From: John Ogness <john.ogness@linutronix.de>
To: Marek Szyprowski <m.szyprowski@samsung.com>,
Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Andrea Parri <parri.andrea@gmail.com>,
Paul McKenney <paulmck@kernel.org>,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH printk v5 6/6] printk: reimplement log_cont using record extension
Date: Sat, 26 Sep 2020 01:05:51 +0206 [thread overview]
Message-ID: <87v9g1bgyg.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <f1651593-3579-5820-6863-5f4973d2bfdc@samsung.com>
On 2020-09-25, Marek Szyprowski <m.szyprowski@samsung.com> wrote:
> This patch landed recently in linux-next as commit f5f022e53b87
> ("printk: reimplement log_cont using record extension"). I've noticed
> that it causes a regression on my test system (ARM 32bit Samsung Exynos
> 4412-based Trats2 board). The messages are printed correctly on the
> serial console during boot, but then when I run 'dmesg' command, the log
> is truncated.
>
> Here is are the last lines of the dmesg log after this patch:
>
> [ 6.649018] Waiting 2 sec before mounting root device...
> [ 6.766423] dwc2 12480000.hsotg: new device is high-speed
> [ 6.845290] dwc2 12480000.hsotg: new device is high-speed
> [ 6.914217] dwc2 12480000.hsotg: new address 51
> [ 8.710351] RAMDISK: squashfs filesystem found at block 0
>
> The corresponding dmesg lines before applying this patch:
>
> [ 8.864320] RAMDISK: squashfs filesystem found at block 0
> [ 8.868410] RAMDISK: Loading 37692KiB [1 disk] into ram disk... /
> [ 9.071670] /
> [ 9.262498] /
> [ 9.540711] /
> [ 9.818031] done.
Ah. One of the more creative printk users...
init/do_mounts_rd.c:rd_load_image(). This is a set of LOG_CONT messages
that try to display a rotating line, complete with '\b' control
characters. The code is totally broken, but that is no excuse for printk
to break. It should be easy to reproduce on any architecture. I will
investigate it further. Thanks for reporting.
John Ogness
next prev parent reply other threads:[~2020-09-25 22:59 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-14 12:33 [PATCH printk v5 0/6] printk: reimplement LOG_CONT handling John Ogness
2020-09-14 12:33 ` [PATCH printk v5 1/6] printk: ringbuffer: relocate get_data() John Ogness
2020-09-14 12:33 ` [PATCH printk v5 2/6] printk: ringbuffer: add BLK_DATALESS() macro John Ogness
2020-09-14 12:33 ` [PATCH printk v5 3/6] printk: ringbuffer: clear initial reserved fields John Ogness
2020-09-14 12:33 ` [PATCH printk v5 4/6] printk: ringbuffer: change representation of states John Ogness
2020-09-14 12:33 ` [PATCH printk v5 5/6] printk: ringbuffer: add finalization/extension support John Ogness
2020-09-15 9:30 ` Petr Mladek
2020-09-14 12:33 ` [PATCH printk v5 6/6] printk: reimplement log_cont using record extension John Ogness
[not found] ` <CGME20200925190829eucas1p2f35866317389cd5e842e99b465632902@eucas1p2.samsung.com>
2020-09-25 19:08 ` Marek Szyprowski
[not found] ` <CGME20200925193852eucas1p10c459f3f90192c1079f8a8f04b872015@eucas1p1.samsung.com>
2020-09-25 19:38 ` Marek Szyprowski
2020-09-25 22:59 ` John Ogness [this message]
2020-09-15 9:47 ` [PATCH printk v5 0/6] printk: reimplement LOG_CONT handling Petr Mladek
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