kernel/linux.git/drivers/md/bcache, branch v5.15.7

bcache: Revert "bcache: use bvec_virt"

2021-11-18T18:17:17+00:00

commit 2878feaed543c35f9dbbe6d8ce36fb67ac803eef upstream. This reverts commit 2fd3e5efe791946be0957c8e1eed9560b541fe46. The above commit replaces page_address(bv->bv_page) by bvec_virt(bv) to avoid directly access to bv->bv_page, but in situation bv->bv_offset is not zero and page_address(bv->bv_page) is not equal to bvec_virt(bv). In such case a memory corruption may happen because memory in next page is tainted by following line in do_btree_node_write(), memcpy(bvec_virt(bv), addr, PAGE_SIZE); This patch reverts the mentioned commit to avoid the memory corruption. Fixes: 2fd3e5efe791 ("bcache: use bvec_virt") Signed-off-by: Coly Li Cc: Christoph Hellwig Cc: stable@vger.kernel.org # 5.15 Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20211103151041.70516-1-colyli@suse.de Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

bcache: fix use-after-free problem in bcache_device_free()

2021-11-18T18:17:17+00:00

commit 8468f45091d2866affed6f6a7aecc20779139173 upstream. In bcache_device_free(), pointer disk is referenced still in ida_simple_remove() after blk_cleanup_disk() gets called on this pointer. This may cause a potential panic by use-after-free on the disk pointer. This patch fixes the problem by calling blk_cleanup_disk() after ida_simple_remove(). Fixes: bc70852fd104 ("bcache: convert to blk_alloc_disk/blk_cleanup_disk") Signed-off-by: Coly Li Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Ulf Hansson Cc: stable@vger.kernel.org # v5.14+ Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20211103064917.67383-1-colyli@suse.de Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

bcache: use bvec_virt

2021-08-16T16:50:33+00:00

Use bvec_virt instead of open coding it. Note that the existing code is fine despite ignoring bv_offset as the bio is known to contain exactly one page from the page allocator per bio_vec. Signed-off-by: Christoph Hellwig Reviewed-by: Coly Li Link: https://lore.kernel.org/r/20210804095634.460779-10-hch@lst.de Signed-off-by: Jens Axboe

bcache: move the del_gendisk call out of bcache_device_free

2021-08-12T16:29:36+00:00

Let the callers call del_gendisk so that we can check if add_disk has been called properly for the cached device case instead of relying on the block layer internal GENHD_FL_UP flag. Signed-off-by: Christoph Hellwig Reviewed-by: Coly Li Link: https://lore.kernel.org/r/20210809064028.1198327-8-hch@lst.de Signed-off-by: Jens Axboe

bcache: add proper error unwinding in bcache_device_init

2021-08-12T16:29:36+00:00

Except for the IDA none of the allocations in bcache_device_init is unwound on error, fix that. Signed-off-by: Christoph Hellwig Acked-by: Coly Li Link: https://lore.kernel.org/r/20210809064028.1198327-7-hch@lst.de Signed-off-by: Jens Axboe

block: move some macros to blkdev.h

2021-08-12T01:40:28+00:00

Move them (PAGE_SECTORS_SHIFT, PAGE_SECTORS and SECTOR_MASK) to the generic header file to remove redundancy. Signed-off-by: Guoqing Jiang Link: https://lore.kernel.org/r/20210721025315.1729118-1-guoqing.jiang@linux.dev Signed-off-by: Jens Axboe

block: make the block holder code optional

2021-08-09T17:50:42+00:00

Move the block holder code into a separate file as it is not in any way related to the other block_dev.c code, and add a new selectable config option for it so that we don't have to build it without any remapped drivers selected. The Kconfig symbol contains a _DEPRECATED suffix to match the comments added in commit 49731baa41df ("block: restore multiple bd_link_disk_holder() support"). Signed-off-by: Christoph Hellwig Reviewed-by: Mike Snitzer Link: https://lore.kernel.org/r/20210804094147.459763-2-hch@lst.de Signed-off-by: Jens Axboe

Merge tag 'for-5.14/block-2021-06-29' of git://git.kernel.dk/linux-block

2021-06-30T19:12:56+00:00

Pull core block updates from Jens Axboe: - disk events cleanup (Christoph) - gendisk and request queue allocation simplifications (Christoph) - bdev_disk_changed cleanups (Christoph) - IO priority improvements (Bart) - Chained bio completion trace fix (Edward) - blk-wbt fixes (Jan) - blk-wbt enable/disable fix (Zhang) - Scheduler dispatch improvements (Jan, Ming) - Shared tagset scheduler improvements (John) - BFQ updates (Paolo, Luca, Pietro) - BFQ lock inversion fix (Jan) - Documentation improvements (Kir) - CLONE_IO block cgroup fix (Tejun) - Remove of ancient and deprecated block dump feature (zhangyi) - Discard merge fix (Ming) - Misc fixes or followup fixes (Colin, Damien, Dan, Long, Max, Thomas, Yang) * tag 'for-5.14/block-2021-06-29' of git://git.kernel.dk/linux-block: (129 commits) block: fix discard request merge block/mq-deadline: Remove a WARN_ON_ONCE() call blk-mq: update hctx->dispatch_busy in case of real scheduler blk: Fix lock inversion between ioc lock and bfqd lock bfq: Remove merged request already in bfq_requests_merged() block: pass a gendisk to bdev_disk_changed block: move bdev_disk_changed block: add the events* attributes to disk_attrs block: move the disk events code to a separate file block: fix trace completion for chained bio block/partitions/msdos: Fix typo inidicator -> indicator block, bfq: reset waker pointer with shared queues block, bfq: check waker only for queues with no in-flight I/O block, bfq: avoid delayed merge of async queues block, bfq: boost throughput by extending queue-merging times block, bfq: consider also creation time in delayed stable merge block, bfq: fix delayed stable merge check block, bfq: let also stably merged queues enjoy weight raising blk-wbt: make sure throttle is enabled properly blk-wbt: introduce a new disable state to prevent false positive by rwb_enabled() ...

Merge tag 'block-5.13-2021-06-12' of git://git.kernel.dk/linux-block

2021-06-12T18:59:58+00:00

Pull block fixes from Jens Axboe: "A few fixes that should go into 5.13: - Fix a regression deadlock introduced in this release between open and remove of a bdev (Christoph) - Fix an async_xor md regression in this release (Xiao) - Fix bcache oversized read issue (Coly)" * tag 'block-5.13-2021-06-12' of git://git.kernel.dk/linux-block: block: loop: fix deadlock between open and remove async_xor: check src_offs is not NULL before updating it bcache: avoid oversized read request in cache missing code path bcache: remove bcache device self-defined readahead

bcache: avoid oversized read request in cache missing code path

2021-06-08T21:06:03+00:00

In the cache missing code path of cached device, if a proper location from the internal B+ tree is matched for a cache miss range, function cached_dev_cache_miss() will be called in cache_lookup_fn() in the following code block, [code block 1] 526 unsigned int sectors = KEY_INODE(k) == s->iop.inode 527 ? min_t(uint64_t, INT_MAX, 528 KEY_START(k) - bio->bi_iter.bi_sector) 529 : INT_MAX; 530 int ret = s->d->cache_miss(b, s, bio, sectors); Here s->d->cache_miss() is the call backfunction pointer initialized as cached_dev_cache_miss(), the last parameter 'sectors' is an important hint to calculate the size of read request to backing device of the missing cache data. Current calculation in above code block may generate oversized value of 'sectors', which consequently may trigger 2 different potential kernel panics by BUG() or BUG_ON() as listed below, 1) BUG_ON() inside bch_btree_insert_key(), [code block 2] 886 BUG_ON(b->ops->is_extents && !KEY_SIZE(k)); 2) BUG() inside biovec_slab(), [code block 3] 51 default: 52 BUG(); 53 return NULL; All the above panics are original from cached_dev_cache_miss() by the oversized parameter 'sectors'. Inside cached_dev_cache_miss(), parameter 'sectors' is used to calculate the size of data read from backing device for the cache missing. This size is stored in s->insert_bio_sectors by the following lines of code, [code block 4] 909 s->insert_bio_sectors = min(sectors, bio_sectors(bio) + reada); Then the actual key inserting to the internal B+ tree is generated and stored in s->iop.replace_key by the following lines of code, [code block 5] 911 s->iop.replace_key = KEY(s->iop.inode, 912 bio->bi_iter.bi_sector + s->insert_bio_sectors, 913 s->insert_bio_sectors); The oversized parameter 'sectors' may trigger panic 1) by BUG_ON() from the above code block. And the bio sending to backing device for the missing data is allocated with hint from s->insert_bio_sectors by the following lines of code, [code block 6] 926 cache_bio = bio_alloc_bioset(GFP_NOWAIT, 927 DIV_ROUND_UP(s->insert_bio_sectors, PAGE_SECTORS), 928 &dc->disk.bio_split); The oversized parameter 'sectors' may trigger panic 2) by BUG() from the agove code block. Now let me explain how the panics happen with the oversized 'sectors'. In code block 5, replace_key is generated by macro KEY(). From the definition of macro KEY(), [code block 7] 71 #define KEY(inode, offset, size) \ 72 ((struct bkey) { \ 73 .high = (1ULL << 63) | ((__u64) (size) << 20) | (inode), \ 74 .low = (offset) \ 75 }) Here 'size' is 16bits width embedded in 64bits member 'high' of struct bkey. But in code block 1, if "KEY_START(k) - bio->bi_iter.bi_sector" is very probably to be larger than (1<<16) - 1, which makes the bkey size calculation in code block 5 is overflowed. In one bug report the value of parameter 'sectors' is 131072 (= 1 << 17), the overflowed 'sectors' results the overflowed s->insert_bio_sectors in code block 4, then makes size field of s->iop.replace_key to be 0 in code block 5. Then the 0- sized s->iop.replace_key is inserted into the internal B+ tree as cache missing check key (a special key to detect and avoid a racing between normal write request and cache missing read request) as, [code block 8] 915 ret = bch_btree_insert_check_key(b, &s->op, &s->iop.replace_key); Then the 0-sized s->iop.replace_key as 3rd parameter triggers the bkey size check BUG_ON() in code block 2, and causes the kernel panic 1). Another kernel panic is from code block 6, is by the bvecs number oversized value s->insert_bio_sectors from code block 4, min(sectors, bio_sectors(bio) + reada) There are two possibility for oversized reresult, - bio_sectors(bio) is valid, but bio_sectors(bio) + reada is oversized. - sectors < bio_sectors(bio) + reada, but sectors is oversized. From a bug report the result of "DIV_ROUND_UP(s->insert_bio_sectors, PAGE_SECTORS)" from code block 6 can be 344, 282, 946, 342 and many other values which larther than BIO_MAX_VECS (a.k.a 256). When calling bio_alloc_bioset() with such larger-than-256 value as the 2nd parameter, this value will eventually be sent to biovec_slab() as parameter 'nr_vecs' in following code path, bio_alloc_bioset() ==> bvec_alloc() ==> biovec_slab() Because parameter 'nr_vecs' is larger-than-256 value, the panic by BUG() in code block 3 is triggered inside biovec_slab(). From the above analysis, we know that the 4th parameter 'sector' sent into cached_dev_cache_miss() may cause overflow in code block 5 and 6, and finally cause kernel panic in code block 2 and 3. And if result of bio_sectors(bio) + reada exceeds valid bvecs number, it may also trigger kernel panic in code block 3 from code block 6. Now the almost-useless readahead size for cache missing request back to backing device is removed, this patch can fix the oversized issue with more simpler method. - add a local variable size_limit, set it by the minimum value from the max bkey size and max bio bvecs number. - set s->insert_bio_sectors by the minimum value from size_limit, sectors, and the sectors size of bio. - replace sectors by s->insert_bio_sectors to do bio_next_split. By the above method with size_limit, s->insert_bio_sectors will never result oversized replace_key size or bio bvecs number. And split bio 'miss' from bio_next_split() will always match the size of 'cache_bio', that is the current maximum bio size we can sent to backing device for fetching the cache missing data. Current problmatic code can be partially found since Linux v3.13-rc1, therefore all maintained stable kernels should try to apply this fix. Reported-by: Alexander Ullrich Reported-by: Diego Ercolani Reported-by: Jan Szubiak Reported-by: Marco Rebhan Reported-by: Matthias Ferdinand Reported-by: Victor Westerhuis Reported-by: Vojtech Pavlik Reported-and-tested-by: Rolf Fokkens Reported-and-tested-by: Thorsten Knabe Signed-off-by: Coly Li Cc: stable@vger.kernel.org Cc: Christoph Hellwig Cc: Kent Overstreet Cc: Nix Cc: Takashi Iwai Link: https://lore.kernel.org/r/20210607125052.21277-3-colyli@suse.de Signed-off-by: Jens Axboe