4.14-stable review patch. If anyone has any objections, please let me know.
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From: NeilBrown neilb@suse.com
commit 52a0d49de3d592a3118e13f35985e3d99eaf43df upstream.
bitmap_create() allocates memory with GFP_KERNEL and so can wait for IO. If called while the array is quiesced, it could wait indefinitely for write out to the array - deadlock. So call bitmap_create() before quiescing the array.
Signed-off-by: NeilBrown neilb@suse.com Signed-off-by: Shaohua Li shli@fb.com Signed-off-by: Jack Wang jinpu.wang@profitbricks.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/md/md.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-)
--- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -6645,22 +6645,26 @@ static int set_bitmap_file(struct mddev return -ENOENT; /* cannot remove what isn't there */ err = 0; if (mddev->pers) { - mddev->pers->quiesce(mddev, 1); if (fd >= 0) { struct bitmap *bitmap;
bitmap = bitmap_create(mddev, -1); + mddev->pers->quiesce(mddev, 1); if (!IS_ERR(bitmap)) { mddev->bitmap = bitmap; err = bitmap_load(mddev); } else err = PTR_ERR(bitmap); - } - if (fd < 0 || err) { + if (err) { + bitmap_destroy(mddev); + fd = -1; + } + mddev->pers->quiesce(mddev, 0); + } else if (fd < 0) { + mddev->pers->quiesce(mddev, 1); bitmap_destroy(mddev); - fd = -1; /* make sure to put the file */ + mddev->pers->quiesce(mddev, 0); } - mddev->pers->quiesce(mddev, 0); } if (fd < 0) { struct file *f = mddev->bitmap_info.file; @@ -6944,8 +6948,8 @@ static int update_array_info(struct mdde mddev->bitmap_info.default_offset; mddev->bitmap_info.space = mddev->bitmap_info.default_space; - mddev->pers->quiesce(mddev, 1); bitmap = bitmap_create(mddev, -1); + mddev->pers->quiesce(mddev, 1); if (!IS_ERR(bitmap)) { mddev->bitmap = bitmap; rv = bitmap_load(mddev);