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From: Tomer Pomeranc <tomerpo@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: gregkh@linuxfoundation.org, arve@android.com, tkjos@android.com,
	brauner@kernel.org, cmllamas@google.com, aliceryhl@google.com,
	stable@vger.kernel.org, Tomer Pomeranc <tomerpo@gmail.com>
Subject: [PATCH 2/2] binder: fix is_failure flag for superseded transaction cleanup
Date: Wed, 12 Aug 2026 22:53:16 +0300	[thread overview]
Message-ID: <20260812195316.259136-3-tomerpo@gmail.com> (raw)
In-Reply-To: <20260812195316.259136-1-tomerpo@gmail.com>

When a TF_UPDATE_TXN transaction supersedes a pending async transaction,
binder_release_entire_buffer() is called with is_failure=false. Since the
superseded transaction was never delivered, binder_apply_fd_fixups() was
never called and no fds were installed in the target process.

With is_failure=false, the BINDER_TYPE_FDA cleanup handler interprets
stale buffer contents as installed fd numbers and passes them to
binder_deferred_fd_close(), closing unrelated file descriptors.

Pass is_failure=true since the transaction was never delivered to the
target, matching the semantics of all other undelivered-transaction
cleanup paths.

Fixes: 9864bb480133 ("binder: add TF_UPDATE_TXN to replace outdated txn")
Cc: stable@vger.kernel.org
Signed-off-by: Tomer Pomeranc <tomerpo@gmail.com>
---
 drivers/android/binder.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index f70aeb63a..bc8bc9ee4 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2930,7 +2930,7 @@ static int binder_proc_transaction(struct binder_transaction *t,
 		t_outdated->buffer = NULL;
 		buffer->transaction = NULL;
 		trace_binder_transaction_update_buffer_release(buffer);
-		binder_release_entire_buffer(proc, NULL, buffer, false);
+		binder_release_entire_buffer(proc, NULL, buffer, true);
 		binder_alloc_free_buf(&proc->alloc, buffer);
 		binder_free_txn_fixups(t_outdated);
 		kfree(t_outdated);
-- 
2.34.1


  parent reply	other threads:[~2026-08-12 19:53 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-12 19:53 [PATCH 0/2] binder: fix TF_UPDATE_TXN supersede cleanup bugs Tomer Pomeranc
2026-08-12 19:53 ` [PATCH 1/2] binder: fix leaked fd fixups on TF_UPDATE_TXN supersede Tomer Pomeranc
2026-08-12 21:31   ` Carlos Llamas
2026-08-12 19:53 ` Tomer Pomeranc [this message]
2026-08-12 21:31   ` [PATCH 2/2] binder: fix is_failure flag for superseded transaction cleanup Carlos Llamas
2026-08-12 21:30 ` [PATCH 0/2] binder: fix TF_UPDATE_TXN supersede cleanup bugs Carlos Llamas

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