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| author | Omar Sandoval <osandov@fb.com> | 2018-04-06 09:57:03 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-25 16:17:35 +0200 |
| commit | 360964411d57d060d0b3f067c7a708ba9aeb5e07 (patch) | |
| tree | eee8f068944ad13aeff1f35339557b66b8c284bb /drivers/block | |
| parent | c18270ac9f8457c3d383e9b9a58e6368e046ce8a (diff) | |
| download | linux-stable-360964411d57d060d0b3f067c7a708ba9aeb5e07.tar.gz linux-stable-360964411d57d060d0b3f067c7a708ba9aeb5e07.tar.bz2 linux-stable-360964411d57d060d0b3f067c7a708ba9aeb5e07.zip | |
loop: fix LOOP_GET_STATUS lock imbalance
commit bdac616db9bbadb90b7d6a406144571015e138f7 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 fef91963555a..1a87f87c88d0 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1282,12 +1282,13 @@ 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))) @@ -1299,12 +1300,13 @@ 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; @@ -1525,12 +1527,13 @@ 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; |