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Commit d6a00b35 authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

uprobes/x86: Fix arch_uprobe_disable_step() && UTASK_SSTEP_TRAPPED interaction 



arch_uprobe_disable_step() should also take UTASK_SSTEP_TRAPPED into
account. In this case the probed insn was not executed, we need to
clear X86_EFLAGS_TF if it was set by us and that is all.

Again, this code will look more clean when we move it into
arch_uprobe_post_xol() and arch_uprobe_abort_xol().

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
parent 3a4664aa

arch/x86/kernel/uprobes.c

+10 −4
Original line number Diff line number Diff line
@@ -706,14 +706,20 @@ void arch_uprobe_disable_step(struct arch_uprobe *auprobe) 
{

	struct task_struct *task = current;

	struct arch_uprobe_task	*autask	= &task->utask->autask;

	bool trapped = (task->utask->state == UTASK_SSTEP_TRAPPED);

	struct pt_regs *regs = task_pt_regs(task);

	/*

	 * The state of TIF_BLOCKSTEP was not saved so we can get an extra

	 * SIGTRAP if we do not clear TF. We need to examine the opcode to

	 * make it right.

	 */

	if (unlikely(trapped)) {

		if (!autask->saved_tf)

			regs->flags &= ~X86_EFLAGS_TF;

	} else {

		if (autask->saved_tf)

			send_sig(SIGTRAP, task, 0);

		else if (!(auprobe->fixups & UPROBE_FIX_SETF))

			regs->flags &= ~X86_EFLAGS_TF;

	}

}