<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/block, branch linux-6.15.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>drbd: add missing kref_get in handle_write_conflicts</title>
<updated>2025-08-20T16:35:51+00:00</updated>
<author>
<name>Sarah Newman</name>
<email>srn@prgmr.com</email>
</author>
<published>2025-06-27T09:57:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=46e3763dcae0ffcf8fcfaff4fc10a90a92ffdd89'/>
<id>46e3763dcae0ffcf8fcfaff4fc10a90a92ffdd89</id>
<content type='text'>
[ Upstream commit 00c9c9628b49e368d140cfa61d7df9b8922ec2a8 ]

With `two-primaries` enabled, DRBD tries to detect "concurrent" writes
and handle write conflicts, so that even if you write to the same sector
simultaneously on both nodes, they end up with the identical data once
the writes are completed.

In handling "superseeded" writes, we forgot a kref_get,
resulting in a premature drbd_destroy_device and use after free,
and further to kernel crashes with symptoms.

Relevance: No one should use DRBD as a random data generator, and apparently
all users of "two-primaries" handle concurrent writes correctly on layer up.
That is cluster file systems use some distributed lock manager,
and live migration in virtualization environments stops writes on one node
before starting writes on the other node.

Which means that other than for "test cases",
this code path is never taken in real life.

FYI, in DRBD 9, things are handled differently nowadays.  We still detect
"write conflicts", but no longer try to be smart about them.
We decided to disconnect hard instead: upper layers must not submit concurrent
writes. If they do, that's their fault.

Signed-off-by: Sarah Newman &lt;srn@prgmr.com&gt;
Signed-off-by: Lars Ellenberg &lt;lars@linbit.com&gt;
Signed-off-by: Christoph Böhmwalder &lt;christoph.boehmwalder@linbit.com&gt;
Link: https://lore.kernel.org/r/20250627095728.800688-1-christoph.boehmwalder@linbit.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 00c9c9628b49e368d140cfa61d7df9b8922ec2a8 ]

With `two-primaries` enabled, DRBD tries to detect "concurrent" writes
and handle write conflicts, so that even if you write to the same sector
simultaneously on both nodes, they end up with the identical data once
the writes are completed.

In handling "superseeded" writes, we forgot a kref_get,
resulting in a premature drbd_destroy_device and use after free,
and further to kernel crashes with symptoms.

Relevance: No one should use DRBD as a random data generator, and apparently
all users of "two-primaries" handle concurrent writes correctly on layer up.
That is cluster file systems use some distributed lock manager,
and live migration in virtualization environments stops writes on one node
before starting writes on the other node.

Which means that other than for "test cases",
this code path is never taken in real life.

FYI, in DRBD 9, things are handled differently nowadays.  We still detect
"write conflicts", but no longer try to be smart about them.
We decided to disconnect hard instead: upper layers must not submit concurrent
writes. If they do, that's their fault.

Signed-off-by: Sarah Newman &lt;srn@prgmr.com&gt;
Signed-off-by: Lars Ellenberg &lt;lars@linbit.com&gt;
Signed-off-by: Christoph Böhmwalder &lt;christoph.boehmwalder@linbit.com&gt;
Link: https://lore.kernel.org/r/20250627095728.800688-1-christoph.boehmwalder@linbit.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>loop: Avoid updating block size under exclusive owner</title>
<updated>2025-08-20T16:35:51+00:00</updated>
<author>
<name>Jan Kara</name>
<email>jack@suse.cz</email>
</author>
<published>2025-07-11T16:32:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b928438cc87c0bf7ae078e4b7b6e14261e84c5c5'/>
<id>b928438cc87c0bf7ae078e4b7b6e14261e84c5c5</id>
<content type='text'>
[ Upstream commit 7e49538288e523427beedd26993d446afef1a6fb ]

Syzbot came up with a reproducer where a loop device block size is
changed underneath a mounted filesystem. This causes a mismatch between
the block device block size and the block size stored in the superblock
causing confusion in various places such as fs/buffer.c. The particular
issue triggered by syzbot was a warning in __getblk_slow() due to
requested buffer size not matching block device block size.

Fix the problem by getting exclusive hold of the loop device to change
its block size. This fails if somebody (such as filesystem) has already
an exclusive ownership of the block device and thus prevents modifying
the loop device under some exclusive owner which doesn't expect it.

Reported-by: syzbot+01ef7a8da81a975e1ccd@syzkaller.appspotmail.com
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Tested-by: syzbot+01ef7a8da81a975e1ccd@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20250711163202.19623-2-jack@suse.cz
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 7e49538288e523427beedd26993d446afef1a6fb ]

Syzbot came up with a reproducer where a loop device block size is
changed underneath a mounted filesystem. This causes a mismatch between
the block device block size and the block size stored in the superblock
causing confusion in various places such as fs/buffer.c. The particular
issue triggered by syzbot was a warning in __getblk_slow() due to
requested buffer size not matching block device block size.

Fix the problem by getting exclusive hold of the loop device to change
its block size. This fails if somebody (such as filesystem) has already
an exclusive ownership of the block device and thus prevents modifying
the loop device under some exclusive owner which doesn't expect it.

Reported-by: syzbot+01ef7a8da81a975e1ccd@syzkaller.appspotmail.com
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Tested-by: syzbot+01ef7a8da81a975e1ccd@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20250711163202.19623-2-jack@suse.cz
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>sunvdc: Balance device refcount in vdc_port_mpgroup_check</title>
<updated>2025-08-20T16:35:45+00:00</updated>
<author>
<name>Ma Ke</name>
<email>make24@iscas.ac.cn</email>
</author>
<published>2025-07-19T07:58:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7ea0bd73e9590ba8a9caa675598b4d4cc85b3db0'/>
<id>7ea0bd73e9590ba8a9caa675598b4d4cc85b3db0</id>
<content type='text'>
commit 63ce53724637e2e7ba51fe3a4f78351715049905 upstream.

Using device_find_child() to locate a probed virtual-device-port node
causes a device refcount imbalance, as device_find_child() internally
calls get_device() to increment the device’s reference count before
returning its pointer. vdc_port_mpgroup_check() directly returns true
upon finding a matching device without releasing the reference via
put_device(). We should call put_device() to decrement refcount.

As comment of device_find_child() says, 'NOTE: you will need to drop
the reference with put_device() after use'.

Found by code review.

Cc: stable@vger.kernel.org
Fixes: 3ee70591d6c4 ("sunvdc: prevent sunvdc panic when mpgroup disk added to guest domain")
Signed-off-by: Ma Ke &lt;make24@iscas.ac.cn&gt;
Link: https://lore.kernel.org/r/20250719075856.3447953-1-make24@iscas.ac.cn
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 63ce53724637e2e7ba51fe3a4f78351715049905 upstream.

Using device_find_child() to locate a probed virtual-device-port node
causes a device refcount imbalance, as device_find_child() internally
calls get_device() to increment the device’s reference count before
returning its pointer. vdc_port_mpgroup_check() directly returns true
upon finding a matching device without releasing the reference via
put_device(). We should call put_device() to decrement refcount.

As comment of device_find_child() says, 'NOTE: you will need to drop
the reference with put_device() after use'.

Found by code review.

Cc: stable@vger.kernel.org
Fixes: 3ee70591d6c4 ("sunvdc: prevent sunvdc panic when mpgroup disk added to guest domain")
Signed-off-by: Ma Ke &lt;make24@iscas.ac.cn&gt;
Link: https://lore.kernel.org/r/20250719075856.3447953-1-make24@iscas.ac.cn
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: mtip32xx: Fix usage of dma_map_sg()</title>
<updated>2025-08-15T10:16:14+00:00</updated>
<author>
<name>Thomas Fourier</name>
<email>fourier.thomas@gmail.com</email>
</author>
<published>2025-06-27T12:11:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ffd9f3fb764d3a1a121cc1f212ac5bdf6e7a1a28'/>
<id>ffd9f3fb764d3a1a121cc1f212ac5bdf6e7a1a28</id>
<content type='text'>
[ Upstream commit 8e1fab9cccc7b806b0cffdceabb09b310b83b553 ]

The dma_map_sg() can fail and, in case of failure, returns 0.  If it
fails, mtip_hw_submit_io() returns an error.

The dma_unmap_sg() requires the nents parameter to be the same as the
one passed to dma_map_sg(). This patch saves the nents in
command-&gt;scatter_ents.

Fixes: 88523a61558a ("block: Add driver for Micron RealSSD pcie flash cards")
Signed-off-by: Thomas Fourier &lt;fourier.thomas@gmail.com&gt;
Reviewed-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20250627121123.203731-2-fourier.thomas@gmail.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 8e1fab9cccc7b806b0cffdceabb09b310b83b553 ]

The dma_map_sg() can fail and, in case of failure, returns 0.  If it
fails, mtip_hw_submit_io() returns an error.

The dma_unmap_sg() requires the nents parameter to be the same as the
one passed to dma_map_sg(). This patch saves the nents in
command-&gt;scatter_ents.

Fixes: 88523a61558a ("block: Add driver for Micron RealSSD pcie flash cards")
Signed-off-by: Thomas Fourier &lt;fourier.thomas@gmail.com&gt;
Reviewed-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20250627121123.203731-2-fourier.thomas@gmail.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>ublk: use vmalloc for ublk_device's __queues</title>
<updated>2025-08-15T10:16:13+00:00</updated>
<author>
<name>Caleb Sander Mateos</name>
<email>csander@purestorage.com</email>
</author>
<published>2025-06-20T15:09:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c4fd938f8d155ddde4aad63cfe44f4660e7baa11'/>
<id>c4fd938f8d155ddde4aad63cfe44f4660e7baa11</id>
<content type='text'>
[ Upstream commit c2f48453b7806d41f5a3270f206a5cd5640ed207 ]

struct ublk_device's __queues points to an allocation with up to
UBLK_MAX_NR_QUEUES (4096) queues, each of which have:
- struct ublk_queue (48 bytes)
- Tail array of up to UBLK_MAX_QUEUE_DEPTH (4096) struct ublk_io's,
  32 bytes each
This means the full allocation can exceed 512 MB, which may well be
impossible to service with contiguous physical pages. Switch to
kvcalloc() and kvfree(), since there is no need for physically
contiguous memory.

Signed-off-by: Caleb Sander Mateos &lt;csander@purestorage.com&gt;
Fixes: 71f28f3136af ("ublk_drv: add io_uring based userspace block driver")
Reviewed-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Link: https://lore.kernel.org/r/20250620151008.3976463-2-csander@purestorage.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 c2f48453b7806d41f5a3270f206a5cd5640ed207 ]

struct ublk_device's __queues points to an allocation with up to
UBLK_MAX_NR_QUEUES (4096) queues, each of which have:
- struct ublk_queue (48 bytes)
- Tail array of up to UBLK_MAX_QUEUE_DEPTH (4096) struct ublk_io's,
  32 bytes each
This means the full allocation can exceed 512 MB, which may well be
impossible to service with contiguous physical pages. Switch to
kvcalloc() and kvfree(), since there is no need for physically
contiguous memory.

Signed-off-by: Caleb Sander Mateos &lt;csander@purestorage.com&gt;
Fixes: 71f28f3136af ("ublk_drv: add io_uring based userspace block driver")
Reviewed-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Link: https://lore.kernel.org/r/20250620151008.3976463-2-csander@purestorage.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>loop: use kiocb helpers to fix lockdep warning</title>
<updated>2025-07-24T06:58:36+00:00</updated>
<author>
<name>Ming Lei</name>
<email>ming.lei@redhat.com</email>
</author>
<published>2025-07-16T11:48:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=932cdb4b61d49b4002f814e5315191ef6d79218c'/>
<id>932cdb4b61d49b4002f814e5315191ef6d79218c</id>
<content type='text'>
[ Upstream commit c4706c5058a7bd7d7c20f3b24a8f523ecad44e83 ]

The lockdep tool can report a circular lock dependency warning in the loop
driver's AIO read/write path:

```
[ 6540.587728] kworker/u96:5/72779 is trying to acquire lock:
[ 6540.593856] ff110001b5968440 (sb_writers#9){.+.+}-{0:0}, at: loop_process_work+0x11a/0xf70 [loop]
[ 6540.603786]
[ 6540.603786] but task is already holding lock:
[ 6540.610291] ff110001b5968440 (sb_writers#9){.+.+}-{0:0}, at: loop_process_work+0x11a/0xf70 [loop]
[ 6540.620210]
[ 6540.620210] other info that might help us debug this:
[ 6540.627499]  Possible unsafe locking scenario:
[ 6540.627499]
[ 6540.634110]        CPU0
[ 6540.636841]        ----
[ 6540.639574]   lock(sb_writers#9);
[ 6540.643281]   lock(sb_writers#9);
[ 6540.646988]
[ 6540.646988]  *** DEADLOCK ***
```

This patch fixes the issue by using the AIO-specific helpers
`kiocb_start_write()` and `kiocb_end_write()`. These functions are
designed to be used with a `kiocb` and manage write sequencing
correctly for asynchronous I/O without introducing the problematic
lock dependency.

The `kiocb` is already part of the `loop_cmd` struct, so this change
also simplifies the completion function `lo_rw_aio_do_completion()` by
using the `iocb` from the `cmd` struct directly, instead of retrieving
the loop device from the request queue.

Fixes: 39d86db34e41 ("loop: add file_start_write() and file_end_write()")
Cc: Changhui Zhong &lt;czhong@redhat.com&gt;
Signed-off-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Link: https://lore.kernel.org/r/20250716114808.3159657-1-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 c4706c5058a7bd7d7c20f3b24a8f523ecad44e83 ]

The lockdep tool can report a circular lock dependency warning in the loop
driver's AIO read/write path:

```
[ 6540.587728] kworker/u96:5/72779 is trying to acquire lock:
[ 6540.593856] ff110001b5968440 (sb_writers#9){.+.+}-{0:0}, at: loop_process_work+0x11a/0xf70 [loop]
[ 6540.603786]
[ 6540.603786] but task is already holding lock:
[ 6540.610291] ff110001b5968440 (sb_writers#9){.+.+}-{0:0}, at: loop_process_work+0x11a/0xf70 [loop]
[ 6540.620210]
[ 6540.620210] other info that might help us debug this:
[ 6540.627499]  Possible unsafe locking scenario:
[ 6540.627499]
[ 6540.634110]        CPU0
[ 6540.636841]        ----
[ 6540.639574]   lock(sb_writers#9);
[ 6540.643281]   lock(sb_writers#9);
[ 6540.646988]
[ 6540.646988]  *** DEADLOCK ***
```

This patch fixes the issue by using the AIO-specific helpers
`kiocb_start_write()` and `kiocb_end_write()`. These functions are
designed to be used with a `kiocb` and manage write sequencing
correctly for asynchronous I/O without introducing the problematic
lock dependency.

The `kiocb` is already part of the `loop_cmd` struct, so this change
also simplifies the completion function `lo_rw_aio_do_completion()` by
using the `iocb` from the `cmd` struct directly, instead of retrieving
the loop device from the request queue.

Fixes: 39d86db34e41 ("loop: add file_start_write() and file_end_write()")
Cc: Changhui Zhong &lt;czhong@redhat.com&gt;
Signed-off-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Link: https://lore.kernel.org/r/20250716114808.3159657-1-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>ublk: sanity check add_dev input for underflow</title>
<updated>2025-07-17T16:44:01+00:00</updated>
<author>
<name>Ronnie Sahlberg</name>
<email>rsahlberg@whamcloud.com</email>
</author>
<published>2025-06-26T02:20:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=73e262d94b5ff72af891aa40a9da7bca4f7e48a3'/>
<id>73e262d94b5ff72af891aa40a9da7bca4f7e48a3</id>
<content type='text'>
[ Upstream commit 969127bf0783a4ac0c8a27e633a9e8ea1738583f ]

Add additional checks that queue depth and number of queues are
non-zero.

Signed-off-by: Ronnie Sahlberg &lt;rsahlberg@whamcloud.com&gt;
Reviewed-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Link: https://lore.kernel.org/r/20250626022046.235018-1-ronniesahlberg@gmail.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 969127bf0783a4ac0c8a27e633a9e8ea1738583f ]

Add additional checks that queue depth and number of queues are
non-zero.

Signed-off-by: Ronnie Sahlberg &lt;rsahlberg@whamcloud.com&gt;
Reviewed-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Link: https://lore.kernel.org/r/20250626022046.235018-1-ronniesahlberg@gmail.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>nbd: fix uaf in nbd_genl_connect() error path</title>
<updated>2025-07-17T16:43:57+00:00</updated>
<author>
<name>Zheng Qixing</name>
<email>zhengqixing@huawei.com</email>
</author>
<published>2025-06-12T13:24:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=002aca89753f666d878ca0eb8584c372684ac4ba'/>
<id>002aca89753f666d878ca0eb8584c372684ac4ba</id>
<content type='text'>
[ Upstream commit aa9552438ebf015fc5f9f890dbfe39f0c53cf37e ]

There is a use-after-free issue in nbd:

block nbd6: Receive control failed (result -104)
block nbd6: shutting down sockets
==================================================================
BUG: KASAN: slab-use-after-free in recv_work+0x694/0xa80 drivers/block/nbd.c:1022
Write of size 4 at addr ffff8880295de478 by task kworker/u33:0/67

CPU: 2 UID: 0 PID: 67 Comm: kworker/u33:0 Not tainted 6.15.0-rc5-syzkaller-00123-g2c89c1b655c0 #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: nbd6-recv recv_work
Call Trace:
 &lt;TASK&gt;
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline]
 recv_work+0x694/0xa80 drivers/block/nbd.c:1022
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 &lt;/TASK&gt;

nbd_genl_connect() does not properly stop the device on certain
error paths after nbd_start_device() has been called. This causes
the error path to put nbd-&gt;config while recv_work continue to use
the config after putting it, leading to use-after-free in recv_work.

This patch moves nbd_start_device() after the backend file creation.

Reported-by: syzbot+48240bab47e705c53126@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68227a04.050a0220.f2294.00b5.GAE@google.com/T/
Fixes: 6497ef8df568 ("nbd: provide a way for userspace processes to identify device backends")
Signed-off-by: Zheng Qixing &lt;zhengqixing@huawei.com&gt;
Reviewed-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Link: https://lore.kernel.org/r/20250612132405.364904-1-zhengqixing@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 aa9552438ebf015fc5f9f890dbfe39f0c53cf37e ]

There is a use-after-free issue in nbd:

block nbd6: Receive control failed (result -104)
block nbd6: shutting down sockets
==================================================================
BUG: KASAN: slab-use-after-free in recv_work+0x694/0xa80 drivers/block/nbd.c:1022
Write of size 4 at addr ffff8880295de478 by task kworker/u33:0/67

CPU: 2 UID: 0 PID: 67 Comm: kworker/u33:0 Not tainted 6.15.0-rc5-syzkaller-00123-g2c89c1b655c0 #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: nbd6-recv recv_work
Call Trace:
 &lt;TASK&gt;
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline]
 recv_work+0x694/0xa80 drivers/block/nbd.c:1022
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 &lt;/TASK&gt;

nbd_genl_connect() does not properly stop the device on certain
error paths after nbd_start_device() has been called. This causes
the error path to put nbd-&gt;config while recv_work continue to use
the config after putting it, leading to use-after-free in recv_work.

This patch moves nbd_start_device() after the backend file creation.

Reported-by: syzbot+48240bab47e705c53126@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68227a04.050a0220.f2294.00b5.GAE@google.com/T/
Fixes: 6497ef8df568 ("nbd: provide a way for userspace processes to identify device backends")
Signed-off-by: Zheng Qixing &lt;zhengqixing@huawei.com&gt;
Reviewed-by: Yu Kuai &lt;yukuai3@huawei.com&gt;
Link: https://lore.kernel.org/r/20250612132405.364904-1-zhengqixing@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>aoe: defer rexmit timer downdev work to workqueue</title>
<updated>2025-07-10T14:08:48+00:00</updated>
<author>
<name>Justin Sanders</name>
<email>jsanders.devel@gmail.com</email>
</author>
<published>2025-06-10T17:06:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5201a02cd746fa6d6511380effebaa461882092e'/>
<id>5201a02cd746fa6d6511380effebaa461882092e</id>
<content type='text'>
[ Upstream commit cffc873d68ab09a0432b8212008c5613f8a70a2c ]

When aoe's rexmit_timer() notices that an aoe target fails to respond to
commands for more than aoe_deadsecs, it calls aoedev_downdev() which
cleans the outstanding aoe and block queues. This can involve sleeping,
such as in blk_mq_freeze_queue(), which should not occur in irq context.

This patch defers that aoedev_downdev() call to the aoe device's
workqueue.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=212665
Signed-off-by: Justin Sanders &lt;jsanders.devel@gmail.com&gt;
Link: https://lore.kernel.org/r/20250610170600.869-2-jsanders.devel@gmail.com
Tested-By: Valentin Kleibel &lt;valentin@vrvis.at&gt;
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 cffc873d68ab09a0432b8212008c5613f8a70a2c ]

When aoe's rexmit_timer() notices that an aoe target fails to respond to
commands for more than aoe_deadsecs, it calls aoedev_downdev() which
cleans the outstanding aoe and block queues. This can involve sleeping,
such as in blk_mq_freeze_queue(), which should not occur in irq context.

This patch defers that aoedev_downdev() call to the aoe device's
workqueue.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=212665
Signed-off-by: Justin Sanders &lt;jsanders.devel@gmail.com&gt;
Link: https://lore.kernel.org/r/20250610170600.869-2-jsanders.devel@gmail.com
Tested-By: Valentin Kleibel &lt;valentin@vrvis.at&gt;
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>ublk: santizize the arguments from userspace when adding a device</title>
<updated>2025-06-27T10:13:39+00:00</updated>
<author>
<name>Ronnie Sahlberg</name>
<email>rsahlberg@whamcloud.com</email>
</author>
<published>2025-06-19T02:10:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e2b2b7cf6368580114851cb3932f2ad9fbf23386'/>
<id>e2b2b7cf6368580114851cb3932f2ad9fbf23386</id>
<content type='text'>
[ Upstream commit 8c8472855884355caf3d8e0c50adf825f83454b2 ]

Sanity check the values for queue depth and number of queues
we get from userspace when adding a device.

Signed-off-by: Ronnie Sahlberg &lt;rsahlberg@whamcloud.com&gt;
Reviewed-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Fixes: 71f28f3136af ("ublk_drv: add io_uring based userspace block driver")
Fixes: 62fe99cef94a ("ublk: add read()/write() support for ublk char device")
Link: https://lore.kernel.org/r/20250619021031.181340-1-ronniesahlberg@gmail.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 8c8472855884355caf3d8e0c50adf825f83454b2 ]

Sanity check the values for queue depth and number of queues
we get from userspace when adding a device.

Signed-off-by: Ronnie Sahlberg &lt;rsahlberg@whamcloud.com&gt;
Reviewed-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Fixes: 71f28f3136af ("ublk_drv: add io_uring based userspace block driver")
Fixes: 62fe99cef94a ("ublk: add read()/write() support for ublk char device")
Link: https://lore.kernel.org/r/20250619021031.181340-1-ronniesahlberg@gmail.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>
</feed>
