On Wed, Feb 21, 2024 at 09:52:23AM +0000, hartmut.bra...@dlr.de wrote: > Hi, > > I updated yesterday and now event a minimal program with > > cc -fsanitize=address > > produces > > ld: error: undefined symbol: __elf_aux_vector > >>> referenced by sanitizer_linux_libcdep.cpp:950 > >>> (/usr/src/contrib/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp:950) > >>> sanitizer_linux_libcdep.o:(__sanitizer::ReExec()) in > >>> archive /usr/lib/clang/17/lib/freebsd/libclang_rt.asan-x86_64.a > cc: error: linker command failed with exit code 1 (use -v to see invocation) > > I think this is caused by the libsys split.
I don't see any such problem on a system running 5f7ac491eef4, which includes the libsys split. Which compiler are you using, and which revision are you running? > Cheers, > Harti > > -----Original Message----- > From: owner-freebsd-curr...@freebsd.org <owner-freebsd-curr...@freebsd.org> > On Behalf Of Brooks Davis > Sent: Friday, February 2, 2024 11:32 PM > To: curr...@freebsd.org > Subject: libc/libsys split coming soon > > TL;DR: The implementation of system calls is moving to a seperate library > (libsys). No changes are required to existing software (except to ensure > that libsys is present when building custom disk images). > > Code: https://github.com/freebsd/freebsd-src/pull/908 > > After nearly a decade of intermittent work, I'm about to land a series of > patches which moves system calls, vdso support, and libc's parsing of the ELF > auxiliary argument vector into a separate library (libsys). I plan to do > this early next week (February 5th). > > This change serves three primary purposes: > 1. It's easier to completely replace system call implementations for > tracing or compartmentalization purposes. > 2. It simplifies the implementation of restrictions on system calls such > as those implemented by OpenBSD's msyscall(2) > (https://man.openbsd.org/msyscall.2). > 3. It allows language runtimes to link with libsys for system call > implementations without requiring libc. > > libsys is an auxiliary filter for libc. This means that for any symbol > defined by both, the libsys version takes precedence at runtime. For system > call implementations, libc contains empty stubs. For others it contains > copies of the functions (this could be further refined at a later date). The > statically linked libc contains the full implementations so linking libsys is > not required. > > Additionally, libthr is now linked with libsys to provide _umtx_op_err(). > > The overall implementation follows https://reviews.freebsd.org/D14609, > but is redone from scratch as multiple commits to facilitate review and > assist git's rename detection. > > Testing: > - Boot testing on amd64, aarch64, and riscv > - make tinderbox (prior version, final run in progress) > - exp-run: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=276391 > - Kyua tests in poudriere amd64 jails: same 359 failures as with the > latest freebsdci build > > Thanks to Ali Mashtizadeh and Tal Garfinkel for D14609 and many apologies for > not landing this in a timely manner. Additional thanks to kib@ for many > rounds of review, markj@ and kib@ for debugging rtld issues exposed by this > patch, and antoine@ for exp-runs. > > Future work: > - Purely functional interfaces to system calls (no errorno). > Unfortunately there isn't an obvious way to do this without > significant (possibly generated) assembly code. > - Investigate msyscall(2) and pinsyscalls(2). > - Reduce the size of stubs in libc. I’ve errored on the > side of not touching the copies that end up in libc to keep diff > size down. We might want to generate empty stubs instead. > > See also: > - Solaris Linker and Libraries Guide: > https://docs.oracle.com/cd/E23824_01/html/819-0690/chapter4-4.html > > -- Brooks >
