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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' | dcdiff --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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