From: Masami Hiramatsu Date: Thu, 17 Apr 2014 08:17:40 +0000 (+0900) Subject: kprobes, x86: Call exception_enter after kprobes handled X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=ecd50f714c42;p=openwrt%2Fstaging%2Fblogic.git kprobes, x86: Call exception_enter after kprobes handled Move exception_enter() call after kprobes handler is done. Since the exception_enter() involves many other functions (like printk), it can cause recursive int3/break loop when kprobes probe such functions. Signed-off-by: Masami Hiramatsu Reviewed-by: Steven Rostedt Cc: Andrew Morton Cc: Borislav Petkov Cc: Jiri Kosina Cc: Kees Cook Cc: Rusty Russell Cc: Seiji Aguchi Link: http://lkml.kernel.org/r/20140417081740.26341.10894.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index e5d4a70814d7..ba9abe9cbce3 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -327,7 +327,6 @@ dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_co if (poke_int3_handler(regs)) return; - prev_state = exception_enter(); #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP, SIGTRAP) == NOTIFY_STOP) @@ -338,6 +337,7 @@ dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_co if (kprobe_int3_handler(regs)) return; #endif + prev_state = exception_enter(); if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP, SIGTRAP) == NOTIFY_STOP) @@ -415,8 +415,6 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) unsigned long dr6; int si_code; - prev_state = exception_enter(); - get_debugreg(dr6, 6); /* Filter out all the reserved bits which are preset to 1 */ @@ -449,6 +447,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) if (kprobe_debug_handler(regs)) goto exit; #endif + prev_state = exception_enter(); if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, error_code, SIGTRAP) == NOTIFY_STOP)