From 68448be208ee06e76665918b37b0a57e3e00c8b4 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Fri, 17 Nov 2017 16:04:29 -0200 Subject: i386: Fix i386 sigaction sa_restorer initialization (BZ#21269) This patch fixes the i386 sa_restorer field initialization for sigaction syscall for kernel with vDSO. As described in bug report, i386 Linux (and compat on x86_64) interprets SA_RESTORER clear with nonzero sa_restorer as a request for stack switching if the SS segment is 'funny'. This means that anything that tries to mix glibc's signal handling with segmentation (for instance through modify_ldt syscall) is randomly broken depending on what values lands in sa_restorer. The testcase added is based on Linux test tools/testing/selftests/x86/ldt_gdt.c, more specifically in do_multicpu_tests function. The main changes are: - C11 atomics instead of plain access. - Remove x86_64 support which simplifies the syscall handling and fallbacks. - Replicate only the test required to trigger the issue. Checked on i686-linux-gnu. [BZ #21269] * sysdeps/unix/sysv/linux/i386/Makefile (tests): Add tst-bz21269. * sysdeps/unix/sysv/linux/i386/sigaction.c (SET_SA_RESTORER): Clear sa_restorer for vDSO case. * sysdeps/unix/sysv/linux/i386/tst-bz21269.c: New file. --- ChangeLog | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'ChangeLog') diff --git a/ChangeLog b/ChangeLog index e0639e9..f54496f 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2018-03-03 Adhemerval Zanella + + [BZ #21269] + * sysdeps/unix/sysv/linux/i386/Makefile (tests): Add tst-bz21269. + * sysdeps/unix/sysv/linux/i386/sigaction.c (SET_SA_RESTORER): Clear + sa_restorer for vDSO case. + * sysdeps/unix/sysv/linux/i386/tst-bz21269.c: New file. + 2018-03-03 Samuel Thibault * scripts/check-installed-headers.sh: Ignore Hurd and Mach headers. -- cgit v1.1