On Fri, Nov 01, 2024 at 11:34:48AM -0700, Andrii Nakryiko wrote: > 00200000-170ad000 r--p 00000000 07:01 5 > 172ac000-498e7000 r-xp 16eac000 07:01 5 > 49ae7000-49b8b000 r--p 494e7000 07:01 5 > 49d8b000-4a228000 rw-p 4958b000 07:01 5 > 4a228000-4c677000 rw-p 00000000 00:00 0 > 4c800000-4ca00000 r-xp 49c00000 07:01 5 > 4ca00000-4f600000 r-xp 49e00000 07:01 5 > 4f600000-5b270000 r-xp 4ca00000 07:01 5 > > Sorry, I'm probably dense and missing something. But from the example > process above, isn't this check violated already? Or it's two > different things? Not sure, honestly. It's hard to tell exactly what's going on, did you strip the file names? The sframe limitation is per file, not per address space. I assume these are one file: > 172ac000-498e7000 r-xp 16eac000 07:01 5 and these are another: > 4c800000-4ca00000 r-xp 49c00000 07:01 5 > 4ca00000-4f600000 r-xp 49e00000 07:01 5 > 4f600000-5b270000 r-xp 4ca00000 07:01 5 Multiple mappings for a single file is fine, as long as they're contiguous. > > Actually I just double checked and even the kernel's ELF loader assumes > > that each executable has only a single text start+end address pair. > > See above, very confused by such assumptions, but I'm hoping we are > talking about two different things here. The "contiguous text" thing seems enforced by the kernel for executables. However it doesn't manage shared libraries, those are mapped by the loader, e.g. /lib64/ld-linux-x86-64.so.2. At a quick glance I can't tell if /lib64/ld-linux-x86-64.so.2 enforces that. > > There's no point in adding complexity to support some hypothetical. I > > can remove the printk though. > > We are talking about fundamental things like format for supporting > frame pointer-less stack trace capture. It will take years to adopt > SFrame everywhere, so I think it's prudent to think a bit ahead beyond > just saying "no real application should need more than 4GB text", IMO. I don't think anybody is saying that... -- Josh
