Re: [PATCH] mm/memory: print also a_ops->readpage in print_bad_pte

[Konstantin Khlebnikov]

On Sat, Apr 4, 2015 at 1:10 AM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, 03 Apr 2015 20:18:18 +0300 Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> wrote:
>
>> A lot of filesystems use generic_file_mmap() and filemap_fault(),
>> f_op->mmap and vm_ops->fault aren't enough to identify filesystem.
>>
>> This prints file name, vm_ops->fault, f_op->mmap and a_ops->readpage
>> (which is almost always implemented and filesystem-specific).
>>
>> Example:
>>
>> [   23.676410] BUG: Bad page map in process sh  pte:1b7e6025 pmd:19bbd067
>> [   23.676887] page:ffffea00006df980 count:4 mapcount:1 mapping:ffff8800196426c0 index:0x97
>> [   23.677481] flags: 0x10000000000000c(referenced|uptodate)
>> [   23.677896] page dumped because: bad pte
>> [   23.678205] addr:00007f52fcb17000 vm_flags:00000075 anon_vma:          (null) mapping:ffff8800196426c0 index:97
>> [   23.678922] file:libc-2.19.so fault:filemap_fault mmap:generic_file_readonly_mmap readpage:v9fs_vfs_readpage
>
> Is that why we print these out?  Just to identify the fs type?
>
> There's always vma->vm_file->f_inode->i_sb->s_magic ;)

Yes, but that also might be anon inode/file mapped by some driver, so
s_magic isn't enough.

>
>
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