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authorAlessandro Astone <ales.astone@gmail.com>2022-04-15 14:00:15 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-04-22 17:22:48 +0200
commit2d1746e3fda0c3612143d7c06f8e1d1830c13e23 (patch)
tree226d74b93d7d31c35fc665645cb72ec57d62583a /drivers/android
parent89b3896056c775bf957c8d287c65290707cdad4a (diff)
binder: Address corner cases in deferred copy and fixup
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@google.com> Cc: stable <stable@kernel.org> Signed-off-by: Alessandro Astone <ales.astone@gmail.com> Link: https://lore.kernel.org/r/20220415120015.52684-2-ales.astone@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/android')
-rw-r--r--drivers/android/binder.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 8351c5638880..31176edb1069 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2295,6 +2295,7 @@ 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);
@@ -2349,7 +2350,11 @@ 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;