forked from TencentOS/TencentOS-kernel
5 Commits
| Author | SHA1 | Message | Date |
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Pavel Begunkov
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c83ac11e1c |
block: don't ignore REQ_NOWAIT for direct IO
[ Upstream commit f8b78caf21d5bc3fcfc40c18898f9d52ed1451a5 ] If IOCB_NOWAIT is set on submission, then that needs to get propagated to REQ_NOWAIT on the block side. Otherwise we completely lose this information, and any issuer of IOCB_NOWAIT IO will potentially end up blocking on eg request allocation on the storage side. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Douglas Anderson
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4203c983ec |
bdev: Reduce time holding bd_mutex in sync in blkdev_close()
[ 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 <dianders@chromium.org> Reviewed-by: Guenter Roeck <groeck@chromium.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Jason Yan
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c421266933 |
block: Fix use-after-free in blkdev_get()
[ 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 <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Domenico Andreoli
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4b11ec8a6d |
hibernate: Allow uswsusp to write to swap
[ Upstream commit 56939e014a6c212b317414faa307029e2e80c3b9 ]
It turns out that there is one use case for programs being able to
write to swap devices, and that is the userspace hibernation code.
Quick fix: disable the S_SWAPFILE check if hibernation is configured.
Fixes: dc617f29dbe5 ("vfs: don't allow writes to swap files")
Reported-by: Domenico Andreoli <domenico.andreoli@linux.com>
Reported-by: Marian Klein <mkleinsoft@gmail.com>
Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Kaixu Xia
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590eaf1fec |
Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces.
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com> |