From: <rcampbell@nvidia.com>
To: <linux-kernel@vger.kernel.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>,
Craig Bergstrom <craigb@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Fengguang Wu <fengguang.wu@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Hans Verkuil <hans.verkuil@cisco.com>,
Mauro Carvalho Chehab <mchehab@s-opensource.com>,
Peter Zijlstra <peterz@infradead.org>,
Sander Eikelenboom <linux@eikelenboom.it>,
Sean Young <sean@mess.org>, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>
Subject: [PATCH 1/1] x86/mm: Fix limit mmap() of /dev/mem to valid physical addresses
Date: Mon, 18 Mar 2019 15:46:53 -0700 [thread overview]
Message-ID: <20190318224653.26549-2-rcampbell@nvidia.com> (raw)
In-Reply-To: <20190318224653.26549-1-rcampbell@nvidia.com>
From: Ralph Campbell <rcampbell@nvidia.com>
If CONFIG_DEBUG_VIRTUAL is enabled, a read or write to /dev/mem can
trigger a VIRTUAL_BUG_ON() depending on the value of high_memory.
For example:
read_mem()
valid_phys_addr_range(p=401f1550, count=8)
__pa(high_memory)
__phys_addr(x=ffffc88000000000)
// __START_KERNEL_map = ffffffff80000000
// y = ffffc88000000000 - ffffffff80000000
VIRTUAL_BUG_ON(phys_addr_valid(400000000000))
// boot_cpu_data.x86_phys_bits=46
Since by design high_memory is outside the range of valid physical
addresses, use the non-error checking version __pa_nodebug(high_memory).
Fixes: be62a32044061cb4a3b70a10598e093f1319102e ("x86/mm: Limit mmap() of
/dev/mem to valid physical addresses")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: Craig Bergstrom <craigb@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sander Eikelenboom <linux@eikelenboom.it>
Cc: Sean Young <sean@mess.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
---
arch/x86/mm/mmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c
index db3165714521..196bed43d5e6 100644
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -230,7 +230,7 @@ bool mmap_address_hint_valid(unsigned long addr, unsigned long len)
/* Can we access it for direct reading/writing? Must be RAM: */
int valid_phys_addr_range(phys_addr_t addr, size_t count)
{
- return addr + count <= __pa(high_memory);
+ return addr + count <= __pa_nodebug(high_memory);
}
/* Can we access it through mmap? Must be a valid physical address: */
--
2.20.1
next prev parent reply other threads:[~2019-03-18 22:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-18 22:46 [PATCH 0/1] x86/mm: Fix limit mmap() of /dev/mem to valid physical rcampbell
2019-03-18 22:46 ` rcampbell [this message]
2019-03-23 19:02 ` [PATCH 1/1] x86/mm: Fix limit mmap() of /dev/mem to valid physical addresses Thomas Gleixner
2019-03-25 22:03 ` Ralph Campbell
2019-03-25 22:55 ` Thomas Gleixner
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