Re: [PATCH 13/23] perf tools: Fix uninitialized pathname on uncompressed fallback in filename__decompress()

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Wed, Jun 10, 2026 at 06:52:20PM -0300, Arnaldo Carvalho de Melo wrote:
> On Wed, Jun 10, 2026 at 08:08:10PM +0000, sashiko-bot@kernel.org wrote:
> > New issues:
> > - [Medium] The commit message explicitly describes a logic flow that would cause a severe data-loss bug, while the code implements the opposite (safe) logic.
> > 
> > Pre-existing issues:
> > - [High] Missing error code propagation and improper negative error handling cause `__open_dso` to mistakenly return valid file descriptors on failure.
> > --
> > 
> > commit 5ae85aedfdb730a58a0d285fd77526ec0c92c20e
> > Author: Arnaldo Carvalho de Melo <acme@redhat.com>
> > 
> > perf tools: Fix uninitialized pathname on uncompressed fallback in filename__decompress()
> > 
> > This commit addresses an issue where filename__decompress() left the
> > pathname parameter uninitialized on the early return path for uncompressed
> > files. The code is updated to set an empty string in this case, and
> > callers are modified to check for this empty string condition.
> > 
> > > Fix by copying the original filename to pathname before the early return,
> > > matching the behavior of the normal decompression path.
> > 
> > [Severity: Medium]
> > Does this commit message accurately describe the implementation?
> > 
> > The code below sets pathname[0] = '\0' instead of copying the filename. If
> > the code had copied the original filename as described here, wouldn't callers
> > assume the populated pathname was a newly created temporary file and call
> > unlink() on it, deleting the user's uncompressed kernel module or binary?
> 
> So this was the only non pre-existing issue found in this series, I
> rebased it on top of the 28 patches I merged in perf-tools-next while
> waiting for this last series to be reviewed and will do a full container
> suite test build, then push everything publicly.

Ah, there was a patch for replacing snprintf with scnprintf by Athira
that made one of the patches in my series to be dropped, same changes.

- Arnaldo