On 4/16/2019 8:30 PM, Alexander Shishkin wrote:
Sai Prakash Ranjan <saiprakash.ran...@codeaurora.org> writes:
From: Mulu He <mul...@codeaurora.org>
Bitmap allocation works on array of unsigned longs and
for stm master allocation when the number of software
channels is 32, 4 bytes are allocated and there is a out of
bound access at the first 8 bytes access of bitmap region.
Does the below fix the problem for you?
From fb22b9ab109b332e58d72df13563e270befbd0e3 Mon Sep 17 00:00:00 2001
From: Alexander Shishkin <alexander.shish...@linux.intel.com>
Date: Tue, 16 Apr 2019 17:47:02 +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.shish...@linux.intel.com>
Fixes: 7bd1d4093c2f ("stm class: Introduce an abstraction for System Trace Module
devices")
Reported-by: Mulu He <mul...@codeaurora.org>
Cc: sta...@vger.kernel.org # v4.4+
---
drivers/hwtracing/stm/core.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c
index 5b5807cbcf7c..8c45e79e47db 100644
--- a/drivers/hwtracing/stm/core.c
+++ b/drivers/hwtracing/stm/core.c
@@ -166,11 +166,9 @@ 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;
++ David
Yes it does fix the issue. Actually initial fix internally was using
BITS_TO_LONGS, don't no why they deferred from it.
Anyways thanks for the patch.
- Sai
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