linux-kernel - [BUG] Odd interaction between uninterruptible syscall and stack overflow

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Message-Id: <1426443140.2736.1@smtp.gmail.com>
Date:	Sun, 15 Mar 2015 20:12:20 +0200
From:	Simonas <s@...lauskas.me>
To:	linux-kernel@...r.kernel.org
Subject: [BUG] Odd interaction between uninterruptible syscall and stack
 overflow

While working on stack related code in Rust’s stdandard library, I 
trigerred a very odd and amusing
issue yesterday. Running this short code

    #include <stdio.h>
    void recurse(void) {
        puts("");
        recurse();
    }
    int main(void) {
        recurse();
    }

intuitively should SIGSEGV and terminate when the stack is exhausted. 
However, on my system this
will hang up inside uninterruptible sleep (the D state) for eternity. 
The amusing part is that this
state will bubble up and also pull various other processes into D state 
as well. Some examples are:

* gnome-terminal (when the window in which this executable was run is 
closed);
* ps aux;
* pkill;
* systemd PID 1 (when the system is being shut down… presence of this 
infinitely D state
  process will also reliably prevent system from suspending);

I guess this happens because the process receives asynchronous SIGSEGV 
during a call to
uninterruptible syscall and believe the process should not go into 
infinite D state in this case.

I’m running Arch Linux’s stock 3.18.6 (-1-ARCH) x86_64 kernel.

I’ve attached dmesg logs, which has some backtraces. This is my first 
time reporting a kernel
issue, so if there’s any information I didn’t provide, I’ll 
gladly provide some on request.

Please CC me, thanks!
Simonas

View attachment "dmesg-out" of type "text/plain" (175641 bytes)