2017-08-22 16:26:26

by Anton Volkov

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Subject: Possible memory leak in cafe_ccic.ko

Hello.

While searching for races in the Linux kernel I've come across
"drivers/media/platform/marvell-ccic/cafe_ccic.ko" module. Here are
questions that I came up with while analyzing results. Lines are given
using the info from Linux v4.12.

Consider the following case:

Thread 1: Thread 2:
mcam_v4l_release
->mcam_free_dma_bufs
cam->dma_bufs[i] = NULL
cam->nbufs = 0
cafe_pci_resume (mcam-core.c: line 413)
->mccic_resume
->mcam_read_setup
->mcam_alloc_dma_bufs
cam->dma_bufs[i] =
dma_alloc_coherent()
(mcam-core.c: line 381)

It looks like mcam_v4l_release() doesn't really shut the device down. In
this case cafe_pci_resume() leaks memory for cam->dma_bufs[i] after
mcam_v4l_release() freed and poisoned them. Is this feasible from your
point of view?

Thank you for your time.

-- Anton Volkov
Linux Verification Center, ISPRAS
web: http://linuxtesting.org
e-mail: [email protected]