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
Kconfig -rw-r--r-- 64.5 KB
Makefile -rw-r--r-- 1.1 KB
calibrate.c -rw-r--r-- 8.5 KB
do_mounts.c -rw-r--r-- 14.4 KB
do_mounts.h -rw-r--r-- 1.4 KB
do_mounts_initrd.c -rw-r--r-- 3.4 KB
do_mounts_md.c -rw-r--r-- 8.2 KB
do_mounts_rd.c -rw-r--r-- 8.7 KB
init_task.c -rw-r--r-- 728 bytes
initramfs.c -rw-r--r-- 13.8 KB
main.c -rw-r--r-- 24.6 KB
noinitramfs.c -rw-r--r-- 1.5 KB
version.c -rw-r--r-- 1.2 KB

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