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Commit 0b5256c7 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Ingo Molnar
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uprobes: Send SIGILL if handle_trampoline() fails 



1. It doesn't make sense to continue if handle_trampoline()
   fails, change handle_swbp() to always return after this call.

2. Turn pr_warn() into uprobe_warn(), and change
   handle_trampoline() to send SIGILL on failure. It is pointless to
   return to user mode with the corrupted instruction_pointer() which
   we can't restore.

Tested-by: default avatarPratyush Anand <panand@redhat.com>
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: default avatarAnton Arapov <arapov@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150721134008.GA4745@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 2bb5e840

kernel/events/uprobes.c

+10 −11
Original line number Diff line number Diff line
@@ -1770,7 +1770,7 @@ handle_uretprobe_chain(struct return_instance *ri, struct pt_regs *regs) 
	up_read(&uprobe->register_rwsem);

}



static bool handle_trampoline(struct pt_regs *regs)

static void handle_trampoline(struct pt_regs *regs)

{

	struct uprobe_task *utask;

	struct return_instance *ri;
@@ -1778,11 +1778,11 @@ static bool handle_trampoline(struct pt_regs *regs) 


	utask = current->utask;

	if (!utask)

		return false;

		goto sigill;



	ri = utask->return_instances;

	if (!ri)

		return false;

		goto sigill;



	/*

	 * TODO: we should throw out return_instance's invalidated by
@@ -1804,8 +1804,12 @@ static bool handle_trampoline(struct pt_regs *regs) 
	}



	utask->return_instances = ri;

	return;



 sigill:

	uprobe_warn(current, "handle uretprobe, sending SIGILL.");

	force_sig_info(SIGILL, SEND_SIG_FORCED, current);



	return true;

}



bool __weak arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs)
@@ -1824,13 +1828,8 @@ static void handle_swbp(struct pt_regs *regs) 
	int uninitialized_var(is_swbp);



	bp_vaddr = uprobe_get_swbp_addr(regs);

	if (bp_vaddr == get_trampoline_vaddr()) {

		if (handle_trampoline(regs))

			return;



		pr_warn("uprobe: unable to handle uretprobe pid/tgid=%d/%d\n",

						current->pid, current->tgid);

	}

	if (bp_vaddr == get_trampoline_vaddr())

		return handle_trampoline(regs);



	uprobe = find_active_uprobe(bp_vaddr, &is_swbp);

	if (!uprobe) {