authorgravatar for zenshixd@proton.meCezary Kupaj <zenshixd@proton.me> 2025-05-14 05:38:38+02:00
committergravatar for noreply@github.comGitHub <noreply@github.com> 2025-05-14 05:38:38+02:00
log518105471e145c90809fb2f5baa53cd08bde31aa
tree8085d5407f5eead69a2af35e872e2afdde00181e
parent5b606d435d139487c23d6fd30e8061dbad741ada
signaturebadge-check Signed by PGP key B5690EEEBB952194

Fix SIGSEGV handler for AArch64 Darwin targets

* ucontext_t ptr is 8-byte aligned instead of 16-byte aligned which @alignCast() expects * Retrieve pc address from ucontext_t since unwind_state is null * Work around __mcontext_data being written incorrectly by the kernel

1 files changed, 27 insertions(+), 3 deletions(-)

lib/std/debug.zig+27-3
...@@ -441,7 +441,13 @@ pub fn dumpStackTraceFromBase(context: *ThreadContext) void {...@@ -441,7 +441,13 @@ pub fn dumpStackTraceFromBase(context: *ThreadContext) void {
441441
442 var it = StackIterator.initWithContext(null, debug_info, context) catch return;442 var it = StackIterator.initWithContext(null, debug_info, context) catch return;
443 defer it.deinit();443 defer it.deinit();
444 printSourceAtAddress(debug_info, stderr, it.unwind_state.?.dwarf_context.pc, tty_config) catch return;444
445 // DWARF unwinding on aarch64-macos is not complete so we need to get pc address from mcontext
446 const pc_addr = if (builtin.target.os.tag.isDarwin() and native_arch == .aarch64)
447 context.mcontext.ss.pc
448 else
449 it.unwind_state.?.dwarf_context.pc;
450 printSourceAtAddress(debug_info, stderr, pc_addr, tty_config) catch return;
445451
446 while (it.next()) |return_address| {452 while (it.next()) |return_address| {
447 printLastUnwindError(&it, debug_info, stderr, tty_config);453 printLastUnwindError(&it, debug_info, stderr, tty_config);
...@@ -1483,8 +1489,26 @@ fn dumpSegfaultInfoPosix(sig: i32, code: i32, addr: usize, ctx_ptr: ?*anyopaque)...@@ -1483,8 +1489,26 @@ fn dumpSegfaultInfoPosix(sig: i32, code: i32, addr: usize, ctx_ptr: ?*anyopaque)
1483 .aarch64,1489 .aarch64,
1484 .aarch64_be,1490 .aarch64_be,
1485 => {1491 => {
1486 const ctx: *posix.ucontext_t = @ptrCast(@alignCast(ctx_ptr));1492 // Some kernels don't align `ctx_ptr` properly. Handle this defensively.
1487 dumpStackTraceFromBase(ctx);1493 const ctx: *align(1) posix.ucontext_t = @ptrCast(ctx_ptr);
1494 var new_ctx: posix.ucontext_t = ctx.*;
1495 if (builtin.os.tag.isDarwin() and builtin.cpu.arch == .aarch64) {
1496 // The kernel incorrectly writes the contents of `__mcontext_data` right after `mcontext`,
1497 // rather than after the 8 bytes of padding that are supposed to sit between the two. Copy the
1498 // contents to the right place so that the `mcontext` pointer will be correct after the
1499 // `relocateContext` call below.
1500 new_ctx.__mcontext_data = @as(*align(1) extern struct {
1501 onstack: c_int,
1502 sigmask: std.c.sigset_t,
1503 stack: std.c.stack_t,
1504 link: ?*std.c.ucontext_t,
1505 mcsize: u64,
1506 mcontext: *std.c.mcontext_t,
1507 __mcontext_data: std.c.mcontext_t align(@sizeOf(usize)), // Disable padding after `mcontext`.
1508 }, @ptrCast(ctx)).__mcontext_data;
1509 }
1510 relocateContext(&new_ctx);
1511 dumpStackTraceFromBase(&new_ctx);
1488 },1512 },
1489 else => {},1513 else => {},
1490 }1514 }