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    SubjectRe: [PATCH -tip tracing/kprobes 3/6] kprobes/x86: Fix to add __kprobes to in-kernel fault handing functions
    Frederic Weisbecker wrote:
    > On Thu, Aug 27, 2009 at 01:23:11PM -0400, Masami Hiramatsu wrote:
    >> Add __kprobes to the functions which handles in-kernel fixable page faults.
    >> Since kprobes can cause those in-kernel page faults by accessing kprobe data
    >> structures, probing those fault functions will cause fault-int3-loop
    >> (do_page_fault has already been marked as __kprobes).
    >>
    >> Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
    >> Cc: Frederic Weisbecker <fweisbec@gmail.com>
    >> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
    >> Cc: Ingo Molnar <mingo@elte.hu>
    >> ---
    >>
    >> arch/x86/mm/fault.c | 11 ++++++-----
    >> 1 files changed, 6 insertions(+), 5 deletions(-)
    >>
    >> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
    >> index bfae139..c322e59 100644
    >> --- a/arch/x86/mm/fault.c
    >> +++ b/arch/x86/mm/fault.c
    >> @@ -38,7 +38,8 @@ enum x86_pf_error_code {
    >> * Returns 0 if mmiotrace is disabled, or if the fault is not
    >> * handled by mmiotrace:
    >> */
    >> -static inline int kmmio_fault(struct pt_regs *regs, unsigned long addr)
    >> +static inline int __kprobes
    >> +kmmio_fault(struct pt_regs *regs, unsigned long addr)
    >> {
    >> if (unlikely(is_kmmio_active()))
    >> if (kmmio_handler(regs, addr) == 1)
    >
    >
    > I guess the problem also resides in a lot of subfunctions such as kmmio_handler
    > and such...

    Hmm, sure.
    kmmio functions should be marked as __kprobes( or __kmmio or __debug? :)).

    Thank you,

    >> @@ -46,7 +47,7 @@ static inline int kmmio_fault(struct pt_regs *regs, unsigned long addr)
    >> return 0;
    >> }
    >>
    >> -static inline int notify_page_fault(struct pt_regs *regs)
    >> +static inline int __kprobes notify_page_fault(struct pt_regs *regs)
    >> {
    >> int ret = 0;
    >>
    >> @@ -239,7 +240,7 @@ void vmalloc_sync_all(void)
    >> *
    >> * Handle a fault on the vmalloc or module mapping area
    >> */
    >> -static noinline int vmalloc_fault(unsigned long address)
    >> +static noinline __kprobes int vmalloc_fault(unsigned long address)
    >> {
    >> unsigned long pgd_paddr;
    >> pmd_t *pmd_k;
    >> @@ -361,7 +362,7 @@ void vmalloc_sync_all(void)
    >> *
    >> * This assumes no large pages in there.
    >> */
    >> -static noinline int vmalloc_fault(unsigned long address)
    >> +static noinline __kprobes int vmalloc_fault(unsigned long address)
    >> {
    >> pgd_t *pgd, *pgd_ref;
    >> pud_t *pud, *pud_ref;
    >> @@ -858,7 +859,7 @@ static int spurious_fault_check(unsigned long error_code, pte_t *pte)
    >> * There are no security implications to leaving a stale TLB when
    >> * increasing the permissions on a page.
    >> */
    >> -static noinline int
    >> +static noinline __kprobes int
    >> spurious_fault(unsigned long error_code, unsigned long address)
    >> {
    >> pgd_t *pgd;
    >>
    >>
    >> --
    >> Masami Hiramatsu
    >>
    >> Software Engineer
    >> Hitachi Computer Products (America), Inc.
    >> Software Solutions Division
    >>
    >> e-mail: mhiramat@redhat.com
    >

    --
    Masami Hiramatsu

    Software Engineer
    Hitachi Computer Products (America), Inc.
    Software Solutions Division

    e-mail: mhiramat@redhat.com



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