Pull more block updates from Jens Axboe:
- MD pull request via Song:
- Improve raid5 sequential IO performance on spinning disks, which
fixes a regression since v6.0 (Jan Kara)
- Fix bitmap offset types, which fixes an issue introduced in this
merge window (Jonathan Derrick)
- Cleanup of hweight type used for cgroup writeback (Maxim)
- Fix a regression with the "has_submit_bio" changes across partitions
(Ming)
- Cleanup of QUEUE_FLAG_ADD_RANDOM clearing.
We used to set this flag on queues non blk-mq queues, and hence some
drivers clear it unconditionally. Since all of these have since been
converted to true blk-mq drivers, drop the useless clear as the bit
is not set (Chaitanya)
- Fix the flags being set in a bio for a flush for drbd (Christoph)
- Cleanup and deduplication of the code handling setting block device
capacity (Damien)
- Fix for ublk handling IO timeouts (Ming)
- Fix for a regression in blk-cgroup teardown (Tao)
- NBD documentation and code fixes (Eric)
- Convert blk-integrity to using device_attributes rather than a second
kobject to manage lifetimes (Thomas)
* tag 'for-6.4/block-2023-05-06' of git://git.kernel.dk/linux:
ublk: add timeout handler
drbd: correctly submit flush bio on barrier
mailmap: add mailmap entries for Jens Axboe
block: Skip destroyed blkg when restart in blkg_destroy_all()
writeback: fix call of incorrect macro
md: Fix bitmap offset type in sb writer
md/raid5: Improve performance for sequential IO
docs nbd: userspace NBD now favors github over sourceforge
block nbd: use req.cookie instead of req.handle
uapi nbd: add cookie alias to handle
uapi nbd: improve doc links to userspace spec
blk-integrity: register sysfs attributes on struct device
blk-integrity: convert to struct device_attribute
blk-integrity: use sysfs_emit
block/drivers: remove dead clear of random flag
block: sync part's ->bd_has_submit_bio with disk's
block: Cleanup set_capacity()/bdev_set_nr_sectors()
the variable 'history' is of type u16, it may be an error
that the hweight32 macro was used for it
I guess macro hweight16 should be used
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 2a81490811d0 ("writeback: implement foreign cgroup inode detection")
Signed-off-by: Maxim Korotkov <korotkov.maxim.s@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230119104443.3002-1-korotkov.maxim.s@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
KASAN report null-ptr-deref:
==================================================================
BUG: KASAN: null-ptr-deref in bdi_split_work_to_wbs+0x5c5/0x7b0
Write of size 8 at addr 0000000000000000 by task sync/943
CPU: 5 PID: 943 Comm: sync Tainted: 6.3.0-rc5-next-20230406-dirty #461
Call Trace:
<TASK>
dump_stack_lvl+0x7f/0xc0
print_report+0x2ba/0x340
kasan_report+0xc4/0x120
kasan_check_range+0x1b7/0x2e0
__kasan_check_write+0x24/0x40
bdi_split_work_to_wbs+0x5c5/0x7b0
sync_inodes_sb+0x195/0x630
sync_inodes_one_sb+0x3a/0x50
iterate_supers+0x106/0x1b0
ksys_sync+0x98/0x160
[...]
==================================================================
The race that causes the above issue is as follows:
cpu1 cpu2
-------------------------|-------------------------
inode_switch_wbs
INIT_WORK(&isw->work, inode_switch_wbs_work_fn)
queue_rcu_work(isw_wq, &isw->work)
// queue_work async
inode_switch_wbs_work_fn
wb_put_many(old_wb, nr_switched)
percpu_ref_put_many
ref->data->release(ref)
cgwb_release
queue_work(cgwb_release_wq, &wb->release_work)
// queue_work async
&wb->release_work
cgwb_release_workfn
ksys_sync
iterate_supers
sync_inodes_one_sb
sync_inodes_sb
bdi_split_work_to_wbs
kmalloc(sizeof(*work), GFP_ATOMIC)
// alloc memory failed
percpu_ref_exit
ref->data = NULL
kfree(data)
wb_get(wb)
percpu_ref_get(&wb->refcnt)
percpu_ref_get_many(ref, 1)
atomic_long_add(nr, &ref->data->count)
atomic64_add(i, v)
// trigger null-ptr-deref
bdi_split_work_to_wbs() traverses &bdi->wb_list to split work into all
wbs. If the allocation of new work fails, the on-stack fallback will be
used and the reference count of the current wb is increased afterwards.
If cgroup writeback membership switches occur before getting the reference
count and the current wb is released as old_wd, then calling wb_get() or
wb_put() will trigger the null pointer dereference above.
This issue was introduced in v4.3-rc7 (see fix tag1). Both
sync_inodes_sb() and __writeback_inodes_sb_nr() calls to
bdi_split_work_to_wbs() can trigger this issue. For scenarios called via
sync_inodes_sb(), originally commit 7fc5854f8c6e ("writeback: synchronize
sync(2) against cgroup writeback membership switches") reduced the
possibility of the issue by adding wb_switch_rwsem, but in v5.14-rc1 (see
fix tag2) removed the "inode_io_list_del_locked(inode, old_wb)" from
inode_switch_wbs_work_fn() so that wb->state contains WB_has_dirty_io,
thus old_wb is not skipped when traversing wbs in bdi_split_work_to_wbs(),
and the issue becomes easily reproducible again.
To solve this problem, percpu_ref_exit() is called under RCU protection to
avoid race between cgwb_release_workfn() and bdi_split_work_to_wbs().
Moreover, replace wb_get() with wb_tryget() in bdi_split_work_to_wbs(),
and skip the current wb if wb_tryget() fails because the wb has already
been shutdown.
Link: https://lkml.kernel.org/r/20230410130826.1492525-1-libaokun1@huawei.com
Fixes: b817525a4a80 ("writeback: bdi_writeback iteration must not skip dying ones")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Hou Tao <houtao1@huawei.com>
Cc: yangerkun <yangerkun@huawei.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Only one caller doesn't have a folio, so move the page_folio() call to that one caller from mem_cgroup_css_from_folio(). Link: https://lkml.kernel.org/r/20230116192507.2146150-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Writeback folio conversions". Remove more calls to compound_head() by passing folios around instead of pages. This patch (of 2): The only caller of inode_attach_wb() which doesn't pass NULL already has a folio, so convert the whole call-chain to take folios. Link: https://lkml.kernel.org/r/20230116192507.2146150-1-willy@infradead.org Link: https://lkml.kernel.org/r/20230116192507.2146150-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull writeback updates from Jens Axboe: - Sanity check adding freed inodes to lists (Jan) - Removal of an old unused define (Miaohe) * tag 'for-6.2/writeback-2022-12-12' of git://git.kernel.dk/linux: writeback: remove obsolete macro EXPIRE_DIRTY_ATIME writeback: Add asserts for adding freed inode to lists
EXPIRE_DIRTY_ATIME is not used anymore. Remove it. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20221210101042.2012931-1-linmiaohe@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
In the past we had several use-after-free issues with inodes getting added to writeback lists after evict() removed them. These are painful to debug so add some asserts to catch the problem earlier. The only non-obvious change in the commit is that we need to tweak redirty_tail_locked() to avoid triggering assertion in inode_io_list_move_locked(). Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20221212113633.29181-1-jack@suse.cz Signed-off-by: Jens Axboe <axboe@kernel.dk>
After commit cbfecb927f42 ("fs: record I_DIRTY_TIME even if inode
already has I_DIRTY_INODE") writeback_single_inode can push inode with
I_DIRTY_TIME set to b_dirty_time list. In case of freeing inode with
I_DIRTY_TIME set this can happen after deletion of inode from i_io_list
at evict. Stack trace is following.
evict
fat_evict_inode
fat_truncate_blocks
fat_flush_inodes
writeback_inode
sync_inode_metadata(inode, sync=0)
writeback_single_inode(inode, wbc) <- wbc->sync_mode == WB_SYNC_NONE
This will lead to use after free in flusher thread.
Similar issue can be triggered if writeback_single_inode in the
stack trace update inode->i_io_list. Add explicit check to avoid it.
Fixes: cbfecb927f42 ("fs: record I_DIRTY_TIME even if inode already has I_DIRTY_INODE")
Reported-by: syzbot+6ba92bd00d5093f7e371@syzkaller.appspotmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Svyatoslav Feldsherov <feldsherov@google.com>
Link: https://lore.kernel.org/r/20221115202001.324188-1-feldsherov@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Currently the I_DIRTY_TIME will never get set if the inode already has I_DIRTY_INODE with assumption that it supersedes I_DIRTY_TIME. That's true, however ext4 will only update the on-disk inode in ->dirty_inode(), not on actual writeback. As a result if the inode already has I_DIRTY_INODE state by the time we get to __mark_inode_dirty() only with I_DIRTY_TIME, the time was already filled into on-disk inode and will not get updated until the next I_DIRTY_INODE update, which might never come if we crash or get a power failure. The problem can be reproduced on ext4 by running xfstest generic/622 with -o iversion mount option. Fix it by allowing I_DIRTY_TIME to be set even if the inode already has I_DIRTY_INODE. Also make sure that the case is properly handled in writeback_single_inode() as well. Additionally changes in xfs_fs_dirty_inode() was made to accommodate for I_DIRTY_TIME in flag. Thanks Jan Kara for suggestions on how to make this work properly. Cc: Dave Chinner <david@fromorbit.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: stable@kernel.org Signed-off-by: Lukas Czerner <lczerner@redhat.com> Suggested-by: Jan Kara <jack@suse.cz> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20220825100657.44217-1-lczerner@redhat.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>