Date:   Mon, 7 Nov 2022 09:25:45 +0800
From:   "liaochang (A)" <liaochang1@...wei.com>
To:     Lukas Bulwahn <lukas.bulwahn@...il.com>
CC:     <apw@...onical.com>, <joe@...ches.com>, <dwaipayanray1@...il.com>,
        <linux-kernel@...r.kernel.org>, <bagasdotme@...il.com>,
        <pbonzini@...hat.com>
Subject: Re: [PATCH -next v2] checkpatch: Add check for array allocator family
 argument order



在 2022/11/4 16:35, Lukas Bulwahn 写道:
> On Fri, Nov 4, 2022 at 8:08 AM Liao Chang <liaochang1@...wei.com> wrote:
>>
>> These array allocator family are sometimes misused with the first and
>> second arguments switchted.
> 
> Just a nit:
> 
> s/switchted/switched/
> 
> But probably you actually mean "swapped". I think there is a slight
> difference between the two words, "switched" and "swapped". And here
> the arguments are swapped. Note: I am also not a native speaker.
> 
> For the implementation change:
> 
> Acked-by: Lukas Bulwahn <lukas.bulwahn@...il.com>
> 
> How many new findings are now identified with this extended check on
> linux-next? Could you run checkpatch on all files of linux-next and
> share the new findings? Then we can do a quick scan if some instances
> should be immediately fixed or some janitor should follow through with
> such a task.

The scan result for v6.1-rc3:

./kernel/watch_queue.c:276:     pages = kcalloc(sizeof(struct page *), nr_pages, GFP_KERNEL);
./virt/kvm/kvm_main.c:411:              mc->objects = kvmalloc_array(sizeof(void *), capacity, gfp);
./tools/objtool/check.c:288:    struct cfi_state *cfi = calloc(sizeof(struct cfi_state), 1);
./tools/objtool/check.c:517:    file->pv_ops = calloc(sizeof(struct pv_state), nr);
./kernel/bpf/bpf_local_storage.c:623:   smap->buckets = kvcalloc(sizeof(*smap->buckets), nbuckets,
./tools/perf/builtin-record.c:4076:             rec->switch_output.filenames = calloc(sizeof(char *),
./fs/btrfs/send.c:7913: sctx->clone_roots = kvcalloc(sizeof(*sctx->clone_roots),
./drivers/scsi/bfa/bfad_bsg.c:3247:     buf_base = kcalloc(sizeof(struct bfad_buf_info) +
./sound/core/seq/seq_memory.c:379:      cellptr = kvmalloc_array(sizeof(struct snd_seq_event_cell), pool->size,
./tools/lib/bpf/libbpf.c:8220:  gen = calloc(sizeof(*gen), 1);
./tools/perf/util/metricgroup.c:269:    metric_events = calloc(sizeof(void *), ids_size + 1);
./tools/perf/util/hist.c:492:           he->res_samples = calloc(sizeof(struct res_sample),
./tools/perf/util/bpf-loader.c:574:     priv = calloc(sizeof(*priv), 1);
./tools/perf/util/synthetic-events.c:1040:      synthesize_threads = calloc(sizeof(pthread_t), thread_nr);
./tools/perf/util/synthetic-events.c:1044:      args = calloc(sizeof(*args), thread_nr);
./tools/perf/util/stat-shadow.c:390:                    metric_events = calloc(sizeof(struct evsel *),
./drivers/soc/fsl/dpio/dpio-service.c:526:      ed = kcalloc(sizeof(struct qbman_eq_desc), 32, GFP_KERNEL);
./drivers/gpu/drm/nouveau/nouveau_svm.c:1000:   buffer->fault = kvcalloc(sizeof(*buffer->fault), buffer->entries, GFP_KERNEL);
./tools/testing/selftests/memfd/fuse_test.c:257:        zero = calloc(sizeof(*zero), mfd_def_size);
./tools/testing/selftests/bpf/test_progs.c:1324:        dispatcher_threads = calloc(sizeof(pthread_t), env.workers);
./tools/testing/selftests/bpf/test_progs.c:1325:        data = calloc(sizeof(struct dispatch_data), env.workers);
./tools/testing/selftests/bpf/test_progs.c:1327:        env.worker_current_test = calloc(sizeof(int), env.workers);
./tools/testing/selftests/bpf/test_progs.c:1642:                env.worker_pids = calloc(sizeof(__pid_t), env.workers);
./tools/testing/selftests/bpf/test_progs.c:1643:                env.worker_socks = calloc(sizeof(int), env.workers);
./tools/testing/selftests/arm64/fp/fp-stress.c:458:     children = calloc(sizeof(*children), tests);
./tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c:87:    link = calloc(sizeof(struct bpf_link *), prog_cnt);
./tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c:91:    prog = calloc(sizeof(struct bpf_program *), prog_cnt);

> 
> Lukas
> 
>>
>> Same issue with calloc, kvcalloc, kvmalloc_array etc.
>>
>> Bleat if sizeof is the first argument.
>>
>> Link: https://lore.kernel.org/lkml/5374345c-7973-6a3c-d559-73bf4ac15079@redhat.com/
>> Signed-off-by: Liao Chang <liaochang1@...wei.com>
>> Acked-by: Joe Perches <joe@...ches.com>
>> ---
>> v2:
>> 1. Acked-by Joe Perches.
>> 2. Use lore links in Link tag.
>>
>> ---
>>  scripts/checkpatch.pl | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
>> index 1e5e66ae5a52..a9a9dc277cff 100755
>> --- a/scripts/checkpatch.pl
>> +++ b/scripts/checkpatch.pl
>> @@ -7128,7 +7128,7 @@ sub process {
>>                 }
>>
>>  # check for alloc argument mismatch
>> -               if ($line =~ /\b((?:devm_)?(?:kcalloc|kmalloc_array))\s*\(\s*sizeof\b/) {
>> +               if ($line =~ /\b((?:devm_)?((?:k|kv)?(calloc|malloc_array)(?:_node)?))\s*\(\s*sizeof\b/) {
>>                         WARN("ALLOC_ARRAY_ARGS",
>>                              "$1 uses number as first arg, sizeof is generally wrong\n" . $herecurr);
>>                 }
>> --
>> 2.17.1
>>
> .

-- 
BR,
Liao, Chang

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