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Commit ecd50f71 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Ingo Molnar
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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: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/20140417081740.26341.10894.stgit@ltc230.yrl.intra.hitachi.co.jp


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 6f6343f5

arch/x86/kernel/traps.c

+2 −3
Original line number Diff line number Diff line
@@ -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)