# git rev-parse -q --verify a180bd1d7e16173d965b263c5a536aa40afa2a2a^{commit} # git fetch -q -n -f git://fs.ozlabs.ibm.com/kernel/linus master warning: The last gc run reported the following. Please correct the root cause and remove .git/gc.log. Automatic cleanup will not be performed until the file is removed. warning: There are too many unreachable loose objects; run 'git prune' to remove them. # git rev-parse -q --verify a180bd1d7e16173d965b263c5a536aa40afa2a2a^{commit} a180bd1d7e16173d965b263c5a536aa40afa2a2a # git checkout -q -f -B kisskb a180bd1d7e16173d965b263c5a536aa40afa2a2a # git clean -qxdf # < git log -1 # commit a180bd1d7e16173d965b263c5a536aa40afa2a2a # Author: Linus Torvalds # Date: Sun Jul 4 16:12:42 2021 -0700 # # iov_iter: remove uaccess_kernel() warning from iov_iter_init() # # This warning was there to catch any architectures that still use # CONFIG_SET_FS, and that would mis-use iov_iter_init() for anything that # wasn't a proper user space pointer. So that # # WARN_ON_ONCE(uaccess_kernel()); # # makes perfect conceptual sense: you really shouldn't use a kernel # pointer with set_fs(KERNEL_DS) and then pass it to iov_iter_init(). # # HOWEVER. # # Guenter Roeck reports that this warning actually triggers in no-mmu # configurations of both ARM and m68k. And the reason isn't that they # pass in a kernel pointer under set_fs(KERNEL_DS) at all: the reason is # that in those configurations, "uaccess_kernel()" is simply not reliable. # # Those no-mmu setups set USER_DS and KERNEL_DS to the same values, so you # can't test for the difference. # # In particular, the no-mmu case for ARM does # # #define USER_DS KERNEL_DS # #define uaccess_kernel() (true) # # so USER_DS and KERNEL_DS have the same value, and uaccess_kernel() is # always trivially true. # # The m68k case is slightly different and not quite as obvious. It does # (spread out over multiple header files just to be extra exciting: # asm/processor.h, asm/segment.h and asm-generic/uaccess.h): # # #define TASK_SIZE (0xFFFFFFFFUL) # #define USER_DS MAKE_MM_SEG(TASK_SIZE) # #define KERNEL_DS MAKE_MM_SEG(~0UL) # #define get_fs() (current_thread_info()->addr_limit) # #define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) # # but the end result is the same: uaccess_kernel() will always be true, # because USER_DS and KERNEL_DS end up having the same value, even if that # value is defined differently. # # This is very arguably a misfeature in those implementations, but in the # end we don't really care. All modern architectures have gotten rid of # set_fs() already, and generic kernel code never uses it. And while the # sanity check was a nice idea, an architecture would have to go the extra # mile to actually break this. # # So this well-intentioned warning isn't really all that likely to find # anything but these known false positives, and as such just isn't worth # maintaining. # # Reported-by: Guenter Roeck # Fixes: 8cd54c1c8480 ("iov_iter: separate direction from flavour") # Cc: Matthew Wilcox # Cc: Al Viro # Signed-off-by: Linus Torvalds # < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-ld --version # < git log --format=%s --max-count=1 a180bd1d7e16173d965b263c5a536aa40afa2a2a # < make -s -j 8 ARCH=x86_64 O=/kisskb/build/linus-rand_x86_64-randconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux- randconfig # Added to kconfig CONFIG_STANDALONE=y # Added to kconfig CONFIG_PREVENT_FIRMWARE_BUILD=y # Added to kconfig CONFIG_CC_STACKPROTECTOR_STRONG=n # Added to kconfig CONFIG_GCC_PLUGINS=n # Added to kconfig CONFIG_GCC_PLUGIN_CYC_COMPLEXITY=n # Added to kconfig CONFIG_GCC_PLUGIN_SANCOV=n # Added to kconfig CONFIG_GCC_PLUGIN_LATENT_ENTROPY=n # Added to kconfig CONFIG_BPF_PRELOAD=n # Added to kconfig # < make -s -j 8 ARCH=x86_64 O=/kisskb/build/linus-rand_x86_64-randconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux- help # make -s -j 8 ARCH=x86_64 O=/kisskb/build/linus-rand_x86_64-randconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux- olddefconfig .config:4353:warning: override: reassigning to symbol STANDALONE .config:4357:warning: override: reassigning to symbol GCC_PLUGIN_CYC_COMPLEXITY .config:4359:warning: override: reassigning to symbol GCC_PLUGIN_LATENT_ENTROPY .config:4360:warning: override: reassigning to symbol BPF_PRELOAD # make -s -j 8 ARCH=x86_64 O=/kisskb/build/linus-rand_x86_64-randconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux- /kisskb/build/tmp/cc1CopDr.s: Assembler messages: /kisskb/build/tmp/cc1CopDr.s:7739: Error: invalid operands (.text.unlikely and .text sections) for `-' make[2]: *** [/kisskb/src/scripts/Makefile.build:273: certs/common.o] Error 1 make[1]: *** [/kisskb/src/Makefile:1847: certs] Error 2 make[1]: *** Waiting for unfinished jobs.... /kisskb/build/tmp/ccaGfpCy.s: Assembler messages: /kisskb/build/tmp/ccaGfpCy.s:132844: Error: invalid operands (.text.unlikely and .text sections) for `-' make[3]: *** [/kisskb/src/scripts/Makefile.build:273: kernel/printk/printk.o] Error 1 make[2]: *** [/kisskb/src/scripts/Makefile.build:516: kernel/printk] Error 2 make[2]: *** Waiting for unfinished jobs.... /kisskb/build/tmp/cc5adLG1.s: Assembler messages: /kisskb/build/tmp/cc5adLG1.s:144861: Error: invalid operands (.text.unlikely and .text sections) for `-' make[3]: *** [/kisskb/src/scripts/Makefile.build:273: kernel/locking/lockdep.o] Error 1 make[2]: *** [/kisskb/src/scripts/Makefile.build:516: kernel/locking] Error 2 make[1]: *** [/kisskb/src/Makefile:1847: kernel] Error 2 /kisskb/build/tmp/cckYUYVM.s: Assembler messages: /kisskb/build/tmp/cckYUYVM.s:59524: Error: invalid operands (.text.unlikely and .text sections) for `-' make[3]: *** [/kisskb/src/scripts/Makefile.build:273: arch/x86/kernel/kgdb.o] Error 1 make[3]: *** Waiting for unfinished jobs.... make[2]: *** [/kisskb/src/scripts/Makefile.build:516: arch/x86/kernel] Error 2 make[1]: *** [/kisskb/src/Makefile:1847: arch/x86] Error 2 make: *** [Makefile:215: __sub-make] Error 2 Command 'make -s -j 8 ARCH=x86_64 O=/kisskb/build/linus-rand_x86_64-randconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux- ' returned non-zero exit status 2 # rm -rf /kisskb/build/linus-rand_x86_64-randconfig_x86_64-gcc8 # Build took: 0:00:41.605831