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From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: Bhupesh <bhupesh@igalia.com>
Cc: akpm@linux-foundation.org, kernel-dev@igalia.com,
	linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
	linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, oliver.sang@intel.com, lkp@intel.com,
	laoar.shao@gmail.com, pmladek@suse.com, rostedt@goodmis.org,
	mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com,
	alexei.starovoitov@gmail.com, andrii.nakryiko@gmail.com,
	mirq-linux@rere.qmqm.pl, peterz@infradead.org,
	willy@infradead.org, david@redhat.com, viro@zeniv.linux.org.uk,
	keescook@chromium.org, ebiederm@xmission.com, brauner@kernel.org,
	jack@suse.cz, mingo@redhat.com, juri.lelli@redhat.com,
	bsegall@google.com, mgorman@suse.de, vschneid@redhat.com,
	linux-trace-kernel@vger.kernel.org, kees@kernel.org,
	torvalds@linux-foundation.org
Subject: Re: [PATCH v7 2/4] include: Set tsk->comm length to 64 bytes
Date: Mon, 11 Aug 2025 17:10:05 +0200	[thread overview]
Message-ID: <aJoHzTKO9xw2CANn@black.igk.intel.com> (raw)
In-Reply-To: <20250811064609.918593-3-bhupesh@igalia.com>

On Mon, Aug 11, 2025 at 12:16:07PM +0530, Bhupesh wrote:
> Historically due to the 16-byte length of TASK_COMM_LEN, the
> users of 'tsk->comm' are restricted to use a fixed-size target
> buffer also of TASK_COMM_LEN for 'memcpy()' like use-cases.
> 
> To fix the same, we now use a 64-byte TASK_COMM_EXT_LEN and
> set the comm element inside 'task_struct' to the same length:
>        struct task_struct {
> 	       .....
>                char    comm[TASK_COMM_EXT_LEN];
> 	       .....
>        };
> 
>        where TASK_COMM_EXT_LEN is 64-bytes.
> 
> Note, that the existing users have not been modified to migrate to
> 'TASK_COMM_EXT_LEN', in case they have hard-coded expectations of
> dealing with only a 'TASK_COMM_LEN' long 'tsk->comm'.

...

> -	BUILD_BUG_ON(sizeof(from) != TASK_COMM_LEN);	\
> +	BUILD_BUG_ON(sizeof(from) < TASK_COMM_LEN);	\

Wondering if we may convert this to static_assert().
(rather in a separate patch)

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2025-08-11 15:10 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-11  6:46 [PATCH v7 0/4] Add support for long task name Bhupesh
2025-08-11  6:46 ` [PATCH v7 1/4] exec: Remove obsolete comments Bhupesh
2025-08-11  6:46 ` [PATCH v7 2/4] include: Set tsk->comm length to 64 bytes Bhupesh
2025-08-11 15:10   ` Andy Shevchenko [this message]
2025-08-13 10:29     ` Bhupesh Sharma
2025-08-11  6:46 ` [PATCH v7 3/4] treewide: Replace 'get_task_comm()' with 'strscpy_pad()' Bhupesh
2025-08-11 11:25   ` kernel test robot
2025-08-11 14:49     ` Bhupesh Sharma
2025-08-11 14:58       ` Andy Shevchenko
2025-08-13 10:26         ` Bhupesh Sharma
2025-08-11 15:05   ` Andy Shevchenko
2025-08-13 10:27     ` Bhupesh Sharma
2025-08-12  3:47   ` kernel test robot
2025-08-11  6:46 ` [PATCH v7 4/4] treewide: Switch memcpy() users of 'task->comm' to a more safer implementation Bhupesh
2025-08-11 15:08   ` Andy Shevchenko
2025-08-11 16:37   ` kernel test robot

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