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Commit 9be260a6 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Linus Torvalds
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prevent kprobes from catching spurious page faults 



Prevent kprobes from catching spurious faults which will cause infinite
recursive page-fault and memory corruption by stack overflow.

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Cc: <stable@kernel.org>		[2.6.28.x]
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 767b5828

arch/x86/mm/fault.c

+6 −2
Original line number Diff line number Diff line
@@ -603,8 +603,6 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) 


	si_code = SEGV_MAPERR;



	if (notify_page_fault(regs))

		return;

	if (unlikely(kmmio_fault(regs, address)))

		return;
@@ -634,6 +632,9 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) 
		if (spurious_fault(address, error_code))

			return;



		/* kprobes don't want to hook the spurious faults. */

		if (notify_page_fault(regs))

			return;

		/*

		 * Don't take the mm semaphore here. If we fixup a prefetch

		 * fault we could otherwise deadlock.
@@ -641,6 +642,9 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) 
		goto bad_area_nosemaphore;

	}



	/* kprobes don't want to hook the spurious faults. */

	if (notify_page_fault(regs))

		return;



	/*

	 * It's safe to allow irq's after cr2 has been saved and the