<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git, branch v5.10.31</title>
<subtitle>Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git</subtitle>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/'/>
<entry>
<title>Linux 5.10.31</title>
<updated>2021-04-16T09:43:22+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2021-04-16T09:43:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=65f1995ea1e930674e76c5888b4643581e11434c'/>
<id>65f1995ea1e930674e76c5888b4643581e11434c</id>
<content type='text'>
Tested-by: Salvatore Bonaccorso &lt;carnil@debian.org&gt;
Tested-by: Pavel Machek (CIP) &lt;pavel@denx.de&gt;
Tested-by: Andrei Rabusov &lt;a.rabusov@tum.de&gt;
Tested-by: Shuah Khan &lt;skhan@linuxfoundation.org&gt;
Tested-by: Jason Self &lt;jason@bluehome.net&gt;
Tested-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Tested-by: Jon Hunter &lt;jonathanh@nvidia.com&gt;
Link: https://lore.kernel.org/r/20210415144413.165663182@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Tested-by: Salvatore Bonaccorso &lt;carnil@debian.org&gt;
Tested-by: Pavel Machek (CIP) &lt;pavel@denx.de&gt;
Tested-by: Andrei Rabusov &lt;a.rabusov@tum.de&gt;
Tested-by: Shuah Khan &lt;skhan@linuxfoundation.org&gt;
Tested-by: Jason Self &lt;jason@bluehome.net&gt;
Tested-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Tested-by: Jon Hunter &lt;jonathanh@nvidia.com&gt;
Link: https://lore.kernel.org/r/20210415144413.165663182@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xen/events: fix setting irq affinity</title>
<updated>2021-04-16T09:43:22+00:00</updated>
<author>
<name>Juergen Gross</name>
<email>jgross@suse.com</email>
</author>
<published>2021-04-12T06:28:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=ceee49ca34bf141f853d14ca2d8fdcf919875a6a'/>
<id>ceee49ca34bf141f853d14ca2d8fdcf919875a6a</id>
<content type='text'>
The backport of upstream patch 25da4618af240fbec61 ("xen/events: don't
unmask an event channel when an eoi is pending") introduced a
regression for stable kernels 5.10 and older: setting IRQ affinity for
IRQs related to interdomain events would no longer work, as moving the
IRQ to its new cpu was not included in the irq_ack callback for those
events.

Fix that by adding the needed call.

Note that kernels 5.11 and later don't need the explicit moving of the
IRQ to the target cpu in the irq_ack callback, due to a rework of the
affinity setting in kernel 5.11.

Signed-off-by: Juergen Gross &lt;jgross@suse.com&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>
The backport of upstream patch 25da4618af240fbec61 ("xen/events: don't
unmask an event channel when an eoi is pending") introduced a
regression for stable kernels 5.10 and older: setting IRQ affinity for
IRQs related to interdomain events would no longer work, as moving the
IRQ to its new cpu was not included in the irq_ack callback for those
events.

Fix that by adding the needed call.

Note that kernels 5.11 and later don't need the explicit moving of the
IRQ to the target cpu in the irq_ack callback, due to a rework of the
affinity setting in kernel 5.11.

Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>net: sfp: cope with SFPs that set both LOS normal and LOS inverted</title>
<updated>2021-04-16T09:43:22+00:00</updated>
<author>
<name>Russell King</name>
<email>rmk+kernel@armlinux.org.uk</email>
</author>
<published>2021-01-10T10:58:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=9d9facd32d89f737605c7135cee7f8189959d098'/>
<id>9d9facd32d89f737605c7135cee7f8189959d098</id>
<content type='text'>
commit 624407d2cf14ff58e53bf4b2af9595c4f21d606e upstream.

The SFP MSA defines two option bits in byte 65 to indicate how the
Rx_LOS signal on SFP pin 8 behaves:

bit 2 - Loss of Signal implemented, signal inverted from standard
        definition in SFP MSA (often called "Signal Detect").
bit 1 - Loss of Signal implemented, signal as defined in SFP MSA
        (often called "Rx_LOS").

Clearly, setting both bits results in a meaningless situation: it would
mean that LOS is implemented in both the normal sense (1 = signal loss)
and inverted sense (0 = signal loss).

Unfortunately, there are modules out there which set both bits, which
will be initially interpret as "inverted" sense, and then, if the LOS
signal changes state, we will toggle between LINK_UP and WAIT_LOS
states.

Change our LOS handling to give well defined behaviour: only interpret
these bits as meaningful if exactly one is set, otherwise treat it as
if LOS is not implemented.

Signed-off-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Link: https://lore.kernel.org/r/E1kyYQa-0004iR-CU@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Cc: Pali Rohár &lt;pali@kernel.org&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 624407d2cf14ff58e53bf4b2af9595c4f21d606e upstream.

The SFP MSA defines two option bits in byte 65 to indicate how the
Rx_LOS signal on SFP pin 8 behaves:

bit 2 - Loss of Signal implemented, signal inverted from standard
        definition in SFP MSA (often called "Signal Detect").
bit 1 - Loss of Signal implemented, signal as defined in SFP MSA
        (often called "Rx_LOS").

Clearly, setting both bits results in a meaningless situation: it would
mean that LOS is implemented in both the normal sense (1 = signal loss)
and inverted sense (0 = signal loss).

Unfortunately, there are modules out there which set both bits, which
will be initially interpret as "inverted" sense, and then, if the LOS
signal changes state, we will toggle between LINK_UP and WAIT_LOS
states.

Change our LOS handling to give well defined behaviour: only interpret
these bits as meaningful if exactly one is set, otherwise treat it as
if LOS is not implemented.

Signed-off-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Link: https://lore.kernel.org/r/E1kyYQa-0004iR-CU@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Cc: Pali Rohár &lt;pali@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: sfp: relax bitrate-derived mode check</title>
<updated>2021-04-16T09:43:22+00:00</updated>
<author>
<name>Russell King</name>
<email>rmk+kernel@armlinux.org.uk</email>
</author>
<published>2020-12-09T11:22:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=2a60ab2dab3df84e6d6690ac7a23e1d921b25a36'/>
<id>2a60ab2dab3df84e6d6690ac7a23e1d921b25a36</id>
<content type='text'>
commit 7a77233ec6d114322e2c4f71b4e26dbecd9ea8a7 upstream.

Do not check the encoding when deriving 1000BASE-X from the bitrate
when no other modes are discovered. Some GPON modules (VSOL V2801F
and CarlitoxxPro CPGOS03-0490 v2.0) indicate NRZ encoding with a
1200Mbaud bitrate, but should be driven with 1000BASE-X on the host
side.

Tested-by: Pali Rohár &lt;pali@kernel.org&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Signed-off-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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 7a77233ec6d114322e2c4f71b4e26dbecd9ea8a7 upstream.

Do not check the encoding when deriving 1000BASE-X from the bitrate
when no other modes are discovered. Some GPON modules (VSOL V2801F
and CarlitoxxPro CPGOS03-0490 v2.0) indicate NRZ encoding with a
1200Mbaud bitrate, but should be driven with 1000BASE-X on the host
side.

Tested-by: Pali Rohár &lt;pali@kernel.org&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Signed-off-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf map: Tighten snprintf() string precision to pass gcc check on some 32-bit arches</title>
<updated>2021-04-16T09:43:22+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2021-03-05T13:02:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=cd8ce27e6caaee47a6d4212e6d9b82e28969cf40'/>
<id>cd8ce27e6caaee47a6d4212e6d9b82e28969cf40</id>
<content type='text'>
commit 77d02bd00cea9f1a87afe58113fa75b983d6c23a upstream.

Noticed on a debian:experimental mips and mipsel cross build build
environment:

  perfbuilder@ec265a086e9b:~$ mips-linux-gnu-gcc --version | head -1
  mips-linux-gnu-gcc (Debian 10.2.1-3) 10.2.1 20201224
  perfbuilder@ec265a086e9b:~$

    CC       /tmp/build/perf/util/map.o
  util/map.c: In function 'map__new':
  util/map.c:109:5: error: '%s' directive output may be truncated writing between 1 and 2147483645 bytes into a region of size 4096 [-Werror=format-truncation=]
    109 |    "%s/platforms/%s/arch-%s/usr/lib/%s",
        |     ^~
  In file included from /usr/mips-linux-gnu/include/stdio.h:867,
                   from util/symbol.h:11,
                   from util/map.c:2:
  /usr/mips-linux-gnu/include/bits/stdio2.h:67:10: note: '__builtin___snprintf_chk' output 32 or more bytes (assuming 4294967321) into a destination of size 4096
     67 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
        |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     68 |        __bos (__s), __fmt, __va_arg_pack ());
        |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cc1: all warnings being treated as errors

Since we have the lenghts for what lands in that place, use it to give
the compiler more info and make it happy.

Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Anders Roxell &lt;anders.roxell@linaro.org&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 77d02bd00cea9f1a87afe58113fa75b983d6c23a upstream.

Noticed on a debian:experimental mips and mipsel cross build build
environment:

  perfbuilder@ec265a086e9b:~$ mips-linux-gnu-gcc --version | head -1
  mips-linux-gnu-gcc (Debian 10.2.1-3) 10.2.1 20201224
  perfbuilder@ec265a086e9b:~$

    CC       /tmp/build/perf/util/map.o
  util/map.c: In function 'map__new':
  util/map.c:109:5: error: '%s' directive output may be truncated writing between 1 and 2147483645 bytes into a region of size 4096 [-Werror=format-truncation=]
    109 |    "%s/platforms/%s/arch-%s/usr/lib/%s",
        |     ^~
  In file included from /usr/mips-linux-gnu/include/stdio.h:867,
                   from util/symbol.h:11,
                   from util/map.c:2:
  /usr/mips-linux-gnu/include/bits/stdio2.h:67:10: note: '__builtin___snprintf_chk' output 32 or more bytes (assuming 4294967321) into a destination of size 4096
     67 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
        |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     68 |        __bos (__s), __fmt, __va_arg_pack ());
        |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cc1: all warnings being treated as errors

Since we have the lenghts for what lands in that place, use it to give
the compiler more info and make it happy.

Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Anders Roxell &lt;anders.roxell@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: x_tables: fix compat match/target pad out-of-bound write</title>
<updated>2021-04-16T09:43:21+00:00</updated>
<author>
<name>Florian Westphal</name>
<email>fw@strlen.de</email>
</author>
<published>2021-04-07T19:38:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=1f3b9000cb44318b0de40a0f495a5a708cd9be6e'/>
<id>1f3b9000cb44318b0de40a0f495a5a708cd9be6e</id>
<content type='text'>
commit b29c457a6511435960115c0f548c4360d5f4801d upstream.

xt_compat_match/target_from_user doesn't check that zeroing the area
to start of next rule won't write past end of allocated ruleset blob.

Remove this code and zero the entire blob beforehand.

Reported-by: syzbot+cfc0247ac173f597aaaa@syzkaller.appspotmail.com
Reported-by: Andy Nguyen &lt;theflow@google.com&gt;
Fixes: 9fa492cdc160c ("[NETFILTER]: x_tables: simplify compat API")
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&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 b29c457a6511435960115c0f548c4360d5f4801d upstream.

xt_compat_match/target_from_user doesn't check that zeroing the area
to start of next rule won't write past end of allocated ruleset blob.

Remove this code and zero the entire blob beforehand.

Reported-by: syzbot+cfc0247ac173f597aaaa@syzkaller.appspotmail.com
Reported-by: Andy Nguyen &lt;theflow@google.com&gt;
Fixes: 9fa492cdc160c ("[NETFILTER]: x_tables: simplify compat API")
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: don't ignore REQ_NOWAIT for direct IO</title>
<updated>2021-04-16T09:43:21+00:00</updated>
<author>
<name>Pavel Begunkov</name>
<email>asml.silence@gmail.com</email>
</author>
<published>2020-11-20T17:10:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=5402a67ac4033e2dceec118286ca1c453f682669'/>
<id>5402a67ac4033e2dceec118286ca1c453f682669</id>
<content type='text'>
[ Upstream commit f8b78caf21d5bc3fcfc40c18898f9d52ed1451a5 ]

If IOCB_NOWAIT is set on submission, then that needs to get propagated to
REQ_NOWAIT on the block side. Otherwise we completely lose this
information, and any issuer of IOCB_NOWAIT IO will potentially end up
blocking on eg request allocation on the storage side.

Signed-off-by: Pavel Begunkov &lt;asml.silence@gmail.com&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 f8b78caf21d5bc3fcfc40c18898f9d52ed1451a5 ]

If IOCB_NOWAIT is set on submission, then that needs to get propagated to
REQ_NOWAIT on the block side. Otherwise we completely lose this
information, and any issuer of IOCB_NOWAIT IO will potentially end up
blocking on eg request allocation on the storage side.

Signed-off-by: Pavel Begunkov &lt;asml.silence@gmail.com&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>riscv,entry: fix misaligned base for excp_vect_table</title>
<updated>2021-04-16T09:43:21+00:00</updated>
<author>
<name>Zihao Yu</name>
<email>yuzihao@ict.ac.cn</email>
</author>
<published>2021-03-17T08:17:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=efa7b6e4017aeccc0d7595e110f2d69a26332b2c'/>
<id>efa7b6e4017aeccc0d7595e110f2d69a26332b2c</id>
<content type='text'>
[ Upstream commit ac8d0b901f0033b783156ab2dc1a0e73ec42409b ]

In RV64, the size of each entry in excp_vect_table is 8 bytes. If the
base of the table is not 8-byte aligned, loading an entry in the table
will raise a misaligned exception. Although such exception will be
handled by opensbi/bbl, this still causes performance degradation.

Signed-off-by: Zihao Yu &lt;yuzihao@ict.ac.cn&gt;
Reviewed-by: Anup Patel &lt;anup@brainfault.org&gt;
Signed-off-by: Palmer Dabbelt &lt;palmerdabbelt@google.com&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 ac8d0b901f0033b783156ab2dc1a0e73ec42409b ]

In RV64, the size of each entry in excp_vect_table is 8 bytes. If the
base of the table is not 8-byte aligned, loading an entry in the table
will raise a misaligned exception. Although such exception will be
handled by opensbi/bbl, this still causes performance degradation.

Signed-off-by: Zihao Yu &lt;yuzihao@ict.ac.cn&gt;
Reviewed-by: Anup Patel &lt;anup@brainfault.org&gt;
Signed-off-by: Palmer Dabbelt &lt;palmerdabbelt@google.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>io_uring: don't mark S_ISBLK async work as unbounded</title>
<updated>2021-04-16T09:43:21+00:00</updated>
<author>
<name>Jens Axboe</name>
<email>axboe@kernel.dk</email>
</author>
<published>2021-04-01T14:38:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=6fbdce3cde97896ff4c2fb99e5d4bba45297a178'/>
<id>6fbdce3cde97896ff4c2fb99e5d4bba45297a178</id>
<content type='text'>
[ Upstream commit 4b982bd0f383db9132e892c0c5144117359a6289 ]

S_ISBLK is marked as unbounded work for async preparation, because it
doesn't match S_ISREG. That is incorrect, as any read/write to a block
device is also a bounded operation. Fix it up and ensure that S_ISBLK
isn't marked unbounded.

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 4b982bd0f383db9132e892c0c5144117359a6289 ]

S_ISBLK is marked as unbounded work for async preparation, because it
doesn't match S_ISREG. That is incorrect, as any read/write to a block
device is also a bounded operation. Fix it up and ensure that S_ISBLK
isn't marked unbounded.

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>null_blk: fix command timeout completion handling</title>
<updated>2021-04-16T09:43:21+00:00</updated>
<author>
<name>Damien Le Moal</name>
<email>damien.lemoal@wdc.com</email>
</author>
<published>2021-03-31T22:52:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=5d4600017beeab73e0d5550f9485564fba66b460'/>
<id>5d4600017beeab73e0d5550f9485564fba66b460</id>
<content type='text'>
[ Upstream commit de3510e52b0a398261271455562458003b8eea62 ]

Memory backed or zoned null block devices may generate actual request
timeout errors due to the submission path being blocked on memory
allocation or zone locking. Unlike fake timeouts or injected timeouts,
the request submission path will call blk_mq_complete_request() or
blk_mq_end_request() for these real timeout errors, causing a double
completion and use after free situation as the block layer timeout
handler executes blk_mq_rq_timed_out() and __blk_mq_free_request() in
blk_mq_check_expired(). This problem often triggers a NULL pointer
dereference such as:

BUG: kernel NULL pointer dereference, address: 0000000000000050
RIP: 0010:blk_mq_sched_mark_restart_hctx+0x5/0x20
...
Call Trace:
  dd_finish_request+0x56/0x80
  blk_mq_free_request+0x37/0x130
  null_handle_cmd+0xbf/0x250 [null_blk]
  ? null_queue_rq+0x67/0xd0 [null_blk]
  blk_mq_dispatch_rq_list+0x122/0x850
  __blk_mq_do_dispatch_sched+0xbb/0x2c0
  __blk_mq_sched_dispatch_requests+0x13d/0x190
  blk_mq_sched_dispatch_requests+0x30/0x60
  __blk_mq_run_hw_queue+0x49/0x90
  process_one_work+0x26c/0x580
  worker_thread+0x55/0x3c0
  ? process_one_work+0x580/0x580
  kthread+0x134/0x150
  ? kthread_create_worker_on_cpu+0x70/0x70
  ret_from_fork+0x1f/0x30

This problem very often triggers when running the full btrfs xfstests
on a memory-backed zoned null block device in a VM with limited amount
of memory.

Avoid this by executing blk_mq_complete_request() in null_timeout_rq()
only for commands that are marked for a fake timeout completion using
the fake_timeout boolean in struct null_cmd. For timeout errors injected
through debugfs, the timeout handler will execute
blk_mq_complete_request()i as before. This is safe as the submission
path does not execute complete requests in this case.

In null_timeout_rq(), also make sure to set the command error field to
BLK_STS_TIMEOUT and to propagate this error through to the request
completion.

Reported-by: Johannes Thumshirn &lt;Johannes.Thumshirn@wdc.com&gt;
Signed-off-by: Damien Le Moal &lt;damien.lemoal@wdc.com&gt;
Tested-by: Johannes Thumshirn &lt;Johannes.Thumshirn@wdc.com&gt;
Reviewed-by: Johannes Thumshirn &lt;Johannes.Thumshirn@wdc.com&gt;
Link: https://lore.kernel.org/r/20210331225244.126426-1-damien.lemoal@wdc.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 de3510e52b0a398261271455562458003b8eea62 ]

Memory backed or zoned null block devices may generate actual request
timeout errors due to the submission path being blocked on memory
allocation or zone locking. Unlike fake timeouts or injected timeouts,
the request submission path will call blk_mq_complete_request() or
blk_mq_end_request() for these real timeout errors, causing a double
completion and use after free situation as the block layer timeout
handler executes blk_mq_rq_timed_out() and __blk_mq_free_request() in
blk_mq_check_expired(). This problem often triggers a NULL pointer
dereference such as:

BUG: kernel NULL pointer dereference, address: 0000000000000050
RIP: 0010:blk_mq_sched_mark_restart_hctx+0x5/0x20
...
Call Trace:
  dd_finish_request+0x56/0x80
  blk_mq_free_request+0x37/0x130
  null_handle_cmd+0xbf/0x250 [null_blk]
  ? null_queue_rq+0x67/0xd0 [null_blk]
  blk_mq_dispatch_rq_list+0x122/0x850
  __blk_mq_do_dispatch_sched+0xbb/0x2c0
  __blk_mq_sched_dispatch_requests+0x13d/0x190
  blk_mq_sched_dispatch_requests+0x30/0x60
  __blk_mq_run_hw_queue+0x49/0x90
  process_one_work+0x26c/0x580
  worker_thread+0x55/0x3c0
  ? process_one_work+0x580/0x580
  kthread+0x134/0x150
  ? kthread_create_worker_on_cpu+0x70/0x70
  ret_from_fork+0x1f/0x30

This problem very often triggers when running the full btrfs xfstests
on a memory-backed zoned null block device in a VM with limited amount
of memory.

Avoid this by executing blk_mq_complete_request() in null_timeout_rq()
only for commands that are marked for a fake timeout completion using
the fake_timeout boolean in struct null_cmd. For timeout errors injected
through debugfs, the timeout handler will execute
blk_mq_complete_request()i as before. This is safe as the submission
path does not execute complete requests in this case.

In null_timeout_rq(), also make sure to set the command error field to
BLK_STS_TIMEOUT and to propagate this error through to the request
completion.

Reported-by: Johannes Thumshirn &lt;Johannes.Thumshirn@wdc.com&gt;
Signed-off-by: Damien Le Moal &lt;damien.lemoal@wdc.com&gt;
Tested-by: Johannes Thumshirn &lt;Johannes.Thumshirn@wdc.com&gt;
Reviewed-by: Johannes Thumshirn &lt;Johannes.Thumshirn@wdc.com&gt;
Link: https://lore.kernel.org/r/20210331225244.126426-1-damien.lemoal@wdc.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>
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