From a143381a7df825e2ae41e49a4bff00ce8b1d5e18 Mon Sep 17 00:00:00 2001 From: Samuel Thibault Date: Thu, 6 Aug 2020 00:01:18 +0200 Subject: Use commit message --- .topmsg | 40 ++++++++++++++++++++++++---------------- 1 file changed, 24 insertions(+), 16 deletions(-) (limited to '.topmsg') diff --git a/.topmsg b/.topmsg index a725712dcd..223e368fca 100644 --- a/.topmsg +++ b/.topmsg @@ -1,21 +1,29 @@ -Subject: Fix sbrk in PIE binaries +Committed from glibc 2.33 -In PIE mode, the program gets loaded at very low address, and thus _end is very -low, just before libraries, and thus initializing the brk to it does not make -sense, since there is no room left there. Hardcode the brk to 0x8000000 for now -as a workaround. +From: Samuel Thibault -id:"20130211040854.GN5926@type.youpi.perso.aquilenet.fr" +hurd: Rework sbrk - +Making the brk start exactly at the end of the main application binary was +requiring to get it through the _end symbol, which does not work any more +with recent toolchains, and actually produces in libc.so a confusing +external _end symbol that produces odd results, see +https://sourceware.org/bugzilla/show_bug.cgi?id=23499 -YYYY-MM-DD Samuel Thibault - Thomas Schwinge +Trying to do so is quite outdated anyway with the tendency for address +randomization. + +Using _end was also allowing to include the main binary data within +the RLIMIT_DATA, but this also seems outdated with dynamic library +loading, and nowadays' memory consumption via malloc and mmap rather than +statically-allocated data. + +This adds a BRK_START macro in that just tells where we +want to start the brk, and thus removes the _end symbol. + +* sysdeps/mach/hurd/i386/vm_param.h: New file. +* sysdeps/mach/hurd/brk.c: Use BRK_START as brk start instead of _end. +Also ignore __data_start. +* hurd/Versions: Remove _end symbol. +* sysdeps/mach/hurd/i386/libc.abilist: Remove _end symbol. - * sysdeps/mach/hurd/brk.c (init_brk): Fix for PIE executables. - * misc/tst-sbrk.c: New file. - * misc/tst-sbrk-pie.c: Likewise. - * misc/tst-sbrk-static.c: Likewise. - * misc/Makefile (tests): Add tst-sbrk, tst-sbrk-pie, tst-sbrk-static. - (tests-pie): Add tst-sbrk-pie. - (tests-static): Add tst-sbrk-static. -- cgit v1.2.3