Messages in this thread Patch in this message | | | Date | Tue, 10 Feb 2009 16:24:36 -0800 | From | Greg KH <> | Subject | [patch 11/56] prevent kprobes from catching spurious page faults |
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2.6.27-stable review patch. If anyone has any objections, please let us know. ------------------
From: Masami Hiramatsu <mhiramat@redhat.com>
commit 9be260a646bf76fa418ee519afa10196b3164681 upstream.
Prevent kprobes from catching spurious faults which will cause infinite recursive page-fault and memory corruption by stack overflow.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/x86/mm/fault.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -607,8 +607,6 @@ void __kprobes do_page_fault(struct pt_r si_code = SEGV_MAPERR; - if (notify_page_fault(regs)) - return; if (unlikely(kmmio_fault(regs, address))) return; @@ -638,6 +636,9 @@ void __kprobes do_page_fault(struct pt_r 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. @@ -645,6 +646,9 @@ void __kprobes do_page_fault(struct pt_r goto bad_area_nosemaphore; } + /* kprobes don't want to hook the spurious faults. */ + if (notify_page_fault(regs)) + return; #ifdef CONFIG_X86_32 /* It's safe to allow irq's after cr2 has been saved and the vmalloc
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