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    Subjecttrap int3 problem while porting a user space application and small cleanup patch
    Hello,

    For a while I've been working on a little tool called mpt-status to be
    able to monitor LSI based controllers. The source can be found here:

    http://www.drugphish.ch/~ratz/mpt-status/

    The issue I'm trying to track down now is why I cannot get it to work on
    a x86_64 kernel (Sun Fire V20z with AMD Opteron(tm) Processor 252 on
    SLES 9 PL3). I suspect 32/64 bit issues between in my ioctl message
    passing between user space and kernel space. Unfortunately when I strace
    the kernel spits out tons of following entries:

    mpt-status[16045] trap int3 rip:400acf rsp:7fbfff70b0 error:0
    mpt-status[16045] trap int3 rip:4008f1 rsp:7fbfff70a8 error:0
    mpt-status[16045] trap int3 rip:400b86 rsp:7fbfff70b0 error:0

    I can only remotely guess what happened because I'm not sound on x64
    trap handling, so my question is: How can I best debug and address this
    issue in my tool?

    I'm pretty sure it has something to do with me including kernel headers
    in a user space tool, but noone has done the sanitizing for the LSI
    related headers residing in drivers/message/fusion. It works on all
    32-bit machines I've tested so far.

    Attached is a small code style cleanup patch that resulted from my
    skimming through the arch/x86_64/kernel/traps.c code to figure out what
    went haywire. If Andi is ok with it, please consider applying.

    Signed-off-by: Roberto Nibali <ratz@drugphish.ch>

    Best regards,
    Roberto Nibali, ratz
    --
    echo
    '[q]sa[ln0=aln256%Pln256/snlbx]sb3135071790101768542287578439snlbxq' | dc
    diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
    index ee1b2da..3442a56 100644
    --- a/arch/x86_64/kernel/traps.c
    +++ b/arch/x86_64/kernel/traps.c
    @@ -108,7 +108,7 @@ int printk_address(unsigned long address
    if (!modname)
    modname = delim = "";
    return printk("<%016lx>{%s%s%s%s%+ld}",
    - address,delim,modname,delim,symname,offset);
    + address, delim, modname, delim, symname, offset);
    }
    #else
    int printk_address(unsigned long address)
    @@ -320,13 +320,12 @@ void show_registers(struct pt_regs *regs
    show_stack(NULL, (unsigned long*)rsp);

    printk("\nCode: ");
    - if(regs->rip < PAGE_OFFSET)
    + if (regs->rip < PAGE_OFFSET)
    goto bad;

    - for(i=0;i<20;i++)
    - {
    + for (i=0; i<20; i++) {
    unsigned char c;
    - if(__get_user(c, &((unsigned char*)regs->rip)[i])) {
    + if (__get_user(c, &((unsigned char*)regs->rip)[i])) {
    bad:
    printk(" Bad RIP value.");
    break;
    @@ -465,7 +464,7 @@ static void __kprobes do_trap(int trapnr
    printk(KERN_INFO
    "%s[%d] trap %s rip:%lx rsp:%lx error:%lx\n",
    tsk->comm, tsk->pid, str,
    - regs->rip,regs->rsp,error_code);
    + regs->rip, regs->rsp, error_code);

    if (info)
    force_sig_info(signr, info, tsk);
    @@ -479,9 +478,9 @@ static void __kprobes do_trap(int trapnr
    {
    const struct exception_table_entry *fixup;
    fixup = search_exception_tables(regs->rip);
    - if (fixup) {
    + if (fixup)
    regs->rip = fixup->fixup;
    - } else
    + else
    die(str, regs, error_code);
    return;
    }
    @@ -554,7 +553,7 @@ asmlinkage void __kprobes do_general_pro
    printk(KERN_INFO
    "%s[%d] general protection rip:%lx rsp:%lx error:%lx\n",
    tsk->comm, tsk->pid,
    - regs->rip,regs->rsp,error_code);
    + regs->rip, regs->rsp, error_code);

    force_sig(SIGSEGV, tsk);
    return;
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