On Fri, 2015-11-20 at 08:32 +0800, kbuild test robot wrote:
> Hi Dan,
>
> [auto build test ERROR on: block/for-next]
> [also build test ERROR on: v4.4-rc1 next-20151119]
Thanks kbuild robot! ;-)
I indeed had rebased this in my tree in front of another patch that
made blk_queue_enter() public. Given that other patch is 4.5 material,
move that declaration change into this patch:
8<----
Subject: block: protect rw_page against device teardown
From: Dan Williams <dan.j.willi...@intel.com>
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: <sta...@vger.kernel.org>
Cc: Jens Axboe <ax...@fb.com>
Cc: Matthew Wilcox <wi...@linux.intel.com>
Cc: Alexander Viro <v...@zeniv.linux.org.uk>
Reported-by: kbuild test robot <l...@intel.com>
Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
---
block/blk.h | 2 --
fs/block_dev.c | 18 ++++++++++++++++--
include/linux/blkdev.h | 2 ++
3 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/block/blk.h b/block/blk.h
index da722eb786df..c43926d3d74d 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -72,8 +72,6 @@ void blk_dequeue_request(struct request *rq);
void __blk_queue_free_tags(struct request_queue *q);
bool __blk_end_bidi_request(struct request *rq, int error,
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);
static inline void blk_queue_enter_live(struct request_queue *q)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index bb0dfb1c7af1..cc0af12acf94 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -390,9 +390,17 @@ int bdev_read_page(struct block_device *bdev, sector_t
sector,
struct page *page)
{
const struct block_device_operations *ops = bdev->bd_disk->fops;
+ int rc = -EOPNOTSUPP;
+
if (!ops->rw_page || bdev_get_integrity(bdev))
- return -EOPNOTSUPP;
- return ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ);
+ return rc;
+
+ rc = blk_queue_enter(bdev->bd_queue, GFP_KERNEL);
+ if (rc)
+ return rc;
+ rc = ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ);
+ blk_queue_exit(bdev->bd_queue);
+ return rc;
}
EXPORT_SYMBOL_GPL(bdev_read_page);
@@ -421,14 +429,20 @@ int bdev_write_page(struct block_device *bdev, sector_t
sector,
int result;
int rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE;
const struct block_device_operations *ops = bdev->bd_disk->fops;
+
if (!ops->rw_page || bdev_get_integrity(bdev))
return -EOPNOTSUPP;
+ result = blk_queue_enter(bdev->bd_queue, GFP_KERNEL);
+ if (result)
+ return result;
+
set_page_writeback(page);
result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, rw);
if (result)
end_page_writeback(page);
else
unlock_page(page);
+ blk_queue_exit(bdev->bd_queue);
return result;
}
EXPORT_SYMBOL_GPL(bdev_write_page);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 3fe27f8d91f0..c0d2b7927c1f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -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,
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_stop_queue(struct request_queue *q);
extern void blk_sync_queue(struct request_queue *q);
