linux-kernel - of_reserved_mem_device_init() prints kernel memory in dmesg

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Message-Id: <TF21MR.NSQQ6SJI3CJ7@crapouillou.net>
Date:   Sun, 27 Nov 2022 22:28:41 +0000
From:   Paul Cercueil <paul@...pouillou.net>
To:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Christoph Hellwig <hch@....de>
Cc:     linux-kernel <linux-kernel@...r.kernel.org>,
        Linux Memory Management List <linux-mm@...ck.org>
Subject: of_reserved_mem_device_init() prints kernel memory in dmesg

Hi Christoph, Marek,

Here's what I get in dmesg on a 6.1-rc6 kernel:

OF: fdt: Reserved memory: reserved region for node 
'video-memory@...0000': base 0x01f00000, size 1 MiB
OF: reserved mem: initialized node video-memory@...0000, compatible id 
shared-dma-pool
ingenic-drm 13050000.lcd-controller: assigned reserved memory node 
<garbage data...>

I would *think* it's because the name is obtained using fdt_get_name() 
in fdt_scan_reserved_mem(), and the pointer becomes invalid as soon as 
the FDT is freed (is it freed?).

Not sure how to fix that myself, I tried to kstrdup(uname) in 
fdt_reserved_mem_save_node(), but it gives me a NULL pointer, probably 
too early in the boot process?

Cheers,
-Paul