user/sven/linux.git/drivers/md, branch v4.4.272

dm snapshot: properly fix a crash when an origin has no snapshots

2021-06-03T06:22:05Z

commit 7e768532b2396bcb7fbf6f82384b85c0f1d2f197 upstream. If an origin target has no snapshots, o->split_boundary is set to 0. This causes BUG_ON(sectors <= 0) in block/bio.c:bio_split(). Fix this by initializing chunk_size, and in turn split_boundary, to rounddown_pow_of_two(UINT_MAX) -- the largest power of two that fits into "unsigned" type. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm snapshot: fix crash with transient storage and zero chunk size

2021-05-26T09:27:32Z

commit c699a0db2d62e3bbb7f0bf35c87edbc8d23e3062 upstream. The following commands will crash the kernel: modprobe brd rd_size=1048576 dmsetup create o --table "0 `blockdev --getsize /dev/ram0` snapshot-origin /dev/ram0" dmsetup create s --table "0 `blockdev --getsize /dev/ram0` snapshot /dev/ram0 /dev/ram1 N 0" The reason is that when we test for zero chunk size, we jump to the label bad_read_metadata without setting the "r" variable. The function snapshot_ctr destroys all the structures and then exits with "r == 0". The kernel then crashes because it falsely believes that snapshot_ctr succeeded. In order to fix the bug, we set the variable "r" to -EINVAL. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm ioctl: fix out of bounds array access when no devices

2021-05-22T08:38:29Z

commit 4edbe1d7bcffcd6269f3b5eb63f710393ff2ec7a upstream. If there are not any dm devices, we need to zero the "dev" argument in the first structure dm_name_list. However, this can cause out of bounds write, because the "needed" variable is zero and len may be less than eight. Fix this bug by reporting DM_BUFFER_FULL_FLAG if the result buffer is too small to hold the "nl->dev" value. Signed-off-by: Mikulas Patocka Reported-by: Dan Carpenter Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer [iwamatsu: Adjust context] Signed-off-by: Nobuhiro Iwamatsu Signed-off-by: Greg Kroah-Hartman

md: md_open returns -EBUSY when entering racing area

2021-05-22T08:38:21Z

commit 6a4db2a60306eb65bfb14ccc9fde035b74a4b4e7 upstream. commit d3374825ce57 ("md: make devices disappear when they are no longer needed.") introduced protection between mddev creating & removing. The md_open shouldn't create mddev when all_mddevs list doesn't contain mddev. With currently code logic, there will be very easy to trigger soft lockup in non-preempt env. This patch changes md_open returning from -ERESTARTSYS to -EBUSY, which will break the infinitely retry when md_open enter racing area. This patch is partly fix soft lockup issue, full fix needs mddev_find is split into two functions: mddev_find & mddev_find_or_alloc. And md_open should call new mddev_find (it only does searching job). For more detail, please refer with Christoph's "split mddev_find" patch in later commits. *** env *** kvm-qemu VM 2C1G with 2 iscsi luns kernel should be non-preempt *** script *** about trigger every time with below script ``` 1 node1="mdcluster1" 2 node2="mdcluster2" 3 4 mdadm -Ss 5 ssh ${node2} "mdadm -Ss" 6 wipefs -a /dev/sda /dev/sdb 7 mdadm -CR /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sda \ /dev/sdb --assume-clean 8 9 for i in {1..10}; do 10 echo ==== $i ====; 11 12 echo "test ...." 13 ssh ${node2} "mdadm -A /dev/md0 /dev/sda /dev/sdb" 14 sleep 1 15 16 echo "clean ....." 17 ssh ${node2} "mdadm -Ss" 18 done ``` I use mdcluster env to trigger soft lockup, but it isn't mdcluster speical bug. To stop md array in mdcluster env will do more jobs than non-cluster array, which will leave enough time/gap to allow kernel to run md_open. *** stack *** ``` [ 884.226509] mddev_put+0x1c/0xe0 [md_mod] [ 884.226515] md_open+0x3c/0xe0 [md_mod] [ 884.226518] __blkdev_get+0x30d/0x710 [ 884.226520] ? bd_acquire+0xd0/0xd0 [ 884.226522] blkdev_get+0x14/0x30 [ 884.226524] do_dentry_open+0x204/0x3a0 [ 884.226531] path_openat+0x2fc/0x1520 [ 884.226534] ? seq_printf+0x4e/0x70 [ 884.226536] do_filp_open+0x9b/0x110 [ 884.226542] ? md_release+0x20/0x20 [md_mod] [ 884.226543] ? seq_read+0x1d8/0x3e0 [ 884.226545] ? kmem_cache_alloc+0x18a/0x270 [ 884.226547] ? do_sys_open+0x1bd/0x260 [ 884.226548] do_sys_open+0x1bd/0x260 [ 884.226551] do_syscall_64+0x5b/0x1e0 [ 884.226554] entry_SYSCALL_64_after_hwframe+0x44/0xa9 ``` *** rootcause *** "mdadm -A" (or other array assemble commands) will start a daemon "mdadm --monitor" by default. When "mdadm -Ss" is running, the stop action will wakeup "mdadm --monitor". The "--monitor" daemon will immediately get info from /proc/mdstat. This time mddev in kernel still exist, so /proc/mdstat still show md device, which makes "mdadm --monitor" to open /dev/md0. The previously "mdadm -Ss" is removing action, the "mdadm --monitor" open action will trigger md_open which is creating action. Racing is happening. ``` : "mdadm -Ss" md_release mddev_put deletes mddev from all_mddevs queue_work for mddev_delayed_delete at this time, "/dev/md0" is still available for opening : "mdadm --monitor ..." md_open + mddev_find can't find mddev of /dev/md0, and create a new mddev and | return. + trigger "if (mddev->gendisk != bdev->bd_disk)" and return -ERESTARTSYS. ``` In non-preempt kernel, is occupying on current CPU. and mddev_delayed_delete which was created in also can't be schedule. In preempt kernel, it can also trigger above racing. But kernel doesn't allow one thread running on a CPU all the time. after running some time, the later "mdadm -A" (refer above script line 13) will call md_alloc to alloc a new gendisk for mddev. it will break md_open statement "if (mddev->gendisk != bdev->bd_disk)" and return 0 to caller, the soft lockup is broken. Cc: stable@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Zhao Heming Signed-off-by: Song Liu Signed-off-by: Greg Kroah-Hartman

md: factor out a mddev_find_locked helper from mddev_find

2021-05-22T08:38:21Z

commit 8b57251f9a91f5e5a599de7549915d2d226cc3af upstream. Factor out a self-contained helper to just lookup a mddev by the dev_t "unit". Cc: stable@vger.kernel.org Reviewed-by: Heming Zhao Signed-off-by: Christoph Hellwig Signed-off-by: Song Liu Signed-off-by: Greg Kroah-Hartman

dm space map common: fix division bug in sm_ll_find_free_block()

2021-05-22T08:38:20Z

commit 5208692e80a1f3c8ce2063a22b675dd5589d1d80 upstream. This division bug meant the search for free metadata space could skip the final allocation bitmap's worth of entries. Fix affects DM thinp, cache and era targets. Cc: stable@vger.kernel.org Signed-off-by: Joe Thornber Tested-by: Ming-Hung Tsai Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm persistent data: packed struct should have an aligned() attribute too

2021-05-22T08:38:20Z

commit a88b2358f1da2c9f9fcc432f2e0a79617fea397c upstream. Otherwise most non-x86 architectures (e.g. riscv, arm) will resort to byte-by-byte access. Cc: stable@vger.kernel.org Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

overflow.h: Add allocation size calculation helpers

2021-04-28T10:05:47Z

commit 610b15c50e86eb1e4b77274fabcaea29ac72d6a8 upstream. In preparation for replacing unchecked overflows for memory allocations, this creates helpers for the 3 most common calculations: array_size(a, b): 2-dimensional array array3_size(a, b, c): 3-dimensional array struct_size(ptr, member, n): struct followed by n-many trailing members Each of these return SIZE_MAX on overflow instead of wrapping around. (Additionally renames a variable named "array_size" to avoid future collision.) Co-developed-by: Matthew Wilcox Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman

dm table: fix iterate_devices based device capability checks

2021-03-11T12:46:35Z

commit a4c8dd9c2d0987cf542a2a0c42684c9c6d78a04e upstream. According to the definition of dm_iterate_devices_fn: * This function must iterate through each section of device used by the * target until it encounters a non-zero return code, which it then returns. * Returns zero if no callout returned non-zero. For some target type (e.g. dm-stripe), one call of iterate_devices() may iterate multiple underlying devices internally, in which case a non-zero return code returned by iterate_devices_callout_fn will stop the iteration in advance. No iterate_devices_callout_fn should return non-zero unless device iteration should stop. Rename dm_table_requires_stable_pages() to dm_table_any_dev_attr() and elevate it for reuse to stop iterating (and return non-zero) on the first device that causes iterate_devices_callout_fn to return non-zero. Use dm_table_any_dev_attr() to properly iterate through devices. Rename device_is_nonrot() to device_is_rotational() and invert logic accordingly to fix improper disposition. [jeffle: backport notes] No stable writes. Also convert the no_sg_merge capability check, which is introduced by commit 200612ec33e5 ("dm table: propagate QUEUE_FLAG_NO_SG_MERGE"), and removed since commit 2705c93742e9 ("block: kill QUEUE_FLAG_NO_SG_MERGE") in v5.1. Fixes: c3c4555edd10 ("dm table: clear add_random unless all devices have it set") Fixes: 4693c9668fdc ("dm table: propagate non rotational flag") Cc: stable@vger.kernel.org Signed-off-by: Jeffle Xu Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm era: Update in-core bitset after committing the metadata

2021-03-03T15:44:24Z

commit 2099b145d77c1d53f5711f029c37cc537897cee6 upstream. In case of a system crash, dm-era might fail to mark blocks as written in its metadata, although the corresponding writes to these blocks were passed down to the origin device and completed successfully. Consider the following sequence of events: 1. We write to a block that has not been yet written in the current era 2. era_map() checks the in-core bitmap for the current era and sees that the block is not marked as written. 3. The write is deferred for submission after the metadata have been updated and committed. 4. The worker thread processes the deferred write (process_deferred_bios()) and marks the block as written in the in-core bitmap, **before** committing the metadata. 5. The worker thread starts committing the metadata. 6. We do more writes that map to the same block as the write of step (1) 7. era_map() checks the in-core bitmap and sees that the block is marked as written, **although the metadata have not been committed yet**. 8. These writes are passed down to the origin device immediately and the device reports them as completed. 9. The system crashes, e.g., power failure, before the commit from step (5) finishes. When the system recovers and we query the dm-era target for the list of written blocks it doesn't report the aforementioned block as written, although the writes of step (6) completed successfully. The issue is that era_map() decides whether to defer or not a write based on non committed information. The root cause of the bug is that we update the in-core bitmap, **before** committing the metadata. Fix this by updating the in-core bitmap **after** successfully committing the metadata. Fixes: eec40579d84873 ("dm: add era target") Cc: stable@vger.kernel.org # v3.15+ Signed-off-by: Nikos Tsironis Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman