Date:   Sun, 19 Feb 2023 09:30:22 +0100
From:   Thomas Bogendoerfer <tsbogend@alpha.franken.de>
To:     Elvira Khabirova <lineprinter0@gmail.com>
Cc:     "Dmitry V. Levin" <ldv@strace.io>, linux-mips@vger.kernel.org,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Ralf Baechle <ralf@linux-mips.org>,
        Paul Burton <paul.burton@mips.com>,
        James Hogan <jhogan@kernel.org>,
        Andreas Henriksson <ah@debian.org>
Subject: Re: [PATCH] mips: fix syscall_get_nr
Message-ID: <20230219083022.GA2924@alpha.franken.de>
References: <20230218233212.1fed456b@akathisia>
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On Sat, Feb 18, 2023 at 11:43:59PM +0100, Elvira Khabirova wrote:
> The implementation of syscall_get_nr on mips used to ignore the task
> argument and return the syscall number of the calling thread instead of
> the target thread.
> 
> The bug was exposed to user space by commit 201766a20e30f ("ptrace: add
> PTRACE_GET_SYSCALL_INFO request") and detected by strace test suite.
> 
> Link: https://github.com/strace/strace/issues/235
> Fixes: c2d9f1775731 ("MIPS: Fix syscall_get_nr for the syscall exit tracing.")
> Cc: <stable@vger.kernel.org> # v3.19+
> Co-developed-by: Dmitry V. Levin <ldv@strace.io>
> Signed-off-by: Dmitry V. Levin <ldv@strace.io>
> Signed-off-by: Elvira Khabirova <lineprinter0@gmail.com>
> ---
>  arch/mips/include/asm/syscall.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/mips/include/asm/syscall.h b/arch/mips/include/asm/syscall.h
> index 25fa651c937d..ebdf4d910af2 100644
> --- a/arch/mips/include/asm/syscall.h
> +++ b/arch/mips/include/asm/syscall.h
> @@ -38,7 +38,7 @@ static inline bool mips_syscall_is_indirect(struct task_struct *task,
>  static inline long syscall_get_nr(struct task_struct *task,
>  				  struct pt_regs *regs)
>  {
> -	return current_thread_info()->syscall;
> +	return task_thread_info(task)->syscall;
>  }
>  
>  static inline void mips_syscall_update_nr(struct task_struct *task,
> -- 

applied to mips-next.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]