From: William Kucharski <william.kucharski@oracle.com>
To: Meelis Roos <mroos@linux.ee>
Cc: Ralph Campbell <rcampbell@nvidia.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: CONFIG_DEBUG_VIRTUAL breaks boot on x86-32
Date: Wed, 27 Mar 2019 04:26:07 -0600 [thread overview]
Message-ID: <4AF9E4BD-58F0-4D12-A495-6192978790B6@oracle.com> (raw)
In-Reply-To: <dca61136-db66-a89e-e79d-679ee2281d8d@linux.ee>
The dmesg output you posted confirms that max_low_pfn is indeed 0x373fe, and it appears
that the value of phys_mem being checked mat be 0x3f401ff1, which translates to pfn 0x3f401,
at least if what's still in registers can be believed.
Since that is indeed greater than max_low_pfn, VIRTUAL_BUG_ON triggers:
VIRTUAL_BUG_ON((phys_addr >> PAGE_SHIFT) > max_low_pfn);
Looking at the call stack of
copy_strings_0x220
__check_object_size+0xef
that looks to translate to this sequence:
copy_from_user(kaddr+offset, str, bytes_to_copy)
check_copy_size(kaddr+offset, bytes_to_copy, FALSE)
check_object_size(kaddr+offset, bytes_to_copy, FALSE)
__check_object_size(kaddr+offset, bytes_to_copy, FALSE)
check_heap_object(kaddr+offset, bytes_to_copy, FALSE)
virt_to_head_page(kaddr+offset)
virt_to_page(kaddr+offset)
pfn_to_page(kaddr+offset)
__pa(kaddr+offset)
__phys_addr(kaddr+offset)
so it appears the address is "too high" for low memory at that point.
prev parent reply other threads:[~2019-03-27 10:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-21 20:22 Meelis Roos
2019-03-26 13:52 ` William Kucharski
2019-03-26 17:50 ` Meelis Roos
2019-03-26 20:11 ` Ralph Campbell
2019-03-27 7:03 ` Meelis Roos
2019-03-27 10:26 ` William Kucharski [this message]
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