Andy Lutomirski ff17bbe0bb x86/vdso: Prevent segfaults due to hoisted vclock reads ... GCC 5.5.0 sometimes cleverly hoists reads of the pvclock and/or hvclock pages before the vclock mode checks. This creates a path through vclock_gettime() in which no vclock is enabled at all (due to disabled TSC on old CPUs, for example) but the pvclock or hvclock page nevertheless read. This will segfault on bare metal. This fixes commit 459e3a2153 ("gcc-9: properly declare the {pv,hv}clock_page storage") in the sense that, before that commit, GCC didn't seem to generate the offending code. There was nothing wrong with that commit per se, and -stable maintainers should backport this to all supported kernels regardless of whether the offending commit was present, since the same crash could just as easily be triggered by the phase of the moon. On GCC 9.1.1, this doesn't seem to affect the generated code at all, so I'm not too concerned about performance regressions from this fix. Cc: stable@vger.kernel.org Cc: x86@kernel.org Cc: Borislav Petkov <bp@alien8.de> Reported-by: Duncan Roe <duncan_roe@optusnet.com.au> Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2019-06-21 13:31:52 -07:00
..
vdso32	x86: Add build salt to the vDSO	2018-07-18 01:18:05 +09:00
.gitignore	x86/asm/entry, x86/vdso: Move the vDSO code to arch/x86/entry/vdso/	2015-06-03 18:51:37 +02:00
Makefile	x86/build/vdso: Add FORCE to the build rule of %.so	2019-04-18 10:05:34 +02:00
checkundef.sh	x86/asm/entry, x86/vdso: Move the vDSO code to arch/x86/entry/vdso/	2015-06-03 18:51:37 +02:00
vclock_gettime.c	x86/vdso: Prevent segfaults due to hoisted vclock reads	2019-06-21 13:31:52 -07:00
vdso-layout.lds.S	x86/vdso: Remove a stale/misleading comment from the linker script	2018-12-05 08:58:12 +01:00
vdso-note.S	x86: Add build salt to the vDSO	2018-07-18 01:18:05 +09:00
vdso.lds.S	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
vdso2c.c	x86/vdso: Remove hpet_page from vDSO	2019-05-08 13:13:57 +02:00
vdso2c.h	x86/vdso: Rename variable to fix -Wshadow warning	2019-04-19 21:33:46 +02:00
vdso32-setup.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
vdsox32.lds.S	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
vgetcpu.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 223	2019-05-30 11:29:55 -07:00
vma.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 214	2019-05-30 11:29:54 -07:00