Breaking Zigs default panic handler

output_content1.txt

Segmentation fault at address 0x3e800033cc6
/home/user/dev/git/zi/zig/master/build/stage3/lib/zig/std/os/linux/x86_64.zig:36:5: 0x22d97c in syscall2 
(stacking_panics)
    return asm volatile ("syscall"
    ^
/home/user/dev/git/zi/zig/master/build/stage3/lib/zig/std/os/linux.zig:991:49: 0x20f19f in nanosleep (sta
cking_panics)
    return syscall2(.nanosleep, @ptrToInt(req), @ptrToInt(rem));
                                                ^
/home/user/dev/git/zi/zig/master/build/stage3/lib/zig/std/os.zig:5253:39: 0x20b681 in nanosleep (stacking
_panics)
        switch (errno(system.nanosleep(&req, &rem))) {
                                      ^
/home/user/dev/git/tryzig/stacking_panics.zig:19:25: 0x20b3b4 in t1Exec (stacking_panics)
        std.os.nanosleep(0, 1_000);
                        ^
/home/user/dev/git/tryzig/stacking_panics.zig:10:15: 0x20b720 in main (stacking_panics)
    try t1Exec();
              ^
/home/user/dev/git/zi/zig/master/build/stage3/lib/zig/std/start.zig:616:37: 0x20ad89 in posixCallMainAndE
xit (stacking_panics)
            const result = root.main() catch |err| {
                                    ^
/home/user/dev/git/zi/zig/master/build/stage3/lib/zig/std/start.zig:376:5: 0x20a7f1 in _start (stacking_p
anics)
    @call(.never_inline, posixCallMainAndExit, .{});
    ^
Abgebrochen (Speicherabzug geschrieben)

output_content2.txt

raised 2526 signals
raised 2527 signals
raised 2528 signals
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raised /home/misterspoon/dev/git/zi/zig/master/build/stage3/lib/zig/std/start.zig2560: signals
376:raised 52561 signals
: raised 25620x signals
20a8e1raised  in 2563_start signals
 (stacking_panicsraised )2564 signals

raised 2565 signals
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  raised  2583  signals
@craised a2584l signals
l(raised .2585n signals
eraised v2586e signals
r_raised i2587n signals
liraised n2588e signals
, raised p2589o signals
siraised x2590C signals
alraised l2591M signals
airaised n2592A signals
ndraised E2593x signals
iraised t2594, signals
 .raised {2595} signals
);raised 
2596 signals
    raised ^2597
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raised 2598 signals
raised 2599 signals
raised Abgebrochen (Speicherabzug geschrieben)

stacking_panics.zig

//! Stacking panics example to break Zig panic handler.
//! principle threads t1, t2
//! - t1 tells t2 its pid
//! - t1 waits blocking + sleeping
//! - t2 signals continuously t1 leading to panic during panic situation

const std = @import("std");

pub fn main() !void {
    try t1Exec();
}

fn t1Exec() !void {
    const pid_t1: std.os.pid_t = @intCast(i32, std.Thread.getCurrentId());
    const t2 = try std.Thread.spawn(.{}, t2Exec, .{pid_t1});
    t2.detach();
    // busy sleeping
    while (true) {
        std.os.nanosleep(0, 1_000);
    }
}

fn t2Exec(pid_t1: std.os.pid_t) void {
    // content 1
    // const res = std.os.linux.tgkill(pid_t1, pid_t1, std.os.SIG.SEGV);
    // std.debug.assert(res == 0);

    // content 2
    var cnt: u64 = 0;
    while (true) {
        // t1 is group leader = "master thread"
        const res = std.os.linux.tgkill(pid_t1, pid_t1, std.os.SIG.SEGV);
        std.debug.print("raised {d} signals\n", .{cnt});
        std.debug.assert(res == 0);
        // std.os.nanosleep(0, 1_000);
        cnt += 1;
    }
}
// zig build-exe stacking-panics.zig && stacking-panics