diff options
| author | chenjie <chenjie6@huawei.com> | 2017-11-30 03:10:54 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-06-01 02:30:00 +0300 |
| commit | 3d886ff142e713000aec6bf6f82944eb03dab28c (patch) | |
| tree | 033770c842d0d7091239b540cefd2aa27820c8b8 /mm/madvise.c | |
| parent | 43da4014d8fb05379f19abe26d61af608bd680fd (diff) | |
| download | linux-3d886ff142e713000aec6bf6f82944eb03dab28c.tar.xz | |
mm/madvise.c: fix madvise() infinite loop under special circumstances
commit 6ea8d958a2c95a1d514015d4e29ba21a8c0a1a91 upstream.
MADVISE_WILLNEED has always been a noop for DAX (formerly XIP) mappings.
Unfortunately madvise_willneed() doesn't communicate this information
properly to the generic madvise syscall implementation. The calling
convention is quite subtle there. madvise_vma() is supposed to either
return an error or update &prev otherwise the main loop will never
advance to the next vma and it will keep looping for ever without a way
to get out of the kernel.
It seems this has been broken since introduction. Nobody has noticed
because nobody seems to be using MADVISE_WILLNEED on these DAX mappings.
[mhocko@suse.com: rewrite changelog]
Link: http://lkml.kernel.org/r/20171127115318.911-1-guoxuenan@huawei.com
Fixes: fe77ba6f4f97 ("[PATCH] xip: madvice/fadvice: execute in place")
Signed-off-by: chenjie <chenjie6@huawei.com>
Signed-off-by: guoxuenan <guoxuenan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: zhangyi (F) <yi.zhang@huawei.com>
Cc: Miao Xie <miaoxie@huawei.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'mm/madvise.c')
| -rw-r--r-- | mm/madvise.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/madvise.c b/mm/madvise.c index 23d3a6b3764f..ec8e59c08d54 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -128,6 +128,7 @@ static long madvise_willneed(struct vm_area_struct * vma, { struct file *file = vma->vm_file; + *prev = vma; if (!file) return -EBADF; @@ -136,7 +137,6 @@ static long madvise_willneed(struct vm_area_struct * vma, return 0; } - *prev = vma; start = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; if (end > vma->vm_end) end = vma->vm_end; |