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path: root/drivers/md/dm-thin.c
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2023-06-21dm thin: fix issue_discard to pass GFP_NOIO to __blkdev_issue_discardMike Snitzer
commit 722d90822321497e2837cfc9000202e256e6b32f upstream. issue_discard() passes GFP_NOWAIT to __blkdev_issue_discard() despite its code assuming bio_alloc() always succeeds. Commit 3dba53a958a75 ("dm thin: use __blkdev_issue_discard for async discard support") clearly shows where things went bad: Before commit 3dba53a958a75, dm-thin.c's open-coded __blkdev_issue_discard_async() properly handled using GFP_NOWAIT. Unfortunately __blkdev_issue_discard() doesn't and it was missed during review. Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer <snitzer@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-13dm: change "unsigned" to "unsigned int"Heinz Mauelshagen
[ Upstream commit 86a3238c7b9b759cb864f4f768ab2e24687dc0e6 ] Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org> Stable-dep-of: f7b58a69fad9 ("dm: fix improper splitting for abnormal bios") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-30dm thin: fix deadlock when swapping to thin deviceColy Li
commit 9bbf5feecc7eab2c370496c1c161bbfe62084028 upstream. This is an already known issue that dm-thin volume cannot be used as swap, otherwise a deadlock may happen when dm-thin internal memory demand triggers swap I/O on the dm-thin volume itself. But thanks to commit a666e5c05e7c ("dm: fix deadlock when swapping to encrypted device"), the limit_swap_bios target flag can also be used for dm-thin to avoid the recursive I/O when it is used as swap. Fix is to simply set ti->limit_swap_bios to true in both pool_ctr() and thin_ctr(). In my test, I create a dm-thin volume /dev/vg/swap and use it as swap device. Then I run fio on another dm-thin volume /dev/vg/main and use large --blocksize to trigger swap I/O onto /dev/vg/swap. The following fio command line is used in my test, fio --name recursive-swap-io --lockmem 1 --iodepth 128 \ --ioengine libaio --filename /dev/vg/main --rw randrw \ --blocksize 1M --numjobs 32 --time_based --runtime=12h Without this fix, the whole system can be locked up within 15 seconds. With this fix, there is no any deadlock or hung task observed after 2 hours of running fio. Furthermore, if blocksize is changed from 1M to 128M, after around 30 seconds fio has no visible I/O, and the out-of-memory killer message shows up in kernel message. After around 20 minutes all fio processes are killed and the whole system is back to being alive. This is exactly what is expected when recursive I/O happens on dm-thin volume when it is used as swap. Depends-on: a666e5c05e7c ("dm: fix deadlock when swapping to encrypted device") Cc: stable@vger.kernel.org Signed-off-by: Coly Li <colyli@suse.de> Acked-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10dm thin: add cond_resched() to various workqueue loopsMike Snitzer
[ Upstream commit e4f80303c2353952e6e980b23914e4214487f2a6 ] Otherwise on resource constrained systems these workqueues may be too greedy. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-07dm thin: Fix UAF in run_timer_softirq()Luo Meng
commit 88430ebcbc0ec637b710b947738839848c20feff upstream. When dm_resume() and dm_destroy() are concurrent, it will lead to UAF, as follows: BUG: KASAN: use-after-free in __run_timers+0x173/0x710 Write of size 8 at addr ffff88816d9490f0 by task swapper/0/0 <snip> Call Trace: <IRQ> dump_stack_lvl+0x73/0x9f print_report.cold+0x132/0xaa2 _raw_spin_lock_irqsave+0xcd/0x160 __run_timers+0x173/0x710 kasan_report+0xad/0x110 __run_timers+0x173/0x710 __asan_store8+0x9c/0x140 __run_timers+0x173/0x710 call_timer_fn+0x310/0x310 pvclock_clocksource_read+0xfa/0x250 kvm_clock_read+0x2c/0x70 kvm_clock_get_cycles+0xd/0x20 ktime_get+0x5c/0x110 lapic_next_event+0x38/0x50 clockevents_program_event+0xf1/0x1e0 run_timer_softirq+0x49/0x90 __do_softirq+0x16e/0x62c __irq_exit_rcu+0x1fa/0x270 irq_exit_rcu+0x12/0x20 sysvec_apic_timer_interrupt+0x8e/0xc0 One of the concurrency UAF can be shown as below: use free do_resume | __find_device_hash_cell | dm_get | atomic_inc(&md->holders) | | dm_destroy | __dm_destroy | if (!dm_suspended_md(md)) | atomic_read(&md->holders) | msleep(1) dm_resume | __dm_resume | dm_table_resume_targets | pool_resume | do_waker #add delay work | dm_put | atomic_dec(&md->holders) | | dm_table_destroy | pool_dtr | __pool_dec | __pool_destroy | destroy_workqueue | kfree(pool) # free pool time out __do_softirq run_timer_softirq # pool has already been freed This can be easily reproduced using: 1. create thin-pool 2. dmsetup suspend pool 3. dmsetup resume pool 4. dmsetup remove_all # Concurrent with 3 The root cause of this UAF bug is that dm_resume() adds timer after dm_destroy() skips cancelling the timer because of suspend status. After timeout, it will call run_timer_softirq(), however pool has already been freed. The concurrency UAF bug will happen. Therefore, cancelling timer again in __pool_destroy(). Cc: stable@vger.kernel.org Fixes: 991d9fa02da0d ("dm: add thin provisioning target") Signed-off-by: Luo Meng <luomeng12@huawei.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-07dm thin: resume even if in FAIL modeLuo Meng
commit 19eb1650afeb1aa86151f61900e9e5f1de5d8d02 upstream. If a thinpool set fail_io while suspending, resume will fail with: device-mapper: resume ioctl on vg-thinpool failed: Invalid argument The thin-pool also can't be removed if an in-flight bio is in the deferred list. This can be easily reproduced using: echo "offline" > /sys/block/sda/device/state dd if=/dev/zero of=/dev/mapper/thin bs=4K count=1 dmsetup suspend /dev/mapper/pool mkfs.ext4 /dev/mapper/thin dmsetup resume /dev/mapper/pool The root cause is maybe_resize_data_dev() will check fail_io and return error before called dm_resume. Fix this by adding FAIL mode check at the end of pool_preresume(). Cc: stable@vger.kernel.org Fixes: da105ed5fd7e ("dm thin metadata: introduce dm_pool_abort_metadata") Signed-off-by: Luo Meng <luomeng12@huawei.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-15dm thin: fix use-after-free crash in dm_sm_register_threshold_callbackLuo Meng
Fault inject on pool metadata device reports: BUG: KASAN: use-after-free in dm_pool_register_metadata_threshold+0x40/0x80 Read of size 8 at addr ffff8881b9d50068 by task dmsetup/950 CPU: 7 PID: 950 Comm: dmsetup Tainted: G W 5.19.0-rc6 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x34/0x44 print_address_description.constprop.0.cold+0xeb/0x3f4 kasan_report.cold+0xe6/0x147 dm_pool_register_metadata_threshold+0x40/0x80 pool_ctr+0xa0a/0x1150 dm_table_add_target+0x2c8/0x640 table_load+0x1fd/0x430 ctl_ioctl+0x2c4/0x5a0 dm_ctl_ioctl+0xa/0x10 __x64_sys_ioctl+0xb3/0xd0 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 This can be easily reproduced using: echo offline > /sys/block/sda/device/state dd if=/dev/zero of=/dev/mapper/thin bs=4k count=10 dmsetup load pool --table "0 20971520 thin-pool /dev/sda /dev/sdb 128 0 0" If a metadata commit fails, the transaction will be aborted and the metadata space maps will be destroyed. If a DM table reload then happens for this failed thin-pool, a use-after-free will occur in dm_sm_register_threshold_callback (called from dm_pool_register_metadata_threshold). Fix this by in dm_pool_register_metadata_threshold() by returning the -EINVAL error if the thin-pool is in fail mode. Also fail pool_ctr() with a new error message: "Error registering metadata threshold". Fixes: ac8c3f3df65e4 ("dm thin: generate event when metadata threshold passed") Cc: stable@vger.kernel.org Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Luo Meng <luomeng12@huawei.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-04-17block: decouple REQ_OP_SECURE_ERASE from REQ_OP_DISCARDChristoph Hellwig
Secure erase is a very different operation from discard in that it is a data integrity operation vs hint. Fully split the limits and helper infrastructure to make the separation more clear. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> [drbd] Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> [nifs2] Acked-by: Jaegeuk Kim <jaegeuk@kernel.org> [f2fs] Acked-by: Coly Li <colyli@suse.de> [bcache] Acked-by: David Sterba <dsterba@suse.com> [btrfs] Acked-by: Chao Yu <chao@kernel.org> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20220415045258.199825-27-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-04-17block: remove QUEUE_FLAG_DISCARDChristoph Hellwig
Just use a non-zero max_discard_sectors as an indicator for discard support, similar to what is done for write zeroes. The only places where needs special attention is the RAID5 driver, which must clear discard support for security reasons by default, even if the default stacking rules would allow for it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> [drbd] Acked-by: Jan Höppner <hoeppner@linux.ibm.com> [s390] Acked-by: Coly Li <colyli@suse.de> [bcache] Acked-by: David Sterba <dsterba@suse.com> [btrfs] Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20220415045258.199825-25-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-03-10dm: simplify dm_sumbit_bio_remap interfaceMike Snitzer
Remove the from_wq argument from dm_sumbit_bio_remap(). Eliminates the need for dm_sumbit_bio_remap() callers to know whether they are calling for a workqueue or from the original dm_submit_bio(). Add map_task to dm_io struct, record the map_task in alloc_io and clear it after all target ->map() calls have completed. Update dm_sumbit_bio_remap to check if 'current' matches io->map_task rather than rely on passed 'from_rq' argument. This change really simplifies the chore of porting each DM target to using dm_sumbit_bio_remap() because there is no longer the risk of programming error by not completely knowing all the different contexts a particular method that calls dm_sumbit_bio_remap() might be used in. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2022-03-10dm thin: use dm_submit_bio_remapMike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2022-03-02dm: stop using bdevnameChristoph Hellwig
Just use the %pg format specifier instead. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2022-02-22dm thin: use time_is_before_jiffies instead of open coding itWang Qing
Use time_is_before_jiffies() to improve code readability. Signed-off-by: Wang Qing <wangqing@vivo.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2022-02-02block: pass a block_device and opf to bio_allocChristoph Hellwig
Pass the block_device and operation that we plan to use this bio for to bio_alloc to optimize the assignment. NULL/0 can be passed, both for the passthrough case on a raw request_queue and to temporarily avoid refactoring some nasty code. Also move the gfp_mask argument after the nr_vecs argument for a much more logical calling convention matching what most of the kernel does. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20220124091107.642561-18-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-02dm-thin: use blkdev_issue_flush instead of open coding itChristoph Hellwig
Use blkdev_issue_flush, which uses an on-stack bio instead of an opencoded version with a bio embedded into struct pool. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220124091107.642561-9-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-02dm: bio_alloc can't fail if it is allowed to sleepChristoph Hellwig
Remove handling of NULL returns from sleeping bio_alloc calls given that those can't fail. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220124091107.642561-6-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18dm: use bdev_nr_sectors and bdev_nr_bytes instead of open coding themChristoph Hellwig
Use the proper helpers to read the block device size. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Mike Snitzer <snitzer@redhat.com> Link: https://lore.kernel.org/r/20211018101130.1838532-6-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-10dm: update target status functions to support IMA measurementTushar Sugandhi
For device mapper targets to take advantage of IMA's measurement capabilities, the status functions for the individual targets need to be updated to handle the status_type_t case for value STATUSTYPE_IMA. Update status functions for the following target types, to log their respective attributes to be measured using IMA. 01. cache 02. crypt 03. integrity 04. linear 05. mirror 06. multipath 07. raid 08. snapshot 09. striped 10. verity For rest of the targets, handle the STATUSTYPE_IMA case by setting the measurement buffer to NULL. For IMA to measure the data on a given system, the IMA policy on the system needs to be updated to have the following line, and the system needs to be restarted for the measurements to take effect. /etc/ima/ima-policy measure func=CRITICAL_DATA label=device-mapper template=ima-buf The measurements will be reflected in the IMA logs, which are located at: /sys/kernel/security/integrity/ima/ascii_runtime_measurements /sys/kernel/security/integrity/ima/binary_runtime_measurements These IMA logs can later be consumed by various attestation clients running on the system, and send them to external services for attesting the system. The DM target data measured by IMA subsystem can alternatively be queried from userspace by setting DM_IMA_MEASUREMENT_FLAG with DM_TABLE_STATUS_CMD. Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-03-26dm thin: remove needless request_queue NULL pointer checkXu Wang
Since commit ff9ea323816d ("block, bdi: an active gendisk always has a request_queue associated with it") the request_queue pointer returned from bdev_get_queue() shall never be NULL. Signed-off-by: Xu Wang <vulab@iscas.ac.cn> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-07-08writeback: remove bdi->congested_fnChristoph Hellwig
Except for pktdvd, the only places setting congested bits are file systems that allocate their own backing_dev_info structures. And pktdvd is a deprecated driver that isn't useful in stack setup either. So remove the dead congested_fn stacking infrastructure. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Song Liu <song@kernel.org> Acked-by: David Sterba <dsterba@suse.com> [axboe: fixup unused variables in bcache/request.c] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01block: rename generic_make_request to submit_bio_noacctChristoph Hellwig
generic_make_request has always been very confusingly misnamed, so rename it to submit_bio_noacct to make it clear that it is submit_bio minus accounting and a few checks. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-14dm thin: change data device's flush_bio to be member of struct poolMikulas Patocka
With commit fe64369163c5 ("dm thin: don't allow changing data device during thin-pool load") it is now possible to re-parent the data device's flush_bio from the pool_c to pool structure. Doing so offers improved lifetime guarantees for the flush_bio so that the call to dm_pool_register_pre_commit_callback can now be done safely from pool_ctr(). Depends-on: fe64369163c5 ("dm thin: don't allow changing data device during thin-pool load") Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-01-14dm thin: don't allow changing data device during thin-pool reloadMikulas Patocka
The existing code allows changing the data device when the thin-pool target is reloaded. This capability is not required and only complicates device lifetime guarantees. This can cause crashes like the one reported here: https://bugzilla.redhat.com/show_bug.cgi?id=1788596 where the kernel tries to issue a flush bio located in a structure that was already freed. Take the first step to simplifying the thin-pool's data device lifetime by disallowing changing it. Like the thin-pool's metadata device, the data device is now set in pool_create() and it cannot be changed for a given thin-pool. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-01-14dm thin: fix use-after-free in metadata_pre_commit_callbackMike Snitzer
dm-thin uses struct pool to hold the state of the pool. There may be multiple pool_c's pointing to a given pool, each pool_c represents a loaded target. pool_c's may be created and destroyed arbitrarily and the pool contains a reference count of pool_c's pointing to it. Since commit 694cfe7f31db3 ("dm thin: Flush data device before committing metadata") a pointer to pool_c is passed to dm_pool_register_pre_commit_callback and this function stores it in pmd->pre_commit_context. If this pool_c is freed, but pool is not (because there is another pool_c referencing it), we end up in a situation where pmd->pre_commit_context structure points to freed pool_c. It causes a crash in metadata_pre_commit_callback. Fix this by moving the dm_pool_register_pre_commit_callback() from pool_ctr() to pool_preresume(). This way the in-core thin-pool metadata is only ever armed with callback data whose lifetime matches the active thin-pool target. In should be noted that this fix preserves the ability to load a thin-pool table that uses a different data block device (that contains the same data) -- though it is unclear if that capability is still useful and/or needed. Fixes: 694cfe7f31db3 ("dm thin: Flush data device before committing metadata") Cc: stable@vger.kernel.org Reported-by: Zdenek Kabelac <zkabelac@redhat.com> Reported-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-12-06dm thin: Flush data device before committing metadataNikos Tsironis
The thin provisioning target maintains per thin device mappings that map virtual blocks to data blocks in the data device. When we write to a shared block, in case of internal snapshots, or provision a new block, in case of external snapshots, we copy the shared block to a new data block (COW), update the mapping for the relevant virtual block and then issue the write to the new data block. Suppose the data device has a volatile write-back cache and the following sequence of events occur: 1. We write to a shared block 2. A new data block is allocated 3. We copy the shared block to the new data block using kcopyd (COW) 4. We insert the new mapping for the virtual block in the btree for that thin device. 5. The commit timeout expires and we commit the metadata, that now includes the new mapping from step (4). 6. The system crashes and the data device's cache has not been flushed, meaning that the COWed data are lost. The next time we read that virtual block of the thin device we read it from the data block allocated in step (2), since the metadata have been successfully committed. The data are lost due to the crash, so we read garbage instead of the old, shared data. This has the following implications: 1. In case of writes to shared blocks, with size smaller than the pool's block size (which means we first copy the whole block and then issue the smaller write), we corrupt data that the user never touched. 2. In case of writes to shared blocks, with size equal to the device's logical block size, we fail to provide atomic sector writes. When the system recovers the user will read garbage from that sector instead of the old data or the new data. 3. Even for writes to shared blocks, with size equal to the pool's block size (overwrites), after the system recovers, the written sectors will contain garbage instead of a random mix of sectors containing either old data or new data, thus we fail again to provide atomic sectors writes. 4. Even when the user flushes the thin device, because we first commit the metadata and then pass down the flush, the same risk for corruption exists (if the system crashes after the metadata have been committed but before the flush is passed down to the data device.) The only case which is unaffected is that of writes with size equal to the pool's block size and with the FUA flag set. But, because FUA writes trigger metadata commits, this case can trigger the corruption indirectly. Moreover, apart from internal and external snapshots, the same issue exists for newly provisioned blocks, when block zeroing is enabled. After the system recovers the provisioned blocks might contain garbage instead of zeroes. To solve this and avoid the potential data corruption we flush the pool's data device **before** committing its metadata. This ensures that the data blocks of any newly inserted mappings are properly written to non-volatile storage and won't be lost in case of a crash. Cc: stable@vger.kernel.org Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com> Acked-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-11-18dm thin: wakeup worker only when deferred bios existJeffle Xu
Single thread fio test (read, bs=4k, ioengine=libaio, iodepth=128, numjobs=1) over dm-thin device has poor performance versus bare nvme device. Further investigation with perf indicates that queue_work_on() consumes over 20% CPU time when doing IO over dm-thin device. The call stack is as follows. - 40.57% thin_map + 22.07% queue_work_on + 9.95% dm_thin_find_block + 2.80% cell_defer_no_holder 1.91% inc_all_io_entry.isra.33.part.34 + 1.78% bio_detain.isra.35 In cell_defer_no_holder(), wakeup_worker() is always called, no matter whether the tc->deferred_bio_list list is empty or not. In single thread IO model, this list is most likely empty. So skip waking up worker thread if tc->deferred_bio_list list is empty. Single thread IO performance improves from 448 MiB/s to 646 MiB/s (+44%) once the needless wake_worker() calls are properly skipped. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-11-05dm thin: replace spin_lock_irqsave with spin_lock_irqMikulas Patocka
If we are in a place where it is known that interrupts are enabled, functions spin_lock_irq/spin_unlock_irq should be used instead of spin_lock_irqsave/spin_unlock_irqrestore. spin_lock_irq and spin_unlock_irq are faster because they don't need to push and pop the flags register. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-03-05dm thin: add sanity checks to thin-pool and external snapshot creationJason Cai (Xiang Feng)
Invoking dm_get_device() twice on the same device path with different modes is dangerous. Because in that case, upgrade_mode() will alloc a new 'dm_dev' and free the old one, which may be referenced by a previous caller. Dereferencing the dangling pointer will trigger kernel NULL pointer dereference. The following two cases can reproduce this issue. Actually, they are invalid setups that must be disallowed, e.g.: 1. Creating a thin-pool with read_only mode, and the same device as both metadata and data. dmsetup create thinp --table \ "0 41943040 thin-pool /dev/vdb /dev/vdb 128 0 1 read_only" BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 ... Call Trace: new_read+0xfb/0x110 [dm_bufio] dm_bm_read_lock+0x43/0x190 [dm_persistent_data] ? kmem_cache_alloc_trace+0x15c/0x1e0 __create_persistent_data_objects+0x65/0x3e0 [dm_thin_pool] dm_pool_metadata_open+0x8c/0xf0 [dm_thin_pool] pool_ctr.cold.79+0x213/0x913 [dm_thin_pool] ? realloc_argv+0x50/0x70 [dm_mod] dm_table_add_target+0x14e/0x330 [dm_mod] table_load+0x122/0x2e0 [dm_mod] ? dev_status+0x40/0x40 [dm_mod] ctl_ioctl+0x1aa/0x3e0 [dm_mod] dm_ctl_ioctl+0xa/0x10 [dm_mod] do_vfs_ioctl+0xa2/0x600 ? handle_mm_fault+0xda/0x200 ? __do_page_fault+0x26c/0x4f0 ksys_ioctl+0x60/0x90 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x55/0x150 entry_SYSCALL_64_after_hwframe+0x44/0xa9 2. Creating a external snapshot using the same thin-pool device. dmsetup create thinp --table \ "0 41943040 thin-pool /dev/vdc /dev/vdb 128 0 2 ignore_discard" dmsetup message /dev/mapper/thinp 0 "create_thin 0" dmsetup create snap --table \ "0 204800 thin /dev/mapper/thinp 0 /dev/mapper/thinp" BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 ... Call Trace: ? __alloc_pages_nodemask+0x13c/0x2e0 retrieve_status+0xa5/0x1f0 [dm_mod] ? dm_get_live_or_inactive_table.isra.7+0x20/0x20 [dm_mod] table_status+0x61/0xa0 [dm_mod] ctl_ioctl+0x1aa/0x3e0 [dm_mod] dm_ctl_ioctl+0xa/0x10 [dm_mod] do_vfs_ioctl+0xa2/0x600 ksys_ioctl+0x60/0x90 ? ksys_write+0x4f/0xb0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x55/0x150 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Signed-off-by: Jason Cai (Xiang Feng) <jason.cai@linux.alibaba.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-02-20dm: eliminate 'split_discard_bios' flag from DM target interfaceMike Snitzer
There is no need to have DM core split discards on behalf of a DM target now that blk_queue_split() handles splitting discards based on the queue_limits. A DM target just needs to set max_discard_sectors, discard_granularity, etc, in queue_limits. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-02-14dm thin: fix bug where bio that overwrites thin block ignores FUANikos Tsironis
When provisioning a new data block for a virtual block, either because the block was previously unallocated or because we are breaking sharing, if the whole block of data is being overwritten the bio that triggered the provisioning is issued immediately, skipping copying or zeroing of the data block. When this bio completes the new mapping is inserted in to the pool's metadata by process_prepared_mapping(), where the bio completion is signaled to the upper layers. This completion is signaled without first committing the metadata. If the bio in question has the REQ_FUA flag set and the system crashes right after its completion and before the next metadata commit, then the write is lost despite the REQ_FUA flag requiring that I/O completion for this request must only be signaled after the data has been committed to non-volatile storage. Fix this by deferring the completion of overwrite bios, with the REQ_FUA flag set, until after the metadata has been committed. Cc: stable@vger.kernel.org Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com> Acked-by: Joe Thornber <ejt@redhat.com> Acked-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-01-15dm thin: fix passdown_double_checking_shared_status()Joe Thornber
Commit 00a0ea33b495 ("dm thin: do not queue freed thin mapping for next stage processing") changed process_prepared_discard_passdown_pt1() to increment all the blocks being discarded until after the passdown had completed to avoid them being prematurely reused. IO issued to a thin device that breaks sharing with a snapshot, followed by a discard issued to snapshot(s) that previously shared the block(s), results in passdown_double_checking_shared_status() being called to iterate through the blocks double checking their reference count is zero and issuing the passdown if so. So a side effect of commit 00a0ea33b495 is passdown_double_checking_shared_status() was broken. Fix this by checking if the block reference count is greater than 1. Also, rename dm_pool_block_is_used() to dm_pool_block_is_shared(). Fixes: 00a0ea33b495 ("dm thin: do not queue freed thin mapping for next stage processing") Cc: stable@vger.kernel.org # 4.9+ Reported-by: ryan.p.norwood@gmail.com Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-12dm thin: bump target versionMike Snitzer
Decoupled version bump from commit f6c367585d0 ("dm thin: send event about thin-pool state change _after_ making it") because version bumps just create conflicts when backporting to the stable trees. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-11dm thin: send event about thin-pool state change _after_ making itMike Snitzer
Sending a DM event before a thin-pool state change is about to happen is a bug. It wasn't realized until it became clear that userspace response to the event raced with the actual state change that the event was meant to notify about. Fix this by first updating internal thin-pool state to reflect what the DM event is being issued about. This fixes a long-standing racey/buggy userspace device-mapper-test-suite 'resize_io' test that would get an event but not find the state it was looking for -- so it would just go on to hang because no other events caused the test to reevaluate the thin-pool's state. Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-10-16dm thin: use refcount_t for thin_c reference countingJohn Pittman
The API surrounding refcount_t should be used in place of atomic_t when variables are being used as reference counters. It can potentially prevent reference counter overflows and use-after-free conditions. In the dm thin layer, one such example is tc->refcount. Change this from the atomic_t API to the refcount_t API to prevent mentioned conditions. Signed-off-by: John Pittman <jpittman@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-09-10dm thin metadata: try to avoid ever aborting transactionsJoe Thornber
Committing a transaction can consume some metadata of it's own, we now reserve a small amount of metadata to cover this. Free metadata reported by the kernel will not include this reserve. If any of the reserve has been used after a commit we enter a new internal state PM_OUT_OF_METADATA_SPACE. This is reported as PM_READ_ONLY, so no userland changes are needed. If the metadata device is resized the pool will move back to PM_WRITE. These changes mean we never need to abort and rollback a transaction due to running out of metadata space. This is particularly important because there have been a handful of reports of data corruption against DM thin-provisioning that can all be attributed to the thin-pool having ran out of metadata space. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-08-07dm thin: stop no_space_timeout worker when switching to write-modeHou Tao
Now both check_for_space() and do_no_space_timeout() will read & write pool->pf.error_if_no_space. If these functions run concurrently, as shown in the following case, the default setting of "queue_if_no_space" can get lost. precondition: * error_if_no_space = false (aka "queue_if_no_space") * pool is in Out-of-Data-Space (OODS) mode * no_space_timeout worker has been queued CPU 0: CPU 1: // delete a thin device process_delete_mesg() // check_for_space() invoked by commit() set_pool_mode(pool, PM_WRITE) pool->pf.error_if_no_space = \ pt->requested_pf.error_if_no_space // timeout, pool is still in OODS mode do_no_space_timeout // "queue_if_no_space" config is lost pool->pf.error_if_no_space = true pool->pf.mode = new_mode Fix it by stopping no_space_timeout worker when switching to write mode. Fixes: bcc696fac11f ("dm thin: stay in out-of-data-space mode once no_space_timeout expires") Cc: stable@vger.kernel.org Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-07-31dm kcopyd: return void from dm_kcopyd_copy()Mike Snitzer
dm_kcopyd_copy() only ever returns 0 so there is no need for callers to account for possible failure. Same goes for dm_kcopyd_zero(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-07-30dm thin: include metadata_low_watermark threshold in pool statusAndy Grover
The metadata low watermark threshold is set by the kernel. But the kernel depends on userspace to extend the thinpool metadata device when the threshold is crossed. Since the metadata low watermark threshold is not visible to userspace, upon receiving an event, userspace cannot tell that the kernel wants the metadata device extended, instead of some other eventing condition. Making it visible (but not settable) enables userspace to affirmatively know the kernel is asking for a metadata device extension, by comparing metadata_low_watermark against nr_free_blocks_metadata, also reported in status. Current solutions like dmeventd have their own thresholds for extending the data and metadata devices, and both devices are checked against their thresholds on each event. This lessens the value of the kernel-set threshold, since userspace will either extend the metadata device sooner, when receiving another event; or will receive the metadata lowater event and do nothing, if dmeventd's threshold is less than the kernel's. (This second case is dangerous. The metadata lowater event will not be re-sent, so no further event will be generated before the metadata device is out if space, unless some other event causes userspace to recheck its thresholds.) Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-06-27dm thin: handle running out of data space vs concurrent discardMike Snitzer
Discards issued to a DM thin device can complete to userspace (via fstrim) _before_ the metadata changes associated with the discards is reflected in the thinp superblock (e.g. free blocks). As such, if a user constructs a test that loops repeatedly over these steps, block allocation can fail due to discards not having completed yet: 1) fill thin device via filesystem file 2) remove file 3) fstrim From initial report, here: https://www.redhat.com/archives/dm-devel/2018-April/msg00022.html "The root cause of this issue is that dm-thin will first remove mapping and increase corresponding blocks' reference count to prevent them from being reused before DISCARD bios get processed by the underlying layers. However. increasing blocks' reference count could also increase the nr_allocated_this_transaction in struct sm_disk which makes smd->old_ll.nr_allocated + smd->nr_allocated_this_transaction bigger than smd->old_ll.nr_blocks. In this case, alloc_data_block() will never commit metadata to reset the begin pointer of struct sm_disk, because sm_disk_get_nr_free() always return an underflow value." While there is room for improvement to the space-map accounting that thinp is making use of: the reality is this test is inherently racey and will result in the previous iteration's fstrim's discard(s) completing vs concurrent block allocation, via dd, in the next iteration of the loop. No amount of space map accounting improvements will be able to allow user's to use a block before a discard of that block has completed. So the best we can really do is allow DM thinp to gracefully handle such aggressive use of all the pool's data by degrading the pool into out-of-data-space (OODS) mode. We _should_ get that behaviour already (if space map accounting didn't falsely cause alloc_data_block() to believe free space was available).. but short of that we handle the current reality that dm_pool_alloc_data_block() can return -ENOSPC. Reported-by: Dennis Yang <dennisyang@qnap.com> Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-06-12Merge tag 'overflow-v4.18-rc1-part2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull more overflow updates from Kees Cook: "The rest of the overflow changes for v4.18-rc1. This includes the explicit overflow fixes from Silvio, further struct_size() conversions from Matthew, and a bug fix from Dan. But the bulk of it is the treewide conversions to use either the 2-factor argument allocators (e.g. kmalloc(a * b, ...) into kmalloc_array(a, b, ...) or the array_size() macros (e.g. vmalloc(a * b) into vmalloc(array_size(a, b)). Coccinelle was fighting me on several fronts, so I've done a bunch of manual whitespace updates in the patches as well. Summary: - Error path bug fix for overflow tests (Dan) - Additional struct_size() conversions (Matthew, Kees) - Explicitly reported overflow fixes (Silvio, Kees) - Add missing kvcalloc() function (Kees) - Treewide conversions of allocators to use either 2-factor argument variant when available, or array_size() and array3_size() as needed (Kees)" * tag 'overflow-v4.18-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (26 commits) treewide: Use array_size in f2fs_kvzalloc() treewide: Use array_size() in f2fs_kzalloc() treewide: Use array_size() in f2fs_kmalloc() treewide: Use array_size() in sock_kmalloc() treewide: Use array_size() in kvzalloc_node() treewide: Use array_size() in vzalloc_node() treewide: Use array_size() in vzalloc() treewide: Use array_size() in vmalloc() treewide: devm_kzalloc() -> devm_kcalloc() treewide: devm_kmalloc() -> devm_kmalloc_array() treewide: kvzalloc() -> kvcalloc() treewide: kvmalloc() -> kvmalloc_array() treewide: kzalloc_node() -> kcalloc_node() treewide: kzalloc() -> kcalloc() treewide: kmalloc() -> kmalloc_array() mm: Introduce kvcalloc() video: uvesafb: Fix integer overflow in allocation UBIFS: Fix potential integer overflow in allocation leds: Use struct_size() in allocation Convert intel uncore to struct_size ...
2018-06-12treewide: Use array_size() in vmalloc()Kees Cook
The vmalloc() function has no 2-factor argument form, so multiplication factors need to be wrapped in array_size(). This patch replaces cases of: vmalloc(a * b) with: vmalloc(array_size(a, b)) as well as handling cases of: vmalloc(a * b * c) with: vmalloc(array3_size(a, b, c)) This does, however, attempt to ignore constant size factors like: vmalloc(4 * 1024) 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 Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( vmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | vmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( vmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(u8) * COUNT + COUNT , ...) | vmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | vmalloc( - sizeof(char) * COUNT + COUNT , ...) | vmalloc( - 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; @@ ( vmalloc( - sizeof(TYPE) * (COUNT_ID) + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT_ID + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT_CONST + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vmalloc( - sizeof(THING) * (COUNT_ID) + array_size(COUNT_ID, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT_ID + array_size(COUNT_ID, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT_CONST + array_size(COUNT_CONST, sizeof(THING)) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ vmalloc( - SIZE * COUNT + array_size(COUNT, SIZE) , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( vmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - 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; @@ ( vmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | vmalloc( - 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; @@ ( vmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - 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; @@ ( vmalloc(C1 * C2 * C3, ...) | vmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants. @@ expression E1, E2; constant C1, C2; @@ ( vmalloc(C1 * C2, ...) | vmalloc( - E1 * E2 + array_size(E1, E2) , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-08dm: adjust structure members to improve alignmentMike Snitzer
Eliminate most holes in DM data structures that were modified by commit 6f1c819c21 ("dm: convert to bioset_init()/mempool_init()"). Also prevent structure members from unnecessarily spanning cache lines. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-06-05dm: Use kzalloc for all structs with embedded biosets/mempoolsKent Overstreet
mempool_init()/bioset_init() require that the mempools/biosets be zeroed first; they probably should not _require_ this, but not allocating those structs with kzalloc is a fairly nonsensical thing to do (calling mempool_exit()/bioset_exit() on an uninitialized mempool/bioset is legal and safe, but only works if said memory was zeroed.) Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-30dm: convert to bioset_init()/mempool_init()Kent Overstreet
Convert dm to embedded bio sets. Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-04-03dm: allow targets to return output from messages they are sentMike Snitzer
Could be useful for a target to return stats or other information. If a target does DMEMIT() anything to @result from its .message method then it must return 1 to the caller. Signed-off-By: Mike Snitzer <snitzer@redhat.com>
2018-01-29dm thin: fix trailing semicolon in __remap_and_issue_shared_cellLuis de Bethencourt
The trailing semicolon is an empty statement that does no operation. Removing it since it doesn't do anything. Signed-off-by: Luis de Bethencourt <luisbg@kernel.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-01-17dm: backfill missing calls to mutex_destroy()Mike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-12-04dm: fix various targets to dm_register_target after module __init resources ↵monty_pavel@sina.com
created A NULL pointer is seen if two concurrent "vgchange -ay -K <vg name>" processes race to load the dm-thin-pool module: PID: 25992 TASK: ffff883cd7d23500 CPU: 4 COMMAND: "vgchange" #0 [ffff883cd743d600] machine_kexec at ffffffff81038fa9 0000001 [ffff883cd743d660] crash_kexec at ffffffff810c5992 0000002 [ffff883cd743d730] oops_end at ffffffff81515c90 0000003 [ffff883cd743d760] no_context at ffffffff81049f1b 0000004 [ffff883cd743d7b0] __bad_area_nosemaphore at ffffffff8104a1a5 0000005 [ffff883cd743d800] bad_area at ffffffff8104a2ce 0000006 [ffff883cd743d830] __do_page_fault at ffffffff8104aa6f 0000007 [ffff883cd743d950] do_page_fault at ffffffff81517bae 0000008 [ffff883cd743d980] page_fault at ffffffff81514f95 [exception RIP: kmem_cache_alloc+108] RIP: ffffffff8116ef3c RSP: ffff883cd743da38 RFLAGS: 00010046 RAX: 0000000000000004 RBX: ffffffff81121b90 RCX: ffff881bf1e78cc0 RDX: 0000000000000000 RSI: 00000000000000d0 RDI: 0000000000000000 RBP: ffff883cd743da68 R8: ffff881bf1a4eb00 R9: 0000000080042000 R10: 0000000000002000 R11: 0000000000000000 R12: 00000000000000d0 R13: 0000000000000000 R14: 00000000000000d0 R15: 0000000000000246 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 0000009 [ffff883cd743da70] mempool_alloc_slab at ffffffff81121ba5 0000010 [ffff883cd743da80] mempool_create_node at ffffffff81122083 0000011 [ffff883cd743dad0] mempool_create at ffffffff811220f4 0000012 [ffff883cd743dae0] pool_ctr at ffffffffa08de049 [dm_thin_pool] 0000013 [ffff883cd743dbd0] dm_table_add_target at ffffffffa0005f2f [dm_mod] 0000014 [ffff883cd743dc30] table_load at ffffffffa0008ba9 [dm_mod] 0000015 [ffff883cd743dc90] ctl_ioctl at ffffffffa0009dc4 [dm_mod] The race results in a NULL pointer because: Process A (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target not registered; c. modprobe dm_thin_pool and wait until end. Process B (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target registered; c. table_load->dm_table_add_target->pool_ctr; d. _new_mapping_cache is NULL and panic. Note: 1. process A and process B are two concurrent processes. 2. pool_target can be detected by process B but _new_mapping_cache initialization has not ended. To fix dm-thin-pool, and other targets (cache, multipath, and snapshot) with the same problem, simply dm_register_target() after all resources created during module init (as labelled with __init) are finished. Cc: stable@vger.kernel.org Signed-off-by: monty <monty_pavel@sina.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-10-25locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns ↵Mark Rutland
to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-14Merge tag 'for-4.14/dm-changes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper updates from Mike Snitzer: - Some request-based DM core and DM multipath fixes and cleanups - Constify a few variables in DM core and DM integrity - Add bufio optimization and checksum failure accounting to DM integrity - Fix DM integrity to avoid checking integrity of failed reads - Fix DM integrity to use init_completion - A couple DM log-writes target fixes - Simplify DAX flushing by eliminating the unnecessary flush abstraction that was stood up for DM's use. * tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dax: remove the pmem_dax_ops->flush abstraction dm integrity: use init_completion instead of COMPLETION_INITIALIZER_ONSTACK dm integrity: make blk_integrity_profile structure const dm integrity: do not check integrity for failed read operations dm log writes: fix >512b sectorsize support dm log writes: don't use all the cpu while waiting to log blocks dm ioctl: constify ioctl lookup table dm: constify argument arrays dm integrity: count and display checksum failures dm integrity: optimize writing dm-bufio buffers that are partially changed dm rq: do not update rq partially in each ending bio dm rq: make dm-sq requeuing behavior consistent with dm-mq behavior dm mpath: complain about unsupported __multipath_map_bio() return values dm mpath: avoid that building with W=1 causes gcc 7 to complain about fall-through
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-07 11:25:01 +0000