The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 51e0f227812ed81a368de54157ebe14396b4be03 Mon Sep 17 00:00:00 2001

From: Alexander Shishkin alexander.shishkin@linux.intel.com Date: Wed, 17 Apr 2019 10:35:35 +0300 Subject: [PATCH] stm class: Fix channel bitmap on 32-bit systems

Commit 7bd1d4093c2f ("stm class: Introduce an abstraction for System Trace Module devices") naively calculates the channel bitmap size in 64-bit chunks regardless of the size of underlying unsigned long, making the bitmap half as big on a 32-bit system. This leads to an out of bounds access with the upper half of the bitmap.

Fix this by using BITS_TO_LONGS. While at it, convert to using struct_size() for the total size calculation of the master struct.

Signed-off-by: Alexander Shishkin alexander.shishkin@linux.intel.com Fixes: 7bd1d4093c2f ("stm class: Introduce an abstraction for System Trace Module devices") Reported-by: Mulu He muluhe@codeaurora.org Cc: stable@vger.kernel.org # v4.4+ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c index 5b5807cbcf7c..e55b902560de 100644 --- a/drivers/hwtracing/stm/core.c +++ b/drivers/hwtracing/stm/core.c @@ -166,11 +166,10 @@ stm_master(struct stm_device *stm, unsigned int idx) static int stp_master_alloc(struct stm_device *stm, unsigned int idx) { struct stp_master *master; - size_t size;

- size = ALIGN(stm->data->sw_nchannels, 8) / 8; - size += sizeof(struct stp_master); - master = kzalloc(size, GFP_ATOMIC); + master = kzalloc(struct_size(master, chan_map, + BITS_TO_LONGS(stm->data->sw_nchannels)), + GFP_ATOMIC); if (!master) return -ENOMEM;