This is a note to let you know that I've just added the patch titled
mm/madvise.c: fix madvise() infinite loop under special circumstances
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-madvise.c-fix-madvise-infinite-loop-under-special-circumstances.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6ea8d958a2c95a1d514015d4e29ba21a8c0a1a91 Mon Sep 17 00:00:00 2001
From: chenjie <chenjie6@xxxxxxxxxx>
Date: Wed, 29 Nov 2017 16:10:54 -0800
Subject: mm/madvise.c: fix madvise() infinite loop under special circumstances
From: chenjie <chenjie6@xxxxxxxxxx>
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@xxxxxxxx: rewrite changelog]
Link: http://lkml.kernel.org/r/20171127115318.911-1-guoxuenan@xxxxxxxxxx
Fixes: fe77ba6f4f97 ("[PATCH] xip: madvice/fadvice: execute in place")
Signed-off-by: chenjie <chenjie6@xxxxxxxxxx>
Signed-off-by: guoxuenan <guoxuenan@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: zhangyi (F) <yi.zhang@xxxxxxxxxx>
Cc: Miao Xie <miaoxie@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Shaohua Li <shli@xxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Carsten Otte <cotte@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/madvise.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -223,15 +223,14 @@ static long madvise_willneed(struct vm_a
{
struct file *file = vma->vm_file;
+ *prev = vma;
#ifdef CONFIG_SWAP
if (!file) {
- *prev = vma;
force_swapin_readahead(vma, start, end);
return 0;
}
if (shmem_mapping(file->f_mapping)) {
- *prev = vma;
force_shm_swapin_readahead(vma, start, end,
file->f_mapping);
return 0;
@@ -246,7 +245,6 @@ static long madvise_willneed(struct vm_a
return 0;
}
- *prev = vma;
start = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
if (end > vma->vm_end)
end = vma->vm_end;
Patches currently in stable-queue which might be from chenjie6@xxxxxxxxxx are
queue-4.4/mm-madvise.c-fix-madvise-infinite-loop-under-special-circumstances.patch