Buildresult: linus/xtensa-allnoconfig/xtensa-gcc8 built on May 15 2020, 06:25

kisskb

Revisions | Branches | Compilers | Configs | Build Results | Build Failures |

Status:	OK
Date/Time:	May 15 2020, 06:25
Duration:	0:00:14.115198
Builder:	ka2
Revision:	Merge tag 'for-linus-2020-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux (`8c1684bb81f173543599f1848c29a2a3b1ee5907)`
Target:	linus/xtensa-allnoconfig/xtensa-gcc8
Branch:	linus
Compiler:	xtensa-gcc8 (xtensa-linux-gcc.br_real (Buildroot 2016.11-git-00613-ge98b4dd) 5.4.0 / GNU ld (GNU Binutils) 2.26.1)
Config:	allnoconfig (download)
Log:	Download original No warnings found in log. Full Log # git rev-parse -q --verify 8c1684bb81f173543599f1848c29a2a3b1ee5907^{commit} 8c1684bb81f173543599f1848c29a2a3b1ee5907 already have revision, skipping fetch # git checkout -q -f -B kisskb 8c1684bb81f173543599f1848c29a2a3b1ee5907 # git clean -qxdf # < git log -1 # commit 8c1684bb81f173543599f1848c29a2a3b1ee5907 # Merge: f44d5c489051 3f2c788a1314 # Author: Linus Torvalds <torvalds@linux-foundation.org> # Date: Thu May 14 11:52:28 2020 -0700 # # Merge tag 'for-linus-2020-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux # # Pull thread fix from Christian Brauner: # "This contains a single fix for all exported legacy fork helpers to # block accidental access to clone3() features in the upper 32 bits of # their respective flags arguments. # # I got Cced on a glibc issue where someone reported consistent failures # for the legacy clone() syscall on ppc64le when sign extension was # performed (since the clone() syscall in glibc exposes the flags # argument as an int whereas the kernel uses unsigned long). # # The legacy clone() syscall is odd in a bunch of ways and here two # things interact: # # - First, legacy clone's flag argument is word-size dependent, i.e. # it's an unsigned long whereas most system calls with flag arguments # use int or unsigned int. # # - Second, legacy clone() ignores unknown and deprecated flags. # # The two of them taken together means that users on 64bit systems can # pass garbage for the upper 32bit of the clone() syscall since forever # and things would just work fine. # # The following program compiled on a 64bit kernel prior to v5.7-rc1 # will succeed and will fail post v5.7-rc1 with EBADF: # # int main(int argc, char argv[]) # { # pid_t pid; # # / Note that legacy clone() has different argument ordering on # * different architectures so this won't work everywhere. # * # * Only set the upper 32 bits. # / # pid = syscall(__NR_clone, 0xffffffff00000000 \| SIGCHLD, # NULL, NULL, NULL, NULL); # if (pid < 0) # exit(EXIT_FAILURE); # if (pid == 0) # exit(EXIT_SUCCESS); # if (wait(NULL) != pid) # exit(EXIT_FAILURE); # # exit(EXIT_SUCCESS); # } # # Since legacy clone() couldn't be extended this was not a problem so # far and nobody really noticed or cared since nothing in the kernel # ever bothered to look at the upper 32 bits. # # But once we introduced clone3() and expanded the flag argument in # struct clone_args to 64 bit we opened this can of worms. With the # first flag-based extension to clone3() making use of the upper 32 bits # of the flag argument we've effectively made it possible for the legacy # clone() syscall to reach clone3() only flags on accident. The sign # extension scenario is just the odd corner-case that we needed to # figure this out. # # The reason we just realized this now and not already when we # introduced CLONE_CLEAR_SIGHAND was that CLONE_INTO_CGROUP assumes that # a valid cgroup file descriptor has been given - whereas # CLONE_CLEAR_SIGHAND doesn't need to verify anything. It just silently # resets the signal handlers to SIG_DFL. # # So the sign extension (or the user accidently passing garbage for the # upper 32 bits) caused the CLONE_INTO_CGROUP bit to be raised and the # kernel to error out when it didn't find a valid cgroup file # descriptor. # # Note, I'm also capping kernel_thread()'s flag argument mainly because # none of the new features make sense for kernel_thread() and we # shouldn't risk them being accidently activated however unlikely. If we # wanted to, we could even make kernel_thread() yell when an unknown # flag has been set which it doesn't do right now. But it's not worth # risking this in a bugfix imho" # # tag 'for-linus-2020-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: # fork: prevent accidental access to clone3 features # < /opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-gcc --version # < /opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-ld --version # < git log --format=%s --max-count=1 8c1684bb81f173543599f1848c29a2a3b1ee5907 # < make -s -j 48 ARCH=xtensa O=/kisskb/build/linus_xtensa-allnoconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux- allnoconfig # < make -s -j 48 ARCH=xtensa O=/kisskb/build/linus_xtensa-allnoconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux- help # make -s -j 48 ARCH=xtensa O=/kisskb/build/linus_xtensa-allnoconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux- olddefconfig # make -s -j 48 ARCH=xtensa O=/kisskb/build/linus_xtensa-allnoconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux- Completed OK # rm -rf /kisskb/build/linus_xtensa-allnoconfig_xtensa # Build took: 0:00:14.115198

© Michael Ellerman 2006-2018.