Re: [PATCH perf-tools-next v6 1/5] perf trace: Fix error checking in btf_struct_scnprintf()

[sashiko-bot@kernel.org]

> btf_dump__dump_type_data() returns the positive number of bytes dumped on
> success, or a negative error code (e.g., -EINVAL) on failure.
> 
> Currently, btf_struct_scnprintf() checks if btf_dump__dump_type_data()
> returns 0. When a negative error code is returned on failure, this check
> evaluates to false, causing the function to proceed down the success path
> and advance arg->augmented.args past the unprinted struct data before
> returning 0.
> 
> Consequently, when syscall__scnprintf_args() falls back to the default
> argument beautifier upon receiving 0 from trace__btf_scnprintf(), the
> fallback beautifier or subsequent arguments read from an erroneously
> advanced augmented arguments buffer.
> 
> Fix this by checking for '<= 0' ensuring that on any failure or 0-byte
> dump, 0 is returned without modifying the augmented arguments pointer.
> 
> Fixes: cb32035214b9 ("perf trace: Pretty print augmented struct args using BTF")
> Reported-by: sashiko-bot <sashiko-bot@kernel.org>
> Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260824133122.751733-1-atomlin@atomlin.com?part=1