The patch titled
Subject: mm/madvise.c: fix madvise() infinite loop under special circumstances
has been added to the -mm tree. Its filename is
mmmadvise-bugfix-of-madvise-systemcall-infinite-loop-under-special-circumstances.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mmmadvise-bugfix-of-madvise-systemcall-infinite-loop-under-special-circumstances.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mmmadvise-bugfix-of-madvise-systemcall-infinite-loop-under-special-circumstances.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: chenjie <chenjie6@xxxxxxxxxx>
Subject: mm/madvise.c: fix madvise() infinite loop under special circumstances
MADVISE_WILLNEED has always been a noop for DAX (formerly XIP) mappings.
Unfortunatelly 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>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/madvise.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff -puN mm/madvise.c~mmmadvise-bugfix-of-madvise-systemcall-infinite-loop-under-special-circumstances mm/madvise.c
--- a/mm/madvise.c~mmmadvise-bugfix-of-madvise-systemcall-infinite-loop-under-special-circumstances
+++ a/mm/madvise.c
@@ -276,15 +276,14 @@ 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;
@@ -299,7 +298,6 @@ 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 -mm which might be from chenjie6@xxxxxxxxxx are
mmmadvise-bugfix-of-madvise-systemcall-infinite-loop-under-special-circumstances.patch