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2019-11-14block: remove (__)blkdev_reread_part as an exported APIChristoph Hellwig1-5/+8
In general drivers should never mess with partition tables directly. Unfortunately s390 and loop do for somewhat historic reasons, but they can use bdev_disk_changed directly instead when we export it as they satisfy the sanity checks we have in __blkdev_reread_part. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Stefan Haberland <sth@linux.ibm.com> [dasd] Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-01loop: fix no-unmap write-zeroes request behaviorDarrick J. Wong1-8/+18
Currently, if the loop device receives a WRITE_ZEROES request, it asks the underlying filesystem to punch out the range. This behavior is correct if unmapping is allowed. However, a NOUNMAP request means that the caller doesn't want us to free the storage backing the range, so punching out the range is incorrect behavior. To satisfy a NOUNMAP | WRITE_ZEROES request, loop should ask the underlying filesystem to FALLOC_FL_ZERO_RANGE, which is (according to the fallocate documentation) required to ensure that the entire range is backed by real storage, which suffices for our purposes. Fixes: 19372e2769179dd ("loop: implement REQ_OP_WRITE_ZEROES") Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-10-01loop: change queue block size to match when using DIOMartijn Coenen1-0/+10
The loop driver assumes that if the passed in fd is opened with O_DIRECT, the caller wants to use direct I/O on the loop device. However, if the underlying block device has a different block size than the loop block queue, direct I/O can't be enabled. Instead of requiring userspace to manually change the blocksize and re-enable direct I/O, just change the queue block sizes to match, as well as the io_min size. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martijn Coenen <maco@android.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-17Merge tag 'for-5.4/block-2019-09-16' of git://git.kernel.dk/linux-blockLinus Torvalds1-0/+1
Pull block updates from Jens Axboe: - Two NVMe pull requests: - ana log parse fix from Anton - nvme quirks support for Apple devices from Ben - fix missing bio completion tracing for multipath stack devices from Hannes and Mikhail - IP TOS settings for nvme rdma and tcp transports from Israel - rq_dma_dir cleanups from Israel - tracing for Get LBA Status command from Minwoo - Some nvme-tcp cleanups from Minwoo, Potnuri and Myself - Some consolidation between the fabrics transports for handling the CAP register - reset race with ns scanning fix for fabrics (move fabrics commands to a dedicated request queue with a different lifetime from the admin request queue)." - controller reset and namespace scan races fixes - nvme discovery log change uevent support - naming improvements from Keith - multiple discovery controllers reject fix from James - some regular cleanups from various people - Series fixing (and re-fixing) null_blk debug printing and nr_devices checks (André) - A few pull requests from Song, with fixes from Andy, Guoqing, Guilherme, Neil, Nigel, and Yufen. - REQ_OP_ZONE_RESET_ALL support (Chaitanya) - Bio merge handling unification (Christoph) - Pick default elevator correctly for devices with special needs (Damien) - Block stats fixes (Hou) - Timeout and support devices nbd fixes (Mike) - Series fixing races around elevator switching and device add/remove (Ming) - sed-opal cleanups (Revanth) - Per device weight support for BFQ (Fam) - Support for blk-iocost, a new model that can properly account cost of IO workloads. (Tejun) - blk-cgroup writeback fixes (Tejun) - paride queue init fixes (zhengbin) - blk_set_runtime_active() cleanup (Stanley) - Block segment mapping optimizations (Bart) - lightnvm fixes (Hans/Minwoo/YueHaibing) - Various little fixes and cleanups * tag 'for-5.4/block-2019-09-16' of git://git.kernel.dk/linux-block: (186 commits) null_blk: format pr_* logs with pr_fmt null_blk: match the type of parameter nr_devices null_blk: do not fail the module load with zero devices block: also check RQF_STATS in blk_mq_need_time_stamp() block: make rq sector size accessible for block stats bfq: Fix bfq linkage error raid5: use bio_end_sector in r5_next_bio raid5: remove STRIPE_OPS_REQ_PENDING md: add feature flag MD_FEATURE_RAID0_LAYOUT md/raid0: avoid RAID0 data corruption due to layout confusion. raid5: don't set STRIPE_HANDLE to stripe which is in batch list raid5: don't increment read_errors on EILSEQ return nvmet: fix a wrong error status returned in error log page nvme: send discovery log page change events to userspace nvme: add uevent variables for controller devices nvme: enable aen regardless of the presence of I/O queues nvme-fabrics: allow discovery subsystems accept a kato nvmet: Use PTR_ERR_OR_ZERO() in nvmet_init_discovery() nvme: Remove redundant assignment of cq vector nvme: Assign subsys instance from first ctrl ...
2019-08-08loop: Add LOOP_SET_DIRECT_IO to compat ioctlAlessio Balsini1-0/+1
Enabling Direct I/O with loop devices helps reducing memory usage by avoiding double caching. 32 bit applications running on 64 bits systems are currently not able to request direct I/O because is missing from the lo_compat_ioctl. This patch fixes the compatibility issue mentioned above by exporting LOOP_SET_DIRECT_IO as additional lo_compat_ioctl() entry. The input argument for this ioctl is a single long converted to a 1-bit boolean, so compatibility is preserved. Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Alessio Balsini <balsini@android.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-08-08loop: set PF_MEMALLOC_NOIO for the worker threadMikulas Patocka1-1/+1
A deadlock with this stacktrace was observed. The loop thread does a GFP_KERNEL allocation, it calls into dm-bufio shrinker and the shrinker depends on I/O completion in the dm-bufio subsystem. In order to fix the deadlock (and other similar ones), we set the flag PF_MEMALLOC_NOIO at loop thread entry. PID: 474 TASK: ffff8813e11f4600 CPU: 10 COMMAND: "kswapd0" #0 [ffff8813dedfb938] __schedule at ffffffff8173f405 #1 [ffff8813dedfb990] schedule at ffffffff8173fa27 #2 [ffff8813dedfb9b0] schedule_timeout at ffffffff81742fec #3 [ffff8813dedfba60] io_schedule_timeout at ffffffff8173f186 #4 [ffff8813dedfbaa0] bit_wait_io at ffffffff8174034f #5 [ffff8813dedfbac0] __wait_on_bit at ffffffff8173fec8 #6 [ffff8813dedfbb10] out_of_line_wait_on_bit at ffffffff8173ff81 #7 [ffff8813dedfbb90] __make_buffer_clean at ffffffffa038736f [dm_bufio] #8 [ffff8813dedfbbb0] __try_evict_buffer at ffffffffa0387bb8 [dm_bufio] #9 [ffff8813dedfbbd0] dm_bufio_shrink_scan at ffffffffa0387cc3 [dm_bufio] #10 [ffff8813dedfbc40] shrink_slab at ffffffff811a87ce #11 [ffff8813dedfbd30] shrink_zone at ffffffff811ad778 #12 [ffff8813dedfbdc0] kswapd at ffffffff811ae92f #13 [ffff8813dedfbec0] kthread at ffffffff810a8428 #14 [ffff8813dedfbf50] ret_from_fork at ffffffff81745242 PID: 14127 TASK: ffff881455749c00 CPU: 11 COMMAND: "loop1" #0 [ffff88272f5af228] __schedule at ffffffff8173f405 #1 [ffff88272f5af280] schedule at ffffffff8173fa27 #2 [ffff88272f5af2a0] schedule_preempt_disabled at ffffffff8173fd5e #3 [ffff88272f5af2b0] __mutex_lock_slowpath at ffffffff81741fb5 #4 [ffff88272f5af330] mutex_lock at ffffffff81742133 #5 [ffff88272f5af350] dm_bufio_shrink_count at ffffffffa03865f9 [dm_bufio] #6 [ffff88272f5af380] shrink_slab at ffffffff811a86bd #7 [ffff88272f5af470] shrink_zone at ffffffff811ad778 #8 [ffff88272f5af500] do_try_to_free_pages at ffffffff811adb34 #9 [ffff88272f5af590] try_to_free_pages at ffffffff811adef8 #10 [ffff88272f5af610] __alloc_pages_nodemask at ffffffff811a09c3 #11 [ffff88272f5af710] alloc_pages_current at ffffffff811e8b71 #12 [ffff88272f5af760] new_slab at ffffffff811f4523 #13 [ffff88272f5af7b0] __slab_alloc at ffffffff8173a1b5 #14 [ffff88272f5af880] kmem_cache_alloc at ffffffff811f484b #15 [ffff88272f5af8d0] do_blockdev_direct_IO at ffffffff812535b3 #16 [ffff88272f5afb00] __blockdev_direct_IO at ffffffff81255dc3 #17 [ffff88272f5afb30] xfs_vm_direct_IO at ffffffffa01fe3fc [xfs] #18 [ffff88272f5afb90] generic_file_read_iter at ffffffff81198994 #19 [ffff88272f5afc50] __dta_xfs_file_read_iter_2398 at ffffffffa020c970 [xfs] #20 [ffff88272f5afcc0] lo_rw_aio at ffffffffa0377042 [loop] #21 [ffff88272f5afd70] loop_queue_work at ffffffffa0377c3b [loop] #22 [ffff88272f5afe60] kthread_worker_fn at ffffffff810a8a0c #23 [ffff88272f5afec0] kthread at ffffffff810a8428 #24 [ffff88272f5aff50] ret_from_fork at ffffffff81745242 Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-07-30loop: Fix mount(2) failure due to race with LOOP_SET_FDJan Kara1-7/+9
Commit 33ec3e53e7b1 ("loop: Don't change loop device under exclusive opener") made LOOP_SET_FD ioctl acquire exclusive block device reference while it updates loop device binding. However this can make perfectly valid mount(2) fail with EBUSY due to racing LOOP_SET_FD holding temporarily the exclusive bdev reference in cases like this: for i in {a..z}{a..z}; do dd if=/dev/zero of=$i.image bs=1k count=0 seek=1024 mkfs.ext2 $i.image mkdir mnt$i done echo "Run" for i in {a..z}{a..z}; do mount -o loop -t ext2 $i.image mnt$i & done Fix the problem by not getting full exclusive bdev reference in LOOP_SET_FD but instead just mark the bdev as being claimed while we update the binding information. This just blocks new exclusive openers instead of failing them with EBUSY thus fixing the problem. Fixes: 33ec3e53e7b1 ("loop: Don't change loop device under exclusive opener") Cc: stable@vger.kernel.org Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-29block: never take page references for ITER_BVECChristoph Hellwig1-12/+4
If we pass pages through an iov_iter we always already have a reference in the caller. Thus remove the ITER_BVEC_FLAG_NO_REF and don't take reference to pages by default for bvec backed iov_iters. Reviewed-by: Minwoo Im <minwoo.im.dev@gmail.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-27loop: Don't change loop device under exclusive openerJan Kara1-1/+17
Loop module allows calling LOOP_SET_FD while there are other openers of the loop device. Even exclusive ones. This can lead to weird consequences such as kernel deadlocks like: mount_bdev() lo_ioctl() udf_fill_super() udf_load_vrs() sb_set_blocksize() - sets desired block size B udf_tread() sb_bread() __bread_gfp(bdev, block, B) loop_set_fd() set_blocksize() - now __getblk_slow() indefinitely loops because B != bdev block size Fix the problem by disallowing LOOP_SET_FD ioctl when there are exclusive openers of a loop device. [Deliberately chosen not to CC stable as a user with priviledges to trigger this race has other means of taking the system down and this has a potential of breaking some weird userspace setup] Reported-and-tested-by: syzbot+10007d66ca02b08f0e60@syzkaller.appspotmail.com Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-01block: loop: mark bvec as ITER_BVEC_FLAG_NO_REFMing Lei1-4/+12
loop is one block device, for any bio submitted to this device, the upper layer does guarantee that pages added to loop's bio won't go away when the bio is in-flight. So mark loop's bvec as ITER_BVEC_FLAG_NO_REF then get_page/put_page can be saved for serving loop's IO. Cc: linux-fsdevel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-01loop: properly observe rotational flag of underlying deviceHolger Hoffstätte1-0/+19
The loop driver always declares the rotational flag of its device as rotational, even when the device of the mapped file is nonrotational, as is the case with SSDs or on tmpfs. This can confuse filesystem tools which are SSD-aware; in my case I frequently forget to tell mkfs.btrfs that my loop device on tmpfs is nonrotational, and that I really don't need any automatic metadata redundancy. The attached patch fixes this by introspecting the rotational flag of the mapped file's underlying block device, if it exists. If the mapped file's filesystem has no associated block device - as is the case on e.g. tmpfs - we assume nonrotational storage. If there is a better way to identify such non-devices I'd love to hear them. Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Cc: holger@applied-asynchrony.com Signed-off-by: Holger Hoffstätte <holger.hoffstaette@googlemail.com> Signed-off-by: Gwendal Grignou <gwendal@chromium.org> Signed-off-by: Benjamin Gordon <bmgordon@chromium.org> Reviewed-by: Guenter Roeck <groeck@chromium.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-03-18loop: access lo_backing_file only when the loop device is Lo_boundDongli Zhang1-1/+1
Commit 758a58d0bc67 ("loop: set GENHD_FL_NO_PART_SCAN after blkdev_reread_part()") separates "lo->lo_backing_file = NULL" and "lo->lo_state = Lo_unbound" into different critical regions protected by loop_ctl_mutex. However, there is below race that the NULL lo->lo_backing_file would be accessed when the backend of a loop is another loop device, e.g., loop0's backend is a file, while loop1's backend is loop0. loop0's backend is file loop1's backend is loop0 __loop_clr_fd() mutex_lock(&loop_ctl_mutex); lo->lo_backing_file = NULL; --> set to NULL mutex_unlock(&loop_ctl_mutex); loop_set_fd() mutex_lock_killable(&loop_ctl_mutex); loop_validate_file() f = l->lo_backing_file; --> NULL access if loop0 is not Lo_unbound mutex_lock(&loop_ctl_mutex); lo->lo_state = Lo_unbound; mutex_unlock(&loop_ctl_mutex); lo->lo_backing_file should be accessed only when the loop device is Lo_bound. In fact, the problem has been introduced already in commit 7ccd0791d985 ("loop: Push loop_ctl_mutex down into loop_clr_fd()") after which loop_validate_file() could see devices in Lo_rundown state with which it did not count. It was harmless at that point but still. Fixes: 7ccd0791d985 ("loop: Push loop_ctl_mutex down into loop_clr_fd()") Reported-by: syzbot+9bdc1adc1c55e7fe765b@syzkaller.appspotmail.com Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-22loop: set GENHD_FL_NO_PART_SCAN after blkdev_reread_part()Dongli Zhang1-4/+17
Commit 0da03cab87e6 ("loop: Fix deadlock when calling blkdev_reread_part()") moves blkdev_reread_part() out of the loop_ctl_mutex. However, GENHD_FL_NO_PART_SCAN is set before __blkdev_reread_part(). As a result, __blkdev_reread_part() will fail the check of GENHD_FL_NO_PART_SCAN and will not rescan the loop device to delete all partitions. Below are steps to reproduce the issue: step1 # dd if=/dev/zero of=tmp.raw bs=1M count=100 step2 # losetup -P /dev/loop0 tmp.raw step3 # parted /dev/loop0 mklabel gpt step4 # parted -a none -s /dev/loop0 mkpart primary 64s 1 step5 # losetup -d /dev/loop0 Step5 will not be able to delete /dev/loop0p1 (introduced by step4) and there is below kernel warning message: [ 464.414043] __loop_clr_fd: partition scan of loop0 failed (rc=-22) This patch sets GENHD_FL_NO_PART_SCAN after blkdev_reread_part(). Fixes: 0da03cab87e6 ("loop: Fix deadlock when calling blkdev_reread_part()") Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-22loop: do not print warn message if partition scan is successfulDongli Zhang1-2/+3
Do not print warn message when the partition scan returns 0. Fixes: d57f3374ba48 ("loop: Move special partition reread handling in loop_clr_fd()") Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-15block: kill BLK_MQ_F_SG_MERGEMing Lei1-1/+1
QUEUE_FLAG_NO_SG_MERGE has been killed, so kill BLK_MQ_F_SG_MERGE too. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-15block: loop: pass multi-page bvec to iov_iterMing Lei1-10/+10
iov_iter is implemented on bvec itererator helpers, so it is safe to pass multi-page bvec to it, and this way is much more efficient than passing one page in each bvec. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-01-09loop: drop caches if offset or block_size are changedJaegeuk Kim1-2/+33
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 <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Reported-by: Martijn Coenen <maco@google.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-22block: loop: remove redundant codeChengguang Xu1-1/+0
Code cleanup for removing redundant break in switch case. Signed-off-by: Chengguang Xu <cgxu519@gmx.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-16block: loop: check error using IS_ERR instead of IS_ERR_OR_NULL in loop_add()Chengguang Xu1-1/+1
blk_mq_init_queue() will not return NULL pointer to its caller, so it's better to replace IS_ERR_OR_NULL using IS_ERR in loop_add(). If in the future things change to check NULL pointer inside loop_add(), we should return -ENOMEM as return code instead of PTR_ERR(NULL). Signed-off-by: Chengguang Xu <cgxu519@gmx.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-07blkcg: remove bio->bi_css and instead use bio->bi_blkgDennis Zhou1-2/+3
Prior patches ensured that any bio that interacts with a request_queue is properly associated with a blkg. This makes bio->bi_css unnecessary as blkg maintains a reference to blkcg already. This removes the bio field bi_css and transfers corresponding uses to access via bi_blkg. Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-12loop: Fix double mutex_unlock(&loop_ctl_mutex) in loop_control_ioctl()Tetsuo Handa1-2/+0
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 <syzbot+c0138741c2290fc5e63f@syzkaller.appspotmail.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Get rid of 'nested' acquisition of loop_ctl_mutexJan Kara1-6/+6
The nested acquisition of loop_ctl_mutex (->lo_ctl_mutex back then) has been introduced by commit f028f3b2f987e "loop: fix circular locking in loop_clr_fd()" to fix lockdep complains about bd_mutex being acquired after lo_ctl_mutex during partition rereading. Now that these are properly fixed, let's stop fooling lockdep. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Avoid circular locking dependency between loop_ctl_mutex and bd_mutexJan Kara1-11/+15
Code in loop_change_fd() drops reference to the old file (and also the new file in a failure case) under loop_ctl_mutex. Similarly to a situation in loop_set_fd() this can create a circular locking dependency if this was the last reference holding the file open. Delay dropping of the file reference until we have released loop_ctl_mutex. Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Fix deadlock when calling blkdev_reread_part()Jan Kara1-12/+16
Calling blkdev_reread_part() under loop_ctl_mutex causes lockdep to complain about circular lock dependency between bdev->bd_mutex and lo->lo_ctl_mutex. The problem is that on loop device open or close lo_open() and lo_release() get called with bdev->bd_mutex held and they need to acquire loop_ctl_mutex. OTOH when loop_reread_partitions() is called with loop_ctl_mutex held, it will call blkdev_reread_part() which acquires bdev->bd_mutex. See syzbot report for details [1]. Move call to blkdev_reread_part() in __loop_clr_fd() from under loop_ctl_mutex to finish fixing of the lockdep warning and the possible deadlock. [1] https://syzkaller.appspot.com/bug?id=bf154052f0eea4bc7712499e4569505907d1588 Reported-by: syzbot <syzbot+4684a000d5abdade83fac55b1e7d1f935ef1936e@syzkaller.appspotmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Move loop_reread_partitions() out of loop_ctl_mutexJan Kara1-5/+14
Calling loop_reread_partitions() under loop_ctl_mutex causes lockdep to complain about circular lock dependency between bdev->bd_mutex and lo->lo_ctl_mutex. The problem is that on loop device open or close lo_open() and lo_release() get called with bdev->bd_mutex held and they need to acquire loop_ctl_mutex. OTOH when loop_reread_partitions() is called with loop_ctl_mutex held, it will call blkdev_reread_part() which acquires bdev->bd_mutex. See syzbot report for details [1]. Move all calls of loop_rescan_partitions() out of loop_ctl_mutex to avoid lockdep warning and fix deadlock possibility. [1] https://syzkaller.appspot.com/bug?id=bf154052f0eea4bc7712499e4569505907d1588 Reported-by: syzbot <syzbot+4684a000d5abdade83fac55b1e7d1f935ef1936e@syzkaller.appspotmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Move special partition reread handling in loop_clr_fd()Jan Kara1-14/+19
The call of __blkdev_reread_part() from loop_reread_partition() happens only when we need to invalidate partitions from loop_release(). Thus move a detection for this into loop_clr_fd() and simplify loop_reread_partition(). This makes loop_reread_partition() safe to use without loop_ctl_mutex because we use only lo->lo_number and lo->lo_file_name in case of error for reporting purposes (thus possibly reporting outdate information is not a big deal) and we are safe from 'lo' going away under us by elevated lo->lo_refcnt. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Push loop_ctl_mutex down to loop_change_fd()Jan Kara1-11/+11
Push loop_ctl_mutex down to loop_change_fd(). We will need this to be able to call loop_reread_partitions() without loop_ctl_mutex. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Push loop_ctl_mutex down to loop_set_fd()Jan Kara1-12/+14
Push lo_ctl_mutex down to loop_set_fd(). We will need this to be able to call loop_reread_partitions() without lo_ctl_mutex. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Push loop_ctl_mutex down to loop_set_status()Jan Kara1-26/+25
Push loop_ctl_mutex down to loop_set_status(). We will need this to be able to call loop_reread_partitions() without loop_ctl_mutex. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Push loop_ctl_mutex down to loop_get_status()Jan Kara1-27/+10
Push loop_ctl_mutex down to loop_get_status() to avoid the unusual convention that the function gets called with loop_ctl_mutex held and releases it. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Push loop_ctl_mutex down into loop_clr_fd()Jan Kara1-20/+29
loop_clr_fd() has a weird locking convention that is expects loop_ctl_mutex held, releases it on success and keeps it on failure. Untangle the mess by moving locking of loop_ctl_mutex into loop_clr_fd(). Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Split setting of lo_state from loop_clr_fdJan Kara1-21/+31
Move setting of lo_state to Lo_rundown out into the callers. That will allow us to unlock loop_ctl_mutex while the loop device is protected from other changes by its special state. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Push lo_ctl_mutex down into individual ioctlsJan Kara1-25/+63
Push acquisition of lo_ctl_mutex down into individual ioctl handling branches. This is a preparatory step for pushing the lock down into individual ioctl handling functions so that they can release the lock as they need it. We also factor out some simple ioctl handlers that will not need any special handling to reduce unnecessary code duplication. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Get rid of loop_index_mutexJan Kara1-21/+20
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 <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08loop: Fold __loop_release into loop_releaseJan Kara1-9/+7
__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 <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08block/loop: Use global lock for ioctl() operation.Tetsuo Handa1-29/+29
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 <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: syzbot <syzbot+bf89c128e05dd6c62523@syzkaller.appspotmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08block/loop: Don't grab "struct file" for vfs_getattr() operation.Tetsuo Handa1-5/+5
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 <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-02Merge tag 'for-linus-20181102' of git://git.kernel.dk/linux-blockLinus Torvalds1-3/+2
Pull block layer fixes from Jens Axboe: "The biggest part of this pull request is the revert of the blkcg cleanup series. It had one fix earlier for a stacked device issue, but another one was reported. Rather than play whack-a-mole with this, revert the entire series and try again for the next kernel release. Apart from that, only small fixes/changes. Summary: - Indentation fixup for mtip32xx (Colin Ian King) - The blkcg cleanup series revert (Dennis Zhou) - Two NVMe fixes. One fixing a regression in the nvme request initialization in this merge window, causing nvme-fc to not work. The other is a suspend/resume p2p resource issue (James, Keith) - Fix sg discard merge, allowing us to merge in cases where we didn't before (Jianchao Wang) - Call rq_qos_exit() after the queue is frozen, preventing a hang (Ming) - Fix brd queue setup, fixing an oops if we fail setting up all devices (Ming)" * tag 'for-linus-20181102' of git://git.kernel.dk/linux-block: nvme-pci: fix conflicting p2p resource adds nvme-fc: fix request private initialization blkcg: revert blkcg cleanups series block: brd: associate with queue until adding disk block: call rq_qos_exit() after queue is frozen mtip32xx: clean an indentation issue, remove extraneous tabs block: fix the DISCARD request merge
2018-11-01Merge branch 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds1-5/+4
Pull AFS updates from Al Viro: "AFS series, with some iov_iter bits included" * 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits) missing bits of "iov_iter: Separate type from direction and use accessor functions" afs: Probe multiple fileservers simultaneously afs: Fix callback handling afs: Eliminate the address pointer from the address list cursor afs: Allow dumping of server cursor on operation failure afs: Implement YFS support in the fs client afs: Expand data structure fields to support YFS afs: Get the target vnode in afs_rmdir() and get a callback on it afs: Calc callback expiry in op reply delivery afs: Fix FS.FetchStatus delivery from updating wrong vnode afs: Implement the YFS cache manager service afs: Remove callback details from afs_callback_break struct afs: Commit the status on a new file/dir/symlink afs: Increase to 64-bit volume ID and 96-bit vnode ID for YFS afs: Don't invoke the server to read data beyond EOF afs: Add a couple of tracepoints to log I/O errors afs: Handle EIO from delivery function afs: Fix TTL on VL server and address lists afs: Implement VL server rotation afs: Improve FS server rotation error handling ...
2018-11-01blkcg: revert blkcg cleanups seriesDennis Zhou1-3/+2
This reverts a series committed earlier due to null pointer exception bug report in [1]. It seems there are edge case interactions that I did not consider and will need some time to understand what causes the adverse interactions. The original series can be found in [2] with a follow up series in [3]. [1] https://www.spinics.net/lists/cgroups/msg20719.html [2] https://lore.kernel.org/lkml/20180911184137.35897-1-dennisszhou@gmail.com/ [3] https://lore.kernel.org/lkml/20181020185612.51587-1-dennis@kernel.org/ This reverts the following commits: d459d853c2ed, b2c3fa546705, 101246ec02b5, b3b9f24f5fcc, e2b0989954ae, f0fcb3ec89f3, c839e7a03f92, bdc2491708c4, 74b7c02a9bc1, 5bf9a1f3b4ef, a7b39b4e961c, 07b05bcc3213, 49f4c2dc2b50, 27e6fa996c53 Signed-off-by: Dennis Zhou <dennis@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-24iov_iter: Separate type from direction and use accessor functionsDavid Howells1-5/+4
In the iov_iter struct, separate the iterator type from the iterator direction and use accessor functions to access them in most places. Convert a bunch of places to use switch-statements to access them rather then chains of bitwise-AND statements. This makes it easier to add further iterator types. Also, this can be more efficient as to implement a switch of small contiguous integers, the compiler can use ~50% fewer compare instructions than it has to use bitwise-and instructions. Further, cease passing the iterator type into the iterator setup function. The iterator function can set that itself. Only the direction is required. Signed-off-by: David Howells <dhowells@redhat.com>
2018-09-21blkcg: remove bio->bi_css and instead use bio->bi_blkgDennis Zhou (Facebook)1-2/+3
Prior patches ensured that all bios are now associated with some blkg. This now makes bio->bi_css unnecessary as blkg maintains a reference to the blkcg already. This patch removes the field bi_css and transfers corresponding uses to access via bi_blkg. Signed-off-by: Dennis Zhou <dennisszhou@gmail.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-09block/loop: mark expected switch fall-throughGustavo A. R. Silva1-0/+1
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-09loop: remove redundant pointer inodeColin Ian King1-2/+0
Pointer inode is being assigned but is never used hence it is redundant and can be removed. Cleans up clang warning: warning: variable 'inode' set but not used [-Wunused-but-set-variable] Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-06Merge tag 'for-linus-20180706' of git://git.kernel.dk/linux-blockLinus Torvalds1-0/+1
Pull block fixes from Jens Axboe: "Two minor fixes for this series: - add LOOP_SET_BLOCK_SIZE as compat ioctl (Evan Green) - drbd use-after-free fix (Lars Ellenberg)" * tag 'for-linus-20180706' of git://git.kernel.dk/linux-block: loop: Add LOOP_SET_BLOCK_SIZE in compat ioctl drbd: fix access after free
2018-07-03loop: Add LOOP_SET_BLOCK_SIZE in compat ioctlEvan Green1-0/+1
This change adds LOOP_SET_BLOCK_SIZE as one of the supported ioctls in lo_compat_ioctl. It only takes an unsigned long argument, and in practice a 32-bit value works fine. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Evan Green <evgreen@chromium.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-06-12treewide: kmalloc() -> kmalloc_array()Kees Cook1-1/+2
The kmalloc() function has a 2-factor argument form, kmalloc_array(). This patch replaces cases of: kmalloc(a * b, gfp) with: kmalloc_array(a * b, gfp) as well as handling cases of: kmalloc(a * b * c, gfp) with: kmalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kmalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kmalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The tools/ directory was manually excluded, since it has its own implementation of kmalloc(). The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(char) * COUNT + COUNT , ...) | kmalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kmalloc + kmalloc_array ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kmalloc(C1 * C2 * C3, ...) | kmalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kmalloc(sizeof(THING) * C2, ...) | kmalloc(sizeof(TYPE) * C2, ...) | kmalloc(C1 * C2 * C3, ...) | kmalloc(C1 * C2, ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - (E1) * E2 + E1, E2 , ...) | - kmalloc + kmalloc_array ( - (E1) * (E2) + E1, E2 , ...) | - kmalloc + kmalloc_array ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-08Merge tag 'for-linus-20180608' of git://git.kernel.dk/linux-blockLinus Torvalds1-30/+38
Pull block fixes from Jens Axboe: "A few fixes for this merge window, where some of them should go in sooner rather than later, hence a new pull this week. This pull request contains: - Set of NVMe fixes, mostly follow up cleanups/fixes to the queue changes, but also teardown/removal and misc changes (Christop/Dan/ Johannes/Sagi/Steve). - Two lightnvm fixes for issues that showed up in this window (Colin/Wei). - Failfast/driver flags inheritance for flush requests (Hannes). - The md device put sanitization and fix (Kent). - dm bio_set inheritance fix (me). - nbd discard granularity fix (Josef). - nbd consistency in command printing (Kevin). - Loop recursion validation fix (Ted). - Partition overlap check (Wang)" [ .. and now my build is warning-free again thanks to the md fix - Linus ] * tag 'for-linus-20180608' of git://git.kernel.dk/linux-block: (22 commits) nvme: cleanup double shift issue nvme-pci: make CMB SQ mod-param read-only nvme-pci: unquiesce dead controller queues nvme-pci: remove HMB teardown on reset nvme-pci: queue creation fixes nvme-pci: remove unnecessary completion doorbell check nvme-pci: remove unnecessary nested locking nvmet: filter newlines from user input nvme-rdma: correctly check for target keyed sgl support nvme: don't hold nvmf_transports_rwsem for more than transport lookups nvmet: return all zeroed buffer when we can't find an active namespace md: Unify mddev destruction paths dm: use bioset_init_from_src() to copy bio_set block: add bioset_init_from_src() helper block: always set partition number to '0' in blk_partition_remap() block: pass failfast and driver-specific flags to flush requests nbd: set discard_alignment to the granularity nbd: Consistently use request pointer in debug messages. block: add verifier for cmdline partition lightnvm: pblk: fix resource leak of invalid_bitmap ...
2018-06-08Merge branch 'work.aio' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds1-0/+3
Pull aio iopriority support from Al Viro: "The rest of aio stuff for this cycle - Adam's aio ioprio series" * 'work.aio' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: aio ioprio use ioprio_check_cap ret val fs: aio ioprio add explicit block layer dependence fs: iomap dio set bio prio from kiocb prio fs: blkdev set bio prio from kiocb prio fs: Add aio iopriority support fs: Convert kiocb rw_hint from enum to u16 block: add ioprio_check_cap function
2018-06-05loop: add recursion validation to LOOP_CHANGE_FDTheodore Ts'o1-30/+38
Refactor the validation code used in LOOP_SET_FD so it is also used in LOOP_CHANGE_FD. Otherwise it is possible to construct a set of loop devices that all refer to each other. This can lead to a infinite loop in starting with "while (is_loop_device(f)) .." in loop_set_fd(). Fix this by refactoring out the validation code and using it for LOOP_CHANGE_FD as well as LOOP_SET_FD. Reported-by: syzbot+4349872271ece473a7c91190b68b4bac7c5dbc87@syzkaller.appspotmail.com Reported-by: syzbot+40bd32c4d9a3cc12a339@syzkaller.appspotmail.com Reported-by: syzbot+769c54e66f994b041be7@syzkaller.appspotmail.com Reported-by: syzbot+0a89a9ce473936c57065@syzkaller.appspotmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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