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    SubjectRe: SMP races in proc with thread_struct
    Date
    On 04 May 2001 15:11:37 +0200, 
    Andreas Schwab <schwab@suse.de> wrote:
    >Keith Owens <kaos@ocs.com.au> writes:
    >|> Wrap the reference to the parent task structure with exception table
    >|> recovery code, like copy_from_user().
    >
    >Exception tables only protect accesses to user virtual memory. Kernel
    >memory references must always be valid in the first place.

    Wrong. Exception tables say that if the kernel gets an exception
    between labels A and B then branch to fixup label C. See show_regs()
    in arch/i386/kernel/process.c and wrmsr_eio() in arch/i386/kernel/msr.c
    for examples which do not depend on user virtual memory.

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