<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/block, branch v6.1.3</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>block: Do not reread partition table on exclusively open device</title>
<updated>2023-01-04T10:29:01+00:00</updated>
<author>
<name>Jan Kara</name>
<email>jack@suse.cz</email>
</author>
<published>2022-11-30T17:56:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a35b4bcb43895c6e57e09bdad1cf3191cb67c63c'/>
<id>a35b4bcb43895c6e57e09bdad1cf3191cb67c63c</id>
<content type='text'>
commit 36369f46e91785688a5f39d7a5590e3f07981316 upstream.

Since commit 10c70d95c0f2 ("block: remove the bd_openers checks in
blk_drop_partitions") we allow rereading of partition table although
there are users of the block device. This has an undesirable consequence
that e.g. if sda and sdb are assembled to a RAID1 device md0 with
partitions, BLKRRPART ioctl on sda will rescan partition table and
create sda1 device. This partition device under a raid device confuses
some programs (such as libstorage-ng used for initial partitioning for
distribution installation) leading to failures.

Fix the problem refusing to rescan partitions if there is another user
that has the block device exclusively open.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20221130135344.2ul4cyfstfs3znxg@quack3
Fixes: 10c70d95c0f2 ("block: remove the bd_openers checks in blk_drop_partitions")
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20221130175653.24299-1-jack@suse.cz
[axboe: fold in followup fix]
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 36369f46e91785688a5f39d7a5590e3f07981316 upstream.

Since commit 10c70d95c0f2 ("block: remove the bd_openers checks in
blk_drop_partitions") we allow rereading of partition table although
there are users of the block device. This has an undesirable consequence
that e.g. if sda and sdb are assembled to a RAID1 device md0 with
partitions, BLKRRPART ioctl on sda will rescan partition table and
create sda1 device. This partition device under a raid device confuses
some programs (such as libstorage-ng used for initial partitioning for
distribution installation) leading to failures.

Fix the problem refusing to rescan partitions if there is another user
that has the block device exclusively open.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20221130135344.2ul4cyfstfs3znxg@quack3
Fixes: 10c70d95c0f2 ("block: remove the bd_openers checks in blk_drop_partitions")
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20221130175653.24299-1-jack@suse.cz
[axboe: fold in followup fix]
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq</title>
<updated>2023-01-04T10:28:51+00:00</updated>
<author>
<name>Yu Kuai</name>
<email>yukuai3@huawei.com</email>
</author>
<published>2022-12-26T03:06:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1ed959fef5b1c6f1a7a3fbea543698c30ebd6678'/>
<id>1ed959fef5b1c6f1a7a3fbea543698c30ebd6678</id>
<content type='text'>
[ Upstream commit 246cf66e300b76099b5dbd3fdd39e9a5dbc53f02 ]

Commit 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq-&gt;bic'")
will access 'bic-&gt;bfqq' in bic_set_bfqq(), however, bfq_exit_icq_bfqq()
can free bfqq first, and then call bic_set_bfqq(), which will cause uaf.

Fix the problem by moving bfq_exit_bfqq() behind bic_set_bfqq().

Fixes: 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq-&gt;bic'")
Reported-by: Yi Zhang &lt;yi.zhang@redhat.com&gt;
Signed-off-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Link: https://lore.kernel.org/r/20221226030605.1437081-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 246cf66e300b76099b5dbd3fdd39e9a5dbc53f02 ]

Commit 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq-&gt;bic'")
will access 'bic-&gt;bfqq' in bic_set_bfqq(), however, bfq_exit_icq_bfqq()
can free bfqq first, and then call bic_set_bfqq(), which will cause uaf.

Fix the problem by moving bfq_exit_bfqq() behind bic_set_bfqq().

Fixes: 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq-&gt;bic'")
Reported-by: Yi Zhang &lt;yi.zhang@redhat.com&gt;
Signed-off-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Link: https://lore.kernel.org/r/20221226030605.1437081-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>blk-iolatency: Fix memory leak on add_disk() failures</title>
<updated>2022-12-31T12:33:11+00:00</updated>
<author>
<name>Tejun Heo</name>
<email>tj@kernel.org</email>
</author>
<published>2022-12-10T18:33:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=215f9437dda09531bcb80605298a24219f01cec5'/>
<id>215f9437dda09531bcb80605298a24219f01cec5</id>
<content type='text'>
commit 813e693023ba10da9e75067780f8378465bf27cc upstream.

When a gendisk is successfully initialized but add_disk() fails such as when
a loop device has invalid number of minor device numbers specified,
blkcg_init_disk() is called during init and then blkcg_exit_disk() during
error handling. Unfortunately, iolatency gets initialized in the former but
doesn't get cleaned up in the latter.

This is because, in non-error cases, the cleanup is performed by
del_gendisk() calling rq_qos_exit(), the assumption being that rq_qos
policies, iolatency being one of them, can only be activated once the disk
is fully registered and visible. That assumption is true for wbt and iocost,
but not so for iolatency as it gets initialized before add_disk() is called.

It is desirable to lazy-init rq_qos policies because they are optional
features and add to hot path overhead once initialized - each IO has to walk
all the registered rq_qos policies. So, we want to switch iolatency to lazy
init too. However, that's a bigger change. As a fix for the immediate
problem, let's just add an extra call to rq_qos_exit() in blkcg_exit_disk().
This is safe because duplicate calls to rq_qos_exit() become noop's.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Reported-by: darklight2357@icloud.com
Cc: Josef Bacik &lt;josef@toxicpanda.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Fixes: d70675121546 ("block: introduce blk-iolatency io controller")
Cc: stable@vger.kernel.org # v4.19+
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Link: https://lore.kernel.org/r/Y5TQ5gm3O4HXrXR3@slm.duckdns.org
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 813e693023ba10da9e75067780f8378465bf27cc upstream.

When a gendisk is successfully initialized but add_disk() fails such as when
a loop device has invalid number of minor device numbers specified,
blkcg_init_disk() is called during init and then blkcg_exit_disk() during
error handling. Unfortunately, iolatency gets initialized in the former but
doesn't get cleaned up in the latter.

This is because, in non-error cases, the cleanup is performed by
del_gendisk() calling rq_qos_exit(), the assumption being that rq_qos
policies, iolatency being one of them, can only be activated once the disk
is fully registered and visible. That assumption is true for wbt and iocost,
but not so for iolatency as it gets initialized before add_disk() is called.

It is desirable to lazy-init rq_qos policies because they are optional
features and add to hot path overhead once initialized - each IO has to walk
all the registered rq_qos policies. So, we want to switch iolatency to lazy
init too. However, that's a bigger change. As a fix for the immediate
problem, let's just add an extra call to rq_qos_exit() in blkcg_exit_disk().
This is safe because duplicate calls to rq_qos_exit() become noop's.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Reported-by: darklight2357@icloud.com
Cc: Josef Bacik &lt;josef@toxicpanda.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Fixes: d70675121546 ("block: introduce blk-iolatency io controller")
Cc: stable@vger.kernel.org # v4.19+
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Link: https://lore.kernel.org/r/Y5TQ5gm3O4HXrXR3@slm.duckdns.org
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>blk-mq: fix possible memleak when register 'hctx' failed</title>
<updated>2022-12-31T12:33:03+00:00</updated>
<author>
<name>Ye Bin</name>
<email>yebin10@huawei.com</email>
</author>
<published>2022-11-17T02:29:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=33e8a3f61814ea30615d0fafaf50477975d6c1ca'/>
<id>33e8a3f61814ea30615d0fafaf50477975d6c1ca</id>
<content type='text'>
[ Upstream commit 4b7a21c57b14fbcd0e1729150189e5933f5088e9 ]

There's issue as follows when do fault injection test:
unreferenced object 0xffff888132a9f400 (size 512):
  comm "insmod", pid 308021, jiffies 4324277909 (age 509.733s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 08 f4 a9 32 81 88 ff ff  ...........2....
    08 f4 a9 32 81 88 ff ff 00 00 00 00 00 00 00 00  ...2............
  backtrace:
    [&lt;00000000e8952bb4&gt;] kmalloc_node_trace+0x22/0xa0
    [&lt;00000000f9980e0f&gt;] blk_mq_alloc_and_init_hctx+0x3f1/0x7e0
    [&lt;000000002e719efa&gt;] blk_mq_realloc_hw_ctxs+0x1e6/0x230
    [&lt;000000004f1fda40&gt;] blk_mq_init_allocated_queue+0x27e/0x910
    [&lt;00000000287123ec&gt;] __blk_mq_alloc_disk+0x67/0xf0
    [&lt;00000000a2a34657&gt;] 0xffffffffa2ad310f
    [&lt;00000000b173f718&gt;] 0xffffffffa2af824a
    [&lt;0000000095a1dabb&gt;] do_one_initcall+0x87/0x2a0
    [&lt;00000000f32fdf93&gt;] do_init_module+0xdf/0x320
    [&lt;00000000cbe8541e&gt;] load_module+0x3006/0x3390
    [&lt;0000000069ed1bdb&gt;] __do_sys_finit_module+0x113/0x1b0
    [&lt;00000000a1a29ae8&gt;] do_syscall_64+0x35/0x80
    [&lt;000000009cd878b0&gt;] entry_SYSCALL_64_after_hwframe+0x46/0xb0

Fault injection context as follows:
 kobject_add
 blk_mq_register_hctx
 blk_mq_sysfs_register
 blk_register_queue
 device_add_disk
 null_add_dev.part.0 [null_blk]

As 'blk_mq_register_hctx' may already add some objects when failed halfway,
but there isn't do fallback, caller don't know which objects add failed.
To solve above issue just do fallback when add objects failed halfway in
'blk_mq_register_hctx'.

Signed-off-by: Ye Bin &lt;yebin10@huawei.com&gt;
Reviewed-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Link: https://lore.kernel.org/r/20221117022940.873959-1-yebin@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 4b7a21c57b14fbcd0e1729150189e5933f5088e9 ]

There's issue as follows when do fault injection test:
unreferenced object 0xffff888132a9f400 (size 512):
  comm "insmod", pid 308021, jiffies 4324277909 (age 509.733s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 08 f4 a9 32 81 88 ff ff  ...........2....
    08 f4 a9 32 81 88 ff ff 00 00 00 00 00 00 00 00  ...2............
  backtrace:
    [&lt;00000000e8952bb4&gt;] kmalloc_node_trace+0x22/0xa0
    [&lt;00000000f9980e0f&gt;] blk_mq_alloc_and_init_hctx+0x3f1/0x7e0
    [&lt;000000002e719efa&gt;] blk_mq_realloc_hw_ctxs+0x1e6/0x230
    [&lt;000000004f1fda40&gt;] blk_mq_init_allocated_queue+0x27e/0x910
    [&lt;00000000287123ec&gt;] __blk_mq_alloc_disk+0x67/0xf0
    [&lt;00000000a2a34657&gt;] 0xffffffffa2ad310f
    [&lt;00000000b173f718&gt;] 0xffffffffa2af824a
    [&lt;0000000095a1dabb&gt;] do_one_initcall+0x87/0x2a0
    [&lt;00000000f32fdf93&gt;] do_init_module+0xdf/0x320
    [&lt;00000000cbe8541e&gt;] load_module+0x3006/0x3390
    [&lt;0000000069ed1bdb&gt;] __do_sys_finit_module+0x113/0x1b0
    [&lt;00000000a1a29ae8&gt;] do_syscall_64+0x35/0x80
    [&lt;000000009cd878b0&gt;] entry_SYSCALL_64_after_hwframe+0x46/0xb0

Fault injection context as follows:
 kobject_add
 blk_mq_register_hctx
 blk_mq_sysfs_register
 blk_register_queue
 device_add_disk
 null_add_dev.part.0 [null_blk]

As 'blk_mq_register_hctx' may already add some objects when failed halfway,
but there isn't do fallback, caller don't know which objects add failed.
To solve above issue just do fallback when add objects failed halfway in
'blk_mq_register_hctx'.

Signed-off-by: Ye Bin &lt;yebin10@huawei.com&gt;
Reviewed-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Link: https://lore.kernel.org/r/20221117022940.873959-1-yebin@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>blk-mq: avoid double -&gt;queue_rq() because of early timeout</title>
<updated>2022-12-31T12:32:59+00:00</updated>
<author>
<name>David Jeffery</name>
<email>djeffery@redhat.com</email>
</author>
<published>2022-10-26T05:19:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8b3d6b029a552d2978bbac275303d11419826a69'/>
<id>8b3d6b029a552d2978bbac275303d11419826a69</id>
<content type='text'>
[ Upstream commit 82c229476b8f6afd7e09bc4dc77d89dc19ff7688 ]

David Jeffery found one double -&gt;queue_rq() issue, so far it can
be triggered in VM use case because of long vmexit latency or preempt
latency of vCPU pthread or long page fault in vCPU pthread, then block
IO req could be timed out before queuing the request to hardware but after
calling blk_mq_start_request() during -&gt;queue_rq(), then timeout handler
may handle it by requeue, then double -&gt;queue_rq() is caused, and kernel
panic.

So far, it is driver's responsibility to cover the race between timeout
and completion, so it seems supposed to be solved in driver in theory,
given driver has enough knowledge.

But it is really one common problem, lots of driver could have similar
issue, and could be hard to fix all affected drivers, even it isn't easy
for driver to handle the race. So David suggests this patch by draining
in-progress -&gt;queue_rq() for solving this issue.

Cc: Stefan Hajnoczi &lt;stefanha@redhat.com&gt;
Cc: Keith Busch &lt;kbusch@kernel.org&gt;
Cc: virtualization@lists.linux-foundation.org
Cc: Bart Van Assche &lt;bvanassche@acm.org&gt;
Signed-off-by: David Jeffery &lt;djeffery@redhat.com&gt;
Signed-off-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Reviewed-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Link: https://lore.kernel.org/r/20221026051957.358818-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 82c229476b8f6afd7e09bc4dc77d89dc19ff7688 ]

David Jeffery found one double -&gt;queue_rq() issue, so far it can
be triggered in VM use case because of long vmexit latency or preempt
latency of vCPU pthread or long page fault in vCPU pthread, then block
IO req could be timed out before queuing the request to hardware but after
calling blk_mq_start_request() during -&gt;queue_rq(), then timeout handler
may handle it by requeue, then double -&gt;queue_rq() is caused, and kernel
panic.

So far, it is driver's responsibility to cover the race between timeout
and completion, so it seems supposed to be solved in driver in theory,
given driver has enough knowledge.

But it is really one common problem, lots of driver could have similar
issue, and could be hard to fix all affected drivers, even it isn't easy
for driver to handle the race. So David suggests this patch by draining
in-progress -&gt;queue_rq() for solving this issue.

Cc: Stefan Hajnoczi &lt;stefanha@redhat.com&gt;
Cc: Keith Busch &lt;kbusch@kernel.org&gt;
Cc: virtualization@lists.linux-foundation.org
Cc: Bart Van Assche &lt;bvanassche@acm.org&gt;
Signed-off-by: David Jeffery &lt;djeffery@redhat.com&gt;
Signed-off-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Reviewed-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Link: https://lore.kernel.org/r/20221026051957.358818-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block, bfq: fix possible uaf for 'bfqq-&gt;bic'</title>
<updated>2022-12-31T12:32:53+00:00</updated>
<author>
<name>Yu Kuai</name>
<email>yukuai3@huawei.com</email>
</author>
<published>2022-12-14T03:04:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=761564d93c8265f65543acf0a576b32d66bfa26a'/>
<id>761564d93c8265f65543acf0a576b32d66bfa26a</id>
<content type='text'>
[ Upstream commit 64dc8c732f5c2b406cc752e6aaa1bd5471159cab ]

Our test report a uaf for 'bfqq-&gt;bic' in 5.10:

==================================================================
BUG: KASAN: use-after-free in bfq_select_queue+0x378/0xa30

CPU: 6 PID: 2318352 Comm: fsstress Kdump: loaded Not tainted 5.10.0-60.18.0.50.h602.kasan.eulerosv2r11.x86_64 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-20220320_160524-szxrtosci10000 04/01/2014
Call Trace:
 bfq_select_queue+0x378/0xa30
 bfq_dispatch_request+0xe8/0x130
 blk_mq_do_dispatch_sched+0x62/0xb0
 __blk_mq_sched_dispatch_requests+0x215/0x2a0
 blk_mq_sched_dispatch_requests+0x8f/0xd0
 __blk_mq_run_hw_queue+0x98/0x180
 __blk_mq_delay_run_hw_queue+0x22b/0x240
 blk_mq_run_hw_queue+0xe3/0x190
 blk_mq_sched_insert_requests+0x107/0x200
 blk_mq_flush_plug_list+0x26e/0x3c0
 blk_finish_plug+0x63/0x90
 __iomap_dio_rw+0x7b5/0x910
 iomap_dio_rw+0x36/0x80
 ext4_dio_read_iter+0x146/0x190 [ext4]
 ext4_file_read_iter+0x1e2/0x230 [ext4]
 new_sync_read+0x29f/0x400
 vfs_read+0x24e/0x2d0
 ksys_read+0xd5/0x1b0
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x61/0xc6

Commit 3bc5e683c67d ("bfq: Split shared queues on move between cgroups")
changes that move process to a new cgroup will allocate a new bfqq to
use, however, the old bfqq and new bfqq can point to the same bic:

1) Initial state, two process with io in the same cgroup.

Process 1       Process 2
 (BIC1)          (BIC2)
  |  Λ            |  Λ
  |  |            |  |
  V  |            V  |
  bfqq1           bfqq2

2) bfqq1 is merged to bfqq2.

Process 1       Process 2
 (BIC1)          (BIC2)
  |               |
   \-------------\|
                  V
  bfqq1           bfqq2(coop)

3) Process 1 exit, then issue new io(denoce IOA) from Process 2.

 (BIC2)
  |  Λ
  |  |
  V  |
  bfqq2(coop)

4) Before IOA is completed, move Process 2 to another cgroup and issue io.

Process 2
 (BIC2)
   Λ
   |\--------------\
   |                V
  bfqq2           bfqq3

Now that BIC2 points to bfqq3, while bfqq2 and bfqq3 both point to BIC2.
If all the requests are completed, and Process 2 exit, BIC2 will be
freed while there is no guarantee that bfqq2 will be freed before BIC2.

Fix the problem by clearing bfqq-&gt;bic while bfqq is detached from bic.

Fixes: 3bc5e683c67d ("bfq: Split shared queues on move between cgroups")
Suggested-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20221214030430.3304151-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 64dc8c732f5c2b406cc752e6aaa1bd5471159cab ]

Our test report a uaf for 'bfqq-&gt;bic' in 5.10:

==================================================================
BUG: KASAN: use-after-free in bfq_select_queue+0x378/0xa30

CPU: 6 PID: 2318352 Comm: fsstress Kdump: loaded Not tainted 5.10.0-60.18.0.50.h602.kasan.eulerosv2r11.x86_64 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-20220320_160524-szxrtosci10000 04/01/2014
Call Trace:
 bfq_select_queue+0x378/0xa30
 bfq_dispatch_request+0xe8/0x130
 blk_mq_do_dispatch_sched+0x62/0xb0
 __blk_mq_sched_dispatch_requests+0x215/0x2a0
 blk_mq_sched_dispatch_requests+0x8f/0xd0
 __blk_mq_run_hw_queue+0x98/0x180
 __blk_mq_delay_run_hw_queue+0x22b/0x240
 blk_mq_run_hw_queue+0xe3/0x190
 blk_mq_sched_insert_requests+0x107/0x200
 blk_mq_flush_plug_list+0x26e/0x3c0
 blk_finish_plug+0x63/0x90
 __iomap_dio_rw+0x7b5/0x910
 iomap_dio_rw+0x36/0x80
 ext4_dio_read_iter+0x146/0x190 [ext4]
 ext4_file_read_iter+0x1e2/0x230 [ext4]
 new_sync_read+0x29f/0x400
 vfs_read+0x24e/0x2d0
 ksys_read+0xd5/0x1b0
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x61/0xc6

Commit 3bc5e683c67d ("bfq: Split shared queues on move between cgroups")
changes that move process to a new cgroup will allocate a new bfqq to
use, however, the old bfqq and new bfqq can point to the same bic:

1) Initial state, two process with io in the same cgroup.

Process 1       Process 2
 (BIC1)          (BIC2)
  |  Λ            |  Λ
  |  |            |  |
  V  |            V  |
  bfqq1           bfqq2

2) bfqq1 is merged to bfqq2.

Process 1       Process 2
 (BIC1)          (BIC2)
  |               |
   \-------------\|
                  V
  bfqq1           bfqq2(coop)

3) Process 1 exit, then issue new io(denoce IOA) from Process 2.

 (BIC2)
  |  Λ
  |  |
  V  |
  bfqq2(coop)

4) Before IOA is completed, move Process 2 to another cgroup and issue io.

Process 2
 (BIC2)
   Λ
   |\--------------\
   |                V
  bfqq2           bfqq3

Now that BIC2 points to bfqq3, while bfqq2 and bfqq3 both point to BIC2.
If all the requests are completed, and Process 2 exit, BIC2 will be
freed while there is no guarantee that bfqq2 will be freed before BIC2.

Fix the problem by clearing bfqq-&gt;bic while bfqq is detached from bic.

Fixes: 3bc5e683c67d ("bfq: Split shared queues on move between cgroups")
Suggested-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20221214030430.3304151-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: clear -&gt;slave_dir when dropping the main slave_dir reference</title>
<updated>2022-12-31T12:32:12+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2022-11-15T14:10:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=475bdd75447acd9e771addf4c15d14a2d483d5c8'/>
<id>475bdd75447acd9e771addf4c15d14a2d483d5c8</id>
<content type='text'>
[ Upstream commit d90db3b1c8676bc88b4309c5a571333de2263b8e ]

Zero out the pointer to -&gt;slave_dir so that the holder code doesn't
incorrectly treat the object as alive when add_disk failed or after
del_gendisk was called.

Fixes: 89f871af1b26 ("dm: delay registering the gendisk")
Reported-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Reviewed-by: Mike Snitzer &lt;snitzer@kernel.org&gt;
Link: https://lore.kernel.org/r/20221115141054.1051801-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit d90db3b1c8676bc88b4309c5a571333de2263b8e ]

Zero out the pointer to -&gt;slave_dir so that the holder code doesn't
incorrectly treat the object as alive when add_disk failed or after
del_gendisk was called.

Fixes: 89f871af1b26 ("dm: delay registering the gendisk")
Reported-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Reviewed-by: Mike Snitzer &lt;snitzer@kernel.org&gt;
Link: https://lore.kernel.org/r/20221115141054.1051801-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bfq: fix waker_bfqq inconsistency crash</title>
<updated>2022-12-31T12:32:10+00:00</updated>
<author>
<name>Khazhismel Kumykov</name>
<email>khazhy@chromium.org</email>
</author>
<published>2022-11-08T18:10:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0544ea57f999fc2aee076ff82cc70091e7fc2585'/>
<id>0544ea57f999fc2aee076ff82cc70091e7fc2585</id>
<content type='text'>
[ Upstream commit a1795c2ccb1e4c49220d2a0d381540024d71647c ]

This fixes crashes in bfq_add_bfqq_busy due to waker_bfqq being NULL,
but woken_list_node still being hashed. This would happen when
bfq_init_rq() expects a brand new allocated queue to be returned from
bfq_get_bfqq_handle_split() and unconditionally updates waker_bfqq
without resetting woken_list_node. Since we can always return oom_bfqq
when attempting to allocate, we cannot assume waker_bfqq starts as NULL.

Avoid setting woken_bfqq for oom_bfqq entirely, as it's not useful.

Crashes would have a stacktrace like:
[160595.656560]  bfq_add_bfqq_busy+0x110/0x1ec
[160595.661142]  bfq_add_request+0x6bc/0x980
[160595.666602]  bfq_insert_request+0x8ec/0x1240
[160595.671762]  bfq_insert_requests+0x58/0x9c
[160595.676420]  blk_mq_sched_insert_request+0x11c/0x198
[160595.682107]  blk_mq_submit_bio+0x270/0x62c
[160595.686759]  __submit_bio_noacct_mq+0xec/0x178
[160595.691926]  submit_bio+0x120/0x184
[160595.695990]  ext4_mpage_readpages+0x77c/0x7c8
[160595.701026]  ext4_readpage+0x60/0xb0
[160595.705158]  filemap_read_page+0x54/0x114
[160595.711961]  filemap_fault+0x228/0x5f4
[160595.716272]  do_read_fault+0xe0/0x1f0
[160595.720487]  do_fault+0x40/0x1c8

Tested by injecting random failures into bfq_get_queue, crashes go away
completely.

Fixes: 8ef3fc3a043c ("block, bfq: make shared queues inherit wakers")
Signed-off-by: Khazhismel Kumykov &lt;khazhy@google.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20221108181030.1611703-1-khazhy@google.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit a1795c2ccb1e4c49220d2a0d381540024d71647c ]

This fixes crashes in bfq_add_bfqq_busy due to waker_bfqq being NULL,
but woken_list_node still being hashed. This would happen when
bfq_init_rq() expects a brand new allocated queue to be returned from
bfq_get_bfqq_handle_split() and unconditionally updates waker_bfqq
without resetting woken_list_node. Since we can always return oom_bfqq
when attempting to allocate, we cannot assume waker_bfqq starts as NULL.

Avoid setting woken_bfqq for oom_bfqq entirely, as it's not useful.

Crashes would have a stacktrace like:
[160595.656560]  bfq_add_bfqq_busy+0x110/0x1ec
[160595.661142]  bfq_add_request+0x6bc/0x980
[160595.666602]  bfq_insert_request+0x8ec/0x1240
[160595.671762]  bfq_insert_requests+0x58/0x9c
[160595.676420]  blk_mq_sched_insert_request+0x11c/0x198
[160595.682107]  blk_mq_submit_bio+0x270/0x62c
[160595.686759]  __submit_bio_noacct_mq+0xec/0x178
[160595.691926]  submit_bio+0x120/0x184
[160595.695990]  ext4_mpage_readpages+0x77c/0x7c8
[160595.701026]  ext4_readpage+0x60/0xb0
[160595.705158]  filemap_read_page+0x54/0x114
[160595.711961]  filemap_fault+0x228/0x5f4
[160595.716272]  do_read_fault+0xe0/0x1f0
[160595.720487]  do_fault+0x40/0x1c8

Tested by injecting random failures into bfq_get_queue, crashes go away
completely.

Fixes: 8ef3fc3a043c ("block, bfq: make shared queues inherit wakers")
Signed-off-by: Khazhismel Kumykov &lt;khazhy@google.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20221108181030.1611703-1-khazhy@google.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'block-6.1-2022-11-25' of git://git.kernel.dk/linux</title>
<updated>2022-11-26T01:50:57+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-11-26T01:50:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=990f320031209ecfdb1bef33798970506d10dae8'/>
<id>990f320031209ecfdb1bef33798970506d10dae8</id>
<content type='text'>
Pull block fixes from Jens Axboe:

 - A few fixes for s390 sads (Stefan, Colin)

 - Ensure that ublk doesn't reorder requests, as that can be problematic
   on devices that need specific ordering (Ming)

 - Fix a queue reference leak in disk allocation handling (Christoph)

* tag 'block-6.1-2022-11-25' of git://git.kernel.dk/linux:
  ublk_drv: don't forward io commands in reserve order
  s390/dasd: fix possible buffer overflow in copy_pair_show
  s390/dasd: fix no record found for raw_track_access
  s390/dasd: increase printing of debug data payload
  s390/dasd: Fix spelling mistake "Ivalid" -&gt; "Invalid"
  blk-mq: fix queue reference leak on blk_mq_alloc_disk_for_queue failure
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull block fixes from Jens Axboe:

 - A few fixes for s390 sads (Stefan, Colin)

 - Ensure that ublk doesn't reorder requests, as that can be problematic
   on devices that need specific ordering (Ming)

 - Fix a queue reference leak in disk allocation handling (Christoph)

* tag 'block-6.1-2022-11-25' of git://git.kernel.dk/linux:
  ublk_drv: don't forward io commands in reserve order
  s390/dasd: fix possible buffer overflow in copy_pair_show
  s390/dasd: fix no record found for raw_track_access
  s390/dasd: increase printing of debug data payload
  s390/dasd: Fix spelling mistake "Ivalid" -&gt; "Invalid"
  blk-mq: fix queue reference leak on blk_mq_alloc_disk_for_queue failure
</pre>
</div>
</content>
</entry>
<entry>
<title>blk-mq: fix queue reference leak on blk_mq_alloc_disk_for_queue failure</title>
<updated>2022-11-22T22:58:08+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2022-11-22T07:27:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=22c17e279a1b03bad7987e4a4192b289b890f293'/>
<id>22c17e279a1b03bad7987e4a4192b289b890f293</id>
<content type='text'>
Drop the request queue reference just acquired when __alloc_disk_node
failed.

Fixes: 6f8191fdf41d ("block: simplify disk shutdown")
Reported-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Link: https://lore.kernel.org/r/20221122072753.426077-1-hch@lst.de
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Drop the request queue reference just acquired when __alloc_disk_node
failed.

Fixes: 6f8191fdf41d ("block: simplify disk shutdown")
Reported-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Damien Le Moal &lt;damien.lemoal@opensource.wdc.com&gt;
Link: https://lore.kernel.org/r/20221122072753.426077-1-hch@lst.de
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
</feed>
