Run the create_image.sh script to: (0) install kernel build utilities; (1) clone an ubuntu kernel (v5.0); (2) apply the three patches available in the root directory; (3) configure the kernel to use KASAN in addition to the configuration for the currently running kernel; (4) compile and install the kernel.

Then reboot and load the newly installed kernel.

To initiate tracing run tracek.sh which sets up kernel ftracing that we use for KASAN logging, it also dumps the current log to output_trace.

On the newly installed kernel, run an IO application that exercises the DMA APIs. We run pings with various messages sizes to trigger DMA map/unmap operations of various lengths in NIC drivers. For example, ping 128 times with 0.01 second intervals between requests sending packets to destination IP $ip with lengths of 8,16,...1496:

for i in `seq 8 8 1496`; do sudo ping -s $i -c 128 -i 0.01 $ip; done

Additional methods to stress IO include:

• compiling the linux kernel
• benchmarks such as filebench and netperf
• listing directories

We provide a script that stresses these components (run_me.sh). To run the script set the following environment variables:

• $ip -- some destination IP address.
• $if -- some local network interface.
• $repeat -- number of repeatitions for the test.

After the IO stressing operation completes, check logs written to the local trace_output_end file for any interesting issues caught by DMA-KASAN.

$ ./tracek.sh or $ trace-cmd show

size 512 [READ, WRITE] __alloc_skb+0xe0/0x3f0
size 512 [WRITE] load_elf_phdrs+0xbf/0x130
size 512 [WRITE] __do_execve_file.isra.0+0x287/0x1080
size 64  [WRITE] sock_alloc_inode+0x4f/0x120
size 328 [READ, WRITE] assoc_array_insert+0xa9/0x7e0

• Compile the kernel with as many models as possible. Sometimes kernel modules will perform DMA operations even if they are not actively being used.
• Excercise as many IO devices as possible. Concurrent operations on the DMA API increases the likelihood of finding bugs.