diff options
author | Tony Luck <tony.luck@intel.com> | 2017-08-16 20:18:03 +0300 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2017-08-17 11:30:49 +0300 |
commit | ce0fa3e56ad20f04d8252353dcd24e924abdafca (patch) | |
tree | dee3cdb69e839f4eb1dc5690deb7e145202124c7 /mm | |
parent | 57bd1905b228f2a14d7506b0302f69f425131e57 (diff) | |
download | linux-ce0fa3e56ad20f04d8252353dcd24e924abdafca.tar.xz |
x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages
Speculative processor accesses may reference any memory that has a
valid page table entry. While a speculative access won't generate
a machine check, it will log the error in a machine check bank. That
could cause escalation of a subsequent error since the overflow bit
will be then set in the machine check bank status register.
Code has to be double-plus-tricky to avoid mentioning the 1:1 virtual
address of the page we want to map out otherwise we may trigger the
very problem we are trying to avoid. We use a non-canonical address
that passes through the usual Linux table walking code to get to the
same "pte".
Thanks to Dave Hansen for reviewing several iterations of this.
Also see:
http://marc.info/?l=linux-mm&m=149860136413338&w=2
Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Elliott, Robert (Persistent Memory) <elliott@hpe.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20170816171803.28342-1-tony.luck@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/memory-failure.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 1cd3b3569af8..88366626c0b7 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1146,6 +1146,8 @@ int memory_failure(unsigned long pfn, int trapno, int flags) return 0; } + arch_unmap_kpfn(pfn); + orig_head = hpage = compound_head(p); num_poisoned_pages_inc(); |