Build took: 0:05:16.966843