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commit 19b7ccf8651df09d274671b53039c672a52ad84d upstream.
Commit 25520d55cdb6 ("block: Inline blk_integrity in struct gendisk")
introduced blk_integrity_revalidate(), which seems to assume ownership
of the stable pages flag and unilaterally clears it if no blk_integrity
profile is registered:
if (bi->profile)
disk->queue->backing_dev_info->capabilities |=
BDI_CAP_STABLE_WRITES;
else
disk->queue->backing_dev_info->capabilities &=
~BDI_CAP_STABLE_WRITES;
It's called from revalidate_disk() and rescan_partitions(), making it
impossible to enable stable pages for drivers that support partitions
and don't use blk_integrity: while the call in revalidate_disk() can be
trivially worked around (see zram, which doesn't support partitions and
hence gets away with zram_revalidate_disk()), rescan_partitions() can
be triggered from userspace at any time. This breaks rbd, where the
ceph messenger is responsible for generating/verifying CRCs.
Since blk_integrity_{un,}register() "must" be used for (un)registering
the integrity profile with the block layer, move BDI_CAP_STABLE_WRITES
setting there. This way drivers that call blk_integrity_register() and
use integrity infrastructure won't interfere with drivers that don't
but still want stable pages.
Fixes: 25520d55cdb6 ("block: Inline blk_integrity in struct gendisk")
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
[idryomov@gmail.com: backport to < 4.11: bdi is embedded in queue]
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ac34f15e0c6d2fd58480052b6985f6991fb53bcc upstream.
When tearing down a block device early in its lifetime, userspace may
still be performing discovery actions like blkdev_ioctl() to re-read
partitions.
The nvdimm_revalidate_disk() implementation depends on
disk->driverfs_dev to be valid at entry. However, it is set to NULL in
del_gendisk() and fatally this is happening *before* the disk device is
deleted from userspace view.
There's no reason for del_gendisk() to clear ->driverfs_dev. That
device is the parent of the disk. It is guaranteed to not be freed
until the disk, as a child, drops its ->parent reference.
We could also fix this issue locally in nvdimm_revalidate_disk() by
using disk_to_dev(disk)->parent, but lets fix it globally since
->driverfs_dev follows the lifetime of the parent. Longer term we
should probably just add a @parent parameter to add_disk(), and stop
carrying this pointer in the gendisk.
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffffa00340a8>] nvdimm_revalidate_disk+0x18/0x90 [libnvdimm]
CPU: 2 PID: 538 Comm: systemd-udevd Tainted: G O 4.4.0-rc5 #2257
[..]
Call Trace:
[<ffffffff8143e5c7>] rescan_partitions+0x87/0x2c0
[<ffffffff810f37f9>] ? __lock_is_held+0x49/0x70
[<ffffffff81438c62>] __blkdev_reread_part+0x72/0xb0
[<ffffffff81438cc5>] blkdev_reread_part+0x25/0x40
[<ffffffff8143982d>] blkdev_ioctl+0x4fd/0x9c0
[<ffffffff811246c9>] ? current_kernel_time64+0x69/0xd0
[<ffffffff812916dd>] block_ioctl+0x3d/0x50
[<ffffffff81264c38>] do_vfs_ioctl+0x308/0x560
[<ffffffff8115dbd1>] ? __audit_syscall_entry+0xb1/0x100
[<ffffffff810031d6>] ? do_audit_syscall_entry+0x66/0x70
[<ffffffff81264f09>] SyS_ioctl+0x79/0x90
[<ffffffff81902672>] entry_SYSCALL_64_fastpath+0x12/0x76
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@fb.com>
Reported-by: Robert Hu <robert.hu@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 36e1f3d107867b25c616c2fd294f5a1c9d4e5d09 upstream.
While stressing memory and IO at the same time we changed SMT settings,
we were able to consistently trigger deadlocks in the mm system, which
froze the entire machine.
I think that under memory stress conditions, the large allocations
performed by blk_mq_init_rq_map may trigger a reclaim, which stalls
waiting on the block layer remmaping completion, thus deadlocking the
system. The trace below was collected after the machine stalled,
waiting for the hotplug event completion.
The simplest fix for this is to make allocations in this path
non-reclaimable, with GFP_NOIO. With this patch, We couldn't hit the
issue anymore.
This should apply on top of Jens's for-next branch cleanly.
Changes since v1:
- Use GFP_NOIO instead of GFP_NOWAIT.
Call Trace:
[c000000f0160aaf0] [c000000f0160ab50] 0xc000000f0160ab50 (unreliable)
[c000000f0160acc0] [c000000000016624] __switch_to+0x2e4/0x430
[c000000f0160ad20] [c000000000b1a880] __schedule+0x310/0x9b0
[c000000f0160ae00] [c000000000b1af68] schedule+0x48/0xc0
[c000000f0160ae30] [c000000000b1b4b0] schedule_preempt_disabled+0x20/0x30
[c000000f0160ae50] [c000000000b1d4fc] __mutex_lock_slowpath+0xec/0x1f0
[c000000f0160aed0] [c000000000b1d678] mutex_lock+0x78/0xa0
[c000000f0160af00] [d000000019413cac] xfs_reclaim_inodes_ag+0x33c/0x380 [xfs]
[c000000f0160b0b0] [d000000019415164] xfs_reclaim_inodes_nr+0x54/0x70 [xfs]
[c000000f0160b0f0] [d0000000194297f8] xfs_fs_free_cached_objects+0x38/0x60 [xfs]
[c000000f0160b120] [c0000000003172c8] super_cache_scan+0x1f8/0x210
[c000000f0160b190] [c00000000026301c] shrink_slab.part.13+0x21c/0x4c0
[c000000f0160b2d0] [c000000000268088] shrink_zone+0x2d8/0x3c0
[c000000f0160b380] [c00000000026834c] do_try_to_free_pages+0x1dc/0x520
[c000000f0160b450] [c00000000026876c] try_to_free_pages+0xdc/0x250
[c000000f0160b4e0] [c000000000251978] __alloc_pages_nodemask+0x868/0x10d0
[c000000f0160b6f0] [c000000000567030] blk_mq_init_rq_map+0x160/0x380
[c000000f0160b7a0] [c00000000056758c] blk_mq_map_swqueue+0x33c/0x360
[c000000f0160b820] [c000000000567904] blk_mq_queue_reinit+0x64/0xb0
[c000000f0160b850] [c00000000056a16c] blk_mq_queue_reinit_notify+0x19c/0x250
[c000000f0160b8a0] [c0000000000f5d38] notifier_call_chain+0x98/0x100
[c000000f0160b8f0] [c0000000000c5fb0] __cpu_notify+0x70/0xe0
[c000000f0160b930] [c0000000000c63c4] notify_prepare+0x44/0xb0
[c000000f0160b9b0] [c0000000000c52f4] cpuhp_invoke_callback+0x84/0x250
[c000000f0160ba10] [c0000000000c570c] cpuhp_up_callbacks+0x5c/0x120
[c000000f0160ba60] [c0000000000c7cb8] _cpu_up+0xf8/0x1d0
[c000000f0160bac0] [c0000000000c7eb0] do_cpu_up+0x120/0x150
[c000000f0160bb40] [c0000000006fe024] cpu_subsys_online+0x64/0xe0
[c000000f0160bb90] [c0000000006f5124] device_online+0xb4/0x120
[c000000f0160bbd0] [c0000000006f5244] online_store+0xb4/0xc0
[c000000f0160bc20] [c0000000006f0a68] dev_attr_store+0x68/0xa0
[c000000f0160bc60] [c0000000003ccc30] sysfs_kf_write+0x80/0xb0
[c000000f0160bca0] [c0000000003cbabc] kernfs_fop_write+0x17c/0x250
[c000000f0160bcf0] [c00000000030fe6c] __vfs_write+0x6c/0x1e0
[c000000f0160bd90] [c000000000311490] vfs_write+0xd0/0x270
[c000000f0160bde0] [c0000000003131fc] SyS_write+0x6c/0x110
[c000000f0160be30] [c000000000009204] system_call+0x38/0xec
Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Cc: Brian King <brking@linux.vnet.ibm.com>
Cc: Douglas Miller <dougmill@linux.vnet.ibm.com>
Cc: linux-block@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f5fe1b51905df7cfe4fdfd85c5fb7bc5b71a094f upstream.
Commit 79bd99596b73 ("blk: improve order of bio handling in generic_make_request()")
changed current->bio_list so that it did not contain *all* of the
queued bios, but only those submitted by the currently running
make_request_fn.
There are two places which walk the list and requeue selected bios,
and others that check if the list is empty. These are no longer
correct.
So redefine current->bio_list to point to an array of two lists, which
contain all queued bios, and adjust various code to test or walk both
lists.
Signed-off-by: NeilBrown <neilb@suse.com>
Fixes: 79bd99596b73 ("blk: improve order of bio handling in generic_make_request()")
Signed-off-by: Jens Axboe <axboe@fb.com>
[jwang: backport to 4.4]
Signed-off-by: Jack Wang <jinpu.wang@profitbricks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Restore changes in device-mapper from upstream version]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
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commit 79bd99596b7305ab08109a8bf44a6a4511dbf1cd upstream.
To avoid recursion on the kernel stack when stacked block devices
are in use, generic_make_request() will, when called recursively,
queue new requests for later handling. They will be handled when the
make_request_fn for the current bio completes.
If any bios are submitted by a make_request_fn, these will ultimately
be handled seqeuntially. If the handling of one of those generates
further requests, they will be added to the end of the queue.
This strict first-in-first-out behaviour can lead to deadlocks in
various ways, normally because a request might need to wait for a
previous request to the same device to complete. This can happen when
they share a mempool, and can happen due to interdependencies
particular to the device. Both md and dm have examples where this happens.
These deadlocks can be erradicated by more selective ordering of bios.
Specifically by handling them in depth-first order. That is: when the
handling of one bio generates one or more further bios, they are
handled immediately after the parent, before any siblings of the
parent. That way, when generic_make_request() calls make_request_fn
for some particular device, we can be certain that all previously
submited requests for that device have been completely handled and are
not waiting for anything in the queue of requests maintained in
generic_make_request().
An easy way to achieve this would be to use a last-in-first-out stack
instead of a queue. However this will change the order of consecutive
bios submitted by a make_request_fn, which could have unexpected consequences.
Instead we take a slightly more complex approach.
A fresh queue is created for each call to a make_request_fn. After it completes,
any bios for a different device are placed on the front of the main queue, followed
by any bios for the same device, followed by all bios that were already on
the queue before the make_request_fn was called.
This provides the depth-first approach without reordering bios on the same level.
This, by itself, it not enough to remove all deadlocks. It just makes
it possible for drivers to take the extra step required themselves.
To avoid deadlocks, drivers must never risk waiting for a request
after submitting one to generic_make_request. This includes never
allocing from a mempool twice in the one call to a make_request_fn.
A common pattern in drivers is to call bio_split() in a loop, handling
the first part and then looping around to possibly split the next part.
Instead, a driver that finds it needs to split a bio should queue
(with generic_make_request) the second part, handle the first part,
and then return. The new code in generic_make_request will ensure the
requests to underlying bios are processed first, then the second bio
that was split off. If it splits again, the same process happens. In
each case one bio will be completely handled before the next one is attempted.
With this is place, it should be possible to disable the
punt_bios_to_recover() recovery thread for many block devices, and
eventually it may be possible to remove it completely.
Ref: http://www.spinics.net/lists/raid/msg54680.html
Tested-by: Jinpu Wang <jinpu.wang@profitbricks.com>
Inspired-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
[jwang: backport to 4.4]
Signed-off-by: Jack Wang <jinpu.wang@profitbricks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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From: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
[ Upstream commit 25cdb64510644f3e854d502d69c73f21c6df88a9 ]
The WRITE_SAME commands are not present in the blk_default_cmd_filter
write_ok list, and thus are failed with -EPERM when the SG_IO ioctl()
is executed without CAP_SYS_RAWIO capability (e.g., unprivileged users).
[ sg_io() -> blk_fill_sghdr_rq() > blk_verify_command() -> -EPERM ]
The problem can be reproduced with the sg_write_same command
# sg_write_same --num 1 --xferlen 512 /dev/sda
#
# capsh --drop=cap_sys_rawio -- -c \
'sg_write_same --num 1 --xferlen 512 /dev/sda'
Write same: pass through os error: Operation not permitted
#
For comparison, the WRITE_VERIFY command does not observe this problem,
since it is in that list:
# capsh --drop=cap_sys_rawio -- -c \
'sg_write_verify --num 1 --ilen 512 --lba 0 /dev/sda'
#
So, this patch adds the WRITE_SAME commands to the list, in order
for the SG_IO ioctl to finish successfully:
# capsh --drop=cap_sys_rawio -- -c \
'sg_write_same --num 1 --xferlen 512 /dev/sda'
#
That case happens to be exercised by QEMU KVM guests with 'scsi-block' devices
(qemu "-device scsi-block" [1], libvirt "<disk type='block' device='lun'>" [2]),
which employs the SG_IO ioctl() and runs as an unprivileged user (libvirt-qemu).
In that scenario, when a filesystem (e.g., ext4) performs its zero-out calls,
which are translated to write-same calls in the guest kernel, and then into
SG_IO ioctls to the host kernel, SCSI I/O errors may be observed in the guest:
[...] sd 0:0:0:0: [sda] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[...] sd 0:0:0:0: [sda] tag#0 Sense Key : Aborted Command [current]
[...] sd 0:0:0:0: [sda] tag#0 Add. Sense: I/O process terminated
[...] sd 0:0:0:0: [sda] tag#0 CDB: Write Same(10) 41 00 01 04 e0 78 00 00 08 00
[...] blk_update_request: I/O error, dev sda, sector 17096824
Links:
[1] http://git.qemu.org/?p=qemu.git;a=commit;h=336a6915bc7089fb20fea4ba99972ad9a97c5f52
[2] https://libvirt.org/formatdomain.html#elementsDisks (see 'disk' -> 'device')
Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Signed-off-by: Brahadambal Srinivasan <latha@linux.vnet.ibm.com>
Reported-by: Manjunatha H R <manjuhr1@in.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 87c279e613f848c691111b29d49de8df3f4f56da upstream.
Commit 0809e3ac6231 ("block: fix plug list flushing for nomerge queues")
updated blk_mq_make_request() to set request_count even when
blk_queue_nomerges() returns true. However, blk_mq_make_request() only
does limited plugging and doesn't use request_count;
blk_sq_make_request() is the one that should have been fixed. Do that
and get rid of the unnecessary work in the mq version.
Fixes: 0809e3ac6231 ("block: fix plug list flushing for nomerge queues")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit c02ebfdddbafa9a6a0f52fbd715e6bfa229af9d3 upstream.
Commit 0e87e58bf60e ("blk-mq: improve warning for running a queue on the
wrong CPU") attempts to avoid triggering the WARN_ON in
__blk_mq_run_hw_queue when the expected CPU is dead. Problem is, in the
last batch execution before round robin, blk_mq_hctx_next_cpu can
schedule a dead CPU and also update next_cpu to the next alive CPU in
the mask, which will trigger the WARN_ON despite the previous
workaround.
The following patch fixes this scenario by always scheduling the value
in hctx->next_cpu. This changes the moment when we round-robin the CPU
running the hctx, but it really doesn't matter, since it still executes
BLK_MQ_CPU_WORK_BATCH times in a row before switching to another CPU.
Fixes: 0e87e58bf60e ("blk-mq: improve warning for running a queue on the wrong CPU")
Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ebc4ff661fbe76781c6b16dfb7b754a5d5073f8e upstream.
cfq_cpd_alloc() which is the cpd_alloc_fn implementation for cfq was
incorrectly hard coding GFP_KERNEL instead of using the mask specified
through the @gfp parameter. This currently doesn't cause any actual
issues because all current callers specify GFP_KERNEL. Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: e4a9bde9589f ("blkcg: replace blkcg_policy->cpd_size with ->cpd_alloc/free_fn() methods")
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 128394eff343fc6d2f32172f03e24829539c5835 upstream.
Both damn things interpret userland pointers embedded into the payload;
worse, they are actually traversing those. Leaving aside the bad
API design, this is very much _not_ safe to call with KERNEL_DS.
Bail out early if that happens.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit bc27c01b5c46d3bfec42c96537c7a3fae0bb2cc4 upstream.
The meaning of the BLK_MQ_S_STOPPED flag is "do not call
.queue_rq()". Hence modify blk_mq_make_request() such that requests
are queued instead of issued if a queue has been stopped.
Reported-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a0ac402cfcdc904f9772e1762b3fda112dcc56a0 upstream.
In theory we could map other things, but there's a reason that function
is called "user_iov". Using anything else (like splice can do) just
confuses it.
Reported-and-tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit bbb427e342495df1cda10051d0566388697499c0 upstream.
Unlocking a mutex twice is wrong. Hence modify blkcg_policy_register()
such that blkcg_pol_mutex is unlocked once if cpd == NULL. This patch
avoids that smatch reports the following error:
block/blk-cgroup.c:1378: blkcg_policy_register() error: double unlock 'mutex:&blkcg_pol_mutex'
Fixes: 06b285bd1125 ("blkcg: fix blkcg_policy_data allocation bug")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3932a86b4b9d1f0b049d64d4591ce58ad18b44ec upstream.
While debugging timeouts happening in my application workload (ScyllaDB), I have
observed calls to open() taking a long time, ranging everywhere from 2 seconds -
the first ones that are enough to time out my application - to more than 30
seconds.
The problem seems to happen because XFS may block on pending metadata updates
under certain circumnstances, and that's confirmed with the following backtrace
taken by the offcputime tool (iovisor/bcc):
ffffffffb90c57b1 finish_task_switch
ffffffffb97dffb5 schedule
ffffffffb97e310c schedule_timeout
ffffffffb97e1f12 __down
ffffffffb90ea821 down
ffffffffc046a9dc xfs_buf_lock
ffffffffc046abfb _xfs_buf_find
ffffffffc046ae4a xfs_buf_get_map
ffffffffc046babd xfs_buf_read_map
ffffffffc0499931 xfs_trans_read_buf_map
ffffffffc044a561 xfs_da_read_buf
ffffffffc0451390 xfs_dir3_leaf_read.constprop.16
ffffffffc0452b90 xfs_dir2_leaf_lookup_int
ffffffffc0452e0f xfs_dir2_leaf_lookup
ffffffffc044d9d3 xfs_dir_lookup
ffffffffc047d1d9 xfs_lookup
ffffffffc0479e53 xfs_vn_lookup
ffffffffb925347a path_openat
ffffffffb9254a71 do_filp_open
ffffffffb9242a94 do_sys_open
ffffffffb9242b9e sys_open
ffffffffb97e42b2 entry_SYSCALL_64_fastpath
00007fb0698162ed [unknown]
Inspecting my run with blktrace, I can see that the xfsaild kthread exhibit very
high "Dispatch wait" times, on the dozens of seconds range and consistent with
the open() times I have saw in that run.
Still from the blktrace output, we can after searching a bit, identify the
request that wasn't dispatched:
8,0 11 152 81.092472813 804 A WM 141698288 + 8 <- (8,1) 141696240
8,0 11 153 81.092472889 804 Q WM 141698288 + 8 [xfsaild/sda1]
8,0 11 154 81.092473207 804 G WM 141698288 + 8 [xfsaild/sda1]
8,0 11 206 81.092496118 804 I WM 141698288 + 8 ( 22911) [xfsaild/sda1]
<==== 'I' means Inserted (into the IO scheduler) ===================================>
8,0 0 289372 96.718761435 0 D WM 141698288 + 8 (15626265317) [swapper/0]
<==== Only 15s later the CFQ scheduler dispatches the request ======================>
As we can see above, in this particular example CFQ took 15 seconds to dispatch
this request. Going back to the full trace, we can see that the xfsaild queue
had plenty of opportunity to run, and it was selected as the active queue many
times. It would just always be preempted by something else (example):
8,0 1 0 81.117912979 0 m N cfq1618SN / insert_request
8,0 1 0 81.117913419 0 m N cfq1618SN / add_to_rr
8,0 1 0 81.117914044 0 m N cfq1618SN / preempt
8,0 1 0 81.117914398 0 m N cfq767A / slice expired t=1
8,0 1 0 81.117914755 0 m N cfq767A / resid=40
8,0 1 0 81.117915340 0 m N / served: vt=1948520448 min_vt=1948520448
8,0 1 0 81.117915858 0 m N cfq767A / sl_used=1 disp=0 charge=0 iops=1 sect=0
where cfq767 is the xfsaild queue and cfq1618 corresponds to one of the ScyllaDB
IO dispatchers.
The requests preempting the xfsaild queue are synchronous requests. That's a
characteristic of ScyllaDB workloads, as we only ever issue O_DIRECT requests.
While it can be argued that preempting ASYNC requests in favor of SYNC is part
of the CFQ logic, I don't believe that doing so for 15+ seconds is anyone's
goal.
Moreover, unless I am misunderstanding something, that breaks the expectation
set by the "fifo_expire_async" tunable, which in my system is set to the
default.
Looking at the code, it seems to me that the issue is that after we make
an async queue active, there is no guarantee that it will execute any request.
When the queue itself tests if it cfq_may_dispatch() it can bail if it sees SYNC
requests in flight. An incoming request from another queue can also preempt it
in such situation before we have the chance to execute anything (as seen in the
trace above).
This patch sets the must_dispatch flag if we notice that we have requests
that are already fifo_expired. This flag is always cleared after
cfq_dispatch_request() returns from cfq_dispatch_requests(), so it won't pin
the queue for subsequent requests (unless they are themselves expired)
Care is taken during preempt to still allow rt requests to preempt us
regardless.
Testing my workload with this patch applied produces much better results.
From the application side I see no timeouts, and the open() latency histogram
generated by systemtap looks much better, with the worst outlier at 131ms:
Latency histogram of xfs_buf_lock acquisition (microseconds):
value |-------------------------------------------------- count
0 | 11
1 |@@@@ 161
2 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 1966
4 |@ 54
8 | 36
16 | 7
32 | 0
64 | 0
~
1024 | 0
2048 | 0
4096 | 1
8192 | 1
16384 | 2
32768 | 0
65536 | 0
131072 | 1
262144 | 0
524288 | 0
Signed-off-by: Glauber Costa <glauber@scylladb.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: linux-block@vger.kernel.org
CC: linux-kernel@vger.kernel.org
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 52b9c330c6a8a4b5a1819bdaddf4ec76ab571e81 upstream.
If ->queue_rq() returns BLK_MQ_RQ_QUEUE_OK, we use continue and skip
over the rest of the loop body. However, dptr is assigned later in the
loop body, and the BLK_MQ_RQ_QUEUE_OK case is exactly the case that we'd
want it for.
NVMe isn't actually using BLK_MQ_F_DEFER_ISSUE yet, nor is any other
in-tree driver, but if the code's going to be there, it might as well
work.
Fixes: 74c450521dd8 ("blk-mq: add a 'list' parameter to ->queue_rq()")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 4d70dca4eadf2f95abe389116ac02b8439c2d16c upstream.
After arbitrary bio size was introduced, the incoming bio may
be very big. We have to split the bio into small bios so that
each holds at most BIO_MAX_PAGES bvecs for safety reason, such
as bio_clone().
This patch fixes the following kernel crash:
> [ 172.660142] BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
> [ 172.660229] IP: [<ffffffff811e53b4>] bio_trim+0xf/0x2a
> [ 172.660289] PGD 7faf3e067 PUD 7f9279067 PMD 0
> [ 172.660399] Oops: 0000 [#1] SMP
> [...]
> [ 172.664780] Call Trace:
> [ 172.664813] [<ffffffffa007f3be>] ? raid1_make_request+0x2e8/0xad7 [raid1]
> [ 172.664846] [<ffffffff811f07da>] ? blk_queue_split+0x377/0x3d4
> [ 172.664880] [<ffffffffa005fb5f>] ? md_make_request+0xf6/0x1e9 [md_mod]
> [ 172.664912] [<ffffffff811eb860>] ? generic_make_request+0xb5/0x155
> [ 172.664947] [<ffffffffa0445c89>] ? prio_io+0x85/0x95 [bcache]
> [ 172.664981] [<ffffffffa0448252>] ? register_cache_set+0x355/0x8d0 [bcache]
> [ 172.665016] [<ffffffffa04497d3>] ? register_bcache+0x1006/0x1174 [bcache]
The issue can be reproduced by the following steps:
- create one raid1 over two virtio-blk
- build bcache device over the above raid1 and another cache device
and bucket size is set as 2Mbytes
- set cache mode as writeback
- run random write over ext4 on the bcache device
Fixes: 54efd50(block: make generic_make_request handle arbitrarily sized bios)
Reported-by: Sebastian Roesner <sroesner-kernelorg@roesner-online.de>
Reported-by: Eric Wheeler <bcache@lists.ewheeler.net>
Cc: Shaohua Li <shli@fb.com>
Acked-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 1b856086813be9371929b6cc62045f9fd470f5a0 upstream.
blk_set_queue_dying() can be called while another thread is
submitting I/O or changing queue flags, e.g. through dm_stop_queue().
Hence protect the QUEUE_FLAG_DYING flag change with locking.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
[ Upstream commit a59e0f5795fe52dad42a99c00287e3766153b312 ]
Go directly to ending a request if it wasn't started. Previously, completing a
request may invoke a driver callback for a request it didn't initialize.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Johannes Thumshirn <jthumshirn at suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit df08c32ce3be5be138c1dbfcba203314a3a7cd6f upstream.
The name for a bdi of a gendisk is derived from the gendisk's devt.
However, since the gendisk is destroyed before the bdi it leaves a
window where a new gendisk could dynamically reuse the same devt while a
bdi with the same name is still live. Arrange for the bdi to hold a
reference against its "owner" disk device while it is registered.
Otherwise we can hit sysfs duplicate name collisions like the following:
WARNING: CPU: 10 PID: 2078 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x64/0x80
sysfs: cannot create duplicate filename '/devices/virtual/bdi/259:1'
Hardware name: HP ProLiant DL580 Gen8, BIOS P79 05/06/2015
0000000000000286 0000000002c04ad5 ffff88006f24f970 ffffffff8134caec
ffff88006f24f9c0 0000000000000000 ffff88006f24f9b0 ffffffff8108c351
0000001f0000000c ffff88105d236000 ffff88105d1031e0 ffff8800357427f8
Call Trace:
[<ffffffff8134caec>] dump_stack+0x63/0x87
[<ffffffff8108c351>] __warn+0xd1/0xf0
[<ffffffff8108c3cf>] warn_slowpath_fmt+0x5f/0x80
[<ffffffff812a0d34>] sysfs_warn_dup+0x64/0x80
[<ffffffff812a0e1e>] sysfs_create_dir_ns+0x7e/0x90
[<ffffffff8134faaa>] kobject_add_internal+0xaa/0x320
[<ffffffff81358d4e>] ? vsnprintf+0x34e/0x4d0
[<ffffffff8134ff55>] kobject_add+0x75/0xd0
[<ffffffff816e66b2>] ? mutex_lock+0x12/0x2f
[<ffffffff8148b0a5>] device_add+0x125/0x610
[<ffffffff8148b788>] device_create_groups_vargs+0xd8/0x100
[<ffffffff8148b7cc>] device_create_vargs+0x1c/0x20
[<ffffffff811b775c>] bdi_register+0x8c/0x180
[<ffffffff811b7877>] bdi_register_dev+0x27/0x30
[<ffffffff813317f5>] add_disk+0x175/0x4a0
Reported-by: Yi Zhang <yizhan@redhat.com>
Tested-by: Yi Zhang <yizhan@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixed up missing 0 return in bdi_register_owner().
Signed-off-by: Jens Axboe <axboe@fb.com>
|
|
commit 20bd723ec6a3261df5e02250cd3a1fbb09a343f2 upstream.
When a bio is cloned, the newly created bio must be associated with
the same blkcg as the original bio (if BLK_CGROUP is enabled). If
this operation is not performed, then the new bio is not associated
with any group, and the group of the current task is returned when
the group of the bio is requested.
Depending on the cloning frequency, this may cause a large
percentage of the bios belonging to a given group to be treated
as if belonging to other groups (in most cases as if belonging to
the root group). The expected group isolation may thereby be broken.
This commit adds the missing association in bio-cloning functions.
Fixes: da2f0f74cf7d ("Btrfs: add support for blkio controllers")
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Reviewed-by: Nikolay Borisov <kernel@kyup.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 77da160530dd1dc94f6ae15a981f24e5f0021e84 upstream.
I got a KASAN report of use-after-free:
==================================================================
BUG: KASAN: use-after-free in klist_iter_exit+0x61/0x70 at addr ffff8800b6581508
Read of size 8 by task trinity-c1/315
=============================================================================
BUG kmalloc-32 (Not tainted): kasan: bad access detected
-----------------------------------------------------------------------------
Disabling lock debugging due to kernel taint
INFO: Allocated in disk_seqf_start+0x66/0x110 age=144 cpu=1 pid=315
___slab_alloc+0x4f1/0x520
__slab_alloc.isra.58+0x56/0x80
kmem_cache_alloc_trace+0x260/0x2a0
disk_seqf_start+0x66/0x110
traverse+0x176/0x860
seq_read+0x7e3/0x11a0
proc_reg_read+0xbc/0x180
do_loop_readv_writev+0x134/0x210
do_readv_writev+0x565/0x660
vfs_readv+0x67/0xa0
do_preadv+0x126/0x170
SyS_preadv+0xc/0x10
do_syscall_64+0x1a1/0x460
return_from_SYSCALL_64+0x0/0x6a
INFO: Freed in disk_seqf_stop+0x42/0x50 age=160 cpu=1 pid=315
__slab_free+0x17a/0x2c0
kfree+0x20a/0x220
disk_seqf_stop+0x42/0x50
traverse+0x3b5/0x860
seq_read+0x7e3/0x11a0
proc_reg_read+0xbc/0x180
do_loop_readv_writev+0x134/0x210
do_readv_writev+0x565/0x660
vfs_readv+0x67/0xa0
do_preadv+0x126/0x170
SyS_preadv+0xc/0x10
do_syscall_64+0x1a1/0x460
return_from_SYSCALL_64+0x0/0x6a
CPU: 1 PID: 315 Comm: trinity-c1 Tainted: G B 4.7.0+ #62
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
ffffea0002d96000 ffff880119b9f918 ffffffff81d6ce81 ffff88011a804480
ffff8800b6581500 ffff880119b9f948 ffffffff8146c7bd ffff88011a804480
ffffea0002d96000 ffff8800b6581500 fffffffffffffff4 ffff880119b9f970
Call Trace:
[<ffffffff81d6ce81>] dump_stack+0x65/0x84
[<ffffffff8146c7bd>] print_trailer+0x10d/0x1a0
[<ffffffff814704ff>] object_err+0x2f/0x40
[<ffffffff814754d1>] kasan_report_error+0x221/0x520
[<ffffffff8147590e>] __asan_report_load8_noabort+0x3e/0x40
[<ffffffff83888161>] klist_iter_exit+0x61/0x70
[<ffffffff82404389>] class_dev_iter_exit+0x9/0x10
[<ffffffff81d2e8ea>] disk_seqf_stop+0x3a/0x50
[<ffffffff8151f812>] seq_read+0x4b2/0x11a0
[<ffffffff815f8fdc>] proc_reg_read+0xbc/0x180
[<ffffffff814b24e4>] do_loop_readv_writev+0x134/0x210
[<ffffffff814b4c45>] do_readv_writev+0x565/0x660
[<ffffffff814b8a17>] vfs_readv+0x67/0xa0
[<ffffffff814b8de6>] do_preadv+0x126/0x170
[<ffffffff814b92ec>] SyS_preadv+0xc/0x10
This problem can occur in the following situation:
open()
- pread()
- .seq_start()
- iter = kmalloc() // succeeds
- seqf->private = iter
- .seq_stop()
- kfree(seqf->private)
- pread()
- .seq_start()
- iter = kmalloc() // fails
- .seq_stop()
- class_dev_iter_exit(seqf->private) // boom! old pointer
As the comment in disk_seqf_stop() says, stop is called even if start
failed, so we need to reinitialise the private pointer to NULL when seq
iteration stops.
An alternative would be to set the private pointer to NULL when the
kmalloc() in disk_seqf_start() fails.
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 8ba8682107ee2ca3347354e018865d8e1967c5f4 upstream.
get_task_ioprio() accesses the task->io_context without holding the task
lock and thus can race with exit_io_context(), leading to a
use-after-free. The reproducer below hits this within a few seconds on
my 4-core QEMU VM:
#define _GNU_SOURCE
#include <assert.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/wait.h>
int main(int argc, char **argv)
{
pid_t pid, child;
long nproc, i;
/* ioprio_set(IOPRIO_WHO_PROCESS, 0, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)); */
syscall(SYS_ioprio_set, 1, 0, 0x6000);
nproc = sysconf(_SC_NPROCESSORS_ONLN);
for (i = 0; i < nproc; i++) {
pid = fork();
assert(pid != -1);
if (pid == 0) {
for (;;) {
pid = fork();
assert(pid != -1);
if (pid == 0) {
_exit(0);
} else {
child = wait(NULL);
assert(child == pid);
}
}
}
pid = fork();
assert(pid != -1);
if (pid == 0) {
for (;;) {
/* ioprio_get(IOPRIO_WHO_PGRP, 0); */
syscall(SYS_ioprio_get, 2, 0);
}
}
}
for (;;) {
/* ioprio_get(IOPRIO_WHO_PGRP, 0); */
syscall(SYS_ioprio_get, 2, 0);
}
return 0;
}
This gets us KASAN dumps like this:
[ 35.526914] ==================================================================
[ 35.530009] BUG: KASAN: out-of-bounds in get_task_ioprio+0x7b/0x90 at addr ffff880066f34e6c
[ 35.530009] Read of size 2 by task ioprio-gpf/363
[ 35.530009] =============================================================================
[ 35.530009] BUG blkdev_ioc (Not tainted): kasan: bad access detected
[ 35.530009] -----------------------------------------------------------------------------
[ 35.530009] Disabling lock debugging due to kernel taint
[ 35.530009] INFO: Allocated in create_task_io_context+0x2b/0x370 age=0 cpu=0 pid=360
[ 35.530009] ___slab_alloc+0x55d/0x5a0
[ 35.530009] __slab_alloc.isra.20+0x2b/0x40
[ 35.530009] kmem_cache_alloc_node+0x84/0x200
[ 35.530009] create_task_io_context+0x2b/0x370
[ 35.530009] get_task_io_context+0x92/0xb0
[ 35.530009] copy_process.part.8+0x5029/0x5660
[ 35.530009] _do_fork+0x155/0x7e0
[ 35.530009] SyS_clone+0x19/0x20
[ 35.530009] do_syscall_64+0x195/0x3a0
[ 35.530009] return_from_SYSCALL_64+0x0/0x6a
[ 35.530009] INFO: Freed in put_io_context+0xe7/0x120 age=0 cpu=0 pid=1060
[ 35.530009] __slab_free+0x27b/0x3d0
[ 35.530009] kmem_cache_free+0x1fb/0x220
[ 35.530009] put_io_context+0xe7/0x120
[ 35.530009] put_io_context_active+0x238/0x380
[ 35.530009] exit_io_context+0x66/0x80
[ 35.530009] do_exit+0x158e/0x2b90
[ 35.530009] do_group_exit+0xe5/0x2b0
[ 35.530009] SyS_exit_group+0x1d/0x20
[ 35.530009] entry_SYSCALL_64_fastpath+0x1a/0xa4
[ 35.530009] INFO: Slab 0xffffea00019bcd00 objects=20 used=4 fp=0xffff880066f34ff0 flags=0x1fffe0000004080
[ 35.530009] INFO: Object 0xffff880066f34e58 @offset=3672 fp=0x0000000000000001
[ 35.530009] ==================================================================
Fix it by grabbing the task lock while we poke at the io_context.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit b30a337ca27c4f40439e4bfb290cba5f88d73bb7 upstream.
The initialization of partition's percpu_ref should have been done before
sending out KOBJ_ADD uevent, which may cause userspace to read partition
table. So the uninitialized percpu_ref may be accessed in data path.
This patch fixes this issue reported by Naveen.
Reported-by: Naveen Kaje <nkaje@codeaurora.org>
Tested-by: Naveen Kaje <nkaje@codeaurora.org>
Fixes: 6c71013ecb7e2(block: partition: convert percpu ref)
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 6acfe68bac7e6f16dc312157b1fa6e2368985013 upstream.
Request-based DM's blk-mq support (dm-mq) was reported to be 50% slower
than if an underlying null_blk device were used directly. One of the
reasons for this drop in performance is that blk_insert_clone_request()
was calling blk_mq_insert_request() with @async=true. This forced the
use of kblockd_schedule_delayed_work_on() to run the blk-mq hw queues
which ushered in ping-ponging between process context (fio in this case)
and kblockd's kworker to submit the cloned request. The ftrace
function_graph tracer showed:
kworker-2013 => fio-12190
fio-12190 => kworker-2013
...
kworker-2013 => fio-12190
fio-12190 => kworker-2013
...
Fixing blk_insert_clone_request()'s blk_mq_insert_request() call to
_not_ use kblockd to submit the cloned requests isn't enough to
eliminate the observed context switches.
In addition to this dm-mq specific blk-core fix, there are 2 DM core
fixes to dm-mq that (when paired with the blk-core fix) completely
eliminate the observed context switching:
1) don't blk_mq_run_hw_queues in blk-mq request completion
Motivated by desire to reduce overhead of dm-mq, punting to kblockd
just increases context switches.
In my testing against a really fast null_blk device there was no benefit
to running blk_mq_run_hw_queues() on completion (and no other blk-mq
driver does this). So hopefully this change doesn't induce the need for
yet another revert like commit 621739b00e16ca2d !
2) use blk_mq_complete_request() in dm_complete_request()
blk_complete_request() doesn't offer the traditional q->mq_ops vs
.request_fn branching pattern that other historic block interfaces
do (e.g. blk_get_request). Using blk_mq_complete_request() for
blk-mq requests is important for performance. It should be noted
that, like blk_complete_request(), blk_mq_complete_request() doesn't
natively handle partial completions -- but the request-based
DM-multipath target does provide the required partial completion
support by dm.c:end_clone_bio() triggering requeueing of the request
via dm-mpath.c:multipath_end_io()'s return of DM_ENDIO_REQUEUE.
dm-mq fix #2 is _much_ more important than #1 for eliminating the
context switches.
Before: cpu : usr=15.10%, sys=59.39%, ctx=7905181, majf=0, minf=475
After: cpu : usr=20.60%, sys=79.35%, ctx=2008, majf=0, minf=472
With these changes multithreaded async read IOPs improved from ~950K
to ~1350K for this dm-mq stacked on null_blk test-case. The raw read
IOPs of the underlying null_blk device for the same workload is ~1950K.
Fixes: 7fb4898e0 ("block: add blk-mq support to blk_insert_cloned_request()")
Fixes: bfebd1cdb ("dm: add full blk-mq support to request-based DM")
Reported-by: Sagi Grimberg <sagig@dev.mellanox.co.il>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 5f009d3f8e6685fe8c6215082c1696a08b411220 upstream.
The new queue limit is not used by the majority of block drivers, and
should be initialized to 0 for the driver's requested settings to be used.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 2d99b55d378c996b9692a0c93dd25f4ed5d58934 upstream.
Commit 35dc248383bbab0a7203fca4d722875bc81ef091 introduced a check for
current->mm to see if we have a user space context and only copies data
if we do. Now if an IO gets interrupted by a signal data isn't copied
into user space any more (as we don't have a user space context) but
user space isn't notified about it.
This patch modifies the behaviour to return -EINTR from bio_uncopy_user()
to notify userland that a signal has interrupted the syscall, otherwise
it could lead to a situation where the caller may get a buffer with
no data returned.
This can be reproduced by issuing SG_IO ioctl()s in one thread while
constantly sending signals to it.
Fixes: 35dc248 [SCSI] sg: Fix user memory corruption when SG_IO is interrupted by a signal
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit d0e5fbb01a67e400e82fefe4896ea40c6447ab98 upstream.
After commit e36f62042880(block: split bios to maxpossible length),
bio can be splitted in the middle of a vector entry, then it
is easy to split out one bio which size isn't aligned with block
size, especially when the block size is bigger than 512.
This patch fixes the issue by making the max io size aligned
to logical block size.
Fixes: e36f62042880(block: split bios to maxpossible length)
Reported-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Cc: Keith Busch <keith.busch@intel.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit e36f6204288088fda50d1c84830340ccb70f85ff upstream.
This splits bio in the middle of a vector to form the largest possible
bio at the h/w's desired alignment, and guarantees the bio being split
will have some data.
The criteria for splitting is changed from the max sectors to the h/w's
optimal sector alignment if it is provided. For h/w that advertise their
block storage's underlying chunk size, it's a big performance win to not
submit commands that cross them. If sector alignment is not provided,
this patch uses the max sectors as before.
This addresses the performance issue commit d380561113 attempted to
fix, but was reverted due to splitting logic error.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
This reverts commit d3805611130af9b911e908af9f67a3f64f4f0914.
If we end up splitting on the first segment, we don't adjust
the sector count. That results in hitting a BUG() with attempting
to split 0 sectors.
As this is just a performance issue and not a regression since
4.3 release, let's just rever this change. That gives us more
time to test a real fix for 4.5, which would be marked for
stable anyway.
|
|
We currently only have an inline/sync helper to restart a stopped
queue. If drivers need an async version, they have to roll their
own. Add a generic helper instead.
Signed-off-by: Jens Axboe <axboe@fb.com>
|
|
For h/w that advertise their block storage's underlying chunk size, it's
a big performance win to not submit commands that cross them. This patch
uses that criteria if it is provided. If it is not provided, this patch
uses the max sectors as before.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
|
|
Pull block layer fixes from Jens Axboe:
"Three small fixes for 4.4 final. Specifically:
- The segment issue fix from Junichi, where the old IO path does a
bio limit split before potentially bouncing the pages. We need to
do that in the right order, to ensure that limitations are met.
- A NVMe surprise removal IO hang fix from Keith.
- A use-after-free in null_blk, introduced by a previous patch in
this series. From Mike Krinkin"
* 'for-linus' of git://git.kernel.dk/linux-block:
null_blk: fix use-after-free error
block: ensure to split after potentially bouncing a bio
NVMe: IO ending fixes on surprise removal
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|
blk_queue_bio() does split then bounce, which makes the segment
counting based on pages before bouncing and could go wrong. Move
the split to after bouncing, like we do for blk-mq, and the we
fix the issue of having the bio count for segments be wrong.
Fixes: 54efd50bfd87 ("block: make generic_make_request handle arbitrarily sized bios")
Cc: stable@vger.kernel.org
Tested-by: Artem S. Tashkinov <t.artem@lycos.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
|
|
Pull block layer fixes from Jens Axboe:
"A set of fixes for the current series. This contains:
- A bunch of fixes for lightnvm, should be the last round for this
series. From Matias and Wenwei.
- A writeback detach inode fix from Ilya, also marked for stable.
- A block (though it says SCSI) fix for an OOPS in SCSI runtime power
management.
- Module init error path fixes for null_blk from Minfei"
* 'for-linus' of git://git.kernel.dk/linux-block:
null_blk: Fix error path in module initialization
lightnvm: do not compile in debugging by default
lightnvm: prevent gennvm module unload on use
lightnvm: fix media mgr registration
lightnvm: replace req queue with nvmdev for lld
lightnvm: comments on constants
lightnvm: check mm before use
lightnvm: refactor spin_unlock in gennvm_get_blk
lightnvm: put blks when luns configure failed
lightnvm: use flags in rrpc_get_blk
block: detach bdev inode from its wb in __blkdev_put()
SCSI: Fix NULL pointer dereference in runtime PM
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|
The following commit which went into mainline through networking tree
3b13758f51de ("cgroups: Allow dynamically changing net_classid")
conflicts in net/core/netclassid_cgroup.c with the following pending
fix in cgroup/for-4.4-fixes.
1f7dd3e5a6e4 ("cgroup: fix handling of multi-destination migration from subtree_control enabling")
The former separates out update_classid() from cgrp_attach() and
updates it to walk all fds of all tasks in the target css so that it
can be used from both migration and config change paths. The latter
drops @css from cgrp_attach().
Resolve the conflict by making cgrp_attach() call update_classid()
with the css from the first task. We can revive @tset walking in
cgrp_attach() but given that net_cls is v1 only where there always is
only one target css during migration, this is fine.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Nina Schiff <ninasc@fb.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI fixes from James Bottomley:
"This is quite a bumper crop of fixes: three from Arnd correcting
various build issues in some configurations, a lock recursion in
qla2xxx. Two potentially exploitable issues in hpsa and mvsas, a
potential null deref in st, a revert of a bdi registration fix that
turned out to cause even more problems, a set of fixes to allow people
who only defined MPT2SAS to still work after the mpt2/mpt3sas merger
and a couple of fixes for issues turned up by the hyper-v storvsc
driver"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
mpt3sas: fix Kconfig dependency problem for mpt2sas back compatibility
Revert "scsi: Fix a bdi reregistration race"
mpt3sas: Add dummy Kconfig option for backwards compatibility
Fix a memory leak in scsi_host_dev_release()
block/sd: Fix device-imposed transfer length limits
scsi_debug: fix prevent_allow+verify regressions
MAINTAINERS: Add myself as co-maintainer of the SCSI subsystem.
sd: Make discard granularity match logical block size when LBPRZ=1
scsi: hpsa: select CONFIG_SCSI_SAS_ATTR
scsi: advansys needs ISA dma api for ISA support
scsi_sysfs: protect against double execution of __scsi_remove_device()
st: fix potential null pointer dereference.
scsi: report 'INQUIRY result too short' once per host
advansys: fix big-endian builds
qla2xxx: Fix rwlock recursion
hpsa: logical vs bitwise AND typo
mvsas: don't allow negative timeouts
mpt3sas: Fix use sas_is_tlr_enabled API before enabling MPI2_SCSIIO_CONTROL_TLR_ON flag
|
|
The routines in scsi_pm.c assume that if a runtime-PM callback is
invoked for a SCSI device, it can only mean that the device's driver
has asked the block layer to handle the runtime power management (by
calling blk_pm_runtime_init(), which among other things sets q->dev).
However, this assumption turns out to be wrong for things like the ses
driver. Normally ses devices are not allowed to do runtime PM, but
userspace can override this setting. If this happens, the kernel gets
a NULL pointer dereference when blk_post_runtime_resume() tries to use
the uninitialized q->dev pointer.
This patch fixes the problem by checking q->dev in block layer before
handle runtime PM. Since ses doesn't define any PM callbacks and call
blk_pm_runtime_init(), the crash won't occur.
This fixes Bugzilla #101371.
https://bugzilla.kernel.org/show_bug.cgi?id=101371
More discussion can be found from below link.
http://marc.info/?l=linux-scsi&m=144163730531875&w=2
Signed-off-by: Ken Xue <Ken.Xue@amd.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Xiangliang Yu <Xiangliang.Yu@amd.com>
Cc: James E.J. Bottomley <JBottomley@odin.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Michael Terry <Michael.terry@canonical.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
|
|
|
|
enabling
Consider the following v2 hierarchy.
P0 (+memory) --- P1 (-memory) --- A
\- B
P0 has memory enabled in its subtree_control while P1 doesn't. If
both A and B contain processes, they would belong to the memory css of
P1. Now if memory is enabled on P1's subtree_control, memory csses
should be created on both A and B and A's processes should be moved to
the former and B's processes the latter. IOW, enabling controllers
can cause atomic migrations into different csses.
The core cgroup migration logic has been updated accordingly but the
controller migration methods haven't and still assume that all tasks
migrate to a single target css; furthermore, the methods were fed the
css in which subtree_control was updated which is the parent of the
target csses. pids controller depends on the migration methods to
move charges and this made the controller attribute charges to the
wrong csses often triggering the following warning by driving a
counter negative.
WARNING: CPU: 1 PID: 1 at kernel/cgroup_pids.c:97 pids_cancel.constprop.6+0x31/0x40()
Modules linked in:
CPU: 1 PID: 1 Comm: systemd Not tainted 4.4.0-rc1+ #29
...
ffffffff81f65382 ffff88007c043b90 ffffffff81551ffc 0000000000000000
ffff88007c043bc8 ffffffff810de202 ffff88007a752000 ffff88007a29ab00
ffff88007c043c80 ffff88007a1d8400 0000000000000001 ffff88007c043bd8
Call Trace:
[<ffffffff81551ffc>] dump_stack+0x4e/0x82
[<ffffffff810de202>] warn_slowpath_common+0x82/0xc0
[<ffffffff810de2fa>] warn_slowpath_null+0x1a/0x20
[<ffffffff8118e031>] pids_cancel.constprop.6+0x31/0x40
[<ffffffff8118e0fd>] pids_can_attach+0x6d/0xf0
[<ffffffff81188a4c>] cgroup_taskset_migrate+0x6c/0x330
[<ffffffff81188e05>] cgroup_migrate+0xf5/0x190
[<ffffffff81189016>] cgroup_attach_task+0x176/0x200
[<ffffffff8118949d>] __cgroup_procs_write+0x2ad/0x460
[<ffffffff81189684>] cgroup_procs_write+0x14/0x20
[<ffffffff811854e5>] cgroup_file_write+0x35/0x1c0
[<ffffffff812e26f1>] kernfs_fop_write+0x141/0x190
[<ffffffff81265f88>] __vfs_write+0x28/0xe0
[<ffffffff812666fc>] vfs_write+0xac/0x1a0
[<ffffffff81267019>] SyS_write+0x49/0xb0
[<ffffffff81bcef32>] entry_SYSCALL_64_fastpath+0x12/0x76
This patch fixes the bug by removing @css parameter from the three
migration methods, ->can_attach, ->cancel_attach() and ->attach() and
updating cgroup_taskset iteration helpers also return the destination
css in addition to the task being migrated. All controllers are
updated accordingly.
* Controllers which don't care whether there are one or multiple
target csses can be converted trivially. cpu, io, freezer, perf,
netclassid and netprio fall in this category.
* cpuset's current implementation assumes that there's single source
and destination and thus doesn't support v2 hierarchy already. The
only change made by this patchset is how that single destination css
is obtained.
* memory migration path already doesn't do anything on v2. How the
single destination css is obtained is updated and the prep stage of
mem_cgroup_can_attach() is reordered to accomodate the change.
* pids is the only controller which was affected by this bug. It now
correctly handles multi-destination migrations and no longer causes
counter underflow from incorrect accounting.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Aleksa Sarai <cyphar@cyphar.com>
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|
When bio has only one physical segment, we should set bio's
bi_seg_front_size as the real(final) size of the single segment.
Fixes: 02e707424c2ea(blk-merge: fix blk_bio_segment_split)
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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|
When a cloned request is retried on other queues it always needs
to be checked against the queue limits of that queue.
Otherwise the calculations for nr_phys_segments might be wrong,
leading to a crash in scsi_init_sgtable().
To clarify this the patch renames blk_rq_check_limits()
to blk_cloned_rq_check_limits() and removes the symbol
export, as the new function should only be used for
cloned requests and never exported.
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Ewan Milne <emilne@redhat.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Fixes: e2a60da74 ("block: Clean up special command handling logic")
Cc: stable@vger.kernel.org # 3.7+
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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|
Today, blockdev --rereadpt /dev/sda will fail with EBUSY if any
partition of sda is mounted (and will fail with EINVAL if pointed
at a partition). But it will pass if the entire block device is
formatted with a filesystem and mounted. I don't think this makes
sense; partitioning should surely not ever change out from under
a mounted device.
So check for bdev->bd_super, and fail that with -EBUSY as well.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
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|
Commit 4f258a46346c ("sd: Fix maximum I/O size for BLOCK_PC requests")
had the unfortunate side-effect of removing an implicit clamp to
BLK_DEF_MAX_SECTORS for REQ_TYPE_FS requests in the block layer
code. This caused problems for some SMR drives.
Debugging this issue revealed a few problems with the existing
infrastructure since the block layer didn't know how to deal with
device-imposed limits, only limits set by the I/O controller.
- Introduce a new queue limit, max_dev_sectors, which is used by the
ULD to signal the maximum sectors for a REQ_TYPE_FS request.
- Ensure that max_dev_sectors is correctly stacked and taken into
account when overriding max_sectors through sysfs.
- Rework sd_read_block_limits() so it saves the max_xfer and opt_xfer
values for later processing.
- In sd_revalidate() set the queue's max_dev_sectors based on the
MAXIMUM TRANSFER LENGTH value in the Block Limits VPD. If this value
is not reported, fall back to a cap based on the CDB TRANSFER LENGTH
field size.
- In sd_revalidate(), use OPTIMAL TRANSFER LENGTH from the Block Limits
VPD--if reported and sane--to signal the preferred device transfer
size for FS requests. Otherwise use BLK_DEF_MAX_SECTORS.
- blk_limits_max_hw_sectors() is no longer used and can be removed.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=93581
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: sweeneygj@gmx.com
Tested-by: Arzeets <anatol.pomozov@gmail.com>
Tested-by: David Eisner <david.eisner@oriel.oxon.org>
Tested-by: Mario Kicherer <dev@kicherer.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
|
|
This reverts commit 1b2ff19e6a957b1ef0f365ad331b608af80e932e.
Jan writes:
--
Thanks for report! After some investigation I found out we allocate
elevator specific data in __get_request() only for non-flush requests. And
this is actually required since the flush machinery uses the space in
struct request for something else. Doh. So my patch is just wrong and not
easy to fix since at the time __get_request() is called we are not sure
whether the flush machinery will be used in the end. Jens, please revert
1b2ff19e6a957b1ef0f365ad331b608af80e932e. Thanks!
I'm somewhat surprised that you can reliably hit the race where flushing
gets disabled for the device just while the request is in flight. But I
guess during boot it makes some sense.
--
So let's just revert it, we can fix the queue run manually after the
fact. This race is rare enough that it didn't trigger in testing, it
requires the specific disable-while-in-flight scenario to trigger.
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|
We only added the request to the request list for the !blk-mq case,
so we should only delete it in that case as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
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|
Pull block layer fixes from Jens Axboe:
"A round of fixes/updates for the current series.
This looks a little bigger than it is, but that's mainly because we
pushed the lightnvm enabled null_blk change out of the merge window so
it could be updated a bit. The rest of the volume is also mostly
lightnvm. In particular:
- Lightnvm. Various fixes, additions, updates from Matias and
Javier, as well as from Wenwei Tao.
- NVMe:
- Fix for potential arithmetic overflow from Keith.
- Also from Keith, ensure that we reap pending completions from
a completion queue before deleting it. Fixes kernel crashes
when resetting a device with IO pending.
- Various little lightnvm related tweaks from Matias.
- Fixup flushes to go through the IO scheduler, for the cases where a
flush is not required. Fixes a case in CFQ where we would be
idling and not see this request, hence not break the idling. From
Jan Kara.
- Use list_{first,prev,next} in elevator.c for cleaner code. From
Gelian Tang.
- Fix for a warning trigger on btrfs and raid on single queue blk-mq
devices, where we would flush plug callbacks with preemption
disabled. From me.
- A mac partition validation fix from Kees Cook.
- Two merge fixes from Ming, marked stable. A third part is adding a
new warning so we'll notice this quicker in the future, if we screw
up the accounting.
- Cleanup of thread name/creation in mtip32xx from Rasmus Villemoes"
* 'for-linus' of git://git.kernel.dk/linux-block: (32 commits)
blk-merge: warn if figured out segment number is bigger than nr_phys_segments
blk-merge: fix blk_bio_segment_split
block: fix segment split
blk-mq: fix calling unplug callbacks with preempt disabled
mac: validate mac_partition is within sector
mtip32xx: use formatting capability of kthread_create_on_node
NVMe: reap completion entries when deleting queue
lightnvm: add free and bad lun info to show luns
lightnvm: keep track of block counts
nvme: lightnvm: use admin queues for admin cmds
lightnvm: missing free on init error
lightnvm: wrong return value and redundant free
null_blk: do not del gendisk with lightnvm
null_blk: use device addressing mode
null_blk: use ppa_cache pool
NVMe: Fix possible arithmetic overflow for max segments
blk-flush: Queue through IO scheduler when flush not required
null_blk: register as a LightNVM device
elevator: use list_{first,prev,next}_entry
lightnvm: cleanup queue before target removal
...
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We had seen lots of reports of this kind issue, so add one
warnning in blk-merge, then it can be triggered easily and
avoid to depend on warning/bug from drivers.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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|
Commit bdced438acd83a(block: setup bi_phys_segments after
splitting) introduces function of computing bio->bi_phys_segments
during bio splitting.
Unfortunately both bio->bi_seg_front_size and bio->bi_seg_back_size
arn't computed, so too many physical segments may be obtained
for one request since both the two are used to check if one segment
across two bios can be possible.
This patch fixes the issue by computing the two variables in
blk_bio_segment_split().
Fixes: bdced438acd83a(block: setup bi_phys_segments after splitting)
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: Mark Salter <msalter@redhat.com>
Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Tested-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
|
|
Inside blk_bio_segment_split(), previous bvec pointer(bvprvp)
always points to the iterator local variable, which is obviously
wrong, so fix it by pointing to the local variable of 'bvprv'.
Fixes: 5014c311baa2b(block: fix bogus compiler warnings in blk-merge.c)
Cc: stable@kernel.org #4.3
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: Mark Salter <msalter@redhat.com>
Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Tested-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
|
|
Liu reported that running certain parts of xfstests threw the
following error:
BUG: sleeping function called from invalid context at mm/page_alloc.c:3190
in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u16:0
3 locks held by kworker/u16:0/6:
#0: ("writeback"){++++.+}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730
#1: ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730
#2: (&type->s_umount_key#44){+++++.}, at: [<ffffffff811e6805>] trylock_super+0x25/0x60
CPU: 5 PID: 6 Comm: kworker/u16:0 Tainted: G OE 4.3.0+ #3
Hardware name: Red Hat KVM, BIOS Bochs 01/01/2011
Workqueue: writeback wb_workfn (flush-btrfs-108)
ffffffff81a3abab ffff88042e282ba8 ffffffff8130191b ffffffff81a3abab
0000000000000c76 ffff88042e282ba8 ffff88042e27c180 ffff88042e282bd8
ffffffff8108ed95 ffff880400000004 0000000000000000 0000000000000c76
Call Trace:
[<ffffffff8130191b>] dump_stack+0x4f/0x74
[<ffffffff8108ed95>] ___might_sleep+0x185/0x240
[<ffffffff8108eea2>] __might_sleep+0x52/0x90
[<ffffffff811817e8>] __alloc_pages_nodemask+0x268/0x410
[<ffffffff8109a43c>] ? sched_clock_local+0x1c/0x90
[<ffffffff8109a6d1>] ? local_clock+0x21/0x40
[<ffffffff810b9eb0>] ? __lock_release+0x420/0x510
[<ffffffff810b534c>] ? __lock_acquired+0x16c/0x3c0
[<ffffffff811ca265>] alloc_pages_current+0xc5/0x210
[<ffffffffa0577105>] ? rbio_is_full+0x55/0x70 [btrfs]
[<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0
[<ffffffff81666d50>] ? _raw_spin_unlock_irqrestore+0x40/0x60
[<ffffffffa0578c0a>] full_stripe_write+0x5a/0xc0 [btrfs]
[<ffffffffa0578ca9>] __raid56_parity_write+0x39/0x60 [btrfs]
[<ffffffffa0578deb>] run_plug+0x11b/0x140 [btrfs]
[<ffffffffa0578e33>] btrfs_raid_unplug+0x23/0x70 [btrfs]
[<ffffffff812d36c2>] blk_flush_plug_list+0x82/0x1f0
[<ffffffff812e0349>] blk_sq_make_request+0x1f9/0x740
[<ffffffff812ceba2>] ? generic_make_request_checks+0x222/0x7c0
[<ffffffff812cf264>] ? blk_queue_enter+0x124/0x310
[<ffffffff812cf1d2>] ? blk_queue_enter+0x92/0x310
[<ffffffff812d0ae2>] generic_make_request+0x172/0x2c0
[<ffffffff812d0ad4>] ? generic_make_request+0x164/0x2c0
[<ffffffff812d0ca0>] submit_bio+0x70/0x140
[<ffffffffa0577b29>] ? rbio_add_io_page+0x99/0x150 [btrfs]
[<ffffffffa0578a89>] finish_rmw+0x4d9/0x600 [btrfs]
[<ffffffffa0578c4c>] full_stripe_write+0x9c/0xc0 [btrfs]
[<ffffffffa057ab7f>] raid56_parity_write+0xef/0x160 [btrfs]
[<ffffffffa052bd83>] btrfs_map_bio+0xe3/0x2d0 [btrfs]
[<ffffffffa04fbd6d>] btrfs_submit_bio_hook+0x8d/0x1d0 [btrfs]
[<ffffffffa05173c4>] submit_one_bio+0x74/0xb0 [btrfs]
[<ffffffffa0517f55>] submit_extent_page+0xe5/0x1c0 [btrfs]
[<ffffffffa0519b18>] __extent_writepage_io+0x408/0x4c0 [btrfs]
[<ffffffffa05179c0>] ? alloc_dummy_extent_buffer+0x140/0x140 [btrfs]
[<ffffffffa051dc88>] __extent_writepage+0x218/0x3a0 [btrfs]
[<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0
[<ffffffffa051e2c9>] extent_write_cache_pages.clone.0+0x2f9/0x400 [btrfs]
[<ffffffffa051e422>] extent_writepages+0x52/0x70 [btrfs]
[<ffffffffa05001f0>] ? btrfs_set_inode_index+0x70/0x70 [btrfs]
[<ffffffffa04fcc17>] btrfs_writepages+0x27/0x30 [btrfs]
[<ffffffff81184df3>] do_writepages+0x23/0x40
[<ffffffff81212229>] __writeback_single_inode+0x89/0x4d0
[<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480
[<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480
[<ffffffff8121295f>] ? writeback_sb_inodes+0x15f/0x480
[<ffffffff81212ad2>] writeback_sb_inodes+0x2d2/0x480
[<ffffffff810b1397>] ? down_read_trylock+0x57/0x60
[<ffffffff811e6805>] ? trylock_super+0x25/0x60
[<ffffffff810d629f>] ? rcu_read_lock_sched_held+0x4f/0x90
[<ffffffff81212d0c>] __writeback_inodes_wb+0x8c/0xc0
[<ffffffff812130b5>] wb_writeback+0x2b5/0x500
[<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0
[<ffffffff810660a8>] ? __local_bh_enable_ip+0x68/0xc0
[<ffffffff81213362>] ? wb_do_writeback+0x62/0x310
[<ffffffff812133c1>] wb_do_writeback+0xc1/0x310
[<ffffffff8107c3d9>] ? set_worker_desc+0x79/0x90
[<ffffffff81213842>] wb_workfn+0x92/0x330
[<ffffffff8107f133>] process_one_work+0x223/0x730
[<ffffffff8107f083>] ? process_one_work+0x173/0x730
[<ffffffff8108035f>] ? worker_thread+0x18f/0x430
[<ffffffff810802ed>] worker_thread+0x11d/0x430
[<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0
[<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0
[<ffffffff810858df>] kthread+0xef/0x110
[<ffffffff8108f74e>] ? schedule_tail+0x1e/0xd0
[<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70
[<ffffffff816673bf>] ret_from_fork+0x3f/0x70
[<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70
The issue is that we've got the software context pinned while
calling blk_flush_plug_list(), which flushes callbacks that
are allowed to sleep. btrfs and raid has such callbacks.
Flip the checks around a bit, so we can enable preempt a bit
earlier and flush plugs without having preempt disabled.
This only affects blk-mq driven devices, and only those that
register a single queue.
Reported-by: Liu Bo <bo.li.liu@oracle.com>
Tested-by: Liu Bo <bo.li.liu@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
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