machine__init() always returns 0 even when memory allocation fails,
because commit 81f981d7ec ("perf machine: Free root_dir in
machine__init() error path") introduced 'int err = -ENOMEM' and an
error cleanup path but left the final 'return 0' instead of
'return err'.
Fix by returning err, check the return value in __machine__new_host()
which was ignoring it, and change machines__init() from void to int so
it too can propagate the error to perf_session__new(), aslr_tool__init()
and test callers.
The error cleanup also used zfree(&machine->kmaps), but kmaps is a
refcounted maps structure — use maps__zput() to properly drop the
reference, matching machine__exit().
Move dsos__init() and threads__init() before the first fallible
allocation (maps__new) so that machine__exit() is safe to call on
any machine struct that machine__init() touched, even on early failure.
Fixes: 81f981d7ec ("perf machine: Free root_dir in machine__init() error path")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix a use after put reference count issue. maps is copied from leader,
but the leader is put on line 79 and then maps is used to read the
reference count below - so a use after put, with the put of maps
happening within thread__put. Fix by reversing the order of puts so
that the leader is put last.
To explain the reference count checker, I wrote this up as a little
example here:
https://perf.wiki.kernel.org/index.php/Reference_Count_Checking
Note, the bug was introduced by the committer and wasn't present in
the original reference count patch set.
Committer notes:
Yes, the bug predated your patch and is detected by the reference count
checking you contributed.
This was just part of splitting up your series into smaller chunks, in
this case either we fix the problem detected while developing this
reference counting infrastructure before the patch introducing REFCNT_CHECKING
or fix it later after the merged infrastructure, when built with
EXTRA_CFLAGS="-DREFCNT_CHECKING=1" detects it when running 'perf test', which
is what this patch does.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20230420030430.489243-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To remove one more direct access to 'struct maps' so that we can
intercept accesses to its instantiations and refcount check it to catch
use after free, etc.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
