From fd8a09b8f4a7e0da67fe64cfb1d023bfb500d7eb Mon Sep 17 00:00:00 2001 From: peter chang Date: Wed, 24 Apr 2013 16:32:25 -0600 Subject: [PATCH] fix memory allocation in the cases we may need to align when using the sg backend we crash w/ a SEGV in fio_sgio_getevents() because of memory corruption from the IO. when we allocate the td's backing store there's a possible post-allocation adjustment to page align the buffers. however, the extra memory that this alignment may need is not taken into account when allocating the buffer. Tested: - the problematic fio file looks like fdha347:~# cat foo.fio [global] bs=64k thread rw=read size=100g time_based=1 runtime=60 iodepth=1 [sdc] ioengine=sg filename=/dev/sg2 numjobs=1 Signed-off-by: peter chang Signed-off-by: Jens Axboe --- backend.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/backend.c b/backend.c index 1c4484be..f48b43dc 100644 --- a/backend.c +++ b/backend.c @@ -910,6 +910,15 @@ static int init_io_u(struct thread_data *td) if ((td->io_ops->flags & FIO_NOIO) || !(td_read(td) || td_write(td))) data_xfer = 0; + /* + * if we may later need to do address alignment, then add any + * possible adjustment here so that we don't cause a buffer + * overflow later. this adjustment may be too much if we get + * lucky and the allocator gives us an aligned address. + */ + if (td->o.odirect || td->o.mem_align || (td->io_ops->flags & FIO_RAWIO)) + td->orig_buffer_size += page_mask + td->o.mem_align; + if (td->o.mem_type == MEM_SHMHUGE || td->o.mem_type == MEM_MMAPHUGE) { unsigned long bs; -- 2.25.1