From: Matti Vaittinen mazziesaccount@gmail.com
[ Upstream commit 7c919b619bcc68158921b1bd968f0e704549bbb6 ]
When noevents is true and small buffer is used the allocated memory for holding the data may be smaller than the hard-coded 64 bytes. This can cause the iio_generic_buffer to crash.
Following was recorded on beagle bone black with v6.0 kernel and the digit fix patch: https://lore.kernel.org/all/Y0f+tKCz+ZAIoroQ@dc75zzyyyyyyyyyyyyycy-3.rev.dna... using valgrind;
==339== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info ==339== Command: /iio_generic_buffer -n kx022-accel -T0 -e -l 10 -a -w 2000000 ==339== Parent PID: 307 ==339== ==339== Syscall param read(buf) points to unaddressable byte(s) ==339== at 0x496BFA4: read (read.c:26) ==339== by 0x11699: main (iio_generic_buffer.c:724) ==339== Address 0x4ab3518 is 0 bytes after a block of size 160 alloc'd ==339== at 0x4864B70: malloc (vg_replace_malloc.c:381) ==339== by 0x115BB: main (iio_generic_buffer.c:677)
Fix this by always using the same size for reading as was used for data storage allocation.
Signed-off-by: Matti Vaittinen mazziesaccount@gmail.com Link: https://lore.kernel.org/r/Y0kMh0t5qUXJw3nQ@dc75zzyyyyyyyyyyyyycy-3.rev.dnain... Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/iio/iio_generic_buffer.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/iio/iio_generic_buffer.c b/tools/iio/iio_generic_buffer.c index 2491c54a5e4f..f8deae4e26a1 100644 --- a/tools/iio/iio_generic_buffer.c +++ b/tools/iio/iio_generic_buffer.c @@ -715,12 +715,12 @@ int main(int argc, char **argv) continue; }
- toread = buf_len; } else { usleep(timedelay); - toread = 64; }
+ toread = buf_len; + read_size = read(buf_fd, data, toread * scan_size); if (read_size < 0) { if (errno == EAGAIN) {