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ryanbreenryanbreen
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Merge pull request #92 from ryanbreen/fix/tcp-timing-and-exec-interrupts
fix(exec): move ext2 I/O outside interrupt-disabled section
2 parents d9b53cb + 2e83e51 commit 1cdf0fd

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2 files changed

+140
-133
lines changed

2 files changed

+140
-133
lines changed

‎kernel/src/syscall/handlers.rs‎

Lines changed: 137 additions & 131 deletions
Original file line numberDiff line numberDiff line change
@@ -1209,158 +1209,164 @@ pub fn sys_execv_with_frame(
12091209
program_name_ptr: u64,
12101210
argv_ptr: u64,
12111211
) -> SyscallResult {
1212-
x86_64::instructions::interrupts::without_interrupts(|| {
1213-
log::info!(
1214-
"sys_execv_with_frame called: program_name_ptr={:#x}, argv_ptr={:#x}",
1215-
program_name_ptr,
1216-
argv_ptr
1217-
);
1212+
// IMPORTANT: Do NOT wrap the entire function in without_interrupts()!
1213+
// ELF loading from ext2 filesystem requires interrupts for VirtIO I/O.
1214+
// Only the final frame manipulation needs to be interrupt-safe.
12181215

1219-
// Get current process and thread
1220-
let current_thread_id = match crate::task::scheduler::current_thread_id() {
1221-
Some(id) => id,
1222-
None => {
1223-
log::error!("sys_execv: No current thread");
1224-
return SyscallResult::Err(22); // EINVAL
1225-
}
1226-
};
1216+
log::info!(
1217+
"sys_execv_with_frame called: program_name_ptr={:#x}, argv_ptr={:#x}",
1218+
program_name_ptr,
1219+
argv_ptr
1220+
);
12271221

1228-
// Read the program name from userspace
1229-
if program_name_ptr == 0 {
1230-
log::error!("sys_execv: NULL program name");
1222+
// Get current process and thread
1223+
let current_thread_id = match crate::task::scheduler::current_thread_id() {
1224+
Some(id) => id,
1225+
None => {
1226+
log::error!("sys_execv: No current thread");
12311227
return SyscallResult::Err(22); // EINVAL
12321228
}
1229+
};
12331230

1234-
let name_bytes = match copy_string_from_user(program_name_ptr, 256) {
1235-
Ok(bytes) => bytes,
1236-
Err(e) => {
1237-
log::error!("sys_execv: Failed to read program name: {}", e);
1238-
return SyscallResult::Err(14); // EFAULT
1239-
}
1240-
};
1241-
1242-
let name_len = name_bytes.iter().position(|&b| b == 0).unwrap_or(name_bytes.len());
1243-
let program_name = match core::str::from_utf8(&name_bytes[..name_len]) {
1244-
Ok(s) => s,
1245-
Err(_) => {
1246-
log::error!("sys_execv: Invalid UTF-8 in program name");
1247-
return SyscallResult::Err(22); // EINVAL
1248-
}
1249-
};
1231+
// Read the program name from userspace
1232+
if program_name_ptr == 0 {
1233+
log::error!("sys_execv: NULL program name");
1234+
return SyscallResult::Err(22); // EINVAL
1235+
}
12501236

1251-
log::info!("sys_execv: Loading program '{}'", program_name);
1237+
let name_bytes = match copy_string_from_user(program_name_ptr, 256) {
1238+
Ok(bytes) => bytes,
1239+
Err(e) => {
1240+
log::error!("sys_execv: Failed to read program name: {}", e);
1241+
return SyscallResult::Err(14); // EFAULT
1242+
}
1243+
};
12521244

1253-
// Read argv array from userspace
1254-
let mut argv_vec: Vec<Vec<u8>> = Vec::new();
1245+
let name_len = name_bytes.iter().position(|&b| b == 0).unwrap_or(name_bytes.len());
1246+
let program_name = match core::str::from_utf8(&name_bytes[..name_len]) {
1247+
Ok(s) => s,
1248+
Err(_) => {
1249+
log::error!("sys_execv: Invalid UTF-8 in program name");
1250+
return SyscallResult::Err(22); // EINVAL
1251+
}
1252+
};
12551253

1256-
if argv_ptr != 0 {
1257-
// Read up to 64 argument pointers
1258-
const MAX_ARGS: usize = 64;
1259-
const MAX_ARG_LEN: usize = 4096;
1254+
log::info!("sys_execv: Loading program '{}'", program_name);
12601255

1261-
for i in 0..MAX_ARGS {
1262-
let ptr_addr = argv_ptr + (i * 8) as u64;
1263-
let arg_ptr_bytes = match copy_from_user(ptr_addr, 8) {
1264-
Ok(bytes) => bytes,
1265-
Err(e) => {
1266-
log::error!("sys_execv: Failed to read argv[{}] pointer: {}", i, e);
1267-
return SyscallResult::Err(14); // EFAULT
1268-
}
1269-
};
1256+
// Read argv array from userspace (with interrupts enabled - safe)
1257+
let mut argv_vec: Vec<Vec<u8>> = Vec::new();
12701258

1271-
// Interpret as u64 pointer
1272-
let arg_ptr = u64::from_le_bytes([
1273-
arg_ptr_bytes[0], arg_ptr_bytes[1], arg_ptr_bytes[2], arg_ptr_bytes[3],
1274-
arg_ptr_bytes[4], arg_ptr_bytes[5], arg_ptr_bytes[6], arg_ptr_bytes[7],
1275-
]);
1259+
if argv_ptr != 0 {
1260+
// Read up to 64 argument pointers
1261+
const MAX_ARGS: usize = 64;
1262+
const MAX_ARG_LEN: usize = 4096;
12761263

1277-
// NULL pointer marks end of argv
1278-
if arg_ptr == 0 {
1279-
break;
1264+
for i in 0..MAX_ARGS {
1265+
let ptr_addr = argv_ptr + (i * 8) as u64;
1266+
let arg_ptr_bytes = match copy_from_user(ptr_addr, 8) {
1267+
Ok(bytes) => bytes,
1268+
Err(e) => {
1269+
log::error!("sys_execv: Failed to read argv[{}] pointer: {}", i, e);
1270+
return SyscallResult::Err(14); // EFAULT
12801271
}
1272+
};
12811273

1282-
// Read the argument string
1283-
let arg_bytes = match copy_string_from_user(arg_ptr, MAX_ARG_LEN) {
1284-
Ok(bytes) => bytes,
1285-
Err(e) => {
1286-
log::error!("sys_execv: Failed to read argv[{}] string at {:#x}: {}", i, arg_ptr, e);
1287-
return SyscallResult::Err(14); // EFAULT
1288-
}
1289-
};
1274+
// Interpret as u64 pointer
1275+
let arg_ptr = u64::from_le_bytes([
1276+
arg_ptr_bytes[0], arg_ptr_bytes[1], arg_ptr_bytes[2], arg_ptr_bytes[3],
1277+
arg_ptr_bytes[4], arg_ptr_bytes[5], arg_ptr_bytes[6], arg_ptr_bytes[7],
1278+
]);
12901279

1291-
// Find null terminator and truncate
1292-
let arg_len = arg_bytes.iter().position(|&b| b == 0).unwrap_or(arg_bytes.len());
1293-
let mut arg = arg_bytes[..arg_len].to_vec();
1294-
arg.push(0); // Ensure null-terminated
1295-
argv_vec.push(arg);
1280+
// NULL pointer marks end of argv
1281+
if arg_ptr == 0 {
1282+
break;
12961283
}
1297-
}
12981284

1299-
// If no argv provided, use program name as argv[0]
1300-
if argv_vec.is_empty() {
1301-
let mut arg0 = program_name.as_bytes().to_vec();
1302-
arg0.push(0);
1303-
argv_vec.push(arg0);
1285+
// Read the argument string
1286+
let arg_bytes = match copy_string_from_user(arg_ptr, MAX_ARG_LEN) {
1287+
Ok(bytes) => bytes,
1288+
Err(e) => {
1289+
log::error!("sys_execv: Failed to read argv[{}] string at {:#x}: {}", i, arg_ptr, e);
1290+
return SyscallResult::Err(14); // EFAULT
1291+
}
1292+
};
1293+
1294+
// Find null terminator and truncate
1295+
let arg_len = arg_bytes.iter().position(|&b| b == 0).unwrap_or(arg_bytes.len());
1296+
let mut arg = arg_bytes[..arg_len].to_vec();
1297+
arg.push(0); // Ensure null-terminated
1298+
argv_vec.push(arg);
13041299
}
1300+
}
13051301

1306-
log::info!("sys_execv: argc={}", argv_vec.len());
1307-
for (i, arg) in argv_vec.iter().enumerate() {
1308-
if let Ok(s) = core::str::from_utf8(&arg[..arg.len().saturating_sub(1)]) {
1309-
log::debug!("sys_execv: argv[{}] = '{}'", i, s);
1310-
}
1302+
// If no argv provided, use program name as argv[0]
1303+
if argv_vec.is_empty() {
1304+
let mut arg0 = program_name.as_bytes().to_vec();
1305+
arg0.push(0);
1306+
argv_vec.push(arg0);
1307+
}
1308+
1309+
log::info!("sys_execv: argc={}", argv_vec.len());
1310+
for (i, arg) in argv_vec.iter().enumerate() {
1311+
if let Ok(s) = core::str::from_utf8(&arg[..arg.len().saturating_sub(1)]) {
1312+
log::debug!("sys_execv: argv[{}] = '{}'", i, s);
13111313
}
1314+
}
13121315

1313-
#[cfg(feature = "testing")]
1314-
{
1315-
// Try to load from ext2 filesystem first, fall back to test disk
1316-
let elf_vec = if program_name.contains('/') {
1317-
// Path-like name: load from ext2 filesystem
1318-
match load_elf_from_ext2(program_name) {
1319-
Ok(data) => data,
1320-
Err(errno) => return SyscallResult::Err(errno as u64),
1321-
}
1322-
} else {
1323-
// Bare name: try ext2 /bin/ first, then fall back to test disk
1324-
let bin_path = alloc::format!("/bin/{}", program_name);
1325-
match load_elf_from_ext2(&bin_path) {
1326-
Ok(data) => data,
1327-
Err(_) => {
1328-
// Fall back to test disk for compatibility
1329-
crate::userspace_test::get_test_binary(program_name)
1330-
}
1316+
#[cfg(feature = "testing")]
1317+
{
1318+
// Load ELF binary WITH interrupts enabled - ext2 I/O needs timer interrupts
1319+
// for proper VirtIO operation
1320+
let elf_vec = if program_name.contains('/') {
1321+
// Path-like name: load from ext2 filesystem
1322+
match load_elf_from_ext2(program_name) {
1323+
Ok(data) => data,
1324+
Err(errno) => return SyscallResult::Err(errno as u64),
1325+
}
1326+
} else {
1327+
// Bare name: try ext2 /bin/ first, then fall back to test disk
1328+
let bin_path = alloc::format!("/bin/{}", program_name);
1329+
match load_elf_from_ext2(&bin_path) {
1330+
Ok(data) => data,
1331+
Err(_) => {
1332+
// Fall back to test disk for compatibility
1333+
crate::userspace_test::get_test_binary(program_name)
13311334
}
1332-
};
1333-
let boxed_slice = elf_vec.into_boxed_slice();
1334-
let elf_data = Box::leak(boxed_slice) as &'static [u8];
1335-
let name_string = alloc::string::String::from(program_name);
1336-
let leaked_name: &'static str = Box::leak(name_string.into_boxed_str());
1335+
}
1336+
};
1337+
let boxed_slice = elf_vec.into_boxed_slice();
1338+
let elf_data = Box::leak(boxed_slice) as &'static [u8];
1339+
let name_string = alloc::string::String::from(program_name);
1340+
let leaked_name: &'static str = Box::leak(name_string.into_boxed_str());
13371341

1338-
// Find current process
1339-
let current_pid = {
1340-
let manager_guard = crate::process::manager();
1341-
if let Some(ref manager) = *manager_guard {
1342-
if let Some((pid, _)) = manager.find_process_by_thread(current_thread_id) {
1343-
pid
1344-
} else {
1345-
log::error!("sys_execv: Thread {} not found in any process", current_thread_id);
1346-
return SyscallResult::Err(3); // ESRCH
1347-
}
1342+
// Find current process
1343+
let current_pid = {
1344+
let manager_guard = crate::process::manager();
1345+
if let Some(ref manager) = *manager_guard {
1346+
if let Some((pid, _)) = manager.find_process_by_thread(current_thread_id) {
1347+
pid
13481348
} else {
1349-
log::error!("sys_execv: Process manager not available");
1350-
return SyscallResult::Err(12); // ENOMEM
1349+
log::error!("sys_execv: Thread {} not found in any process", current_thread_id);
1350+
return SyscallResult::Err(3); // ESRCH
13511351
}
1352-
};
1352+
} else {
1353+
log::error!("sys_execv: Process manager not available");
1354+
return SyscallResult::Err(12); // ENOMEM
1355+
}
1356+
};
13531357

1354-
log::info!(
1355-
"sys_execv: Replacing process {} (thread {}) with new program",
1356-
current_pid.as_u64(),
1357-
current_thread_id
1358-
);
1358+
log::info!(
1359+
"sys_execv: Replacing process {} (thread {}) with new program",
1360+
current_pid.as_u64(),
1361+
current_thread_id
1362+
);
13591363

1360-
// Convert argv_vec to slice of slices for exec_process_with_argv
1361-
let argv_slices: Vec<&[u8]> = argv_vec.iter().map(|v| v.as_slice()).collect();
1364+
// Convert argv_vec to slice of slices for exec_process_with_argv
1365+
let argv_slices: Vec<&[u8]> = argv_vec.iter().map(|v| v.as_slice()).collect();
13621366

1363-
// Replace the process's address space with argv support
1367+
// CRITICAL SECTION: Frame manipulation and process state changes
1368+
// Only this part needs interrupts disabled for atomicity
1369+
x86_64::instructions::interrupts::without_interrupts(|| {
13641370
let mut manager_guard = crate::process::manager();
13651371
if let Some(ref mut manager) = *manager_guard {
13661372
match manager.exec_process_with_argv(current_pid, elf_data, Some(leaked_name), &argv_slices) {
@@ -1424,13 +1430,13 @@ pub fn sys_execv_with_frame(
14241430
log::error!("sys_execv: Process manager not available");
14251431
SyscallResult::Err(12) // ENOMEM
14261432
}
1427-
}
1433+
})
1434+
}
14281435

1429-
#[cfg(not(feature = "testing"))]
1430-
{
1431-
SyscallResult::Err(38) // ENOSYS
1432-
}
1433-
})
1436+
#[cfg(not(feature = "testing"))]
1437+
{
1438+
SyscallResult::Err(38) // ENOSYS
1439+
}
14341440
}
14351441

14361442
/// sys_exec - Replace the current process with a new program (deprecated)

‎userspace/tests/tcp_socket_test.rs‎

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -47,8 +47,9 @@ const EPIPE: i32 = 32;
4747
const ECONNREFUSED: i32 = 111;
4848
const ETIMEDOUT: i32 = 110;
4949

50-
// Maximum retries for loopback operations - if exceeded, indicates a bug
51-
const MAX_LOOPBACK_RETRIES: usize = 3;
50+
// Maximum retries for loopback operations - needs to be generous for CI environments
51+
// where system load can cause delays in packet processing
52+
const MAX_LOOPBACK_RETRIES: usize = 10;
5253

5354
#[no_mangle]
5455
pub extern "C" fn _start() -> ! {

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