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>
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pleb_defconfig
CONFIG_EXPERIMENTAL=y
# CONFIG_SWAP is not set
CONFIG_SYSVIPC=y
CONFIG_LOG_BUF_SHIFT=14
CONFIG_BLK_DEV_INITRD=y
CONFIG_EXPERT=y
# CONFIG_HOTPLUG is not set
# CONFIG_SHMEM is not set
CONFIG_MODULES=y
# CONFIG_IOSCHED_DEADLINE is not set
# CONFIG_IOSCHED_CFQ is not set
CONFIG_ARCH_SA1100=y
CONFIG_SA1100_PLEB=y
CONFIG_ZBOOT_ROM_TEXT=0x0
CONFIG_ZBOOT_ROM_BSS=0x0
CONFIG_CMDLINE="console=ttySA0,9600 mem=16M@0xc0000000 mem=16M@0xc8000000 root=/dev/ram initrd=0xc0400000,4M"
CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y
CONFIG_CPU_FREQ_GOV_ONDEMAND=y
CONFIG_FPE_NWFPE=y
CONFIG_NET=y
CONFIG_PACKET=y
CONFIG_UNIX=y
CONFIG_INET=y
CONFIG_SYN_COOKIES=y
# CONFIG_IPV6 is not set
CONFIG_MTD=y
CONFIG_MTD_PARTITIONS=y
CONFIG_MTD_REDBOOT_PARTS=y
CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED=y
CONFIG_MTD_CMDLINE_PARTS=y
CONFIG_MTD_CHAR=y
CONFIG_MTD_BLOCK=y
CONFIG_MTD_CFI=y
CONFIG_MTD_CFI_INTELEXT=y
CONFIG_MTD_SA1100=y
CONFIG_BLK_DEV_LOOP=y
CONFIG_BLK_DEV_RAM=y
CONFIG_BLK_DEV_RAM_SIZE=8192
CONFIG_NETDEVICES=y
CONFIG_NET_ETHERNET=y
CONFIG_SMC91X=y
# CONFIG_INPUT is not set
# CONFIG_SERIO is not set
# CONFIG_VT is not set
CONFIG_SERIAL_SA1100=y
CONFIG_SERIAL_SA1100_CONSOLE=y
CONFIG_EXT2_FS=y
CONFIG_EXT3_FS=y
# CONFIG_EXT3_FS_XATTR is not set
# CONFIG_DNOTIFY is not set
CONFIG_MSDOS_FS=m
CONFIG_VFAT_FS=m
CONFIG_NFS_FS=m
CONFIG_NFS_V3=y
CONFIG_NLS=y
CONFIG_MAGIC_SYSRQ=y
CONFIG_DEBUG_KERNEL=y
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