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Merge pull request #144 from sched-ext/rustland-fix-mem-alignment

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scx_rustland: prevent misaligned pointer dereference
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Tejun Heo 2024-02-20 08:15:38 -10:00 committed by GitHub
commit e9f7477770
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1 changed files with 10 additions and 3 deletions
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13
scheds/rust/scx_rustland/src/bpf.rs
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@ -212,8 +212,15 @@ pub struct BpfScheduler<'cb> {
}
// Buffer to store a task read from the ring buffer.
//
// NOTE: make the buffer aligned to 64-bits to prevent misaligned dereferences when accessing the
// buffer using a pointer.
const BUFSIZE: usize = std::mem::size_of::<QueuedTask>();
static mut BUF: [u8; BUFSIZE] = [0; BUFSIZE];
#[repr(align(8))]
struct AlignedBuffer([u8; BUFSIZE]);
static mut BUF: AlignedBuffer = AlignedBuffer([0; BUFSIZE]);
impl<'cb> BpfScheduler<'cb> {
pub fn init(slice_us: u64, nr_cpus_online: i32, partial: bool, debug: bool) -> Result<Self> {
@ -228,7 +235,7 @@ impl<'cb> BpfScheduler<'cb> {
// Copy one item from the ring buffer.
fn callback(data: &[u8]) -> i32 {
unsafe {
BUF.copy_from_slice(data);
BUF.0.copy_from_slice(data);
}
// Return an unsupported error to stop early and consume only one item.
@ -378,7 +385,7 @@ impl<'cb> BpfScheduler<'cb> {
Ok(()) => Ok(None),
Err(error) if error.kind() == libbpf_rs::ErrorKind::Other => {
// A valid task is received, convert data to a proper task struct.
let task = unsafe { EnqueuedMessage::from_bytes(&BUF).to_queued_task() };
let task = unsafe { EnqueuedMessage::from_bytes(&BUF.0).to_queued_task() };
Ok(Some(task))
}
Err(error) => Err(error),