From 68e26a2ceea85a149cb23286504cbdcec1ae814e Mon Sep 17 00:00:00 2001 From: Jakub Konka Date: Mon, 2 Aug 2021 11:10:07 +0200 Subject: 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. 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. --- lib/std/debug.zig | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'lib/std/debug.zig') diff --git a/lib/std/debug.zig b/lib/std/debug.zig index f74d0b3f91..c3ef9dec4c 100644 --- a/lib/std/debug.zig +++ b/lib/std/debug.zig @@ -438,7 +438,12 @@ pub fn writeCurrentStackTrace( } var it = StackIterator.init(start_addr, null); while (it.next()) |return_address| { - try printSourceAtAddress(debug_info, out_stream, return_address - 1, tty_config); + // 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. + const address = if (return_address == 0) return_address else return_address - 1; + try printSourceAtAddress(debug_info, out_stream, address, tty_config); } } -- cgit v1.2.3