This is a note to let you know that I've just added the patch titled
x86/fpu/math-emu: Fix possible uninitialized variable use
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: x86-fpu-math-emu-fix-possible-uninitialized-variable-use.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 75e2f0a6b16141cb347f442033ec907380d4d66e Mon Sep 17 00:00:00 2001
From: Arnd Bergmann arnd@arndb.de Date: Wed, 19 Jul 2017 14:53:00 +0200 Subject: x86/fpu/math-emu: Fix possible uninitialized variable use MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
From: Arnd Bergmann arnd@arndb.de
commit 75e2f0a6b16141cb347f442033ec907380d4d66e upstream.
When building the kernel with "make EXTRA_CFLAGS=...", this overrides the "PARANOID" preprocessor macro defined in arch/x86/math-emu/Makefile, and we run into a build warning:
arch/x86/math-emu/reg_compare.c: In function ‘compare_i_st_st’: arch/x86/math-emu/reg_compare.c:254:6: error: ‘f’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
This fixes the implementation to work correctly even without the PARANOID flag, and also fixes the Makefile to not use the EXTRA_CFLAGS variable but instead use the ccflags-y variable in the Makefile that is meant for this purpose.
Signed-off-by: Arnd Bergmann arnd@arndb.de Cc: Bill Metzenthen billm@melbpc.org.au Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/20170719125310.2487451-3-arnd@arndb.de Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/math-emu/Makefile | 4 ++-- arch/x86/math-emu/reg_compare.c | 16 ++++++++-------- 2 files changed, 10 insertions(+), 10 deletions(-)
--- a/arch/x86/math-emu/Makefile +++ b/arch/x86/math-emu/Makefile @@ -5,8 +5,8 @@ #DEBUG = -DDEBUGGING DEBUG = PARANOID = -DPARANOID -EXTRA_CFLAGS := $(PARANOID) $(DEBUG) -fno-builtin $(MATH_EMULATION) -EXTRA_AFLAGS := $(PARANOID) +ccflags-y += $(PARANOID) $(DEBUG) -fno-builtin $(MATH_EMULATION) +asflags-y += $(PARANOID)
# From 'C' language sources: C_OBJS =fpu_entry.o errors.o \ --- a/arch/x86/math-emu/reg_compare.c +++ b/arch/x86/math-emu/reg_compare.c @@ -168,7 +168,7 @@ static int compare(FPU_REG const *b, int /* This function requires that st(0) is not empty */ int FPU_compare_st_data(FPU_REG const *loaded_data, u_char loaded_tag) { - int f = 0, c; + int f, c;
c = compare(loaded_data, loaded_tag);
@@ -189,12 +189,12 @@ int FPU_compare_st_data(FPU_REG const *l case COMP_No_Comp: f = SW_C3 | SW_C2 | SW_C0; break; -#ifdef PARANOID default: +#ifdef PARANOID EXCEPTION(EX_INTERNAL | 0x121); +#endif /* PARANOID */ f = SW_C3 | SW_C2 | SW_C0; break; -#endif /* PARANOID */ } setcc(f); if (c & COMP_Denormal) { @@ -205,7 +205,7 @@ int FPU_compare_st_data(FPU_REG const *l
static int compare_st_st(int nr) { - int f = 0, c; + int f, c; FPU_REG *st_ptr;
if (!NOT_EMPTY(0) || !NOT_EMPTY(nr)) { @@ -235,12 +235,12 @@ static int compare_st_st(int nr) case COMP_No_Comp: f = SW_C3 | SW_C2 | SW_C0; break; -#ifdef PARANOID default: +#ifdef PARANOID EXCEPTION(EX_INTERNAL | 0x122); +#endif /* PARANOID */ f = SW_C3 | SW_C2 | SW_C0; break; -#endif /* PARANOID */ } setcc(f); if (c & COMP_Denormal) { @@ -283,12 +283,12 @@ static int compare_i_st_st(int nr) case COMP_No_Comp: f = X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF; break; -#ifdef PARANOID default: +#ifdef PARANOID EXCEPTION(EX_INTERNAL | 0x122); +#endif /* PARANOID */ f = 0; break; -#endif /* PARANOID */ } FPU_EFLAGS = (FPU_EFLAGS & ~(X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF)) | f; if (c & COMP_Denormal) {
Patches currently in stable-queue which might be from arnd@arndb.de are
queue-4.4/kasan-rework-kconfig-settings.patch queue-4.4/hdpvr-hide-unused-variable.patch queue-4.4/mtd-ichxrom-maybe-uninitialized-with-gcc-4.9.patch queue-4.4/profile-hide-unused-functions-when-config_proc_fs.patch queue-4.4/perf-x86-shut-up-false-positive-wmaybe-uninitialized-warning.patch queue-4.4/hwrng-exynos-use-__maybe_unused-to-hide-pm-functions.patch queue-4.4/usb-cdc_subset-only-build-when-one-driver-is-enabled.patch queue-4.4/ipv4-ipconfig-avoid-unused-ic_proto_used-symbol.patch queue-4.4/revert-power-bq27xxx_battery-remove-unneeded-dependency-in-kconfig.patch queue-4.4/go7007-add-media_camera_support-dependency.patch queue-4.4/scsi-advansys-fix-build-warning-for-pci-n.patch queue-4.4/ssb-mark-ssb_bus_register-as-__maybe_unused.patch queue-4.4/tty-cyclades-cyz_interrupt-is-only-used-for-pci.patch queue-4.4/infiniband-cxgb4-use-pr-format-string-for-printing-resources.patch queue-4.4/video-fbdev-via-remove-possibly-unused-variables.patch queue-4.4/binfmt_elf-compat-avoid-unused-function-warning.patch queue-4.4/drm-gma500-remove-helper-function.patch queue-4.4/fbdev-s6e8ax0-avoid-unused-function-warnings.patch queue-4.4/netfilter-ipvs-avoid-unused-variable-warnings.patch queue-4.4/idle-i7300-add-pci-dependency.patch queue-4.4/b2c2-flexcop-avoid-unused-function-warnings.patch queue-4.4/fbdev-auo_k190x-avoid-unused-function-warnings.patch queue-4.4/cw1200-fix-bogus-maybe-uninitialized-warning.patch queue-4.4/x86-build-silence-the-build-with-make-s.patch queue-4.4/gpio-xgene-mark-pm-functions-as-__maybe_unused.patch queue-4.4/kvm-add-x86_local_apic-dependency.patch queue-4.4/arm-tegra-select-usb_ulpi-from-ehci-rather-than-platform.patch queue-4.4/asoc-mediatek-add-i2c-dependency.patch queue-4.4/reiserfs-avoid-a-wmaybe-uninitialized-warning.patch queue-4.4/scsi-advansys-fix-uninitialized-data-access.patch queue-4.4/mtd-sh_flctl-pass-fifo-as-physical-address.patch queue-4.4/driver-core-use-dev-argument-in-dev_dbg_ratelimited-stub.patch queue-4.4/modsign-hide-openssl-output-in-silent-builds.patch queue-4.4/net-hp100-remove-unnecessary-ifdefs.patch queue-4.4/genirq-msi-add-stubs-for-get_cached_msi_msg-pci_write_msi_msg.patch queue-4.4/asoc-intel-kconfig-fix-build-when-acpi-is-not-enabled.patch queue-4.4/asoc-ux500-add-module_license-tag.patch queue-4.4/wireless-cw1200-use-__maybe_unused-to-hide-pm-functions_.patch queue-4.4/mptfusion-hide-unused-seq_mpt_print_ioc_summary-function.patch queue-4.4/tlan-avoid-unused-label-with-pci-n.patch queue-4.4/usb-musb-ux500-remove-duplicate-check-for-dma_is_compatible.patch queue-4.4/mtd-cfi-enforce-valid-geometry-configuration.patch queue-4.4/thermal-spear-use-__maybe_unused-for-pm-functions.patch queue-4.4/x86-microcode-amd-change-load_microcode_amd-s-param-to-bool-to-fix-preemptibility-bug.patch queue-4.4/video-fbdev-mmp-add-module_license.patch queue-4.4/fbdev-sis-enforce-selection-of-at-least-one-backend.patch queue-4.4/x86-boot-avoid-warning-for-zero-filling-.bss.patch queue-4.4/power-bq27xxx_battery-mark-some-symbols-__maybe_unused.patch queue-4.4/scsi-mvumi-use-__maybe_unused-to-hide-pm-functions.patch queue-4.4/usb-phy-msm-add-regulator-dependency.patch queue-4.4/isdn-icn-remove-a-warning.patch queue-4.4/ncr5380-shut-up-gcc-indentation-warning.patch queue-4.4/arm64-dts-add-cooling-cells-to-cpu-nodes.patch queue-4.4/vmxnet3-prevent-building-with-64k-pages.patch queue-4.4/genksyms-fix-segfault-with-invalid-declarations.patch queue-4.4/x86-platform-add-pci-dependency-for-punit_atom_debug.patch queue-4.4/target-user-fix-cast-from-pointer-to-phys_addr_t.patch queue-4.4/rtlwifi-fix-gcc-6-indentation-warning.patch queue-4.4/alsa-hda-ca0132-fix-possible-null-pointer-use.patch queue-4.4/thermal-fix-intel_soc_dts_iosf_core-dependencies.patch queue-4.4/arm64-define-bug-instruction-without-config_bug.patch queue-4.4/v4l-remove-media_tuner-dependency-for-video_tuner.patch queue-4.4/tc358743-fix-register-i2c_rd-wr-functions.patch queue-4.4/scsi-fdomain-drop-fdomain_pci_tbl-when-built-in.patch queue-4.4/scsi-initio-remove-duplicate-module-device-table.patch queue-4.4/netlink-fix-nla_put_-u8-u16-u32-for-kasan.patch queue-4.4/x86-fpu-math-emu-fix-possible-uninitialized-variable-use.patch queue-4.4/asoc-rockchip-use-__maybe_unused-to-hide-st_irq_syscfg_resume.patch queue-4.4/staging-ste_rmi4-avoid-unused-function-warnings.patch queue-4.4/em28xx-only-use-mt9v011-if-camera-support-is-enabled.patch queue-4.4/pwc-hide-unused-label.patch queue-4.4/input-tca8418_keypad-hide-gcc-4.9-wmaybe-uninitialized-warning.patch queue-4.4/fbdev-sm712fb-avoid-unused-function-warnings.patch queue-4.4/isdn-sc-work-around-type-mismatch-warning.patch queue-4.4/tty-hvc_xen-hide-xen_console_remove-when-unused.patch queue-4.4/virtio_balloon-prevent-uninitialized-variable-use.patch queue-4.4/drm-nouveau-hide-gcc-4.9-wmaybe-uninitialized.patch queue-4.4/dell-wmi-dell-laptop-depends-dmi.patch queue-4.4/x86-add-multiuser-dependency-for-kvm.patch queue-4.4/md-avoid-warning-for-32-bit-sector_t.patch queue-4.4/isdn-eicon-reduce-stack-size-of-sig_ind-function.patch