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block: protect rw_page against device teardown

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Fix use after free crashes like the following:

 general protection fault: 0000 [#1] SMP
 Call Trace:
  [<ffffffffa0050216>] ? pmem_do_bvec.isra.12+0xa6/0xf0 [nd_pmem]
  [<ffffffffa0050ba2>] pmem_rw_page+0x42/0x80 [nd_pmem]
  [<ffffffff8128fd90>] bdev_read_page+0x50/0x60
  [<ffffffff812972f0>] do_mpage_readpage+0x510/0x770
  [<ffffffff8128fd20>] ? I_BDEV+0x20/0x20
  [<ffffffff811d86dc>] ? lru_cache_add+0x1c/0x50
  [<ffffffff81297657>] mpage_readpages+0x107/0x170
  [<ffffffff8128fd20>] ? I_BDEV+0x20/0x20
  [<ffffffff8128fd20>] ? I_BDEV+0x20/0x20
  [<ffffffff8129058d>] blkdev_readpages+0x1d/0x20
  [<ffffffff811d615f>] __do_page_cache_readahead+0x28f/0x310
  [<ffffffff811d6039>] ? __do_page_cache_readahead+0x169/0x310
  [<ffffffff811c5abd>] ? pagecache_get_page+0x2d/0x1d0
  [<ffffffff811c76f6>] filemap_fault+0x396/0x530
  [<ffffffff811f816e>] __do_fault+0x4e/0xf0
  [<ffffffff811fce7d>] handle_mm_fault+0x11bd/0x1b50

Cc: <stable@vger.kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Reported-by: kbuild test robot <lkp@intel.com>
Acked-by: Matthew Wilcox <willy@linux.intel.com>
[willy: symmetry fixups]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2015-11-19 13:29:28 -08:00
parent 0df9d41ab5
commit 2e6edc9538
3 changed files with 18 additions and 4 deletions
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2
block/blk.h
View File

@ -72,8 +72,6 @@ void blk_dequeue_request(struct request *rq);
void __blk_queue_free_tags(struct request_queue *q); void __blk_queue_free_tags(struct request_queue *q);
bool __blk_end_bidi_request(struct request *rq, int error, bool __blk_end_bidi_request(struct request *rq, int error,
unsigned int nr_bytes, unsigned int bidi_bytes); unsigned int nr_bytes, unsigned int bidi_bytes);
int blk_queue_enter(struct request_queue *q, gfp_t gfp);
void blk_queue_exit(struct request_queue *q);
void blk_freeze_queue(struct request_queue *q); void blk_freeze_queue(struct request_queue *q);
static inline void blk_queue_enter_live(struct request_queue *q) static inline void blk_queue_enter_live(struct request_queue *q)

18
fs/block_dev.c
View File

@ -390,9 +390,17 @@ int bdev_read_page(struct block_device *bdev, sector_t sector,
struct page *page) struct page *page)
{ {
const struct block_device_operations *ops = bdev->bd_disk->fops; const struct block_device_operations *ops = bdev->bd_disk->fops;
int result = -EOPNOTSUPP;
if (!ops->rw_page || bdev_get_integrity(bdev)) if (!ops->rw_page || bdev_get_integrity(bdev))
return -EOPNOTSUPP; return result;
return ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ);
result = blk_queue_enter(bdev->bd_queue, GFP_KERNEL);
if (result)
return result;
result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ);
blk_queue_exit(bdev->bd_queue);
return result;
} }
EXPORT_SYMBOL_GPL(bdev_read_page); EXPORT_SYMBOL_GPL(bdev_read_page);
@ -421,14 +429,20 @@ int bdev_write_page(struct block_device *bdev, sector_t sector,
int result; int result;
int rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE; int rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE;
const struct block_device_operations *ops = bdev->bd_disk->fops; const struct block_device_operations *ops = bdev->bd_disk->fops;
if (!ops->rw_page || bdev_get_integrity(bdev)) if (!ops->rw_page || bdev_get_integrity(bdev))
return -EOPNOTSUPP; return -EOPNOTSUPP;
result = blk_queue_enter(bdev->bd_queue, GFP_KERNEL);
if (result)
return result;
set_page_writeback(page); set_page_writeback(page);
result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, rw); result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, rw);
if (result) if (result)
end_page_writeback(page); end_page_writeback(page);
else else
unlock_page(page); unlock_page(page);
blk_queue_exit(bdev->bd_queue);
return result; return result;
} }
EXPORT_SYMBOL_GPL(bdev_write_page); EXPORT_SYMBOL_GPL(bdev_write_page);

2
include/linux/blkdev.h
View File

@ -794,6 +794,8 @@ extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t, extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
struct scsi_ioctl_command __user *); struct scsi_ioctl_command __user *);
extern int blk_queue_enter(struct request_queue *q, gfp_t gfp);
extern void blk_queue_exit(struct request_queue *q);
extern void blk_start_queue(struct request_queue *q); extern void blk_start_queue(struct request_queue *q);
extern void blk_stop_queue(struct request_queue *q); extern void blk_stop_queue(struct request_queue *q);
extern void blk_sync_queue(struct request_queue *q); extern void blk_sync_queue(struct request_queue *q);