Frederic, This one's for you.
Looks good as the exception_enter() is to catch when userspace causes the exception which wouldn't be the case for kprobes. When kprobes needs to do work, it would have already been in the kernel and the NO_HZ_FULL and RCU should be aware of that. But for me: Reviewed-by: Steven Rostedt <rost...@goodmis.org> -- Steve On Wed, 05 Mar 2014 20:59:46 +0900 Masami Hiramatsu <masami.hiramatsu...@hitachi.com> wrote: > 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 <masami.hiramatsu...@hitachi.com> > --- > arch/x86/kernel/traps.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c > index e5d4a70..ba9abe9 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) > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
