Re: [PATCH 1/9] perf machine: Propagate machine__init() error to callers

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Calling `perf_session__delete()` on early failure before `perf_env__init()` is called attempts to lock and destroy uninitialized mutexes and rw_semaphores.
--

commit 0e04858ad5c2ebb0c7b3cfa94d694fd312c0bd25
Author: Arnaldo Carvalho de Melo <acme@redhat.com>

perf machine: Propagate machine__init() error to callers

This commit updates machine__init() to return an error code upon failure
instead of 0. It modifies callers like machines__init() to check the
return value and propagate the error further up the stack.

> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index 1a9a008ddda35..26bacb6c1a572 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -160,7 +160,9 @@ struct perf_session *__perf_session__new(struct perf_data *data,
>  	session->decomp_data.zstd_decomp = &session->zstd_data;
>  	session->active_decomp = &session->decomp_data;
>  	INIT_LIST_HEAD(&session->auxtrace_index);
> -	machines__init(&session->machines);
> +	if (machines__init(&session->machines))
> +		goto out_delete;
> +

[Severity: Medium]
Will jumping to out_delete here cause a crash when cleaning up the
environment?

When this goto is taken, perf_session__delete() is called, which in turn
calls perf_env__exit().

However, perf_env__init(&session->header.env) is only called later in
__perf_session__new(), meaning the environment is still zero-initialized
from the zalloc() of the session.

When perf_env__exit() runs, it does:

perf_env__exit()
    mutex_destroy(&env->lock);
    perf_env__purge_bpf(env);

And perf_env__purge_bpf() calls down_write(&env->bpf_progs.lock).

Could attempting to destroy and lock these uninitialized synchronization
primitives lead to undefined behavior depending on the underlying libc
implementation?

>  	ordered_events__init(&session->ordered_events,
>  			     ordered_events__deliver_event, NULL);
>

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260615223249.36598-1-acme@kernel.org?part=1