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| author |   Omar Sandoval <osandov@fb.com> | 2018-04-06 09:57:03 -0700 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2018-04-10 08:38:46 -0600 |
| commit | bdac616db9bbadb90b7d6a406144571015e138f7 (patch) | |
| tree | d883f14fdc2dc308c13aae0cf80042deec2ffd6b /drivers/block | |
| parent | block/loop: fix deadlock after loop_set_status (diff) | |
| download | linux-dev-bdac616db9bbadb90b7d6a406144571015e138f7.tar.xz linux-dev-bdac616db9bbadb90b7d6a406144571015e138f7.zip | |
loop: fix LOOP_GET_STATUS lock imbalance
Commit 2d1d4c1e591f made loop_get_status() drop lo_ctx_mutex before
returning, but the loop_get_status_old(), loop_get_status64(), and
loop_get_status_compat() wrappers don't call loop_get_status() if the
passed argument is NULL. The callers expect that the lock is dropped, so
make sure we drop it in that case, too.
Reported-by: syzbot+31e8daa8b3fc129e75f2@syzkaller.appspotmail.com
Fixes: 2d1d4c1e591f ("loop: don't call into filesystem while holding lo_ctl_mutex")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/loop.c | 33 |
1 files changed, 18 insertions, 15 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index e5fc020cceda..c9d04497a415 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1287,12 +1287,13 @@ static int loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { struct loop_info info; struct loop_info64 info64; - int err = 0; + int err; - if (!arg) - err = -EINVAL; - if (!err) - err = loop_get_status(lo, &info64); + if (!arg) { + mutex_unlock(&lo->lo_ctl_mutex); + return -EINVAL; + } + err = loop_get_status(lo, &info64); if (!err) err = loop_info64_to_old(&info64, &info); if (!err && copy_to_user(arg, &info, sizeof(info))) @@ -1304,12 +1305,13 @@ loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) { static int loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { struct loop_info64 info64; - int err = 0; + int err; - if (!arg) - err = -EINVAL; - if (!err) - err = loop_get_status(lo, &info64); + if (!arg) { + mutex_unlock(&lo->lo_ctl_mutex); + return -EINVAL; + } + err = loop_get_status(lo, &info64); if (!err && copy_to_user(arg, &info64, sizeof(info64))) err = -EFAULT; @@ -1533,12 +1535,13 @@ loop_get_status_compat(struct loop_device *lo, struct compat_loop_info __user *arg) { struct loop_info64 info64; - int err = 0; + int err; - if (!arg) - err = -EINVAL; - if (!err) - err = loop_get_status(lo, &info64); + if (!arg) { + mutex_unlock(&lo->lo_ctl_mutex); + return -EINVAL; + } + err = loop_get_status(lo, &info64); if (!err) err = loop_info64_to_compat(&info64, arg); return err; |