linux-stable.git/drivers/block/loop.c, branch v4.14.136

Revert "block/loop: Use global lock for ioctl() operation."

2019-05-02T07:40:33+00:00

This reverts commit 57da9a9742200f391d1cf93fea389f7ddc25ec9a which is
commit 310ca162d779efee8a2dc3731439680f3e9c1e86 upstream.

Jan Kara has reported seeing problems with this patch applied, as has
Salvatore Bonaccorso, so let's drop it for now.

Reported-by: Salvatore Bonaccorso 
Reported-by: Jan Kara 
Cc: Tetsuo Handa 
Cc: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

Revert "loop: Fold __loop_release into loop_release"

2019-03-05T16:57:58+00:00

This reverts commit f1e81ba8a3fa56dcc48828869b392b29559a0ac3 which is
commit 967d1dc144b50ad005e5eecdfadfbcfb399ffff6 upstream.

It does not work properly in the 4.14.y tree and causes more problems
than it fixes, so revert it.

Reported-by: Thomas Lindroth 
Reported-by: Jan Kara 
Cc: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

Revert "loop: Get rid of loop_index_mutex"

2019-03-05T16:57:57+00:00

This reverts commit c1e63df4f30c3918476ac9bc594355b0e9629893 which is
commit 0a42e99b58a208839626465af194cfe640ef9493 upstream.

It does not work properly in the 4.14.y tree and causes more problems
than it fixes, so revert it.

Reported-by: Thomas Lindroth 
Reported-by: Jan Kara 
Cc: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

Revert "loop: Fix double mutex_unlock(&loop_ctl_mutex) in loop_control_ioctl()"

2019-03-05T16:57:57+00:00

This reverts commit d2762edcb6af99fc9322bab0b1d4e71a427760e8 which is
commit 628bd85947091830a8c4872adfd5ed1d515a9cf2 upstream.

It does not work properly in the 4.14.y tree and causes more problems
than it fixes, so revert it.

Reported-by: Thomas Lindroth 
Reported-by: Jan Kara 
Cc: syzbot 
Cc: Ming Lei 
Cc: Tetsuo Handa 
Cc: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

loop: drop caches if offset or block_size are changed

2019-01-23T07:09:51+00:00

commit 5db470e229e22b7eda6e23b5566e532c96fb5bc3 upstream.

If we don't drop caches used in old offset or block_size, we can get old data
from new offset/block_size, which gives unexpected data to user.

For example, Martijn found a loopback bug in the below scenario.
1) LOOP_SET_FD loads first two pages on loop file
2) LOOP_SET_STATUS64 changes the offset on the loop file
3) mount is failed due to the cached pages having wrong superblock

Cc: Jens Axboe 
Cc: linux-block@vger.kernel.org
Reported-by: Martijn Coenen 
Reviewed-by: Bart Van Assche 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

loop: Fix double mutex_unlock(&loop_ctl_mutex) in loop_control_ioctl()

2019-01-23T07:09:51+00:00

commit 628bd85947091830a8c4872adfd5ed1d515a9cf2 upstream.

Commit 0a42e99b58a20883 ("loop: Get rid of loop_index_mutex") forgot to
remove mutex_unlock(&loop_ctl_mutex) from loop_control_ioctl() when
replacing loop_index_mutex with loop_ctl_mutex.

Fixes: 0a42e99b58a20883 ("loop: Get rid of loop_index_mutex")
Reported-by: syzbot 
Reviewed-by: Ming Lei 
Reviewed-by: Jan Kara 
Signed-off-by: Tetsuo Handa 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

loop: Get rid of loop_index_mutex

2019-01-23T07:09:51+00:00

commit 0a42e99b58a208839626465af194cfe640ef9493 upstream.

Now that loop_ctl_mutex is global, just get rid of loop_index_mutex as
there is no good reason to keep these two separate and it just
complicates the locking.

Signed-off-by: Jan Kara 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

loop: Fold __loop_release into loop_release

2019-01-23T07:09:51+00:00

commit 967d1dc144b50ad005e5eecdfadfbcfb399ffff6 upstream.

__loop_release() has a single call site. Fold it there. This is
currently not a huge win but it will make following replacement of
loop_index_mutex more obvious.

Signed-off-by: Jan Kara 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block/loop: Use global lock for ioctl() operation.

2019-01-23T07:09:51+00:00

commit 310ca162d779efee8a2dc3731439680f3e9c1e86 upstream.

syzbot is reporting NULL pointer dereference [1] which is caused by
race condition between ioctl(loop_fd, LOOP_CLR_FD, 0) versus
ioctl(other_loop_fd, LOOP_SET_FD, loop_fd) due to traversing other
loop devices at loop_validate_file() without holding corresponding
lo->lo_ctl_mutex locks.

Since ioctl() request on loop devices is not frequent operation, we don't
need fine grained locking. Let's use global lock in order to allow safe
traversal at loop_validate_file().

Note that syzbot is also reporting circular locking dependency between
bdev->bd_mutex and lo->lo_ctl_mutex [2] which is caused by calling
blkdev_reread_part() with lock held. This patch does not address it.

[1] https://syzkaller.appspot.com/bug?id=f3cfe26e785d85f9ee259f385515291d21bd80a3
[2] https://syzkaller.appspot.com/bug?id=bf154052f0eea4bc7712499e4569505907d15889

Signed-off-by: Tetsuo Handa 
Reported-by: syzbot 
Reviewed-by: Jan Kara 
Signed-off-by: Jan Kara 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block/loop: Don't grab "struct file" for vfs_getattr() operation.

2019-01-23T07:09:51+00:00

commit b1ab5fa309e6c49e4e06270ec67dd7b3e9971d04 upstream.

vfs_getattr() needs "struct path" rather than "struct file".
Let's use path_get()/path_put() rather than get_file()/fput().

Signed-off-by: Tetsuo Handa 
Reviewed-by: Jan Kara 
Signed-off-by: Jan Kara 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman