This is a note to let you know that I've just added the patch titled staging: ion: Prevent incorrect reference counting behavour to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: staging-ion-prevent-incorrect-reference-counting-behavour.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From lee.jones@xxxxxxxxxx Sat Nov 27 12:56:17 2021 From: Lee Jones <lee.jones@xxxxxxxxxx> Date: Fri, 26 Nov 2021 10:33:35 +0000 Subject: staging: ion: Prevent incorrect reference counting behavour To: lee.jones@xxxxxxxxxx Cc: devel@xxxxxxxxxxxxxxxxxxxx, arve@xxxxxxxxxxx, stable@xxxxxxxxxxxxxxx, riandrews@xxxxxxxxxxx, labbott@xxxxxxxxxx, sumit.semwal@xxxxxxxxxx, Dan Carpenter <dan.carpenter@xxxxxxxxxx> Message-ID: <20211126103335.880816-1-lee.jones@xxxxxxxxxx> From: Lee Jones <lee.jones@xxxxxxxxxx> Supply additional checks in order to prevent unexpected results. Fixes: b892bf75b2034 ("ion: Switch ion to use dma-buf") Suggested-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/staging/android/ion/ion.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/staging/android/ion/ion.c +++ b/drivers/staging/android/ion/ion.c @@ -489,6 +489,9 @@ static void *ion_buffer_kmap_get(struct void *vaddr; if (buffer->kmap_cnt) { + if (buffer->kmap_cnt == INT_MAX) + return ERR_PTR(-EOVERFLOW); + buffer->kmap_cnt++; return buffer->vaddr; } @@ -509,6 +512,9 @@ static void *ion_handle_kmap_get(struct void *vaddr; if (handle->kmap_cnt) { + if (handle->kmap_cnt == INT_MAX) + return ERR_PTR(-EOVERFLOW); + handle->kmap_cnt++; return buffer->vaddr; } Patches currently in stable-queue which might be from lee.jones@xxxxxxxxxx are queue-4.9/staging-ion-prevent-incorrect-reference-counting-behavour.patch