Patch "mm/madvise.c: fix madvise() infinite loop under special circumstances" has been added to the 3.18-stable tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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 3.18-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-3.18 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 |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -221,9 +221,9 @@ static long madvise_willneed(struct vm_a
 {
 	struct file *file = vma->vm_file;
 
+	*prev = vma;
 #ifdef CONFIG_SWAP
 	if (!file || mapping_cap_swap_backed(file->f_mapping)) {
-		*prev = vma;
 		if (!file)
 			force_swapin_readahead(vma, start, end);
 		else
@@ -241,7 +241,6 @@ 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-3.18/mm-madvise.c-fix-madvise-infinite-loop-under-special-circumstances.patch



[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]