zig

commit 23e212a9d0b5cfdff991a40ca264f9d1284f0d5f (tree)
parent bd0dd225e843801b4b6162cbd2709c7325ab87b7
Author: Xavier Bouchoux <xavierb@gmail.com>
Date:   Sat, 15 Oct 2022 16:58:29 +0200

std: check for overflow in dumpStackTraceFromBase

same change as [68e26a2ceea85a1] "std: check for overflow in writeCurrentStackTrace"

On arm64 macOS, the address of the last frame is 0x0 rather than
a positive value like 0x1 on x86_64 macOS, therefore, we overflow
an integer trying to subtract 1 when printing the stack trace. This
patch fixes it by first checking for this condition before trying
to subtract 1.

Same behaviour on i386-windows-msvc.

Note that we do not need to signal the `SignalIterator` about this
as it will correctly detect this condition on the subsequent iteration
and return `null`, thus terminating the loop.

Diffstat:
M
lib/std/debug.zig
 | 
9
++++++++-

1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/lib/std/debug.zig b/lib/std/debug.zig
@@ -187,7 +187,13 @@ pub fn dumpStackTraceFromBase(bp: usize, ip: usize) void {
         printSourceAtAddress(debug_info, stderr, ip, tty_config) catch return;
         var it = StackIterator.init(null, bp);
         while (it.next()) |return_address| {
-            printSourceAtAddress(debug_info, stderr, return_address - 1, tty_config) catch return;
+            // On arm64 macOS, the address of the last frame is 0x0 rather than 0x1 as on x86_64 macOS,
+            // therefore, we do a check for `return_address == 0` before subtracting 1 from it to avoid
+            // an overflow. We do not need to signal `StackIterator` as it will correctly detect this
+            // condition on the subsequent iteration and return `null` thus terminating the loop.
+            // same behaviour for i386-windows-msvc
+            const address = if (return_address == 0) return_address else return_address - 1;
+            printSourceAtAddress(debug_info, stderr, address, tty_config) catch return;
         }
     }
 }
@@ -563,6 +569,7 @@ pub fn writeCurrentStackTrace(
         // therefore, we do a check for `return_address == 0` before subtracting 1 from it to avoid
         // an overflow. We do not need to signal `StackIterator` as it will correctly detect this
         // condition on the subsequent iteration and return `null` thus terminating the loop.
+        // same behaviour for i386-windows-msvc
         const address = if (return_address == 0) return_address else return_address - 1;
         try printSourceAtAddress(debug_info, out_stream, address, tty_config);
     }