Revision 61f01dd941ba9e06d2bf05994450ecc3d61b6b8b authored by Andy Lutomirski on 26 April 2015, 23:47:59 UTC, committed by Linus Torvalds on 27 April 2015, 00:57:38 UTC
AMD CPUs don't reinitialize the SS descriptor on SYSRET, so SYSRET with
SS == 0 results in an invalid usermode state in which SS is apparently
equal to __USER_DS but causes #SS if used.

Work around the issue by setting SS to __KERNEL_DS __switch_to, thus
ensuring that SYSRET never happens with SS set to NULL.

This was exposed by a recent vDSO cleanup.

Fixes: e7d6eefaaa44 x86/vdso32/syscall.S: Do not load __USER32_DS to %ss
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 1190944
History
File Mode Size
Makefile -rw-r--r-- 421 bytes
asm-offsets.c -rw-r--r-- 1.3 KB
crisksyms.c -rw-r--r-- 1.7 KB
devicetree.c -rw-r--r-- 317 bytes
irq.c -rw-r--r-- 1.6 KB
module.c -rw-r--r-- 2.3 KB
process.c -rw-r--r-- 1.5 KB
profile.c -rw-r--r-- 1.9 KB
ptrace.c -rw-r--r-- 1.5 KB
setup.c -rw-r--r-- 5.9 KB
sys_cris.c -rw-r--r-- 958 bytes
time.c -rw-r--r-- 2.0 KB
traps.c -rw-r--r-- 5.1 KB
vmlinux.lds.S -rw-r--r-- 2.6 KB

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