[PATCH 1/2] binder: fix leaked fd fixups on TF_UPDATE_TXN supersede

[Tomer Pomeranc]

When a TF_UPDATE_TXN transaction supersedes a pending async transaction
in a frozen process, the outdated transaction is freed with kfree()
directly. This skips binder_free_txn_fixups(), leaking all
binder_txn_fd_fixup entries and their fget()'d struct file references.

The leaked file refcounts never reach zero, so the struct file objects
are permanently pinned in memory. They survive process exit and
accumulate across invocations until file-max exhaustion.

Every other transaction cleanup path (binder_free_transaction(),
binder_transaction() error paths, binder_release_work()) correctly
calls binder_free_txn_fixups(). Add the missing call before kfree()
in the t_outdated cleanup block.

Fixes: 9864bb480133 ("binder: add TF_UPDATE_TXN to replace outdated txn")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Tomer Pomeranc <tomerpo@xxxxxxxxx>
---
 drivers/android/binder.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 8f2ef1bd5..f70aeb63a 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2932,6 +2932,7 @@ static int binder_proc_transaction(struct binder_transaction *t,
 		trace_binder_transaction_update_buffer_release(buffer);
 		binder_release_entire_buffer(proc, NULL, buffer, false);
 		binder_alloc_free_buf(&proc->alloc, buffer);
+		binder_free_txn_fixups(t_outdated);
 		kfree(t_outdated);
 		binder_stats_deleted(BINDER_STAT_TRANSACTION);
 	}
-- 
2.34.1