binder: additional transaction error logs

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.

Acked-by: Todd Kjos <tkjos@google.com>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20220429235644.697372-6-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 88f502848397dabf9e86eefc0406cb43e23520f4..d9253b2a7bd9f5cf2b4204d4eeff4a01caac1343 100644 (file)
--- 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;
@@ -2834,6 +2837,8 @@ 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;
@@ -2899,6 +2904,8 @@ 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
                         */
@@ -2908,6 +2915,8 @@ 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__;
@@ -2915,6 +2924,8 @@ 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__;
@@ -2986,6 +2997,8 @@ 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__;
@@ -2997,6 +3010,8 @@ 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__;
@@ -3043,6 +3058,8 @@ 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__;
@@ -3051,7 +3068,8 @@ 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__;
@@ -3065,9 +3083,15 @@ 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;
@@ -3150,6 +3174,8 @@ 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__;
@@ -3208,6 +3234,8 @@ 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__;
@@ -3225,6 +3253,8 @@ 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__;
@@ -3245,6 +3275,8 @@ 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__;
@@ -3314,6 +3346,8 @@ 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__;
@@ -3341,6 +3375,8 @@ 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__;
@@ -3364,6 +3400,8 @@ 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__;
@@ -3471,6 +3509,8 @@ 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: