From: Petr Mladek <pmladek@suse.com>
To: Wang Wensheng <wsw9603@163.com>
Cc: rostedt@goodmis.org, john.ogness@linutronix.de,
senozhatsky@chromium.org, d-tatianin@yandex-team.ru,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] printk_ringbuffer: Fix space_used() when blk_lpos->next overflows
Date: Tue, 27 Oct 2026 16:02:34 +0100 [thread overview]
Message-ID: <auC9CsSPmO5TS38s@pathway.suse.cz> (raw)
In-Reply-To: <20261004075755.363989-1-wsw9603@163.com>
On Sun 2026-10-04 15:57:55, Wang Wensheng wrote:
> Since commit 67e1b0052f6b ("printk_ringbuffer: don't needlessly wrap data
> blocks around") blk_lpos is treated as not wrapped when blk_lpos->next
> overflows to the start of data_ring. We use the indices of blk_lpos->next
> and blk_lpos->start to calculate the size of the data_block. This computes
> zero minus a small positive value, resulting in underflow and an
> unexpectedly large value. Simply using the original lpos with wrap-counts
> solves the problem.
>
> Fixes: 67e1b0052f6b ("printk_ringbuffer: don't needlessly wrap data blocks around")
> Signed-off-by: Wang Wensheng <wsw9603@163.com>
JFYI, the patch has been committed into printk/linux.git,
branch for-7.4-fixups.
Best Regards,
Petr
prev parent reply other threads:[~2026-10-27 15:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-04 7:57 [PATCH] printk_ringbuffer: Fix space_used() when blk_lpos->next overflows Wang Wensheng
2026-10-19 15:08 ` John Ogness
2026-10-27 13:50 ` Petr Mladek
2026-10-27 15:02 ` Petr Mladek [this message]
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