<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/block, branch v6.6.26</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 force full zone append completion in req_bio_endio()</title>
<updated>2024-04-03T13:28:56+00:00</updated>
<author>
<name>Damien Le Moal</name>
<email>dlemoal@kernel.org</email>
</author>
<published>2024-03-28T00:43:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cc80b5d7fbef8fed43cae6dcc11685488b80e801'/>
<id>cc80b5d7fbef8fed43cae6dcc11685488b80e801</id>
<content type='text'>
commit 55251fbdf0146c252ceff146a1bb145546f3e034 upstream.

This reverts commit 748dc0b65ec2b4b7b3dbd7befcc4a54fdcac7988.

Partial zone append completions cannot be supported as there is no
guarantees that the fragmented data will be written sequentially in the
same manner as with a full command. Commit 748dc0b65ec2 ("block: fix
partial zone append completion handling in req_bio_endio()") changed
req_bio_endio() to always advance a partially failed BIO by its full
length, but this can lead to incorrect accounting. So revert this
change and let low level device drivers handle this case by always
failing completely zone append operations. With this revert, users will
still see an IO error for a partially completed zone append BIO.

Fixes: 748dc0b65ec2 ("block: fix partial zone append completion handling in req_bio_endio()")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal &lt;dlemoal@kernel.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Link: https://lore.kernel.org/r/20240328004409.594888-2-dlemoal@kernel.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 55251fbdf0146c252ceff146a1bb145546f3e034 upstream.

This reverts commit 748dc0b65ec2b4b7b3dbd7befcc4a54fdcac7988.

Partial zone append completions cannot be supported as there is no
guarantees that the fragmented data will be written sequentially in the
same manner as with a full command. Commit 748dc0b65ec2 ("block: fix
partial zone append completion handling in req_bio_endio()") changed
req_bio_endio() to always advance a partially failed BIO by its full
length, but this can lead to incorrect accounting. So revert this
change and let low level device drivers handle this case by always
failing completely zone append operations. With this revert, users will
still see an IO error for a partially completed zone append BIO.

Fixes: 748dc0b65ec2 ("block: fix partial zone append completion handling in req_bio_endio()")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal &lt;dlemoal@kernel.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Link: https://lore.kernel.org/r/20240328004409.594888-2-dlemoal@kernel.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>Revert "block/mq-deadline: use correct way to throttling write requests"</title>
<updated>2024-04-03T13:28:33+00:00</updated>
<author>
<name>Bart Van Assche</name>
<email>bvanassche@acm.org</email>
</author>
<published>2024-03-13T21:42:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9a31f4b61448fccc4f240a95decb369d141c3360'/>
<id>9a31f4b61448fccc4f240a95decb369d141c3360</id>
<content type='text'>
[ Upstream commit 256aab46e31683d76d45ccbedc287b4d3f3e322b ]

The code "max(1U, 3 * (1U &lt;&lt; shift)  / 4)" comes from the Kyber I/O
scheduler. The Kyber I/O scheduler maintains one internal queue per hwq
and hence derives its async_depth from the number of hwq tags. Using
this approach for the mq-deadline scheduler is wrong since the
mq-deadline scheduler maintains one internal queue for all hwqs
combined. Hence this revert.

Cc: stable@vger.kernel.org
Cc: Damien Le Moal &lt;dlemoal@kernel.org&gt;
Cc: Harshit Mogalapalli &lt;harshit.m.mogalapalli@oracle.com&gt;
Cc: Zhiguo Niu &lt;Zhiguo.Niu@unisoc.com&gt;
Fixes: d47f9717e5cf ("block/mq-deadline: use correct way to throttling write requests")
Signed-off-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Link: https://lore.kernel.org/r/20240313214218.1736147-1-bvanassche@acm.org
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 256aab46e31683d76d45ccbedc287b4d3f3e322b ]

The code "max(1U, 3 * (1U &lt;&lt; shift)  / 4)" comes from the Kyber I/O
scheduler. The Kyber I/O scheduler maintains one internal queue per hwq
and hence derives its async_depth from the number of hwq tags. Using
this approach for the mq-deadline scheduler is wrong since the
mq-deadline scheduler maintains one internal queue for all hwqs
combined. Hence this revert.

Cc: stable@vger.kernel.org
Cc: Damien Le Moal &lt;dlemoal@kernel.org&gt;
Cc: Harshit Mogalapalli &lt;harshit.m.mogalapalli@oracle.com&gt;
Cc: Zhiguo Niu &lt;Zhiguo.Niu@unisoc.com&gt;
Fixes: d47f9717e5cf ("block/mq-deadline: use correct way to throttling write requests")
Signed-off-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Link: https://lore.kernel.org/r/20240313214218.1736147-1-bvanassche@acm.org
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: Fix page refcounts for unaligned buffers in __bio_release_pages()</title>
<updated>2024-04-03T13:28:27+00:00</updated>
<author>
<name>Tony Battersby</name>
<email>tonyb@cybernetics.com</email>
</author>
<published>2024-02-29T18:08:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7d3765550374f71248c55e6206ea1d6fd4537e65'/>
<id>7d3765550374f71248c55e6206ea1d6fd4537e65</id>
<content type='text'>
[ Upstream commit 38b43539d64b2fa020b3b9a752a986769f87f7a6 ]

Fix an incorrect number of pages being released for buffers that do not
start at the beginning of a page.

Fixes: 1b151e2435fc ("block: Remove special-casing of compound pages")
Cc: stable@vger.kernel.org
Signed-off-by: Tony Battersby &lt;tonyb@cybernetics.com&gt;
Tested-by: Greg Edwards &lt;gedwards@ddn.com&gt;
Link: https://lore.kernel.org/r/86e592a9-98d4-4cff-a646-0c0084328356@cybernetics.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 38b43539d64b2fa020b3b9a752a986769f87f7a6 ]

Fix an incorrect number of pages being released for buffers that do not
start at the beginning of a page.

Fixes: 1b151e2435fc ("block: Remove special-casing of compound pages")
Cc: stable@vger.kernel.org
Signed-off-by: Tony Battersby &lt;tonyb@cybernetics.com&gt;
Tested-by: Greg Edwards &lt;gedwards@ddn.com&gt;
Link: https://lore.kernel.org/r/86e592a9-98d4-4cff-a646-0c0084328356@cybernetics.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 zone limits for a non-zoned stacked queue</title>
<updated>2024-04-03T13:28:20+00:00</updated>
<author>
<name>Damien Le Moal</name>
<email>dlemoal@kernel.org</email>
</author>
<published>2024-02-22T13:17:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fe86d01ce7db878a6bca37bb3aa7d969659da939'/>
<id>fe86d01ce7db878a6bca37bb3aa7d969659da939</id>
<content type='text'>
[ Upstream commit c8f6f88d25929ad2f290b428efcae3b526f3eab0 ]

Device mapper may create a non-zoned mapped device out of a zoned device
(e.g., the dm-zoned target). In such case, some queue limit such as the
max_zone_append_sectors and zone_write_granularity endup being non zero
values for a block device that is not zoned. Avoid this by clearing
these limits in blk_stack_limits() when the stacked zoned limit is
false.

Fixes: 3093a479727b ("block: inherit the zoned characteristics in blk_stack_limits")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal &lt;dlemoal@kernel.org&gt;
Link: https://lore.kernel.org/r/20240222131724.1803520-1-dlemoal@kernel.org
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 c8f6f88d25929ad2f290b428efcae3b526f3eab0 ]

Device mapper may create a non-zoned mapped device out of a zoned device
(e.g., the dm-zoned target). In such case, some queue limit such as the
max_zone_append_sectors and zone_write_granularity endup being non zero
values for a block device that is not zoned. Avoid this by clearing
these limits in blk_stack_limits() when the stacked zoned limit is
false.

Fixes: 3093a479727b ("block: inherit the zoned characteristics in blk_stack_limits")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal &lt;dlemoal@kernel.org&gt;
Link: https://lore.kernel.org/r/20240222131724.1803520-1-dlemoal@kernel.org
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: Provide bdev_open_* functions</title>
<updated>2024-03-26T22:19:40+00:00</updated>
<author>
<name>Jan Kara</name>
<email>jack@suse.cz</email>
</author>
<published>2023-09-27T09:34:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=dd0bd429125045e0b5bd87dea1c43b2e593f6213'/>
<id>dd0bd429125045e0b5bd87dea1c43b2e593f6213</id>
<content type='text'>
[ Upstream commit e719b4d156749f02eafed31a3c515f2aa9dcc72a ]

Create struct bdev_handle that contains all parameters that need to be
passed to blkdev_put() and provide bdev_open_* functions that return
this structure instead of plain bdev pointer. This will eventually allow
us to pass one more argument to blkdev_put() (renamed to bdev_release())
without too much hassle.

Acked-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Christian Brauner &lt;brauner@kernel.org&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20230927093442.25915-1-jack@suse.cz
Signed-off-by: Christian Brauner &lt;brauner@kernel.org&gt;
Stable-dep-of: 0f28be64d132 ("erofs: fix lockdep false positives on initializing erofs_pseudo_mnt")
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 e719b4d156749f02eafed31a3c515f2aa9dcc72a ]

Create struct bdev_handle that contains all parameters that need to be
passed to blkdev_put() and provide bdev_open_* functions that return
this structure instead of plain bdev pointer. This will eventually allow
us to pass one more argument to blkdev_put() (renamed to bdev_release())
without too much hassle.

Acked-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Christian Brauner &lt;brauner@kernel.org&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20230927093442.25915-1-jack@suse.cz
Signed-off-by: Christian Brauner &lt;brauner@kernel.org&gt;
Stable-dep-of: 0f28be64d132 ("erofs: fix lockdep false positives on initializing erofs_pseudo_mnt")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: sed-opal: handle empty atoms when parsing response</title>
<updated>2024-03-26T22:19:12+00:00</updated>
<author>
<name>Greg Joyce</name>
<email>gjoyce@linux.ibm.com</email>
</author>
<published>2024-02-16T21:04:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=031b6233fe7ef75c6f21f7cefb56e89a677712f0'/>
<id>031b6233fe7ef75c6f21f7cefb56e89a677712f0</id>
<content type='text'>
[ Upstream commit 5429c8de56f6b2bd8f537df3a1e04e67b9c04282 ]

The SED Opal response parsing function response_parse() does not
handle the case of an empty atom in the response. This causes
the entry count to be too high and the response fails to be
parsed. Recognizing, but ignoring, empty atoms allows response
handling to succeed.

Signed-off-by: Greg Joyce &lt;gjoyce@linux.ibm.com&gt;
Link: https://lore.kernel.org/r/20240216210417.3526064-2-gjoyce@linux.ibm.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 5429c8de56f6b2bd8f537df3a1e04e67b9c04282 ]

The SED Opal response parsing function response_parse() does not
handle the case of an empty atom in the response. This causes
the entry count to be too high and the response fails to be
parsed. Recognizing, but ignoring, empty atoms allows response
handling to succeed.

Signed-off-by: Greg Joyce &lt;gjoyce@linux.ibm.com&gt;
Link: https://lore.kernel.org/r/20240216210417.3526064-2-gjoyce@linux.ibm.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: Fix WARNING in _copy_from_iter</title>
<updated>2024-03-01T12:34:49+00:00</updated>
<author>
<name>Christian A. Ehrhardt</name>
<email>lk@c--e.de</email>
</author>
<published>2024-01-21T20:26:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0f1bae071de9967602807472921829a54b2e5956'/>
<id>0f1bae071de9967602807472921829a54b2e5956</id>
<content type='text'>
[ Upstream commit 13f3956eb5681a4045a8dfdef48df5dc4d9f58a6 ]

Syzkaller reports a warning in _copy_from_iter because an
iov_iter is supposedly used in the wrong direction. The reason
is that syzcaller managed to generate a request with
a transfer direction of SG_DXFER_TO_FROM_DEV. This instructs
the kernel to copy user buffers into the kernel, read into
the copied buffers and then copy the data back to user space.

Thus the iovec is used in both directions.

Detect this situation in the block layer and construct a new
iterator with the correct direction for the copy-in.

Reported-by: syzbot+a532b03fdfee2c137666@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/0000000000009b92c10604d7a5e9@google.com/t/
Reported-by: syzbot+63dec323ac56c28e644f@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/0000000000003faaa105f6e7c658@google.com/T/
Signed-off-by: Christian A. Ehrhardt &lt;lk@c--e.de&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Link: https://lore.kernel.org/r/20240121202634.275068-1-lk@c--e.de
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 13f3956eb5681a4045a8dfdef48df5dc4d9f58a6 ]

Syzkaller reports a warning in _copy_from_iter because an
iov_iter is supposedly used in the wrong direction. The reason
is that syzcaller managed to generate a request with
a transfer direction of SG_DXFER_TO_FROM_DEV. This instructs
the kernel to copy user buffers into the kernel, read into
the copied buffers and then copy the data back to user space.

Thus the iovec is used in both directions.

Detect this situation in the block layer and construct a new
iterator with the correct direction for the copy-in.

Reported-by: syzbot+a532b03fdfee2c137666@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/0000000000009b92c10604d7a5e9@google.com/t/
Reported-by: syzbot+63dec323ac56c28e644f@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/0000000000003faaa105f6e7c658@google.com/T/
Signed-off-by: Christian A. Ehrhardt &lt;lk@c--e.de&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Link: https://lore.kernel.org/r/20240121202634.275068-1-lk@c--e.de
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: fix partial zone append completion handling in req_bio_endio()</title>
<updated>2024-02-23T08:25:18+00:00</updated>
<author>
<name>Damien Le Moal</name>
<email>dlemoal@kernel.org</email>
</author>
<published>2024-01-10T09:29:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b2261c2e763e0f9c25d5dcd2d34920ae7de30387'/>
<id>b2261c2e763e0f9c25d5dcd2d34920ae7de30387</id>
<content type='text'>
[ Upstream commit 748dc0b65ec2b4b7b3dbd7befcc4a54fdcac7988 ]

Partial completions of zone append request is not allowed but if a zone
append completion indicates a number of completed bytes different from
the original BIO size, only the BIO status is set to error. This leads
to bio_advance() not setting the BIO size to 0 and thus to not call
bio_endio() at the end of req_bio_endio().

Make sure a partially completed zone append is failed and completed
immediately by forcing the completed number of bytes (nbytes) to be
equal to the BIO size, thus ensuring that bio_endio() is called.

Fixes: 297db731847e ("block: fix req_bio_endio append error handling")
Cc: stable@kernel.vger.org
Signed-off-by: Damien Le Moal &lt;dlemoal@kernel.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Johannes Thumshirn &lt;johannes.thumshirn@wdc.com&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.de&gt;
Link: https://lore.kernel.org/r/20240110092942.442334-1-dlemoal@kernel.org
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 748dc0b65ec2b4b7b3dbd7befcc4a54fdcac7988 ]

Partial completions of zone append request is not allowed but if a zone
append completion indicates a number of completed bytes different from
the original BIO size, only the BIO status is set to error. This leads
to bio_advance() not setting the BIO size to 0 and thus to not call
bio_endio() at the end of req_bio_endio().

Make sure a partially completed zone append is failed and completed
immediately by forcing the completed number of bytes (nbytes) to be
equal to the BIO size, thus ensuring that bio_endio() is called.

Fixes: 297db731847e ("block: fix req_bio_endio append error handling")
Cc: stable@kernel.vger.org
Signed-off-by: Damien Le Moal &lt;dlemoal@kernel.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Johannes Thumshirn &lt;johannes.thumshirn@wdc.com&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.de&gt;
Link: https://lore.kernel.org/r/20240110092942.442334-1-dlemoal@kernel.org
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-wbt: Fix detection of dirty-throttled tasks</title>
<updated>2024-02-23T08:25:16+00:00</updated>
<author>
<name>Jan Kara</name>
<email>jack@suse.cz</email>
</author>
<published>2024-01-23T17:58:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=601b5540c154b12287e230223cd632bc131d1147'/>
<id>601b5540c154b12287e230223cd632bc131d1147</id>
<content type='text'>
commit f814bdda774c183b0cc15ec8f3b6e7c6f4527ba5 upstream.

The detection of dirty-throttled tasks in blk-wbt has been subtly broken
since its beginning in 2016. Namely if we are doing cgroup writeback and
the throttled task is not in the root cgroup, balance_dirty_pages() will
set dirty_sleep for the non-root bdi_writeback structure. However
blk-wbt checks dirty_sleep only in the root cgroup bdi_writeback
structure. Thus detection of recently throttled tasks is not working in
this case (we noticed this when we switched to cgroup v2 and suddently
writeback was slow).

Since blk-wbt has no easy way to get to proper bdi_writeback and
furthermore its intention has always been to work on the whole device
rather than on individual cgroups, just move the dirty_sleep timestamp
from bdi_writeback to backing_dev_info. That fixes the checking for
recently throttled task and saves memory for everybody as a bonus.

CC: stable@vger.kernel.org
Fixes: b57d74aff9ab ("writeback: track if we're sleeping on progress in balance_dirty_pages()")
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20240123175826.21452-1-jack@suse.cz
[axboe: fixup indentation errors]
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
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<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit f814bdda774c183b0cc15ec8f3b6e7c6f4527ba5 upstream.

The detection of dirty-throttled tasks in blk-wbt has been subtly broken
since its beginning in 2016. Namely if we are doing cgroup writeback and
the throttled task is not in the root cgroup, balance_dirty_pages() will
set dirty_sleep for the non-root bdi_writeback structure. However
blk-wbt checks dirty_sleep only in the root cgroup bdi_writeback
structure. Thus detection of recently throttled tasks is not working in
this case (we noticed this when we switched to cgroup v2 and suddently
writeback was slow).

Since blk-wbt has no easy way to get to proper bdi_writeback and
furthermore its intention has always been to work on the whole device
rather than on individual cgroups, just move the dirty_sleep timestamp
from bdi_writeback to backing_dev_info. That fixes the checking for
recently throttled task and saves memory for everybody as a bonus.

CC: stable@vger.kernel.org
Fixes: b57d74aff9ab ("writeback: track if we're sleeping on progress in balance_dirty_pages()")
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Link: https://lore.kernel.org/r/20240123175826.21452-1-jack@suse.cz
[axboe: fixup indentation errors]
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
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</content>
</entry>
<entry>
<title>blk-iocost: Fix an UBSAN shift-out-of-bounds warning</title>
<updated>2024-02-16T18:10:53+00:00</updated>
<author>
<name>Tejun Heo</name>
<email>tj@kernel.org</email>
</author>
<published>2023-11-20T22:25:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=27b216130e64651e76ed583742a1b4e4d08a67c3'/>
<id>27b216130e64651e76ed583742a1b4e4d08a67c3</id>
<content type='text'>
[ Upstream commit 2a427b49d02995ea4a6ff93a1432c40fa4d36821 ]

When iocg_kick_delay() is called from a CPU different than the one which set
the delay, @now may be in the past of @iocg-&gt;delay_at leading to the
following warning:

  UBSAN: shift-out-of-bounds in block/blk-iocost.c:1359:23
  shift exponent 18446744073709 is too large for 64-bit type 'u64' (aka 'unsigned long long')
  ...
  Call Trace:
   &lt;TASK&gt;
   dump_stack_lvl+0x79/0xc0
   __ubsan_handle_shift_out_of_bounds+0x2ab/0x300
   iocg_kick_delay+0x222/0x230
   ioc_rqos_merge+0x1d7/0x2c0
   __rq_qos_merge+0x2c/0x80
   bio_attempt_back_merge+0x83/0x190
   blk_attempt_plug_merge+0x101/0x150
   blk_mq_submit_bio+0x2b1/0x720
   submit_bio_noacct_nocheck+0x320/0x3e0
   __swap_writepage+0x2ab/0x9d0

The underflow itself doesn't really affect the behavior in any meaningful
way; however, the past timestamp may exaggerate the delay amount calculated
later in the code, which shouldn't be a material problem given the nature of
the delay mechanism.

If @now is in the past, this CPU is racing another CPU which recently set up
the delay and there's nothing this CPU can contribute w.r.t. the delay.
Let's bail early from iocg_kick_delay() in such cases.

Reported-by: Breno Leitão &lt;leitao@debian.org&gt;
Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Fixes: 5160a5a53c0c ("blk-iocost: implement delay adjustment hysteresis")
Link: https://lore.kernel.org/r/ZVvc9L_CYk5LO1fT@slm.duckdns.org
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 2a427b49d02995ea4a6ff93a1432c40fa4d36821 ]

When iocg_kick_delay() is called from a CPU different than the one which set
the delay, @now may be in the past of @iocg-&gt;delay_at leading to the
following warning:

  UBSAN: shift-out-of-bounds in block/blk-iocost.c:1359:23
  shift exponent 18446744073709 is too large for 64-bit type 'u64' (aka 'unsigned long long')
  ...
  Call Trace:
   &lt;TASK&gt;
   dump_stack_lvl+0x79/0xc0
   __ubsan_handle_shift_out_of_bounds+0x2ab/0x300
   iocg_kick_delay+0x222/0x230
   ioc_rqos_merge+0x1d7/0x2c0
   __rq_qos_merge+0x2c/0x80
   bio_attempt_back_merge+0x83/0x190
   blk_attempt_plug_merge+0x101/0x150
   blk_mq_submit_bio+0x2b1/0x720
   submit_bio_noacct_nocheck+0x320/0x3e0
   __swap_writepage+0x2ab/0x9d0

The underflow itself doesn't really affect the behavior in any meaningful
way; however, the past timestamp may exaggerate the delay amount calculated
later in the code, which shouldn't be a material problem given the nature of
the delay mechanism.

If @now is in the past, this CPU is racing another CPU which recently set up
the delay and there's nothing this CPU can contribute w.r.t. the delay.
Let's bail early from iocg_kick_delay() in such cases.

Reported-by: Breno Leitão &lt;leitao@debian.org&gt;
Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Fixes: 5160a5a53c0c ("blk-iocost: implement delay adjustment hysteresis")
Link: https://lore.kernel.org/r/ZVvc9L_CYk5LO1fT@slm.duckdns.org
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>
