<feed xmlns='http://www.w3.org/2005/Atom'>
<title>lwn.git/include, branch v5.17-rc2</title>
<subtitle>Linux kernel documentation tree maintained by Jonathan Corbet</subtitle>
<id>http://mirrors.hust.edu.cn/git/lwn.git/atom?h=v5.17-rc2</id>
<link rel='self' href='http://mirrors.hust.edu.cn/git/lwn.git/atom?h=v5.17-rc2'/>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/'/>
<updated>2022-01-30T07:56:58+00:00</updated>
<entry>
<title>psi: fix "no previous prototype" warnings when CONFIG_CGROUPS=n</title>
<updated>2022-01-30T07:56:58+00:00</updated>
<author>
<name>Suren Baghdasaryan</name>
<email>surenb@google.com</email>
</author>
<published>2022-01-29T21:41:17+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=51e50fbd3efc6064c30ed73a5e009018b36e290a'/>
<id>urn:sha1:51e50fbd3efc6064c30ed73a5e009018b36e290a</id>
<content type='text'>
When CONFIG_CGROUPS is disabled psi code generates the following
warnings:

  kernel/sched/psi.c:1112:21: warning: no previous prototype for 'psi_trigger_create' [-Wmissing-prototypes]
      1112 | struct psi_trigger *psi_trigger_create(struct psi_group *group,
           |                     ^~~~~~~~~~~~~~~~~~
  kernel/sched/psi.c:1182:6: warning: no previous prototype for 'psi_trigger_destroy' [-Wmissing-prototypes]
      1182 | void psi_trigger_destroy(struct psi_trigger *t)
           |      ^~~~~~~~~~~~~~~~~~~
  kernel/sched/psi.c:1249:10: warning: no previous prototype for 'psi_trigger_poll' [-Wmissing-prototypes]
      1249 | __poll_t psi_trigger_poll(void **trigger_ptr,
           |          ^~~~~~~~~~~~~~~~

Change the declarations of these functions in the header to provide the
prototypes even when they are unused.

Link: https://lkml.kernel.org/r/20220119223940.787748-2-surenb@google.com
Fixes: 0e94682b73bf ("psi: introduce psi monitor")
Signed-off-by: Suren Baghdasaryan &lt;surenb@google.com&gt;
Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm, kasan: use compare-exchange operation to set KASAN page tag</title>
<updated>2022-01-30T07:56:58+00:00</updated>
<author>
<name>Peter Collingbourne</name>
<email>pcc@google.com</email>
</author>
<published>2022-01-29T21:41:14+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=27fe73394a1c6d0b07fa4d95f1bca116d1cc66e9'/>
<id>urn:sha1:27fe73394a1c6d0b07fa4d95f1bca116d1cc66e9</id>
<content type='text'>
It has been reported that the tag setting operation on newly-allocated
pages can cause the page flags to be corrupted when performed
concurrently with other flag updates as a result of the use of
non-atomic operations.

Fix the problem by using a compare-exchange loop to update the tag.

Link: https://lkml.kernel.org/r/20220120020148.1632253-1-pcc@google.com
Link: https://linux-review.googlesource.com/id/I456b24a2b9067d93968d43b4bb3351c0cec63101
Fixes: 2813b9c02962 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc")
Signed-off-by: Peter Collingbourne &lt;pcc@google.com&gt;
Reviewed-by: Andrey Konovalov &lt;andreyknvl@gmail.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>mm: page-&gt;mapping folio-&gt;mapping should have the same offset</title>
<updated>2022-01-30T07:56:58+00:00</updated>
<author>
<name>Wei Yang</name>
<email>richard.weiyang@gmail.com</email>
</author>
<published>2022-01-29T21:41:04+00:00</published>
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<id>urn:sha1:536f4217ced62b671bd759f6b549621a5654a70f</id>
<content type='text'>
As with the other members of folio, the offset of page-&gt;mapping and
folio-&gt;mapping must be the same.  The compile-time check was
inadvertently removed during development.  Add it back.

[willy@infradead.org: changelog redo]

Link: https://lkml.kernel.org/r/20220104011734.21714-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang &lt;richard.weiyang@gmail.com&gt;
Reviewed-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>include/linux/sysctl.h: fix register_sysctl_mount_point() return type</title>
<updated>2022-01-30T07:56:58+00:00</updated>
<author>
<name>Andrew Morton</name>
<email>akpm@linux-foundation.org</email>
</author>
<published>2022-01-29T21:40:52+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=6cb917411e028dcb66ce8f5db1b47361b78d7d3f'/>
<id>urn:sha1:6cb917411e028dcb66ce8f5db1b47361b78d7d3f</id>
<content type='text'>
The CONFIG_SYSCTL=n stub returns the wrong type.

Fixes: ee9efac48a082 ("sysctl: add helper to register a sysctl mount point")
Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Acked-by: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
Cc: Tong Zhang &lt;ztong0001@gmail.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 'tty-5.17-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty</title>
<updated>2022-01-29T13:23:13+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-01-29T13:23:13+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=bb37101b36332345a1e1c1f9f2f3bcc8ad7edb65'/>
<id>urn:sha1:bb37101b36332345a1e1c1f9f2f3bcc8ad7edb65</id>
<content type='text'>
Pull tty/serial driver fixes from Greg KH:
 "Here are some small bug fixes and reverts for reported problems with
  the tty core and drivers. They include:

   - revert the fifo use for the 8250 console mode. It caused too many
     regressions and problems, and had a bug in it as well. This is
     being reworked and should show up in a later -rc1 release, but it's
     not ready for 5.17

   - rpmsg tty race fix

   - restore the cyclades.h uapi header file. Turns out a compiler test
     suite used it for some unknown reason. Bring it back just for the
     parts that are used by the builder test so they continue to build.
     No functionality is restored as no one actually has this hardware
     anymore, nor is it really tested.

   - stm32 driver fixes

   - n_gsm flow control fixes

   - pl011 driver fix

   - rs485 initialization fix

  All of these have been in linux-next this week with no reported
  problems"

* tag 'tty-5.17-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  kbuild: remove include/linux/cyclades.h from header file check
  serial: core: Initialize rs485 RTS polarity already on probe
  serial: pl011: Fix incorrect rs485 RTS polarity on set_mctrl
  serial: stm32: fix software flow control transfer
  serial: stm32: prevent TDR register overwrite when sending x_char
  tty: n_gsm: fix SW flow control encoding/handling
  serial: 8250: of: Fix mapped region size when using reg-offset property
  tty: rpmsg: Fix race condition releasing tty port
  tty: Partially revert the removal of the Cyclades public API
  tty: Add support for Brainboxes UC cards.
  Revert "tty: serial: Use fifo in 8250 console driver"
</content>
</entry>
<entry>
<title>Merge tag 'usb-5.17-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb</title>
<updated>2022-01-29T13:17:20+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-01-29T13:17:20+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=44aa31a2bfaab2ad36614f05162cda88ade9ce65'/>
<id>urn:sha1:44aa31a2bfaab2ad36614f05162cda88ade9ce65</id>
<content type='text'>
Pull USB driver fixes from Greg KH:
 "Here are some small USB driver fixes for 5.17-rc2 that resolve a
  number of reported problems. These include:

   - typec driver fixes

   - xhci platform driver fixes for suspending

   - ulpi core fix

   - role.h build fix

   - new device ids

   - syzbot-reported bugfixes

   - gadget driver fixes

   - dwc3 driver fixes

   - other small fixes

  All of these have been in linux-next this week with no reported
  issues"

* tag 'usb-5.17-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: cdnsp: Fix segmentation fault in cdns_lost_power function
  usb: dwc2: gadget: don't try to disable ep0 in dwc2_hsotg_suspend
  usb: gadget: at91_udc: fix incorrect print type
  usb: dwc3: xilinx: Fix error handling when getting USB3 PHY
  usb: dwc3: xilinx: Skip resets and USB3 register settings for USB2.0 mode
  usb: xhci-plat: fix crash when suspend if remote wake enable
  usb: common: ulpi: Fix crash in ulpi_match()
  usb: gadget: f_sourcesink: Fix isoc transfer for USB_SPEED_SUPER_PLUS
  ucsi_ccg: Check DEV_INT bit only when starting CCG4
  USB: core: Fix hang in usb_kill_urb by adding memory barriers
  usb-storage: Add unusual-devs entry for VL817 USB-SATA bridge
  usb: typec: tcpm: Do not disconnect when receiving VSAFE0V
  usb: typec: tcpm: Do not disconnect while receiving VBUS off
  usb: typec: Don't try to register component master without components
  usb: typec: Only attempt to link USB ports if there is fwnode
  usb: typec: tcpci: don't touch CC line if it's Vconn source
  usb: roles: fix include/linux/usb/role.h compile issue
</content>
</entry>
<entry>
<title>Merge tag 'block-5.17-2022-01-28' of git://git.kernel.dk/linux-block</title>
<updated>2022-01-29T13:01:08+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-01-29T13:01:08+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=cb323ee75d24e7acc2f188d123ba6df46159cf09'/>
<id>urn:sha1:cb323ee75d24e7acc2f188d123ba6df46159cf09</id>
<content type='text'>
Pull block fixes from Jens Axboe:

 - NVMe pull request
      - add the IGNORE_DEV_SUBNQN quirk for Intel P4500/P4600 SSDs (Wu
        Zheng)
      - remove the unneeded ret variable in nvmf_dev_show (Changcheng
        Deng)

 - Fix for a hang regression introduced with a patch in the merge
   window, where low queue depth devices would not always get woken
   correctly (Laibin)

 - Small series fixing an IO accounting issue with bio backed dm devices
   (Mike, Yu)

* tag 'block-5.17-2022-01-28' of git://git.kernel.dk/linux-block:
  dm: properly fix redundant bio-based IO accounting
  dm: revert partial fix for redundant bio-based IO accounting
  block: add bio_start_io_acct_time() to control start_time
  blk-mq: Fix wrong wakeup batch configuration which will cause hang
  nvme-fabrics: remove the unneeded ret variable in nvmf_dev_show
  nvme-pci: add the IGNORE_DEV_SUBNQN quirk for Intel P4500/P4600 SSDs
  blk-mq: fix missing blk_account_io_done() in error path
  block: fix memory leak in disk_register_independent_access_ranges
</content>
</entry>
<entry>
<title>Merge tag 'fixes-v5.17-lsm-ceph-null' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security</title>
<updated>2022-01-29T06:52:27+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-01-29T06:52:27+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=d1e7f0919ea84911e2ab965418cd502ba6a906e1'/>
<id>urn:sha1:d1e7f0919ea84911e2ab965418cd502ba6a906e1</id>
<content type='text'>
Pull security sybsystem fix from James Morris:
 "Fix NULL pointer crash in LSM via Ceph, from Vivek Goyal"

* tag 'fixes-v5.17-lsm-ceph-null' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  security, lsm: dentry_init_security() Handle multi LSM registration
</content>
</entry>
<entry>
<title>block: add bio_start_io_acct_time() to control start_time</title>
<updated>2022-01-28T19:28:15+00:00</updated>
<author>
<name>Mike Snitzer</name>
<email>snitzer@redhat.com</email>
</author>
<published>2022-01-28T15:58:39+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=e45c47d1f94e0cc7b6b079fdb4bcce2995e2adc4'/>
<id>urn:sha1:e45c47d1f94e0cc7b6b079fdb4bcce2995e2adc4</id>
<content type='text'>
bio_start_io_acct_time() interface is like bio_start_io_acct() that
allows start_time to be passed in. This gives drivers the ability to
defer starting accounting until after IO is issued (but possibily not
entirely due to bio splitting).

Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Mike Snitzer &lt;snitzer@redhat.com&gt;
Link: https://lore.kernel.org/r/20220128155841.39644-2-snitzer@redhat.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
</entry>
<entry>
<title>security, lsm: dentry_init_security() Handle multi LSM registration</title>
<updated>2022-01-28T18:53:26+00:00</updated>
<author>
<name>Vivek Goyal</name>
<email>vgoyal@redhat.com</email>
</author>
<published>2022-01-26T20:35:14+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=7f5056b9e7b71149bf11073f00a57fa1ac2921a9'/>
<id>urn:sha1:7f5056b9e7b71149bf11073f00a57fa1ac2921a9</id>
<content type='text'>
A ceph user has reported that ceph is crashing with kernel NULL pointer
dereference. Following is the backtrace.

/proc/version: Linux version 5.16.2-arch1-1 (linux@archlinux) (gcc (GCC)
11.1.0, GNU ld (GNU Binutils) 2.36.1) #1 SMP PREEMPT Thu, 20 Jan 2022
16:18:29 +0000
distro / arch: Arch Linux / x86_64
SELinux is not enabled
ceph cluster version: 16.2.7 (dd0603118f56ab514f133c8d2e3adfc983942503)

relevant dmesg output:
[   30.947129] BUG: kernel NULL pointer dereference, address:
0000000000000000
[   30.947206] #PF: supervisor read access in kernel mode
[   30.947258] #PF: error_code(0x0000) - not-present page
[   30.947310] PGD 0 P4D 0
[   30.947342] Oops: 0000 [#1] PREEMPT SMP PTI
[   30.947388] CPU: 5 PID: 778 Comm: touch Not tainted 5.16.2-arch1-1 #1
86fbf2c313cc37a553d65deb81d98e9dcc2a3659
[   30.947486] Hardware name: Gigabyte Technology Co., Ltd. B365M
DS3H/B365M DS3H, BIOS F5 08/13/2019
[   30.947569] RIP: 0010:strlen+0x0/0x20
[   30.947616] Code: b6 07 38 d0 74 16 48 83 c7 01 84 c0 74 05 48 39 f7 75
ec 31 c0 31 d2 89 d6 89 d7 c3 48 89 f8 31 d2 89 d6 89 d7 c3 0
f 1f 40 00 &lt;80&gt; 3f 00 74 12 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 31
ff
[   30.947782] RSP: 0018:ffffa4ed80ffbbb8 EFLAGS: 00010246
[   30.947836] RAX: 0000000000000000 RBX: ffffa4ed80ffbc60 RCX:
0000000000000000
[   30.947904] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
0000000000000000
[   30.947971] RBP: ffff94b0d15c0ae0 R08: 0000000000000000 R09:
0000000000000000
[   30.948040] R10: 0000000000000000 R11: 0000000000000000 R12:
0000000000000000
[   30.948106] R13: 0000000000000001 R14: ffffa4ed80ffbc60 R15:
0000000000000000
[   30.948174] FS:  00007fc7520f0740(0000) GS:ffff94b7ced40000(0000)
knlGS:0000000000000000
[   30.948252] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   30.948308] CR2: 0000000000000000 CR3: 0000000104a40001 CR4:
00000000003706e0
[   30.948376] Call Trace:
[   30.948404]  &lt;TASK&gt;
[   30.948431]  ceph_security_init_secctx+0x7b/0x240 [ceph
49f9c4b9bf5be8760f19f1747e26da33920bce4b]
[   30.948582]  ceph_atomic_open+0x51e/0x8a0 [ceph
49f9c4b9bf5be8760f19f1747e26da33920bce4b]
[   30.948708]  ? get_cached_acl+0x4d/0xa0
[   30.948759]  path_openat+0x60d/0x1030
[   30.948809]  do_filp_open+0xa5/0x150
[   30.948859]  do_sys_openat2+0xc4/0x190
[   30.948904]  __x64_sys_openat+0x53/0xa0
[   30.948948]  do_syscall_64+0x5c/0x90
[   30.948989]  ? exc_page_fault+0x72/0x180
[   30.949034]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   30.949091] RIP: 0033:0x7fc7521e25bb
[   30.950849] Code: 25 00 00 41 00 3d 00 00 41 00 74 4b 64 8b 04 25 18 00
00 00 85 c0 75 67 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 0
0 00 0f 05 &lt;48&gt; 3d 00 f0 ff ff 0f 87 91 00 00 00 48 8b 54 24 28 64 48 2b 14
25

Core of the problem is that ceph checks for return code from
security_dentry_init_security() and if return code is 0, it assumes
everything is fine and continues to call strlen(name), which crashes.

Typically SELinux LSM returns 0 and sets name to "security.selinux" and
it is not a problem. Or if selinux is not compiled in or disabled, it
returns -EOPNOTSUP and ceph deals with it.

But somehow in this configuration, 0 is being returned and "name" is
not being initialized and that's creating the problem.

Our suspicion is that BPF LSM is registering a hook for
dentry_init_security() and returns hook default of 0.

LSM_HOOK(int, 0, dentry_init_security, struct dentry *dentry,...)

I have not been able to reproduce it just by doing CONFIG_BPF_LSM=y.
Stephen has tested the patch though and confirms it solves the problem
for him.

dentry_init_security() is written in such a way that it expects only one
LSM to register the hook. Atleast that's the expectation with current code.

If another LSM returns a hook and returns default, it will simply return
0 as of now and that will break ceph.

Hence, suggestion is that change semantics of this hook a bit. If there
are no LSMs or no LSM is taking ownership and initializing security context,
then return -EOPNOTSUP. Also allow at max one LSM to initialize security
context. This hook can't deal with multiple LSMs trying to init security
context. This patch implements this new behavior.

Reported-by: Stephen Muth &lt;smuth4@gmail.com&gt;
Tested-by: Stephen Muth &lt;smuth4@gmail.com&gt;
Suggested-by: Casey Schaufler &lt;casey@schaufler-ca.com&gt;
Acked-by: Casey Schaufler &lt;casey@schaufler-ca.com&gt;
Reviewed-by: Serge Hallyn &lt;serge@hallyn.com&gt;
Cc: Jeff Layton &lt;jlayton@kernel.org&gt;
Cc: Christian Brauner &lt;brauner@kernel.org&gt;
Cc: Paul Moore &lt;paul@paul-moore.com&gt;
Cc: &lt;stable@vger.kernel.org&gt; # 5.16.0
Signed-off-by: Vivek Goyal &lt;vgoyal@redhat.com&gt;
Reviewed-by: Jeff Layton &lt;jlayton@kernel.org&gt;
Acked-by: Paul Moore &lt;paul@paul-moore.com&gt;
Acked-by: Christian Brauner &lt;brauner@kernel.org&gt;
Signed-off-by: James Morris &lt;jmorris@namei.org&gt;
</content>
</entry>
</feed>
