user/sven/linux.git/fs/block_dev.c, branch v4.14.258

block: reexpand iov_iter after read/write

2021-05-22T08:57:43Z

[ Upstream commit cf7b39a0cbf6bf57aa07a008d46cf695add05b4c ] We get a bug: BUG: KASAN: slab-out-of-bounds in iov_iter_revert+0x11c/0x404 lib/iov_iter.c:1139 Read of size 8 at addr ffff0000d3fb11f8 by task CPU: 0 PID: 12582 Comm: syz-executor.2 Not tainted 5.10.0-00843-g352c8610ccd2 #2 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x0/0x2d0 arch/arm64/kernel/stacktrace.c:132 show_stack+0x28/0x34 arch/arm64/kernel/stacktrace.c:196 __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x110/0x164 lib/dump_stack.c:118 print_address_description+0x78/0x5c8 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report+0x148/0x1e4 mm/kasan/report.c:562 check_memory_region_inline mm/kasan/generic.c:183 [inline] __asan_load8+0xb4/0xbc mm/kasan/generic.c:252 iov_iter_revert+0x11c/0x404 lib/iov_iter.c:1139 io_read fs/io_uring.c:3421 [inline] io_issue_sqe+0x2344/0x2d64 fs/io_uring.c:5943 __io_queue_sqe+0x19c/0x520 fs/io_uring.c:6260 io_queue_sqe+0x2a4/0x590 fs/io_uring.c:6326 io_submit_sqe fs/io_uring.c:6395 [inline] io_submit_sqes+0x4c0/0xa04 fs/io_uring.c:6624 __do_sys_io_uring_enter fs/io_uring.c:9013 [inline] __se_sys_io_uring_enter fs/io_uring.c:8960 [inline] __arm64_sys_io_uring_enter+0x190/0x708 fs/io_uring.c:8960 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall arch/arm64/kernel/syscall.c:48 [inline] el0_svc_common arch/arm64/kernel/syscall.c:158 [inline] do_el0_svc+0x120/0x290 arch/arm64/kernel/syscall.c:227 el0_svc+0x1c/0x28 arch/arm64/kernel/entry-common.c:367 el0_sync_handler+0x98/0x170 arch/arm64/kernel/entry-common.c:383 el0_sync+0x140/0x180 arch/arm64/kernel/entry.S:670 Allocated by task 12570: stack_trace_save+0x80/0xb8 kernel/stacktrace.c:121 kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0xdc/0x120 mm/kasan/common.c:461 kasan_kmalloc+0xc/0x14 mm/kasan/common.c:475 __kmalloc+0x23c/0x334 mm/slub.c:3970 kmalloc include/linux/slab.h:557 [inline] __io_alloc_async_data+0x68/0x9c fs/io_uring.c:3210 io_setup_async_rw fs/io_uring.c:3229 [inline] io_read fs/io_uring.c:3436 [inline] io_issue_sqe+0x2954/0x2d64 fs/io_uring.c:5943 __io_queue_sqe+0x19c/0x520 fs/io_uring.c:6260 io_queue_sqe+0x2a4/0x590 fs/io_uring.c:6326 io_submit_sqe fs/io_uring.c:6395 [inline] io_submit_sqes+0x4c0/0xa04 fs/io_uring.c:6624 __do_sys_io_uring_enter fs/io_uring.c:9013 [inline] __se_sys_io_uring_enter fs/io_uring.c:8960 [inline] __arm64_sys_io_uring_enter+0x190/0x708 fs/io_uring.c:8960 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall arch/arm64/kernel/syscall.c:48 [inline] el0_svc_common arch/arm64/kernel/syscall.c:158 [inline] do_el0_svc+0x120/0x290 arch/arm64/kernel/syscall.c:227 el0_svc+0x1c/0x28 arch/arm64/kernel/entry-common.c:367 el0_sync_handler+0x98/0x170 arch/arm64/kernel/entry-common.c:383 el0_sync+0x140/0x180 arch/arm64/kernel/entry.S:670 Freed by task 12570: stack_trace_save+0x80/0xb8 kernel/stacktrace.c:121 kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track+0x38/0x6c mm/kasan/common.c:56 kasan_set_free_info+0x20/0x40 mm/kasan/generic.c:355 __kasan_slab_free+0x124/0x150 mm/kasan/common.c:422 kasan_slab_free+0x10/0x1c mm/kasan/common.c:431 slab_free_hook mm/slub.c:1544 [inline] slab_free_freelist_hook mm/slub.c:1577 [inline] slab_free mm/slub.c:3142 [inline] kfree+0x104/0x38c mm/slub.c:4124 io_dismantle_req fs/io_uring.c:1855 [inline] __io_free_req+0x70/0x254 fs/io_uring.c:1867 io_put_req_find_next fs/io_uring.c:2173 [inline] __io_queue_sqe+0x1fc/0x520 fs/io_uring.c:6279 __io_req_task_submit+0x154/0x21c fs/io_uring.c:2051 io_req_task_submit+0x2c/0x44 fs/io_uring.c:2063 task_work_run+0xdc/0x128 kernel/task_work.c:151 get_signal+0x6f8/0x980 kernel/signal.c:2562 do_signal+0x108/0x3a4 arch/arm64/kernel/signal.c:658 do_notify_resume+0xbc/0x25c arch/arm64/kernel/signal.c:722 work_pending+0xc/0x180 blkdev_read_iter can truncate iov_iter's count since the count + pos may exceed the size of the blkdev. This will confuse io_read that we have consume the iovec. And once we do the iov_iter_revert in io_read, we will trigger the slab-out-of-bounds. Fix it by reexpand the count with size has been truncated. blkdev_write_iter can trigger the problem too. Signed-off-by: yangerkun Acked-by: Pavel Begunkov Link: https://lore.kernel.org/r/20210401071807.3328235-1-yangerkun@huawei.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bdev: Reduce time holding bd_mutex in sync in blkdev_close()

2020-10-01T11:12:41Z

[ Upstream commit b849dd84b6ccfe32622988b79b7b073861fcf9f7 ] While trying to "dd" to the block device for a USB stick, I encountered a hung task warning (blocked for > 120 seconds). I managed to come up with an easy way to reproduce this on my system (where /dev/sdb is the block device for my USB stick) with: while true; do dd if=/dev/zero of=/dev/sdb bs=4M; done With my reproduction here are the relevant bits from the hung task detector: INFO: task udevd:294 blocked for more than 122 seconds. ... udevd D 0 294 1 0x00400008 Call trace: ... mutex_lock_nested+0x40/0x50 __blkdev_get+0x7c/0x3d4 blkdev_get+0x118/0x138 blkdev_open+0x94/0xa8 do_dentry_open+0x268/0x3a0 vfs_open+0x34/0x40 path_openat+0x39c/0xdf4 do_filp_open+0x90/0x10c do_sys_open+0x150/0x3c8 ... ... Showing all locks held in the system: ... 1 lock held by dd/2798: #0: ffffff814ac1a3b8 (&bdev->bd_mutex){+.+.}, at: __blkdev_put+0x50/0x204 ... dd D 0 2798 2764 0x00400208 Call trace: ... schedule+0x8c/0xbc io_schedule+0x1c/0x40 wait_on_page_bit_common+0x238/0x338 __lock_page+0x5c/0x68 write_cache_pages+0x194/0x500 generic_writepages+0x64/0xa4 blkdev_writepages+0x24/0x30 do_writepages+0x48/0xa8 __filemap_fdatawrite_range+0xac/0xd8 filemap_write_and_wait+0x30/0x84 __blkdev_put+0x88/0x204 blkdev_put+0xc4/0xe4 blkdev_close+0x28/0x38 __fput+0xe0/0x238 ____fput+0x1c/0x28 task_work_run+0xb0/0xe4 do_notify_resume+0xfc0/0x14bc work_pending+0x8/0x14 The problem appears related to the fact that my USB disk is terribly slow and that I have a lot of RAM in my system to cache things. Specifically my writes seem to be happening at ~15 MB/s and I've got ~4 GB of RAM in my system that can be used for buffering. To write 4 GB of buffer to disk thus takes ~4000 MB / ~15 MB/s = ~267 seconds. The 267 second number is a problem because in __blkdev_put() we call sync_blockdev() while holding the bd_mutex. Any other callers who want the bd_mutex will be blocked for the whole time. The problem is made worse because I believe blkdev_put() specifically tells other tasks (namely udev) to go try to access the device at right around the same time we're going to hold the mutex for a long time. Putting some traces around this (after disabling the hung task detector), I could confirm: dd: 437.608600: __blkdev_put() right before sync_blockdev() for sdb udevd: 437.623901: blkdev_open() right before blkdev_get() for sdb dd: 661.468451: __blkdev_put() right after sync_blockdev() for sdb udevd: 663.820426: blkdev_open() right after blkdev_get() for sdb A simple fix for this is to realize that sync_blockdev() works fine if you're not holding the mutex. Also, it's not the end of the world if you sync a little early (though it can have performance impacts). Thus we can make a guess that we're going to need to do the sync and then do it without holding the mutex. We still do one last sync with the mutex but it should be much, much faster. With this, my hung task warnings for my test case are gone. Signed-off-by: Douglas Anderson Reviewed-by: Guenter Roeck Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block: Fix use-after-free in blkdev_get()

2020-06-25T13:41:58Z

[ Upstream commit 2d3a8e2deddea6c89961c422ec0c5b851e648c14 ] In blkdev_get() we call __blkdev_get() to do some internal jobs and if there is some errors in __blkdev_get(), the bdput() is called which means we have released the refcount of the bdev (actually the refcount of the bdev inode). This means we cannot access bdev after that point. But acctually bdev is still accessed in blkdev_get() after calling __blkdev_get(). This results in use-after-free if the refcount is the last one we released in __blkdev_get(). Let's take a look at the following scenerio: CPU0 CPU1 CPU2 blkdev_open blkdev_open Remove disk bd_acquire blkdev_get __blkdev_get del_gendisk bdev_unhash_inode bd_acquire bdev_get_gendisk bd_forget failed because of unhashed bdput bdput (the last one) bdev_evict_inode access bdev => use after free [ 459.350216] BUG: KASAN: use-after-free in __lock_acquire+0x24c1/0x31b0 [ 459.351190] Read of size 8 at addr ffff88806c815a80 by task syz-executor.0/20132 [ 459.352347] [ 459.352594] CPU: 0 PID: 20132 Comm: syz-executor.0 Not tainted 4.19.90 #2 [ 459.353628] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 [ 459.354947] Call Trace: [ 459.355337] dump_stack+0x111/0x19e [ 459.355879] ? __lock_acquire+0x24c1/0x31b0 [ 459.356523] print_address_description+0x60/0x223 [ 459.357248] ? __lock_acquire+0x24c1/0x31b0 [ 459.357887] kasan_report.cold+0xae/0x2d8 [ 459.358503] __lock_acquire+0x24c1/0x31b0 [ 459.359120] ? _raw_spin_unlock_irq+0x24/0x40 [ 459.359784] ? lockdep_hardirqs_on+0x37b/0x580 [ 459.360465] ? _raw_spin_unlock_irq+0x24/0x40 [ 459.361123] ? finish_task_switch+0x125/0x600 [ 459.361812] ? finish_task_switch+0xee/0x600 [ 459.362471] ? mark_held_locks+0xf0/0xf0 [ 459.363108] ? __schedule+0x96f/0x21d0 [ 459.363716] lock_acquire+0x111/0x320 [ 459.364285] ? blkdev_get+0xce/0xbe0 [ 459.364846] ? blkdev_get+0xce/0xbe0 [ 459.365390] __mutex_lock+0xf9/0x12a0 [ 459.365948] ? blkdev_get+0xce/0xbe0 [ 459.366493] ? bdev_evict_inode+0x1f0/0x1f0 [ 459.367130] ? blkdev_get+0xce/0xbe0 [ 459.367678] ? destroy_inode+0xbc/0x110 [ 459.368261] ? mutex_trylock+0x1a0/0x1a0 [ 459.368867] ? __blkdev_get+0x3e6/0x1280 [ 459.369463] ? bdev_disk_changed+0x1d0/0x1d0 [ 459.370114] ? blkdev_get+0xce/0xbe0 [ 459.370656] blkdev_get+0xce/0xbe0 [ 459.371178] ? find_held_lock+0x2c/0x110 [ 459.371774] ? __blkdev_get+0x1280/0x1280 [ 459.372383] ? lock_downgrade+0x680/0x680 [ 459.373002] ? lock_acquire+0x111/0x320 [ 459.373587] ? bd_acquire+0x21/0x2c0 [ 459.374134] ? do_raw_spin_unlock+0x4f/0x250 [ 459.374780] blkdev_open+0x202/0x290 [ 459.375325] do_dentry_open+0x49e/0x1050 [ 459.375924] ? blkdev_get_by_dev+0x70/0x70 [ 459.376543] ? __x64_sys_fchdir+0x1f0/0x1f0 [ 459.377192] ? inode_permission+0xbe/0x3a0 [ 459.377818] path_openat+0x148c/0x3f50 [ 459.378392] ? kmem_cache_alloc+0xd5/0x280 [ 459.379016] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 459.379802] ? path_lookupat.isra.0+0x900/0x900 [ 459.380489] ? __lock_is_held+0xad/0x140 [ 459.381093] do_filp_open+0x1a1/0x280 [ 459.381654] ? may_open_dev+0xf0/0xf0 [ 459.382214] ? find_held_lock+0x2c/0x110 [ 459.382816] ? lock_downgrade+0x680/0x680 [ 459.383425] ? __lock_is_held+0xad/0x140 [ 459.384024] ? do_raw_spin_unlock+0x4f/0x250 [ 459.384668] ? _raw_spin_unlock+0x1f/0x30 [ 459.385280] ? __alloc_fd+0x448/0x560 [ 459.385841] do_sys_open+0x3c3/0x500 [ 459.386386] ? filp_open+0x70/0x70 [ 459.386911] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 459.387610] ? trace_hardirqs_off_caller+0x55/0x1c0 [ 459.388342] ? do_syscall_64+0x1a/0x520 [ 459.388930] do_syscall_64+0xc3/0x520 [ 459.389490] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 459.390248] RIP: 0033:0x416211 [ 459.390720] Code: 75 14 b8 02 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 19 00 00 c3 48 83 ec 08 e8 0a fa ff ff 48 89 04 24 b8 02 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fa ff ff 48 89 d0 48 83 c4 08 48 3d 01 [ 459.393483] RSP: 002b:00007fe45dfe9a60 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 [ 459.394610] RAX: ffffffffffffffda RBX: 00007fe45dfea6d4 RCX: 0000000000416211 [ 459.395678] RDX: 00007fe45dfe9b0a RSI: 0000000000000002 RDI: 00007fe45dfe9b00 [ 459.396758] RBP: 000000000076bf20 R08: 0000000000000000 R09: 000000000000000a [ 459.397930] R10: 0000000000000075 R11: 0000000000000293 R12: 00000000ffffffff [ 459.399022] R13: 0000000000000bd9 R14: 00000000004cdb80 R15: 000000000076bf2c [ 459.400168] [ 459.400430] Allocated by task 20132: [ 459.401038] kasan_kmalloc+0xbf/0xe0 [ 459.401652] kmem_cache_alloc+0xd5/0x280 [ 459.402330] bdev_alloc_inode+0x18/0x40 [ 459.402970] alloc_inode+0x5f/0x180 [ 459.403510] iget5_locked+0x57/0xd0 [ 459.404095] bdget+0x94/0x4e0 [ 459.404607] bd_acquire+0xfa/0x2c0 [ 459.405113] blkdev_open+0x110/0x290 [ 459.405702] do_dentry_open+0x49e/0x1050 [ 459.406340] path_openat+0x148c/0x3f50 [ 459.406926] do_filp_open+0x1a1/0x280 [ 459.407471] do_sys_open+0x3c3/0x500 [ 459.408010] do_syscall_64+0xc3/0x520 [ 459.408572] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 459.409415] [ 459.409679] Freed by task 1262: [ 459.410212] __kasan_slab_free+0x129/0x170 [ 459.410919] kmem_cache_free+0xb2/0x2a0 [ 459.411564] rcu_process_callbacks+0xbb2/0x2320 [ 459.412318] __do_softirq+0x225/0x8ac Fix this by delaying bdput() to the end of blkdev_get() which means we have finished accessing bdev. Fixes: 77ea887e433a ("implement in-kernel gendisk events handling") Reported-by: Hulk Robot Signed-off-by: Jason Yan Tested-by: Sedat Dilek Reviewed-by: Jan Kara Reviewed-by: Christoph Hellwig Reviewed-by: Dan Carpenter Cc: Christoph Hellwig Cc: Jens Axboe Cc: Ming Lei Cc: Jan Kara Cc: Dan Carpenter Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block: fix the return errno for direct IO

2019-04-17T06:37:53Z

commit a89afe58f1a74aac768a5eb77af95ef4ee15beaa upstream. If the last bio returned is not dio->bio, the status of the bio will not assigned to dio->bio if it is error. This will cause the whole IO status wrong. ksoftirqd/21-117 [021] ..s. 4017.966090: 8,0 C N 4883648 [0] -0 [018] ..s. 4017.970888: 8,0 C WS 4924800 + 1024 [0] -0 [018] ..s. 4017.970909: 8,0 D WS 4935424 + 1024 [] -0 [018] ..s. 4017.970924: 8,0 D WS 4936448 + 321 [] ksoftirqd/21-117 [021] ..s. 4017.995033: 8,0 C R 4883648 + 336 [65475] ksoftirqd/21-117 [021] d.s. 4018.001988: myprobe1: (blkdev_bio_end_io+0x0/0x168) bi_status=7 ksoftirqd/21-117 [021] d.s. 4018.001992: myprobe: (aio_complete_rw+0x0/0x148) x0=0xffff802f2595ad80 res=0x12a000 res2=0x0 We always have to assign bio->bi_status to dio->bio.bi_status because we will only check dio->bio.bi_status when we return the whole IO to the upper layer. Fixes: 542ff7bf18c6 ("block: new direct I/O implementation") Cc: stable@vger.kernel.org Cc: Christoph Hellwig Cc: Jens Axboe Reviewed-by: Ming Lei Signed-off-by: Jason Yan Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

blockdev: Fix livelocks on loop device

2019-01-23T07:09:50Z

commit 04906b2f542c23626b0ef6219b808406f8dddbe9 upstream. bd_set_size() updates also block device's block size. This is somewhat unexpected from its name and at this point, only blkdev_open() uses this functionality. Furthermore, this can result in changing block size under a filesystem mounted on a loop device which leads to livelocks inside __getblk_gfp() like: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 10863 Comm: syz-executor0 Not tainted 4.18.0-rc5+ #151 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x3f/0x50 kernel/kcov.c:106 ... Call Trace: init_page_buffers+0x3e2/0x530 fs/buffer.c:904 grow_dev_page fs/buffer.c:947 [inline] grow_buffers fs/buffer.c:1009 [inline] __getblk_slow fs/buffer.c:1036 [inline] __getblk_gfp+0x906/0xb10 fs/buffer.c:1313 __bread_gfp+0x2d/0x310 fs/buffer.c:1347 sb_bread include/linux/buffer_head.h:307 [inline] fat12_ent_bread+0x14e/0x3d0 fs/fat/fatent.c:75 fat_ent_read_block fs/fat/fatent.c:441 [inline] fat_alloc_clusters+0x8ce/0x16e0 fs/fat/fatent.c:489 fat_add_cluster+0x7a/0x150 fs/fat/inode.c:101 __fat_get_block fs/fat/inode.c:148 [inline] ... Trivial reproducer for the problem looks like: truncate -s 1G /tmp/image losetup /dev/loop0 /tmp/image mkfs.ext4 -b 1024 /dev/loop0 mount -t ext4 /dev/loop0 /mnt losetup -c /dev/loop0 l /mnt Fix the problem by moving initialization of a block device block size into a separate function and call it when needed. Thanks to Tetsuo Handa for help with debugging the problem. Reported-by: syzbot+9933e4476f365f5d5a1b@syzkaller.appspotmail.com Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

blkdev: __blkdev_direct_IO_simple: fix leak in error case

2018-08-03T05:50:42Z

commit 9362dd1109f87a9d0a798fbc890cb339c171ed35 upstream. Fixes: 72ecad22d9f1 ("block: support a full bio worth of IO for simplified bdev direct-io") Reviewed-by: Ming Lei Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Signed-off-by: Martin Wilck Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

fs/mpage.c: fix mpage_writepage() for pages with buffers

2017-10-13T23:18:33Z

When using FAT on a block device which supports rw_page, we can hit BUG_ON(!PageLocked(page)) in try_to_free_buffers(). This is because we call clean_buffers() after unlocking the page we've written. Introduce a new clean_page_buffers() which cleans all buffers associated with a page and call it from within bdev_write_page(). [akpm@linux-foundation.org: s/PAGE_SIZE/~0U/ per Linus and Matthew] Link: http://lkml.kernel.org/r/20171006211541.GA7409@bombadil.infradead.org Signed-off-by: Matthew Wilcox Reported-by: Toshi Kani Reported-by: OGAWA Hirofumi Tested-by: Toshi Kani Acked-by: Johannes Thumshirn Cc: Ross Zwisler Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'work.read_write' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2017-09-15T02:29:55Z

Pull nowait read support from Al Viro: "Support IOCB_NOWAIT for buffered reads and block devices" * 'work.read_write' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: block_dev: support RFW_NOWAIT on block device nodes fs: support RWF_NOWAIT for buffered reads fs: support IOCB_NOWAIT in generic_file_buffered_read fs: pass iocb to do_generic_file_read

block_dev: support RFW_NOWAIT on block device nodes

2017-09-04T23:04:23Z

All support is already there in the generic code, we just need to wire it up. Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Signed-off-by: Al Viro

block: replace bi_bdev with a gendisk pointer and partitions index

2017-08-23T18:49:55Z

This way we don't need a block_device structure to submit I/O. The block_device has different life time rules from the gendisk and request_queue and is usually only available when the block device node is open. Other callers need to explicitly create one (e.g. the lightnvm passthrough code, or the new nvme multipathing code). For the actual I/O path all that we need is the gendisk, which exists once per block device. But given that the block layer also does partition remapping we additionally need a partition index, which is used for said remapping in generic_make_request. Note that all the block drivers generally want request_queue or sometimes the gendisk, so this removes a layer of indirection all over the stack. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe