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| author | Tony Luck <tony.luck@intel.com> | 2017-08-16 20:18:03 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-09-20 09:27:48 +0300 |
| commit | 6506d1d7d0c209bdba330b6c2e9cfab7174d7cba (patch) | |
| tree | 0e01647d27e70e0245e6b77f251a6978b536117e /mm/memory-failure.c | |
| parent | 5b7b3fe58c813a2970bb221fa3f56165d5abf9f1 (diff) | |
| download | linux-6506d1d7d0c209bdba330b6c2e9cfab7174d7cba.tar.xz | |
x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages
commit ce0fa3e56ad20f04d8252353dcd24e924abdafca upstream.
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
Link: http://lkml.kernel.org/r/20170816171803.28342-1-tony.luck@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm/memory-failure.c')
| -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(); |