Re: [PATCH 4/4] mm/memory-failure: Fall back to vma_address() when ->notify_failure() fails

["HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.com>]

On Fri, Aug 26, 2022 at 10:18:14AM -0700, Dan Williams wrote:
> In the case where a filesystem is polled to take over the memory failure
> and receives -EOPNOTSUPP it indicates that page->index and page->mapping
> are valid for reverse mapping the failure address. Introduce
> FSDAX_INVALID_PGOFF to distinguish when add_to_kill() is being called
> from mf_dax_kill_procs() by a filesytem vs the typical memory_failure()
> path.
> 
> Otherwise, vma_pgoff_address() is called with an invalid fsdax_pgoff
> which then trips this failing signature:
> 
>  kernel BUG at mm/memory-failure.c:319!
>  invalid opcode: 0000 [#1] PREEMPT SMP PTI
>  CPU: 13 PID: 1262 Comm: dax-pmd Tainted: G           OE    N 6.0.0-rc2+ #62
>  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
>  RIP: 0010:add_to_kill.cold+0x19d/0x209
>  [..]
>  Call Trace:
>   <TASK>
>   collect_procs.part.0+0x2c4/0x460
>   memory_failure+0x71b/0xba0
>   ? _printk+0x58/0x73
>   do_madvise.part.0.cold+0xaf/0xc5
> 
> Fixes: c36e20249571 ("mm: introduce mf_dax_kill_procs() for fsdax case")
> Cc: Shiyang Ruan <ruansy.fnst@fujitsu.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Darrick J. Wong <djwong@kernel.org>
> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Cc: Dave Chinner <david@fromorbit.com>
> Cc: Goldwyn Rodrigues <rgoldwyn@suse.de>
> Cc: Jane Chu <jane.chu@oracle.com>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Miaohe Lin <linmiaohe@huawei.com>
> Cc: Ritesh Harjani <riteshh@linux.ibm.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>