From: Chuck Ebbert <76306.1226@compuserve.com> Date: Tue, 26 Sep 2006 08:52:32 +0000 (+0200) Subject: [PATCH] fix is_at_popf() for compat tasks X-Git-Tag: v2.6.19-rc1~1077^2~143 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a752d7194c4fb5a3e767c95542d04fc5decb1d52;p=linux-2.6 [PATCH] fix is_at_popf() for compat tasks When testing for the REX instruction prefix, first check for 32-bit mode because in compat mode the REX prefix is an increment instruction. Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andi Kleen --- diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c index d35ec1bc69..3a52c7bcfd 100644 --- a/arch/x86_64/kernel/ptrace.c +++ b/arch/x86_64/kernel/ptrace.c @@ -141,8 +141,11 @@ static int is_at_popf(struct task_struct *child, struct pt_regs *regs) case 0xf0: case 0xf2: case 0xf3: continue; - /* REX prefixes */ case 0x40 ... 0x4f: + if (regs->cs != __USER_CS) + /* 32-bit mode: register increment */ + return 0; + /* 64-bit mode: REX prefix */ continue; /* CHECKME: f0, f2, f3 */