Re: dtracing unlink

[Thomas Klausner <wiz%netbsd.org@localhost>]

On Sat, Oct 21, 2023 at 06:10:17AM +0000, RVP wrote:
> On Fri, 20 Oct 2023, bch wrote:
> 
> > What OS release/architecture are you using that is getting favorable
> > results?
> > 
> 
> $ uname -a
> NetBSD x202e.localdomain 10.99.10 NetBSD 10.99.10 (GENERIC) #0: Thu Oct 19 23:43:40 UTC 2023  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64
> 
> > I’m following along on ~up-to-the-minute -current AMD64 on my Thinkpad, and
> > only seeing the same memory errors as wiz’ original example.
> > 
> 
> Do the copyinstr in ::entry like this:
> 
> ```
> #!/usr/sbin/dtrace -s
> 
> #pragma D option destructive
> #pragma D option quiet
> 
> syscall::unlink:entry
> {
> 	self->file = copyinstr(arg0);
> }
> 
> syscall::unlink:return
> {
> 	printf("%d %s\n", pid, self->file);
> 	self->file = 0;
> }
> ```

With that I see:

# ./dtrace.unlink2
dtrace: buffer size lowered to 1m
dtrace: error on enabled probe ID 1 (ID 404: syscall::unlink:entry): invalid address (0xc000048240) in action #1 at DIF offset 12
: No such file or directory
dtrace: error on enabled probe ID 2 (ID 405: syscall::unlink:return): invalid address (0x0) in action #2
: No such file or directory

 Thomas