4.4-stable review patch. If anyone has any objections, please let me know.
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From: Masami Hiramatsu mhiramat@kernel.org
commit eb0146daefdde65665b7f076fbff7b49dade95b9 upstream.
Prohibit kprobes on do_undefinstr because kprobes on arm is implemented by undefined instruction. This means if we probe do_undefinstr(), it can cause infinit recursive exception.
Fixes: 24ba613c9d6c ("ARM kprobes: core code") Signed-off-by: Masami Hiramatsu mhiramat@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Russell King rmk+kernel@armlinux.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm/kernel/traps.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -19,6 +19,7 @@ #include <linux/uaccess.h> #include <linux/hardirq.h> #include <linux/kdebug.h> +#include <linux/kprobes.h> #include <linux/module.h> #include <linux/kexec.h> #include <linux/bug.h> @@ -395,7 +396,8 @@ void unregister_undef_hook(struct undef_ raw_spin_unlock_irqrestore(&undef_lock, flags); }
-static int call_undef_hook(struct pt_regs *regs, unsigned int instr) +static nokprobe_inline +int call_undef_hook(struct pt_regs *regs, unsigned int instr) { struct undef_hook *hook; unsigned long flags; @@ -468,6 +470,7 @@ die_sig:
arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6); } +NOKPROBE_SYMBOL(do_undefinstr)
/* * Handle FIQ similarly to NMI on x86 systems.