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From: Stefan Metzmacher <metze@samba.org>
To: Jens Axboe <axboe@kernel.dk>, io-uring@vger.kernel.org
Cc: torvalds@linux-foundation.org, ebiederm@xmission.com,
	oleg@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/6] Allow signals for IO threads
Date: Sat, 27 Mar 2021 02:46:24 +0100	[thread overview]
Message-ID: <358c5225-c23f-de08-65cb-ca3349793c0e@samba.org> (raw)
In-Reply-To: <8efd9977-003b-be65-8ae2-4b04d8dd1224@samba.org>


Hi Jens,

> root@ub1704-166:~# LANG=C gdb --pid 1320
> GNU gdb (Ubuntu 9.2-0ubuntu1~20.04) 9.2
> Copyright (C) 2020 Free Software Foundation, Inc.
> License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
> This is free software: you are free to change and redistribute it.
> There is NO WARRANTY, to the extent permitted by law.
> Type "show copying" and "show warranty" for details.
> This GDB was configured as "x86_64-linux-gnu".
> Type "show configuration" for configuration details.
> For bug reporting instructions, please see:
> <http://www.gnu.org/software/gdb/bugs/>.
> Find the GDB manual and other documentation resources online at:
>     <http://www.gnu.org/software/gdb/documentation/>.
> 
> For help, type "help".
> Type "apropos word" to search for commands related to "word".
> Attaching to process 1320
> [New LWP 1321]
> [New LWP 1322]
> 
> warning: Selected architecture i386:x86-64 is not compatible with reported target architecture i386
> 
> warning: Architecture rejected target-supplied description
> syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
> 38      ../sysdeps/unix/sysv/linux/x86_64/syscall.S: No such file or directory.
> (gdb)

Ok, the following makes gdb happy again:

--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -163,6 +163,8 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
        /* Kernel thread ? */
        if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
                memset(childregs, 0, sizeof(struct pt_regs));
+               if (p->flags & PF_IO_WORKER)
+                       childregs->cs = current_pt_regs()->cs;
                kthread_frame_init(frame, sp, arg);
                return 0;
        }

I'm wondering if we should decouple the PF_KTHREAD and PF_IO_WORKER cases even more
and keep as much of a userspace-like copy_thread as possible.

metze

  parent reply	other threads:[~2021-03-27  1:47 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26  0:39 [PATCH 0/6] Allow signals for IO threads Jens Axboe
2021-03-26  0:39 ` [PATCH 1/8] io_uring: handle signals for IO threads like a normal thread Jens Axboe
2021-03-26  0:39 ` [PATCH 2/8] kernel: unmask SIGSTOP for IO threads Jens Axboe
2021-03-26 13:48   ` Oleg Nesterov
2021-03-26 15:01     ` Jens Axboe
2021-03-26 15:23       ` Stefan Metzmacher
2021-03-26 15:29         ` Jens Axboe
2021-03-26 18:01           ` Stefan Metzmacher
2021-03-26 18:59             ` Jens Axboe
2021-04-01 14:53             ` Stefan Metzmacher
2021-03-26  0:39 ` [PATCH 3/8] Revert "signal: don't allow sending any signals to PF_IO_WORKER threads" Jens Axboe
2021-03-26  0:39 ` [PATCH 4/8] Revert "kernel: treat PF_IO_WORKER like PF_KTHREAD for ptrace/signals" Jens Axboe
2021-03-26  0:39 ` [PATCH 5/8] Revert "kernel: freezer should treat PF_IO_WORKER like PF_KTHREAD for freezing" Jens Axboe
2021-03-26  0:39 ` [PATCH 6/8] Revert "signal: don't allow STOP on PF_IO_WORKER threads" Jens Axboe
2021-03-26 11:48 ` [PATCH 0/6] Allow signals for IO threads Stefan Metzmacher
2021-03-26 12:56   ` Jens Axboe
2021-03-26 13:31     ` Stefan Metzmacher
2021-03-26 13:54       ` Jens Axboe
2021-03-26 13:59         ` Jens Axboe
2021-03-26 14:38           ` Jens Axboe
2021-03-26 14:43             ` Stefan Metzmacher
2021-03-26 14:45               ` Stefan Metzmacher
2021-03-26 14:53                 ` Jens Axboe
2021-03-26 14:55                   ` Jens Axboe
2021-03-26 15:08                     ` Stefan Metzmacher
2021-03-26 15:10                       ` Jens Axboe
2021-03-26 15:11                         ` Stefan Metzmacher
2021-03-26 15:12                           ` Jens Axboe
2021-03-26 15:04                   ` Stefan Metzmacher
2021-03-26 15:09                     ` Jens Axboe
2021-03-26 14:50               ` Jens Axboe
2021-03-27  1:46       ` Stefan Metzmacher [this message]
2021-03-27 16:41         ` Jens Axboe
2021-04-01 14:58         ` Stefan Metzmacher
2021-04-01 15:39           ` Linus Torvalds
2021-04-01 16:00             ` Stefan Metzmacher
2021-04-01 16:24               ` Linus Torvalds
2021-04-01 16:55                 ` Stefan Metzmacher
2021-04-03  0:48                 ` Stefan Metzmacher

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