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Fix deadlock in line_discipline.rs

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This commit is contained in:
Ruize Tang
2024-11-26 23:35:24 +08:00
committed by Tate, Hongliang Tian
parent f762eb8913
commit 1b65ae6255
1 changed files with 6 additions and 1 deletions
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7
kernel/src/device/tty/line_discipline.rs
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@ -29,6 +29,11 @@ const BUFFER_CAPACITY: usize = 4096;
pub type LdiscSignalSender = Arc<dyn Fn(KernelSignal) + Send + Sync + 'static>;
// Lock ordering to prevent deadlock (circular dependencies):
// 1. `termios`
// 2. `current_line`
// 3. `read_buffer`
// 4. `work_item_para`
pub struct LineDiscipline {
/// Current line
current_line: SpinLock<CurrentLine, LocalIrqDisabled>,
@ -273,6 +278,7 @@ impl LineDiscipline {
///
/// If no bytes are available, this method returns 0 immediately.
fn poll_read(&self, dst: &mut [u8]) -> usize {
let termios = self.termios.lock();
let mut buffer = self.read_buffer.lock();
let len = buffer.len();
let max_read_len = len.min(dst.len());
@ -282,7 +288,6 @@ impl LineDiscipline {
let mut read_len = 0;
for dst_i in dst.iter_mut().take(max_read_len) {
if let Some(next_char) = buffer.pop() {
let termios = self.termios.lock();
if termios.is_canonical_mode() {
// canonical mode, read until meet new line
if is_line_terminator(next_char, &termios) {