# git rev-parse -q --verify b39ab98e2f4728d98973fd1bc531e3c4cbccb21c^{commit} b39ab98e2f4728d98973fd1bc531e3c4cbccb21c already have revision, skipping fetch # git checkout -q -f -B kisskb b39ab98e2f4728d98973fd1bc531e3c4cbccb21c # git clean -qxdf # git log -1 commit b39ab98e2f4728d98973fd1bc531e3c4cbccb21c Author: Linus Torvalds Date: Mon Oct 30 10:09:56 2017 -0700 Mark 'ioremap_page_range()' as possibly sleeping It turns out that some drivers seem to think it's ok to remap page ranges from within interrupts and even NMI's. That is definitely not the case, since the page table build-up is simply not interrupt-safe. This showed up in the zero-day robot that reported it for the ACPI APEI GHES ("Generic Hardware Error Source") driver. Normally it had been hidden by the fact that no page table operations had been needed because the vmalloc area had been set up by other things. Apparently due to a recent change to the GHEI driver: commit 77b246b32b2c ("acpi: apei: check for pending errors when probing GHES entries") 0day actually caught a case during bootup whenthe ioremap called down to page allocation. But that recent change only showed the symptom, it wasn't the root cause of the problem. Hopefully it is limited to just that one driver. If you need to access random physical memory, you either need to ioremap in process context, or you need to use the FIXMAP facility to set one particular fixmap entry to the required mapping - that can be done safely. Cc: Borislav Petkov Cc: Len Brown Cc: Tony Luck Cc: Fengguang Wu Cc: Tyler Baicar Cc: Will Deacon Signed-off-by: Linus Torvalds # < /opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux-gcc --version # < git log --format=%s --max-count=1 b39ab98e2f4728d98973fd1bc531e3c4cbccb21c # < make -j 10 ARCH=i386 O=/home/kisskb/slave/build/linus_i386-randconfig_i386 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux- randconfig KCONFIG_SEED=0xC859C1E0 # Added to kconfig CONFIG_STANDALONE=y # Added to kconfig CONFIG_PREVENT_FIRMWARE_BUILD=y # yes \n | make -j 10 ARCH=i386 O=/home/kisskb/slave/build/linus_i386-randconfig_i386 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux- oldconfig yes: standard output: Broken pipe yes: write error # make -j 10 ARCH=i386 O=/home/kisskb/slave/build/linus_i386-randconfig_i386 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux- make[1]: Entering directory '/home/kisskb/slave/build/linus_i386-randconfig_i386' GEN ./Makefile scripts/kconfig/conf --silentoldconfig Kconfig SYSTBL arch/x86/entry/syscalls/../../include/generated/asm/syscalls_32.h SYSHDR arch/x86/entry/syscalls/../../include/generated/uapi/asm/unistd_32.h SYSHDR arch/x86/entry/syscalls/../../include/generated/uapi/asm/unistd_64.h SYSHDR arch/x86/entry/syscalls/../../include/generated/uapi/asm/unistd_x32.h HOSTCC scripts/basic/bin2c CHK include/config/kernel.release Cannot use CONFIG_CC_STACKPROTECTOR_REGULAR: -fstack-protector available but compiler is broken /home/kisskb/slave/src/Makefile:1096: recipe for target 'prepare-compiler-check' failed make[1]: *** [prepare-compiler-check] Error 1 make[1]: *** Waiting for unfinished jobs.... UPD include/config/kernel.release make[1]: *** wait: No child processes. Stop. Makefile:145: recipe for target 'sub-make' failed make: *** [sub-make] Error 2 Command 'make -j 10 ARCH=i386 O=/home/kisskb/slave/build/linus_i386-randconfig_i386 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/i386-linux/bin/i386-linux- ' returned non-zero exit status 2 # rm -rf /home/kisskb/slave/build/linus_i386-randconfig_i386 # Build took: 0:00:07.566510