Re: [PATCH v2 5/5] binder: additional transaction error logs

From: Todd Kjos
Date: Mon May 02 2022 - 11:30:06 EST


On Fri, Apr 29, 2022 at 4:57 PM 'Carlos Llamas' via kernel-team
<kernel-team@xxxxxxxxxxx> wrote:
>
> Log readable and specific error messages whenever a transaction failure
> happens. This will ensure better context is given to regular users about
> these unique error cases, without having to decode a cryptic log.
>
> Signed-off-by: Carlos Llamas <cmllamas@xxxxxxxxxx>

Acked-by: Todd Kjos <tkjos@xxxxxxxxxx>

> ---
> drivers/android/binder.c | 48 ++++++++++++++++++++++++++++++++++++----
> 1 file changed, 44 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index bfb21e258427..d7c5e2dde270 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -147,6 +147,9 @@ static __printf(2, 3) void binder_debug(int mask, const char *format, ...)
> }
> }
>
> +#define binder_txn_error(x...) \
> + binder_debug(BINDER_DEBUG_FAILED_TRANSACTION, x)
> +
> static __printf(1, 2) void binder_user_error(const char *format, ...)
> {
> struct va_format vaf;
> @@ -2823,6 +2826,8 @@ static void binder_transaction(struct binder_proc *proc,
> if (target_thread == NULL) {
> /* annotation for sparse */
> __release(&target_thread->proc->inner_lock);
> + binder_txn_error("%d:%d reply target not found\n",
> + thread->pid, proc->pid);
> return_error = BR_DEAD_REPLY;
> return_error_line = __LINE__;
> goto err_dead_binder;
> @@ -2888,6 +2893,8 @@ static void binder_transaction(struct binder_proc *proc,
> }
> }
> if (!target_node) {
> + binder_txn_error("%d:%d cannot find target node\n",
> + thread->pid, proc->pid);
> /*
> * return_error is set above
> */
> @@ -2897,6 +2904,8 @@ static void binder_transaction(struct binder_proc *proc,
> }
> e->to_node = target_node->debug_id;
> if (WARN_ON(proc == target_proc)) {
> + binder_txn_error("%d:%d self transactions not allowed\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = -EINVAL;
> return_error_line = __LINE__;
> @@ -2904,6 +2913,8 @@ static void binder_transaction(struct binder_proc *proc,
> }
> if (security_binder_transaction(proc->cred,
> target_proc->cred) < 0) {
> + binder_txn_error("%d:%d transaction credentials failed\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = -EPERM;
> return_error_line = __LINE__;
> @@ -2975,6 +2986,8 @@ static void binder_transaction(struct binder_proc *proc,
> /* TODO: reuse incoming transaction for reply */
> t = kzalloc(sizeof(*t), GFP_KERNEL);
> if (t == NULL) {
> + binder_txn_error("%d:%d cannot allocate transaction\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = -ENOMEM;
> return_error_line = __LINE__;
> @@ -2986,6 +2999,8 @@ static void binder_transaction(struct binder_proc *proc,
>
> tcomplete = kzalloc(sizeof(*tcomplete), GFP_KERNEL);
> if (tcomplete == NULL) {
> + binder_txn_error("%d:%d cannot allocate work for transaction\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = -ENOMEM;
> return_error_line = __LINE__;
> @@ -3032,6 +3047,8 @@ static void binder_transaction(struct binder_proc *proc,
> security_cred_getsecid(proc->cred, &secid);
> ret = security_secid_to_secctx(secid, &secctx, &secctx_sz);
> if (ret) {
> + binder_txn_error("%d:%d failed to get security context\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = ret;
> return_error_line = __LINE__;
> @@ -3040,7 +3057,8 @@ static void binder_transaction(struct binder_proc *proc,
> added_size = ALIGN(secctx_sz, sizeof(u64));
> extra_buffers_size += added_size;
> if (extra_buffers_size < added_size) {
> - /* integer overflow of extra_buffers_size */
> + binder_txn_error("%d:%d integer overflow of extra_buffers_size\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = -EINVAL;
> return_error_line = __LINE__;
> @@ -3054,9 +3072,15 @@ static void binder_transaction(struct binder_proc *proc,
> tr->offsets_size, extra_buffers_size,
> !reply && (t->flags & TF_ONE_WAY), current->tgid);
> if (IS_ERR(t->buffer)) {
> - /*
> - * -ESRCH indicates VMA cleared. The target is dying.
> - */
> + char *s;
> +
> + ret = PTR_ERR(t->buffer);
> + s = (ret == -ESRCH) ? ": vma cleared, target dead or dying"
> + : (ret == -ENOSPC) ? ": no space left"
> + : (ret == -ENOMEM) ? ": memory allocation failed"
> + : "";
> + binder_txn_error("cannot allocate buffer%s", s);
> +
> return_error_param = PTR_ERR(t->buffer);
> return_error = return_error_param == -ESRCH ?
> BR_DEAD_REPLY : BR_FAILED_REPLY;
> @@ -3139,6 +3163,8 @@ static void binder_transaction(struct binder_proc *proc,
> t->buffer,
> buffer_offset,
> sizeof(object_offset))) {
> + binder_txn_error("%d:%d copy offset from buffer failed\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = -EINVAL;
> return_error_line = __LINE__;
> @@ -3197,6 +3223,8 @@ static void binder_transaction(struct binder_proc *proc,
> t->buffer,
> object_offset,
> fp, sizeof(*fp))) {
> + binder_txn_error("%d:%d translate binder failed\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = ret;
> return_error_line = __LINE__;
> @@ -3214,6 +3242,8 @@ static void binder_transaction(struct binder_proc *proc,
> t->buffer,
> object_offset,
> fp, sizeof(*fp))) {
> + binder_txn_error("%d:%d translate handle failed\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = ret;
> return_error_line = __LINE__;
> @@ -3234,6 +3264,8 @@ static void binder_transaction(struct binder_proc *proc,
> t->buffer,
> object_offset,
> fp, sizeof(*fp))) {
> + binder_txn_error("%d:%d translate fd failed\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = ret;
> return_error_line = __LINE__;
> @@ -3303,6 +3335,8 @@ static void binder_transaction(struct binder_proc *proc,
> object_offset,
> fda, sizeof(*fda));
> if (ret) {
> + binder_txn_error("%d:%d translate fd array failed\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = ret > 0 ? -EINVAL : ret;
> return_error_line = __LINE__;
> @@ -3330,6 +3364,8 @@ static void binder_transaction(struct binder_proc *proc,
> (const void __user *)(uintptr_t)bp->buffer,
> bp->length);
> if (ret) {
> + binder_txn_error("%d:%d deferred copy failed\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = ret;
> return_error_line = __LINE__;
> @@ -3353,6 +3389,8 @@ static void binder_transaction(struct binder_proc *proc,
> t->buffer,
> object_offset,
> bp, sizeof(*bp))) {
> + binder_txn_error("%d:%d failed to fixup parent\n",
> + thread->pid, proc->pid);
> return_error = BR_FAILED_REPLY;
> return_error_param = ret;
> return_error_line = __LINE__;
> @@ -3460,6 +3498,8 @@ static void binder_transaction(struct binder_proc *proc,
> return;
>
> err_dead_proc_or_thread:
> + binder_txn_error("%d:%d dead process or thread\n",
> + thread->pid, proc->pid);
> return_error_line = __LINE__;
> binder_dequeue_work(proc, tcomplete);
> err_translate_failed:
> --
> 2.36.0.464.gb9c8b46e94-goog
>
> --
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