Patch series "mm/debug_vm_pgtable: Some minor updates", v3.

This series contains some cleanups and new test suggestions from Catalin
from an earlier discussion.

https://lore.kernel.org/linux-mm/20201123142237.GF17833@gaia/

This patch (of 2):

This adds validation tests for dirtiness after write protect conversion
for each page table level.  There are two new separate test types involved
here.

The first test ensures that a given page table entry does not become dirty
after pxx_wrprotect().  This is important for platforms like arm64 which
transfers and drops the hardware dirty bit (!PTE_RDONLY) to the software
dirty bit while making it an write protected one.  This test ensures that
no fresh page table entry could be created with hardware dirty bit set.
The second test ensures that a given page table entry always preserve the
dirty information across pxx_wrprotect().

This adds two previously missing PUD level basic tests and while here
fixes pxx_wrprotect() related typos in the documentation file.

Link: https://lkml.kernel.org/r/1611137241-26220-1-git-send-email-anshuman.khandual@arm.com
Link: https://lkml.kernel.org/r/1611137241-26220-2-git-send-email-anshuman.khandual@arm.comSigned-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390]
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Steven Price <steven.price@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The memcg_data is only valid on the head page, not the tail pages.  Change
the format and location of the printout within the dump to match the other
parts of struct page better.

Link: https://lkml.kernel.org/r/20210114190200.1894484-1-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add whitespace to fix coding style issues, improve code reading.

Link: https://lkml.kernel.org/r/1612847403-5594-1-git-send-email-daizhiyuan@phytium.com.cnSigned-off-by: Zhiyuan Dai <daizhiyuan@phytium.com.cn>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The boot param and config determine the value of memcg_sysfs_enabled,
which is unused since commit 10befea9 ("mm: memcg/slab: use a single
set of kmem_caches for all allocations") as there are no per-memcg kmem
caches anymore.

Link: https://lkml.kernel.org/r/20210127124745.7928-1-vbabka@suse.czSigned-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In deactivate_slab() we currently move all but one objects on the cpu
freelist to the page freelist one by one using the costly cmpxchg_double()
operation.  Then we unfreeze the page while moving the last object on page
freelist, with a final cmpxchg_double().

This can be optimized to avoid the cmpxchg_double() per object.  Just
count the objects on cpu freelist (to adjust page->inuse properly) and
also remember the last object in the chain.  Then splice page->freelist to
the last object and effectively add the whole cpu freelist to
page->freelist while unfreezing the page, with a single cmpxchg_double().

Link: https://lkml.kernel.org/r/20210115183543.15097-1-vbabka@suse.czSigned-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Jann Horn <jannh@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

SLAB has been using get/put_online_cpus() around creating, destroying and
shrinking kmem caches since 95402b38 ("cpu-hotplug: replace
per-subsystem mutexes with get_online_cpus()") in 2008, which is supposed
to be replacing a private mutex (cache_chain_mutex, called slab_mutex
today) with system-wide mechanism, but in case of SLAB it's in fact used
in addition to the existing mutex, without explanation why.

SLUB appears to have avoided the cpu hotplug lock initially, but gained it
due to common code unification, such as 20cea968 ("mm, sl[aou]b: Move
kmem_cache_create mutex handling to common code").

Regardless of the history, checking if the hotplug lock is actually needed
today suggests that it's not, and therefore it's better to avoid this
system-wide lock and the ordering this imposes wrt other locks (such as
slab_mutex).

Specifically, in SLAB we have for_each_online_cpu() in do_tune_cpucache()
protected by slab_mutex, and cpu hotplug callbacks that also take the
slab_mutex, which is also taken by the common slab function that currently
also take the hotplug lock.  Thus the slab_mutex protection should be
sufficient.  Also per-cpu array caches are allocated for each possible
cpu, so not affected by their online/offline state.

In SLUB we have for_each_online_cpu() in functions that show statistics
and are already unprotected today, as racing with hotplug is not harmful.
Otherwise SLUB relies on percpu allocator.  The slub_cpu_dead() hotplug
callback takes the slab_mutex.

To sum up, this patch removes get/put_online_cpus() calls from slab as it
should be safe without further adjustments.

Link: https://lkml.kernel.org/r/20210113131634.3671-4-vbabka@suse.czSigned-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Qian Cai <cai@redhat.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Since commit 03afc0e2 ("slab: get_online_mems for
kmem_cache_{create,destroy,shrink}") we are taking memory hotplug lock for
SLAB and SLUB when creating, destroying or shrinking a cache.  It is quite
a heavy lock and it's best to avoid it if possible, as we had several
issues with lockdep complaining about ordering in the past, see e.g.
e4f8e513 ("mm/slub: fix a deadlock in show_slab_objects()").

The problem scenario in 03afc0e2 (solved by the memory hotplug lock)
can be summarized as follows: while there's slab_mutex synchronizing new
kmem cache creation and SLUB's MEM_GOING_ONLINE callback
slab_mem_going_online_callback(), we may miss creation of kmem_cache_node
for the hotplugged node in the new kmem cache, because the hotplug
callback doesn't yet see the new cache, and cache creation in
init_kmem_cache_nodes() only inits kmem_cache_node for nodes in the
N_NORMAL_MEMORY nodemask, which however may not yet include the new node,
as that happens only later after the MEM_GOING_ONLINE callback.

Instead of using get/put_online_mems(), the problem can be solved by SLUB
maintaining its own nodemask of nodes for which it has allocated the
per-node kmem_cache_node structures.  This nodemask would generally mirror
the N_NORMAL_MEMORY nodemask, but would be updated only in under SLUB's
control in its memory hotplug callbacks under the slab_mutex.  This patch
adds such nodemask and its handling.

Commit 03afc0e2 mentiones "issues like [the one above]", but there
don't appear to be further issues.  All the paths (shared for SLAB and
SLUB) taking the memory hotplug locks are also taking the slab_mutex,
except kmem_cache_shrink() where 03afc0e2 replaced slab_mutex with
get/put_online_mems().

We however cannot simply restore slab_mutex in kmem_cache_shrink(), as
SLUB can enters the function from a write to sysfs 'shrink' file, thus
holding kernfs lock, and in kmem_cache_create() the kernfs lock is nested
within slab_mutex.  But on closer inspection we don't actually need to
protect kmem_cache_shrink() from hotplug callbacks: While SLUB's
__kmem_cache_shrink() does for_each_kmem_cache_node(), missing a new node
added in parallel hotplug is not fatal, and parallel hotremove does not
free kmem_cache_node's anymore after the previous patch, so use-after free
cannot happen.  The per-node shrinking itself is protected by
n->list_lock.  Same is true for SLAB, and SLOB is no-op.

SLAB also doesn't need the memory hotplug locking, which it only gained by
03afc0e2 through the shared paths in slab_common.c.  Its memory
hotplug callbacks are also protected by slab_mutex against races with
these paths.  The problem of SLUB relying on N_NORMAL_MEMORY doesn't apply
to SLAB, as its setup_kmem_cache_nodes relies on N_ONLINE, and the new
node is already set there during the MEM_GOING_ONLINE callback, so no
special care is needed for SLAB.

As such, this patch removes all get/put_online_mems() usage by the slab
subsystem.

Link: https://lkml.kernel.org/r/20210113131634.3671-3-vbabka@suse.czSigned-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Qian Cai <cai@redhat.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "mm, slab, slub: remove cpu and memory hotplug locks".

Some related work caused me to look at how we use get/put_mems_online()
and get/put_online_cpus() during kmem cache
creation/descruction/shrinking, and realize that it should be actually
safe to remove all of that with rather small effort (as e.g.  Michal Hocko
suspected in some of the past discussions already).  This has the benefit
to avoid rather heavy locks that have caused locking order issues already
in the past.  So this is the result, Patches 2 and 3 remove memory hotplug
and cpu hotplug locking, respectively.  Patch 1 is due to realization that
in fact some races exist despite the locks (even if not removed), but the
most sane solution is not to introduce more of them, but rather accept
some wasted memory in scenarios that should be rare anyway (full memory
hot remove), as we do the same in other contexts already.

This patch (of 3):

Commit e4f8e513 ("mm/slub: fix a deadlock in show_slab_objects()") has
fixed a problematic locking order by removing the memory hotplug lock
get/put_online_mems() from show_slab_objects().  During the discussion, it
was argued [1] that this is OK, because existing slabs on the node would
prevent a hotremove to proceed.

That's true, but per-node kmem_cache_node structures are not necessarily
allocated on the same node and may exist even without actual slab pages on
the same node.  Any path that uses get_node() directly or via
for_each_kmem_cache_node() (such as show_slab_objects()) can race with
freeing of kmem_cache_node even with the !NULL check, resulting in
use-after-free.

To that end, commit e4f8e513 argues in a comment that:

 * We don't really need mem_hotplug_lock (to hold off
 * slab_mem_going_offline_callback) here because slab's memory hot
 * unplug code doesn't destroy the kmem_cache->node[] data.

While it's true that slab_mem_going_offline_callback() doesn't free the
kmem_cache_node, the later callback slab_mem_offline_callback() actually
does, so the race and use-after-free exists.  Not just for
show_slab_objects() after commit e4f8e513, but also many other places
that are not under slab_mutex.  And adding slab_mutex locking or other
synchronization to SLUB paths such as get_any_partial() would be bad for
performance and error-prone.

The easiest solution is therefore to make the abovementioned comment true
and stop freeing the kmem_cache_node structures, accepting some wasted
memory in the full memory node removal scenario.  Analogically we also
don't free hotremoved pgdat as mentioned in [1], nor the similar per-node
structures in SLAB.  Importantly this approach will not block the
hotremove, as generally such nodes should be movable in order to succeed
hotremove in the first place, and thus the GFP_KERNEL allocated
kmem_cache_node will come from elsewhere.

[1] https://lore.kernel.org/linux-mm/20190924151147.GB23050@dhcp22.suse.cz/

Link: https://lkml.kernel.org/r/20210113131634.3671-1-vbabka@suse.cz
Link: https://lkml.kernel.org/r/20210113131634.3671-2-vbabka@suse.czSigned-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Qian Cai <cai@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If kmemleak is enabled, it uses a kmem cache for its own objects.  These
objects are used to hold information kmemleak uses, including a stack
trace.  If slub_debug is also turned on, each of them has *another* stack
trace, so the overhead adds up, and on my tests (on ARCH=um, admittedly)
2/3rds of the allocations end up being doing the stack tracing.

Turn off SLAB_STORE_USER if SLAB_NOLEAKTRACE was given, to avoid storing
the essentially same data twice.

Link: https://lkml.kernel.org/r/20210113215114.d94efa13ba30.I117b6764e725b3192318bbcf4269b13b709539ae@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix some coding style issues, improve code reading.  Adds whitespace to
clearly separate the parameters.

Link: https://lkml.kernel.org/r/1612841499-32166-1-git-send-email-daizhiyuan@phytium.com.cnSigned-off-by: Zhiyuan Dai <daizhiyuan@phytium.com.cn>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This argument hasn't been used since e153362a ("slub: Remove objsize
check in kmem_cache_flags()") so simply remove it.

Link: https://lkml.kernel.org/r/20210126095733.974665-1-nborisov@suse.comSigned-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently, a trace record generated by the RCU core is as below.

... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=00000000f3b49a66

It doesn't tell us what the RCU core has freed.

This patch adds the slab name to trace_kmem_cache_free().
The new format is as follows.

... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=0000000037f79c8d name=dentry
... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=00000000f78cb7b5 name=sock_inode_cache
... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=0000000018768985 name=pool_workqueue
... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=000000006a6cb484 name=radix_tree_node

We can use it to understand what the RCU core is going to free. For
example, some users maybe interested in when the RCU core starts
freeing reclaimable slabs like dentry to reduce memory pressure.

Link: https://lkml.kernel.org/r/20201216072804.8838-1-jian.w.wen@oracle.comSigned-off-by: Jacob Wen <jian.w.wen@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[akpm@linux-foundation.org: update inode_operations.tmpfile]

Link: http://lkml.kernel.org/r/20190206073349.GA15311@avx2Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Delete duplicate words in fs/*.c.
The doubled words that are being dropped are:
  that, be, the, in, and, for

Link: https://lkml.kernel.org/r/20201224052810.25315-1-rdunlap@infradead.orgSigned-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix the following coccicheck warnings:

  fs/ocfs2/refcounttree.c:981:16-18: WARNING !A || A && B is equivalent to !A || B.

Link: https://lkml.kernel.org/r/1612235424-80367-1-git-send-email-jiapeng.chong@linux.alibaba.comSigned-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The error handling in this function frees "reg" but it is still on the
"o2hb_all_regions" list so it will lead to a use after freew.  Joseph Qi
points out that we need to clear the bit in the "o2hb_region_bitmap" as
well

Link: https://lkml.kernel.org/r/YBk4M6HUG8jB/jc7@mwanda
Fixes: 1cf257f5 ("ocfs2: fix memory leak")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There are some definitions which is not used anymore in OCFS2 module, so
as to be removed.

Link: https://lkml.kernel.org/r/2021011916182284700534@chinatelecom.cnSigned-off-by: Guozhonghua <guozh88@chinatelecom.cn>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

iput handles NULL pointers gracefully, so there's no need to check the
pointer before the call.

Link: https://lkml.kernel.org/r/20201231040535.4091761-1-yili@winhong.comSigned-off-by: Yi Li <yili@winhong.com>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Mounting a corrupted filesystem with NTFS resulted in a kernel crash.

We should check for valid STANDARD_INFORMATION attribute offset and length
before trying to access it

Link: https://lkml.kernel.org/r/20210217155930.1506815-1-rkovhaev@gmail.com
Link: https://syzkaller.appspot.com/bug?extid=c584225dabdea2f71969Signed-off-by: Rustam Kovhaev <rkovhaev@gmail.com>
Reported-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com
Tested-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com
Acked-by: Anton Altaparmakov <anton@tuxera.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Drop the repeated words "the" and "in" in comments.

Link: https://lkml.kernel.org/r/20210125194937.24627-1-rdunlap@infradead.orgSigned-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Here are some of the more common spelling mistakes and typos that I've
found while fixing up spelling mistakes in the kernel since September 2020

Link: https://lkml.kernel.org/r/20210210124318.55082-1-colin.king@canonical.comSigned-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Increase "allocted" and "exeeds" spelling error check.

Link: https://lkml.kernel.org/r/20210127081919.1928-1-dingsenjie@163.comSigned-off-by: dingsenjie <dingsenjie@yulong.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Increase exeeds spelling error check.

Link: https://lkml.kernel.org/r/20210127060049.915-1-zuoqilin1@163.comSigned-off-by: zuoqilin <zuoqilin@yulong.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Increase maping spelling error check.

Link: https://lkml.kernel.org/r/20210121092125.2663-1-tangchunyou@163.comSigned-off-by: WenZhang <zhangwen@yulong.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Since CONFIG_EXPERIMENTAL was removed in 2013, go ahead and drop it
from any defconfig files.

Link: https://lkml.kernel.org/r/20210115010011.29483-1-rdunlap@infradead.org
Fixes: 3d374d09 ("final removal of CONFIG_EXPERIMENTAL")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Brian Cain <bcain@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull keyring updates from David Howells:
 "Here's a set of minor keyrings fixes/cleanups that I've collected from
  various people for the upcoming merge window.

  A couple of them might, in theory, be visible to userspace:

   - Make blacklist_vet_description() reject uppercase letters as they
     don't match the all-lowercase hex string generated for a blacklist
     search.

     This may want reconsideration in the future, but, currently, you
     can't add to the blacklist keyring from userspace and the only
     source of blacklist keys generates lowercase descriptions.

   - Fix blacklist_init() to use a new KEY_ALLOC_* flag to indicate that
     it wants KEY_FLAG_KEEP to be set rather than passing KEY_FLAG_KEEP
     into keyring_alloc() as KEY_FLAG_KEEP isn't a valid alloc flag.

     This isn't currently a problem as the blacklist keyring isn't
     currently writable by userspace.

  The rest of the patches are cleanups and I don't think they should
  have any visible effect"

* tag 'keys-misc-20210126' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  watch_queue: rectify kernel-doc for init_watch()
  certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID
  certs: Fix blacklist flag type confusion
  PKCS#7: Fix missing include
  certs: Fix blacklisted hexadecimal hash string check
  certs/blacklist: fix kernel doc interface issue
  crypto: public_key: Remove redundant header file from public_key.h
  keys: remove trailing semicolon in macro definition
  crypto: pkcs7: Use match_string() helper to simplify the code
  PKCS#7: drop function from kernel-doc pkcs7_validate_trust_one
  encrypted-keys: Replace HTTP links with HTTPS ones
  crypto: asymmetric_keys: fix some comments in pkcs7_parser.h
  KEYS: remove redundant memset
  security: keys: delete repeated words in comments
  KEYS: asymmetric: Fix kerneldoc
  security/keys: use kvfree_sensitive()
  watch_queue: Drop references to /dev/watch_queue
  keys: Remove outdated __user annotations
  security: keys: Fix fall-through warnings for Clang

Pull more clang LTO updates from Kees Cook:
 "Clang LTO x86 enablement.

  Full disclosure: while this has _not_ been in linux-next (since it
  initially looked like the objtool dependencies weren't going to make
  v5.12), it has been under daily build and runtime testing by Sami for
  quite some time. These x86 portions have been discussed on lkml, with
  Peter, Josh, and others helping nail things down.

  The bulk of the changes are to get objtool working happily. The rest
  of the x86 enablement is very small.

  Summary:

   - Generate __mcount_loc in objtool (Peter Zijlstra)

   - Support running objtool against vmlinux.o (Sami Tolvanen)

   - Clang LTO enablement for x86 (Sami Tolvanen)"

Link: https://lore.kernel.org/lkml/20201013003203.4168817-26-samitolvanen@google.com/
Link: https://lore.kernel.org/lkml/cover.1611263461.git.jpoimboe@redhat.com/

* tag 'clang-lto-v5.12-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  kbuild: lto: force rebuilds when switching CONFIG_LTO
  x86, build: allow LTO to be selected
  x86, cpu: disable LTO for cpu.c
  x86, vdso: disable LTO only for vDSO
  kbuild: lto: postpone objtool
  objtool: Split noinstr validation from --vmlinux
  x86, build: use objtool mcount
  tracing: add support for objtool mcount
  objtool: Don't autodetect vmlinux.o
  objtool: Fix __mcount_loc generation with Clang's assembler
  objtool: Add a pass for generating __mcount_loc

Pull sparc updates from David Miller:
 "A host of mall cleanups and adjustments that have accumulated while I
  was away, nothing major"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc: (26 commits)
  sparc: make xchg() into a statement expression
  sparc64: Use arch_validate_flags() to validate ADI flag
  sparc32: Fix comparing pointer to 0 coccicheck warning
  sparc: fix led.c driver when PROC_FS is not enabled
  sparc: Fix handling of page table constructor failure
  sparc64: only select COMPAT_BINFMT_ELF if BINFMT_ELF is set
  tty: hvcs: Drop unnecessary if block
  tty: vcc: Drop unnecessary if block
  tty: vcc: Drop impossible to hit WARN_ON
  sparc: sparc64_defconfig: add necessary configs for qemu
  sparc64: switch defconfig from the legacy ide driver to libata
  sparc32: Preserve clone syscall flags argument for restarts due to signals
  sparc32: Limit memblock allocation to low memory
  sparc: Replace test_ti_thread_flag() with test_tsk_thread_flag()
  sbus: char: Remove meaningless jump label out_free
  sparc32: signal: Fix stack trampoline for RT signals
  sparc: remove SA_STATIC_ALLOC macro definition
  sparc: use for_each_child_of_node() macro
  sparc: Use fallthrough pseudo-keyword
  sparc32: srmmu: improve type safety of __nocache_fix()
  ...

Pull dmaengine updates from Vinod Koul:
 "We have couple of drivers removed a new driver and bunch of new device
  support and few updates to drivers for this round.

  New drivers/devices:
   - Intel LGM SoC DMA driver
   - Actions Semi S500 DMA controller
   - Renesas r8a779a0 dma controller
   - Ingenic JZ4760(B) dma controller
   - Intel KeemBay AxiDMA controller

  Removed:
   - Coh901318 dma driver
   - Zte zx dma driver
   - Sirfsoc dma driver

  Updates:
   - mmp_pdma, mmp_tdma gained module support
   - imx-sdma become modern and dropped platform data support
   - dw-axi driver gained slave and cyclic dma support"

* tag 'dmaengine-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine: (58 commits)
  dmaengine: dw-axi-dmac: remove redundant null check on desc
  dmaengine: xilinx_dma: Alloc tx descriptors GFP_NOWAIT
  dmaengine: dw-axi-dmac: Virtually split the linked-list
  dmaengine: dw-axi-dmac: Set constraint to the Max segment size
  dmaengine: dw-axi-dmac: Add Intel KeemBay AxiDMA BYTE and HALFWORD registers
  dmaengine: dw-axi-dmac: Add Intel KeemBay AxiDMA handshake
  dmaengine: dw-axi-dmac: Add Intel KeemBay AxiDMA support
  dmaengine: drivers: Kconfig: add HAS_IOMEM dependency to DW_AXI_DMAC
  dmaengine: dw-axi-dmac: Add Intel KeemBay DMA register fields
  dt-binding: dma: dw-axi-dmac: Add support for Intel KeemBay AxiDMA
  dmaengine: dw-axi-dmac: Support burst residue granularity
  dmaengine: dw-axi-dmac: Support of_dma_controller_register()
  dmaegine: dw-axi-dmac: Support device_prep_dma_cyclic()
  dmaengine: dw-axi-dmac: Support device_prep_slave_sg
  dmaengine: dw-axi-dmac: Add device_config operation
  dmaengine: dw-axi-dmac: Add device_synchronize() callback
  dmaengine: dw-axi-dmac: move dma_pool_create() to alloc_chan_resources()
  dmaengine: dw-axi-dmac: simplify descriptor management
  dt-bindings: dma: Add YAML schemas for dw-axi-dmac
  dmaengine: ti: k3-psil: optimize struct psil_endpoint_config for size
  ...

Pull more ACPI updates from Rafael Wysocki:
 "Fix race condition in generic_serial_bus (I2C) and GPIO Operation
  Region handling in ACPICA and reduce some related code duplication
  (Hans de Goede)"

* tag 'acpi-5.12-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPICA: Remove some code duplication from acpi_ev_address_space_dispatch
  ACPICA: Fix race in generic_serial_bus (I2C) and GPIO op_region parameter handling

Pull more power management updates from Rafael Wysocki:
 "These are fixes and cleanups on top of the power management material
  for 5.12-rc1 merged previously.

  Specifics:

   - Address cpufreq regression introduced in 5.11 that causes CPU
     frequency reporting to be distorted on systems with CPPC that use
     acpi-cpufreq as the scaling driver (Rafael Wysocki).

   - Fix regression introduced during the 5.10 development cycle related
     to CPU hotplug and policy recreation in the qcom-cpufreq-hw driver
     (Shawn Guo).

   - Fix recent regression in the operating performance points (OPP)
     framework that may cause frequency updates to be skipped by mistake
     in some cases (Jonathan Marek).

   - Simplify schedutil governor code and remove a misleading comment
     from it (Yue Hu).

   - Fix kerneldoc comment typo in the cpufreq core (Yue Hu)"

* tag 'pm-5.12-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: Fix typo in kerneldoc comment
  cpufreq: schedutil: Remove update_lock comment from struct sugov_policy definition
  cpufreq: schedutil: Remove needless sg_policy parameter from ignore_dl_rate_limit()
  cpufreq: ACPI: Set cpuinfo.max_freq directly if max boost is known
  cpufreq: qcom-hw: drop devm_xxx() calls from init/exit hooks
  opp: Don't skip freq update for different frequency

Pull input updates from Dmitry Torokhov:
 "Mostly existing driver fixes plus a new driver for game controllers
  directly connected to Nintendo 64, and an enhancement for keyboards
  driven by Chrome OS EC to communicate layout of the top row to
  userspace"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (47 commits)
  Input: st1232 - fix NORMAL vs. IDLE state handling
  Input: aiptek - convert sysfs sprintf/snprintf family to sysfs_emit
  Input: alps - fix spelling of "positive"
  ARM: dts: cros-ec-keyboard: Use keymap macros
  dt-bindings: input: Fix the keymap for LOCK key
  dt-bindings: input: Create macros for cros-ec keymap
  Input: cros-ec-keyb - expose function row physical map to userspace
  dt-bindings: input: cros-ec-keyb: Add a new property describing top row
  Input: applespi - fix occasional crc errors under load.
  Input: applespi - don't wait for responses to commands indefinitely.
  Input: st1232 - add IDLE state as ready condition
  Input: zinitix - fix return type of zinitix_init_touch()
  Input: i8042 - add ASUS Zenbook Flip to noselftest list
  Input: add missing dependencies on CONFIG_HAS_IOMEM
  Input: joydev - prevent potential read overflow in ioctl
  Input: elo - fix an error code in elo_connect()
  Input: xpad - add support for PowerA Enhanced Wired Controller for Xbox Series X|S
  Input: sur40 - fix an error code in sur40_probe()
  Input: elants_i2c - detect enum overflow
  Input: zinitix - remove unneeded semicolon
  ...

Pull HID updates from Jiri Kosina:

 - support for "Unified Battery" feature on Logitech devices from Filipe
   Laíns

 - power management improvements for intel-ish driver from Zhang Lixu

 - support for Goodix devices from Douglas Anderson

 - improved handling of generic HID keyboard in order to make it easier
   for userspace to figure out the details of the device, from Dmitry
   Torokhov

 - Playstation DualSense support from Roderick Colenbrander

 - other assorted small fixes and device ID additions.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid: (49 commits)
  HID: playstation: add DualSense player LED support.
  HID: playstation: add microphone mute support for DualSense.
  HID: playstation: add initial DualSense lightbar support.
  HID: wacom: Ignore attempts to overwrite the touch_max value from HID
  HID: playstation: fix array size comparison (off-by-one)
  HID: playstation: fix unused variable in ps_battery_get_property.
  HID: playstation: report DualSense hardware and firmware version.
  HID: playstation: add DualSense classic rumble support.
  HID: playstation: add DualSense Bluetooth support.
  HID: playstation: track devices in list.
  HID: playstation: add DualSense accelerometer and gyroscope support.
  HID: playstation: add DualSense touchpad support.
  HID: playstation: add DualSense battery support.
  HID: playstation: use DualSense MAC address as unique identifier.
  HID: playstation: initial DualSense USB support.
  HID: ite: Enable QUIRK_TOUCHPAD_ON_OFF_REPORT on Acer Aspire Switch 10E
  HID: Ignore battery for Elan touchscreen on HP Spectre X360 15-df0xxx
  HID: logitech-dj: add support for the new lightspeed connection iteration
  HID: intel-ish-hid: ipc: Add Tiger Lake H PCI device ID
  HID: logitech-dj: add support for keyboard events in eQUAD step 4 Gaming
  ...

Commit 0da6bcd9 ("scripts: dtc: Build fdtoverlay tool") enabled
building fdtoverlay, but failed to add it to .gitignore.

Also add a note to keep hostprogs in sync with .gitignore.

Fixes: 0da6bcd9 ("scripts: dtc: Build fdtoverlay tool")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>

When doing non-clean builds and switching between CONFIG_LTO=n and
CONFIG_LTO=y, the build system (correctly) didn't notice that assembly
and LTO-excluded C object files were rewritten in place by objtool (to
add the .orc_unwind* sections), since their build command lines were the
same between CONFIG_LTO=y and CONFIG_LTO=n. The objtool step would fail:

vmlinux.o: warning: objtool: file already has .orc_unwind section, skipping
make: *** [Makefile:1194: vmlinux] Error 255

Avoid this by making sure the build will see a difference between an LTO
and non-LTO build (by including "-fno-lto" in KBUILD_*FLAGS). This will
get ignored when CC_FLAGS_LTO is present, and will not be included at
all when CONFIG_LTO=n.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>

Pull gfs2 updates from Andreas Gruenbacher:

 - Log space and revoke accounting rework to fix some failed asserts.

 - Local resource group glock sharing for better local performance.

 - Add support for version 1802 filesystems: trusted xattr support and
   '-o rgrplvb' mounts by default.

 - Actually synchronize on the inode glock's FREEING bit during withdraw
   ("gfs2: fix glock confusion in function signal_our_withdraw").

 - Fix parallel recovery of multiple journals ("gfs2: keep bios separate
   for each journal").

 - Various other bug fixes.

* tag 'gfs2-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2: (49 commits)
  gfs2: Don't get stuck with I/O plugged in gfs2_ail1_flush
  gfs2: Per-revoke accounting in transactions
  gfs2: Rework the log space allocation logic
  gfs2: Minor calc_reserved cleanup
  gfs2: Use resource group glock sharing
  gfs2: Allow node-wide exclusive glock sharing
  gfs2: Add local resource group locking
  gfs2: Add per-reservation reserved block accounting
  gfs2: Rename rs_{free -> requested} and rd_{reserved -> requested}
  gfs2: Check for active reservation in gfs2_release
  gfs2: Don't search for unreserved space twice
  gfs2: Only pass reservation down to gfs2_rbm_find
  gfs2: Also reflect single-block allocations in rgd->rd_extfail_pt
  gfs2: Recursive gfs2_quota_hold in gfs2_iomap_end
  gfs2: Add trusted xattr support
  gfs2: Enable rgrplvb for sb_fs_format 1802
  gfs2: Don't skip dlm unlock if glock has an lvb
  gfs2: Lock imbalance on error path in gfs2_recover_one
  gfs2: Move function gfs2_ail_empty_tr
  gfs2: Get rid of current_tail()
  ...

Pull idmapped mounts from Christian Brauner:
 "This introduces idmapped mounts which has been in the making for some
  time. Simply put, different mounts can expose the same file or
  directory with different ownership. This initial implementation comes
  with ports for fat, ext4 and with Christoph's port for xfs with more
  filesystems being actively worked on by independent people and
  maintainers.

  Idmapping mounts handle a wide range of long standing use-cases. Here
  are just a few:

   - Idmapped mounts make it possible to easily share files between
     multiple users or multiple machines especially in complex
     scenarios. For example, idmapped mounts will be used in the
     implementation of portable home directories in
     systemd-homed.service(8) where they allow users to move their home
     directory to an external storage device and use it on multiple
     computers where they are assigned different uids and gids. This
     effectively makes it possible to assign random uids and gids at
     login time.

   - It is possible to share files from the host with unprivileged
     containers without having to change ownership permanently through
     chown(2).

   - It is possible to idmap a container's rootfs and without having to
     mangle every file. For example, Chromebooks use it to share the
     user's Download folder with their unprivileged containers in their
     Linux subsystem.

   - It is possible to share files between containers with
     non-overlapping idmappings.

   - Filesystem that lack a proper concept of ownership such as fat can
     use idmapped mounts to implement discretionary access (DAC)
     permission checking.

   - They allow users to efficiently changing ownership on a per-mount
     basis without having to (recursively) chown(2) all files. In
     contrast to chown (2) changing ownership of large sets of files is
     instantenous with idmapped mounts. This is especially useful when
     ownership of a whole root filesystem of a virtual machine or
     container is changed. With idmapped mounts a single syscall
     mount_setattr syscall will be sufficient to change the ownership of
     all files.

   - Idmapped mounts always take the current ownership into account as
     idmappings specify what a given uid or gid is supposed to be mapped
     to. This contrasts with the chown(2) syscall which cannot by itself
     take the current ownership of the files it changes into account. It
     simply changes the ownership to the specified uid and gid. This is
     especially problematic when recursively chown(2)ing a large set of
     files which is commong with the aforementioned portable home
     directory and container and vm scenario.

   - Idmapped mounts allow to change ownership locally, restricting it
     to specific mounts, and temporarily as the ownership changes only
     apply as long as the mount exists.

  Several userspace projects have either already put up patches and
  pull-requests for this feature or will do so should you decide to pull
  this:

   - systemd: In a wide variety of scenarios but especially right away
     in their implementation of portable home directories.

         https://systemd.io/HOME_DIRECTORY/

   - container runtimes: containerd, runC, LXD:To share data between
     host and unprivileged containers, unprivileged and privileged
     containers, etc. The pull request for idmapped mounts support in
     containerd, the default Kubernetes runtime is already up for quite
     a while now: https://github.com/containerd/containerd/pull/4734

   - The virtio-fs developers and several users have expressed interest
     in using this feature with virtual machines once virtio-fs is
     ported.

   - ChromeOS: Sharing host-directories with unprivileged containers.

  I've tightly synced with all those projects and all of those listed
  here have also expressed their need/desire for this feature on the
  mailing list. For more info on how people use this there's a bunch of
  talks about this too. Here's just two recent ones:

      https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf
      https://fosdem.org/2021/schedule/event/containers_idmap/

  This comes with an extensive xfstests suite covering both ext4 and
  xfs:

      https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts

  It covers truncation, creation, opening, xattrs, vfscaps, setid
  execution, setgid inheritance and more both with idmapped and
  non-idmapped mounts. It already helped to discover an unrelated xfs
  setgid inheritance bug which has since been fixed in mainline. It will
  be sent for inclusion with the xfstests project should you decide to
  merge this.

  In order to support per-mount idmappings vfsmounts are marked with
  user namespaces. The idmapping of the user namespace will be used to
  map the ids of vfs objects when they are accessed through that mount.
  By default all vfsmounts are marked with the initial user namespace.
  The initial user namespace is used to indicate that a mount is not
  idmapped. All operations behave as before and this is verified in the
  testsuite.

  Based on prior discussions we want to attach the whole user namespace
  and not just a dedicated idmapping struct. This allows us to reuse all
  the helpers that already exist for dealing with idmappings instead of
  introducing a whole new range of helpers. In addition, if we decide in
  the future that we are confident enough to enable unprivileged users
  to setup idmapped mounts the permission checking can take into account
  whether the caller is privileged in the user namespace the mount is
  currently marked with.

  The user namespace the mount will be marked with can be specified by
  passing a file descriptor refering to the user namespace as an
  argument to the new mount_setattr() syscall together with the new
  MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
  of extensibility.

  The following conditions must be met in order to create an idmapped
  mount:

   - The caller must currently have the CAP_SYS_ADMIN capability in the
     user namespace the underlying filesystem has been mounted in.

   - The underlying filesystem must support idmapped mounts.

   - The mount must not already be idmapped. This also implies that the
     idmapping of a mount cannot be altered once it has been idmapped.

   - The mount must be a detached/anonymous mount, i.e. it must have
     been created by calling open_tree() with the OPEN_TREE_CLONE flag
     and it must not already have been visible in the filesystem.

  The last two points guarantee easier semantics for userspace and the
  kernel and make the implementation significantly simpler.

  By default vfsmounts are marked with the initial user namespace and no
  behavioral or performance changes are observed.

  The manpage with a detailed description can be found here:

      https://git.kernel.org/brauner/man-pages/c/1d7b902e2875a1ff342e036a9f866a995640aea8

  In order to support idmapped mounts, filesystems need to be changed
  and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The
  patches to convert individual filesystem are not very large or
  complicated overall as can be seen from the included fat, ext4, and
  xfs ports. Patches for other filesystems are actively worked on and
  will be sent out separately. The xfstestsuite can be used to verify
  that port has been done correctly.

  The mount_setattr() syscall is motivated independent of the idmapped
  mounts patches and it's been around since July 2019. One of the most
  valuable features of the new mount api is the ability to perform
  mounts based on file descriptors only.

  Together with the lookup restrictions available in the openat2()
  RESOLVE_* flag namespace which we added in v5.6 this is the first time
  we are close to hardened and race-free (e.g. symlinks) mounting and
  path resolution.

  While userspace has started porting to the new mount api to mount
  proper filesystems and create new bind-mounts it is currently not
  possible to change mount options of an already existing bind mount in
  the new mount api since the mount_setattr() syscall is missing.

  With the addition of the mount_setattr() syscall we remove this last
  restriction and userspace can now fully port to the new mount api,
  covering every use-case the old mount api could. We also add the
  crucial ability to recursively change mount options for a whole mount
  tree, both removing and adding mount options at the same time. This
  syscall has been requested multiple times by various people and
  projects.

  There is a simple tool available at

      https://github.com/brauner/mount-idmapped

  that allows to create idmapped mounts so people can play with this
  patch series. I'll add support for the regular mount binary should you
  decide to pull this in the following weeks:

  Here's an example to a simple idmapped mount of another user's home
  directory:

	u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt

	u1001@f2-vm:/$ ls -al /home/ubuntu/
	total 28
	drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 .
	drwxr-xr-x 4 root   root   4096 Oct 28 04:00 ..
	-rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history
	-rw-r--r-- 1 ubuntu ubuntu  220 Feb 25  2020 .bash_logout
	-rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25  2020 .bashrc
	-rw-r--r-- 1 ubuntu ubuntu  807 Feb 25  2020 .profile
	-rw-r--r-- 1 ubuntu ubuntu    0 Oct 16 16:11 .sudo_as_admin_successful
	-rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo

	u1001@f2-vm:/$ ls -al /mnt/
	total 28
	drwxr-xr-x  2 u1001 u1001 4096 Oct 28 22:07 .
	drwxr-xr-x 29 root  root  4096 Oct 28 22:01 ..
	-rw-------  1 u1001 u1001 3154 Oct 28 22:12 .bash_history
	-rw-r--r--  1 u1001 u1001  220 Feb 25  2020 .bash_logout
	-rw-r--r--  1 u1001 u1001 3771 Feb 25  2020 .bashrc
	-rw-r--r--  1 u1001 u1001  807 Feb 25  2020 .profile
	-rw-r--r--  1 u1001 u1001    0 Oct 16 16:11 .sudo_as_admin_successful
	-rw-------  1 u1001 u1001 1144 Oct 28 00:43 .viminfo

	u1001@f2-vm:/$ touch /mnt/my-file

	u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file

	u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file

	u1001@f2-vm:/$ ls -al /mnt/my-file
	-rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file

	u1001@f2-vm:/$ ls -al /home/ubuntu/my-file
	-rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file

	u1001@f2-vm:/$ getfacl /mnt/my-file
	getfacl: Removing leading '/' from absolute path names
	# file: mnt/my-file
	# owner: u1001
	# group: u1001
	user::rw-
	user:u1001:rwx
	group::rw-
	mask::rwx
	other::r--

	u1001@f2-vm:/$ getfacl /home/ubuntu/my-file
	getfacl: Removing leading '/' from absolute path names
	# file: home/ubuntu/my-file
	# owner: ubuntu
	# group: ubuntu
	user::rw-
	user:ubuntu:rwx
	group::rw-
	mask::rwx
	other::r--"

* tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits)
  xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl
  xfs: support idmapped mounts
  ext4: support idmapped mounts
  fat: handle idmapped mounts
  tests: add mount_setattr() selftests
  fs: introduce MOUNT_ATTR_IDMAP
  fs: add mount_setattr()
  fs: add attr_flags_to_mnt_flags helper
  fs: split out functions to hold writers
  namespace: only take read lock in do_reconfigure_mnt()
  mount: make {lock,unlock}_mount_hash() static
  namespace: take lock_mount_hash() directly when changing flags
  nfs: do not export idmapped mounts
  overlayfs: do not mount on top of idmapped mounts
  ecryptfs: do not mount on top of idmapped mounts
  ima: handle idmapped mounts
  apparmor: handle idmapped mounts
  fs: make helpers idmap mount aware
  exec: handle idmapped mounts
  would_dump: handle idmapped mounts
  ...

Pass code model and stack alignment to the linker as these are not
stored in LLVM bitcode, and allow CONFIG_LTO_CLANG* to be enabled.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>

Clang incorrectly inlines functions with differing stack protector
attributes, which breaks __restore_processor_state() that relies on
stack protector being disabled. This change disables LTO for cpu.c
to work aroung the bug.

Link: https://bugs.llvm.org/show_bug.cgi?id=47479Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

Disable LTO for the vDSO. Note that while we could use Clang's LTO
for the 64-bit vDSO, it won't add noticeable benefit for the small
amount of C code.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>