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Message-ID: <20221130035805.1823970-6-cmllamas@google.com>
Date: Wed, 30 Nov 2022 03:58:04 +0000
From: Carlos Llamas <cmllamas@...gle.com>
To: stable@...nel.org, Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Arve Hjønnevåg" <arve@...roid.com>,
Todd Kjos <tkjos@...roid.com>,
Martijn Coenen <maco@...roid.com>,
Joel Fernandes <joel@...lfernandes.org>,
Christian Brauner <christian@...uner.io>,
Hridya Valsaraju <hridya@...gle.com>,
Suren Baghdasaryan <surenb@...gle.com>
Cc: linux-kernel@...r.kernel.org, kernel-team@...roid.com,
Alessandro Astone <ales.astone@...il.com>,
Todd Kjos <tkjos@...gle.com>,
Carlos Llamas <cmllamas@...gle.com>
Subject: [PATCH 5.10 5/6] binder: Address corner cases in deferred copy and fixup
From: Alessandro Astone <ales.astone@...il.com>
commit 2d1746e3fda0c3612143d7c06f8e1d1830c13e23 upstream.
When handling BINDER_TYPE_FDA object we are pushing a parent fixup
with a certain skip_size but no scatter-gather copy object, since
the copy is handled standalone.
If BINDER_TYPE_FDA is the last children the scatter-gather copy
loop will never stop to skip it, thus we are left with an item in
the parent fixup list. This will trigger the BUG_ON().
This is reproducible in android when playing a video.
We receive a transaction that looks like this:
obj[0] BINDER_TYPE_PTR, parent
obj[1] BINDER_TYPE_PTR, child
obj[2] BINDER_TYPE_PTR, child
obj[3] BINDER_TYPE_FDA, child
Fixes: 09184ae9b575 ("binder: defer copies of pre-patched txn data")
Acked-by: Todd Kjos <tkjos@...gle.com>
Cc: stable <stable@...nel.org>
Signed-off-by: Alessandro Astone <ales.astone@...il.com>
Link: https://lore.kernel.org/r/20220415120015.52684-2-ales.astone@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Carlos Llamas <cmllamas@...gle.com>
---
drivers/android/binder.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 398ce65b578b..1ba8a98094b4 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2695,6 +2695,7 @@ static int binder_do_deferred_txn_copies(struct binder_alloc *alloc,
{
int ret = 0;
struct binder_sg_copy *sgc, *tmpsgc;
+ struct binder_ptr_fixup *tmppf;
struct binder_ptr_fixup *pf =
list_first_entry_or_null(pf_head, struct binder_ptr_fixup,
node);
@@ -2749,7 +2750,11 @@ static int binder_do_deferred_txn_copies(struct binder_alloc *alloc,
list_del(&sgc->node);
kfree(sgc);
}
- BUG_ON(!list_empty(pf_head));
+ list_for_each_entry_safe(pf, tmppf, pf_head, node) {
+ BUG_ON(pf->skip_size == 0);
+ list_del(&pf->node);
+ kfree(pf);
+ }
BUG_ON(!list_empty(sgc_head));
return ret > 0 ? -EINVAL : ret;
--
2.38.1.584.g0f3c55d4c2-goog
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