commit 6c287605fd ("mm: remember exclusively mapped anonymous pages with
PG_anon_exclusive") made sure that when PageAnonExclusive() has to be
cleared during temporary unmapping of a page, that the PTE is
cleared/invalidated and that the TLB is flushed.
What we want to achieve in all cases is that we cannot end up with a pin on
an anonymous page that may be shared, because such pins would be
unreliable and could result in memory corruptions when the mapped page
and the pin go out of sync due to a write fault.
That TLB flush handling was inspired by an outdated comment in
mm/ksm.c:write_protect_page(), which similarly required the TLB flush in
the past to synchronize with GUP-fast. However, ever since general RCU GUP
fast was introduced in commit 2667f50e8b ("mm: introduce a general RCU
get_user_pages_fast()"), a TLB flush is no longer sufficient to handle
concurrent GUP-fast in all cases -- it only handles traditional IPI-based
GUP-fast correctly.
Peter Xu (thankfully) questioned whether that TLB flush is really
required. On architectures that send an IPI broadcast on TLB flush,
it works as expected. To synchronize with RCU GUP-fast properly, we're
conceptually fine, however, we have to enforce a certain memory order and
are missing memory barriers.
Let's document that, avoid the TLB flush where possible and use proper
explicit memory barriers where required. We shouldn't really care about the
additional memory barriers here, as we're not on extremely hot paths --
and we're getting rid of some TLB flushes.
We use a smp_mb() pair for handling concurrent pinning and a
smp_rmb()/smp_wmb() pair for handling the corner case of only temporary
PTE changes but permanent PageAnonExclusive changes.
One extreme example, whereby GUP-fast takes a R/O pin and KSM wants to
convert an exclusive anonymous page to a KSM page, and that page is already
mapped write-protected (-> no PTE change) would be:
Thread 0 (KSM) Thread 1 (GUP-fast)
(B1) Read the PTE
# (B2) skipped without FOLL_WRITE
(A1) Clear PTE
smp_mb()
(A2) Check pinned
(B3) Pin the mapped page
smp_mb()
(A3) Clear PageAnonExclusive
smp_wmb()
(A4) Restore PTE
(B4) Check if the PTE changed
smp_rmb()
(B5) Check PageAnonExclusive
Thread 1 will properly detect that PageAnonExclusive was cleared and
back off.
Note that we don't need a memory barrier between checking if the page is
pinned and clearing PageAnonExclusive, because stores are not
speculated.
The possible issues due to reordering are of theoretical nature so far
and attempts to reproduce the race failed.
Especially the "no PTE change" case isn't the common case, because we'd
need an exclusive anonymous page that's mapped R/O and the PTE is clean
in KSM code -- and using KSM with page pinning isn't extremely common.
Further, the clear+TLB flush we used for now implies a memory barrier.
So the problematic missing part should be the missing memory barrier
after pinning but before checking if the PTE changed.
Link: https://lkml.kernel.org/r/20220901083559.67446-1-david@redhat.com
Fixes: 6c287605fd ("mm: remember exclusively mapped anonymous pages with PG_anon_exclusive")
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Christoph von Recklinghausen <crecklin@redhat.com>
Cc: Don Dutile <ddutile@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Current ll_rw_block() helper is fragile because it assumes that locked
buffer means it's under IO which is submitted by some other who holds
the lock, it skip buffer if it failed to get the lock, so it's only
safe on the readahead path. Unfortunately, now that most filesystems
still use this helper mistakenly on the sync metadata read path. There
is no guarantee that the one who holds the buffer lock always submit IO
(e.g. buffer_migrate_folio_norefs() after commit 88dbcbb3a4 ("blkdev:
avoid migration stalls for blkdev pages"), it could lead to false
positive -EIO when submitting reading IO.
This patch add some friendly buffer read helpers to prepare replacing
ll_rw_block() and similar calls. We can only call bh_readahead_[]
helpers for the readahead paths.
Link: https://lkml.kernel.org/r/20220901133505.2510834-3-yi.zhang@huawei.com
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kswapd_run/stop() will set pgdat->kswapd to NULL, which could race with
kswapd_is_running() in kcompactd(),
kswapd_run/stop() kcompactd()
kswapd_is_running()
pgdat->kswapd // error or nomal ptr
verify pgdat->kswapd
// load non-NULL
pgdat->kswapd
pgdat->kswapd = NULL
task_is_running(pgdat->kswapd)
// Null pointer derefence
KASAN reports the null-ptr-deref shown below,
vmscan: Failed to start kswapd on node 0
...
BUG: KASAN: null-ptr-deref in kcompactd+0x440/0x504
Read of size 8 at addr 0000000000000024 by task kcompactd0/37
CPU: 0 PID: 37 Comm: kcompactd0 Kdump: loaded Tainted: G OE 5.10.60 #1
Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
Call trace:
dump_backtrace+0x0/0x394
show_stack+0x34/0x4c
dump_stack+0x158/0x1e4
__kasan_report+0x138/0x140
kasan_report+0x44/0xdc
__asan_load8+0x94/0xd0
kcompactd+0x440/0x504
kthread+0x1a4/0x1f0
ret_from_fork+0x10/0x18
At present kswapd/kcompactd_run() and kswapd/kcompactd_stop() are protected
by mem_hotplug_begin/done(), but without kcompactd(). There is no need to
involve memory hotplug lock in kcompactd(), so let's add a new mutex to
protect pgdat->kswapd accesses.
Also, because the kcompactd task will check the state of kswapd task, it's
better to call kcompactd_stop() before kswapd_stop() to reduce lock
conflicts.
[akpm@linux-foundation.org: add comments]
Link: https://lkml.kernel.org/r/20220827111959.186838-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In commit 2f1ee0913c ("Revert "mm: use early_pfn_to_nid in
page_ext_init""), we call page_ext_init() after page_alloc_init_late() to
avoid some panic problem. It seems that we cannot track early page
allocations in current kernel even if page structure has been initialized
early.
This patch introduces a new boot parameter 'early_page_ext' to resolve
this problem. If we pass it to the kernel, page_ext_init() will be moved
up and the feature 'deferred initialization of struct pages' will be
disabled to initialize the page allocator early and prevent the panic
problem above. It can help us to catch early page allocations. This is
useful especially when we find that the free memory value is not the same
right after different kernel booting.
[akpm@linux-foundation.org: fix section issue by removing __meminitdata]
Link: https://lkml.kernel.org/r/20220825102714.669-1-lizhe.67@bytedance.com
Signed-off-by: Li Zhe <lizhe.67@bytedance.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
For several years, MEMCG_CHARGE_BATCH was kept at 32 but with bigger
machines and the network intensive workloads requiring througput in Gbps,
32 is too small and makes the memcg charging path a bottleneck. For now,
increase it to 64 for easy acceptance to 6.0. We will need to revisit
this in future for ever increasing demand of higher performance.
Please note that the memcg charge path drain the per-cpu memcg charge
stock, so there should not be any oom behavior change. Though it does
have impact on rstat flushing and high limit reclaim backoff.
To evaluate the impact of this optimization, on a 72 CPUs machine, we
ran the following workload in a three level of cgroup hierarchy.
$ netserver -6
# 36 instances of netperf with following params
$ netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K
Results (average throughput of netperf):
Without (6.0-rc1) 10482.7 Mbps
With patch 17064.7 Mbps (62.7% improvement)
With the patch, the throughput improved by 62.7%.
Link: https://lkml.kernel.org/r/20220825000506.239406-4-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Michal Koutný" <mkoutny@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
With memcg v2 enabled, memcg->memory.usage is a very hot member for the
workloads doing memcg charging on multiple CPUs concurrently.
Particularly the network intensive workloads. In addition, there is a
false cache sharing between memory.usage and memory.high on the charge
path. This patch moves the usage into a separate cacheline and move all
the read most fields into separate cacheline.
To evaluate the impact of this optimization, on a 72 CPUs machine, we ran
the following workload in a three level of cgroup hierarchy.
$ netserver -6
# 36 instances of netperf with following params
$ netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K
Results (average throughput of netperf):
Without (6.0-rc1) 10482.7 Mbps
With patch 12413.7 Mbps (18.4% improvement)
With the patch, the throughput improved by 18.4%.
One side-effect of this patch is the increase in the size of struct
mem_cgroup. For example with this patch on 64 bit build, the size of
struct mem_cgroup increased from 4032 bytes to 4416 bytes. However for
the performance improvement, this additional size is worth it. In
addition there are opportunities to reduce the size of struct mem_cgroup
like deprecation of kmem and tcpmem page counters and better packing.
Link: https://lkml.kernel.org/r/20220825000506.239406-3-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The below is one path where race between page_ext and offline of the
respective memory blocks will cause use-after-free on the access of
page_ext structure.
process1 process2
--------- ---------
a)doing /proc/page_owner doing memory offline
through offline_pages.
b) PageBuddy check is failed
thus proceed to get the
page_owner information
through page_ext access.
page_ext = lookup_page_ext(page);
migrate_pages();
.................
Since all pages are successfully
migrated as part of the offline
operation,send MEM_OFFLINE notification
where for page_ext it calls:
offline_page_ext()-->
__free_page_ext()-->
free_page_ext()-->
vfree(ms->page_ext)
mem_section->page_ext = NULL
c) Check for the PAGE_EXT
flags in the page_ext->flags
access results into the
use-after-free (leading to
the translation faults).
As mentioned above, there is really no synchronization between page_ext
access and its freeing in the memory_offline.
The memory offline steps(roughly) on a memory block is as below:
1) Isolate all the pages
2) while(1)
try free the pages to buddy.(->free_list[MIGRATE_ISOLATE])
3) delete the pages from this buddy list.
4) Then free page_ext.(Note: The struct page is still alive as it is
freed only during hot remove of the memory which frees the memmap,
which steps the user might not perform).
This design leads to the state where struct page is alive but the struct
page_ext is freed, where the later is ideally part of the former which
just representing the page_flags (check [3] for why this design is
chosen).
The abovementioned race is just one example __but the problem persists in
the other paths too involving page_ext->flags access(eg:
page_is_idle())__.
Fix all the paths where offline races with page_ext access by maintaining
synchronization with rcu lock and is achieved in 3 steps:
1) Invalidate all the page_ext's of the sections of a memory block by
storing a flag in the LSB of mem_section->page_ext.
2) Wait until all the existing readers to finish working with the
->page_ext's with synchronize_rcu(). Any parallel process that starts
after this call will not get page_ext, through lookup_page_ext(), for
the block parallel offline operation is being performed.
3) Now safely free all sections ->page_ext's of the block on which
offline operation is being performed.
Note: If synchronize_rcu() takes time then optimizations can be done in
this path through call_rcu()[2].
Thanks to David Hildenbrand for his views/suggestions on the initial
discussion[1] and Pavan kondeti for various inputs on this patch.
[1] https://lore.kernel.org/linux-mm/59edde13-4167-8550-86f0-11fc67882107@quicinc.com/
[2] https://lore.kernel.org/all/a26ce299-aed1-b8ad-711e-a49e82bdd180@quicinc.com/T/#u
[3] https://lore.kernel.org/all/6fa6b7aa-731e-891c-3efb-a03d6a700efa@redhat.com/
[quic_charante@quicinc.com: rename label `loop' to `ext_put_continue' per David]
Link: https://lkml.kernel.org/r/1661496993-11473-1-git-send-email-quic_charante@quicinc.com
Link: https://lkml.kernel.org/r/1660830600-9068-1-git-send-email-quic_charante@quicinc.com
Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Fernand Sieber <sieberf@amazon.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Pavan Kondeti <quic_pkondeti@quicinc.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The promotion hot threshold is workload and system configuration
dependent. So in this patch, a method to adjust the hot threshold
automatically is implemented. The basic idea is to control the number of
the candidate promotion pages to match the promotion rate limit. If the
hint page fault latency of a page is less than the hot threshold, we will
try to promote the page, and the page is called the candidate promotion
page.
If the number of the candidate promotion pages in the statistics interval
is much more than the promotion rate limit, the hot threshold will be
decreased to reduce the number of the candidate promotion pages.
Otherwise, the hot threshold will be increased to increase the number of
the candidate promotion pages.
To make the above method works, in each statistics interval, the total
number of the pages to check (on which the hint page faults occur) and the
hot/cold distribution need to be stable. Because the page tables are
scanned linearly in NUMA balancing, but the hot/cold distribution isn't
uniform along the address usually, the statistics interval should be
larger than the NUMA balancing scan period. So in the patch, the max scan
period is used as statistics interval and it works well in our tests.
Link: https://lkml.kernel.org/r/20220713083954.34196-4-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: osalvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In NUMA balancing memory tiering mode, if there are hot pages in slow
memory node and cold pages in fast memory node, we need to promote/demote
hot/cold pages between the fast and cold memory nodes.
A choice is to promote/demote as fast as possible. But the CPU cycles and
memory bandwidth consumed by the high promoting/demoting throughput will
hurt the latency of some workload because of accessing inflating and slow
memory bandwidth contention.
A way to resolve this issue is to restrict the max promoting/demoting
throughput. It will take longer to finish the promoting/demoting. But
the workload latency will be better. This is implemented in this patch as
the page promotion rate limit mechanism.
The number of the candidate pages to be promoted to the fast memory node
via NUMA balancing is counted, if the count exceeds the limit specified by
the users, the NUMA balancing promotion will be stopped until the next
second.
A new sysctl knob kernel.numa_balancing_promote_rate_limit_MBps is added
for the users to specify the limit.
Link: https://lkml.kernel.org/r/20220713083954.34196-3-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: osalvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "memory tiering: hot page selection", v4.
To optimize page placement in a memory tiering system with NUMA balancing,
the hot pages in the slow memory nodes need to be identified.
Essentially, the original NUMA balancing implementation selects the mostly
recently accessed (MRU) pages to promote. But this isn't a perfect
algorithm to identify the hot pages. Because the pages with quite low
access frequency may be accessed eventually given the NUMA balancing page
table scanning period could be quite long (e.g. 60 seconds). So in this
patchset, we implement a new hot page identification algorithm based on
the latency between NUMA balancing page table scanning and hint page
fault. Which is a kind of mostly frequently accessed (MFU) algorithm.
In NUMA balancing memory tiering mode, if there are hot pages in slow
memory node and cold pages in fast memory node, we need to promote/demote
hot/cold pages between the fast and cold memory nodes.
A choice is to promote/demote as fast as possible. But the CPU cycles and
memory bandwidth consumed by the high promoting/demoting throughput will
hurt the latency of some workload because of accessing inflating and slow
memory bandwidth contention.
A way to resolve this issue is to restrict the max promoting/demoting
throughput. It will take longer to finish the promoting/demoting. But
the workload latency will be better. This is implemented in this patchset
as the page promotion rate limit mechanism.
The promotion hot threshold is workload and system configuration
dependent. So in this patchset, a method to adjust the hot threshold
automatically is implemented. The basic idea is to control the number of
the candidate promotion pages to match the promotion rate limit.
We used the pmbench memory accessing benchmark tested the patchset on a
2-socket server system with DRAM and PMEM installed. The test results are
as follows,
pmbench score promote rate
(accesses/s) MB/s
------------- ------------
base 146887704.1 725.6
hot selection 165695601.2 544.0
rate limit 162814569.8 165.2
auto adjustment 170495294.0 136.9
From the results above,
With hot page selection patch [1/3], the pmbench score increases about
12.8%, and promote rate (overhead) decreases about 25.0%, compared with
base kernel.
With rate limit patch [2/3], pmbench score decreases about 1.7%, and
promote rate decreases about 69.6%, compared with hot page selection
patch.
With threshold auto adjustment patch [3/3], pmbench score increases about
4.7%, and promote rate decrease about 17.1%, compared with rate limit
patch.
Baolin helped to test the patchset with MySQL on a machine which contains
1 DRAM node (30G) and 1 PMEM node (126G).
sysbench /usr/share/sysbench/oltp_read_write.lua \
......
--tables=200 \
--table-size=1000000 \
--report-interval=10 \
--threads=16 \
--time=120
The tps can be improved about 5%.
This patch (of 3):
To optimize page placement in a memory tiering system with NUMA balancing,
the hot pages in the slow memory node need to be identified. Essentially,
the original NUMA balancing implementation selects the mostly recently
accessed (MRU) pages to promote. But this isn't a perfect algorithm to
identify the hot pages. Because the pages with quite low access frequency
may be accessed eventually given the NUMA balancing page table scanning
period could be quite long (e.g. 60 seconds). The most frequently
accessed (MFU) algorithm is better.
So, in this patch we implemented a better hot page selection algorithm.
Which is based on NUMA balancing page table scanning and hint page fault
as follows,
- When the page tables of the processes are scanned to change PTE/PMD
to be PROT_NONE, the current time is recorded in struct page as scan
time.
- When the page is accessed, hint page fault will occur. The scan
time is gotten from the struct page. And The hint page fault
latency is defined as
hint page fault time - scan time
The shorter the hint page fault latency of a page is, the higher the
probability of their access frequency to be higher. So the hint page
fault latency is a better estimation of the page hot/cold.
It's hard to find some extra space in struct page to hold the scan time.
Fortunately, we can reuse some bits used by the original NUMA balancing.
NUMA balancing uses some bits in struct page to store the page accessing
CPU and PID (referring to page_cpupid_xchg_last()). Which is used by the
multi-stage node selection algorithm to avoid to migrate pages shared
accessed by the NUMA nodes back and forth. But for pages in the slow
memory node, even if they are shared accessed by multiple NUMA nodes, as
long as the pages are hot, they need to be promoted to the fast memory
node. So the accessing CPU and PID information are unnecessary for the
slow memory pages. We can reuse these bits in struct page to record the
scan time. For the fast memory pages, these bits are used as before.
For the hot threshold, the default value is 1 second, which works well in
our performance test. All pages with hint page fault latency < hot
threshold will be considered hot.
It's hard for users to determine the hot threshold. So we don't provide a
kernel ABI to set it, just provide a debugfs interface for advanced users
to experiment. We will continue to work on a hot threshold automatic
adjustment mechanism.
The downside of the above method is that the response time to the workload
hot spot changing may be much longer. For example,
- A previous cold memory area becomes hot
- The hint page fault will be triggered. But the hint page fault
latency isn't shorter than the hot threshold. So the pages will
not be promoted.
- When the memory area is scanned again, maybe after a scan period,
the hint page fault latency measured will be shorter than the hot
threshold and the pages will be promoted.
To mitigate this, if there are enough free space in the fast memory node,
the hot threshold will not be used, all pages will be promoted upon the
hint page fault for fast response.
Thanks Zhong Jiang reported and tested the fix for a bug when disabling
memory tiering mode dynamically.
Link: https://lkml.kernel.org/r/20220713083954.34196-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20220713083954.34196-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Wei Xu <weixugc@google.com>
Cc: osalvador <osalvador@suse.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
By default kfence allocation can happen for any slab object, whose size is
up to PAGE_SIZE, as long as that allocation is the first allocation after
expiration of kfence sample interval. But in certain debugging scenarios
we may be interested in debugging corruptions involving some specific slub
objects like dentry or ext4_* etc. In such cases limiting kfence for
allocations involving only specific slub objects will increase the
probablity of catching the issue since kfence pool will not be consumed by
other slab objects.
This patch introduces a sysfs interface
'/sys/kernel/slab/<name>/skip_kfence' to disable kfence for specific
slabs. Having the interface work in this way does not impact
current/default behavior of kfence and allows us to use kfence for
specific slabs (when needed) as well. The decision to skip/use kfence is
taken depending on whether kmem_cache.flags has (newly introduced)
SLAB_SKIP_KFENCE flag set or not.
Link: https://lkml.kernel.org/r/20220814195353.2540848-1-imran.f.khan@oracle.com
Signed-off-by: Imran Khan <imran.f.khan@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@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>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Muchun Song found that after MPOL_PREFERRED_MANY policy was introduced in
commit b27abaccf8 ("mm/mempolicy: add MPOL_PREFERRED_MANY for multiple
preferred nodes"), the policy_nodemask_current()'s semantics for this new
policy has been changed, which returns 'preferred' nodes instead of
'allowed' nodes.
With the changed semantic of policy_nodemask_current, a task with
MPOL_PREFERRED_MANY policy could fail to get its reservation even though
it can fall back to other nodes (either defined by cpusets or all online
nodes) for that reservation failing mmap calles unnecessarily early.
The fix is to not consider MPOL_PREFERRED_MANY for reservations at all
because they, unlike MPOL_MBIND, do not pose any actual hard constrain.
Michal suggested the policy_nodemask_current() is only used by hugetlb,
and could be moved to hugetlb code with more explicit name to enforce the
'allowed' semantics for which only MPOL_BIND policy matters.
apply_policy_zone() is made extern to be called in hugetlb code and its
return value is changed to bool.
[1]. https://lore.kernel.org/lkml/20220801084207.39086-1-songmuchun@bytedance.com/t/
Link: https://lkml.kernel.org/r/20220805005903.95563-1-feng.tang@intel.com
Fixes: b27abaccf8 ("mm/mempolicy: add MPOL_PREFERRED_MANY for multiple preferred nodes")
Signed-off-by: Feng Tang <feng.tang@intel.com>
Reported-by: Muchun Song <songmuchun@bytedance.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ben Widawsky <bwidawsk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Historically, it has been shown that intercepting kernel faults with
userfaultfd (thereby forcing the kernel to wait for an arbitrary amount of
time) can be exploited, or at least can make some kinds of exploits
easier. So, in 37cd0575b8 "userfaultfd: add UFFD_USER_MODE_ONLY" we
changed things so, in order for kernel faults to be handled by
userfaultfd, either the process needs CAP_SYS_PTRACE, or this sysctl must
be configured so that any unprivileged user can do it.
In a typical implementation of a hypervisor with live migration (take
QEMU/KVM as one such example), we do indeed need to be able to handle
kernel faults. But, both options above are less than ideal:
- Toggling the sysctl increases attack surface by allowing any
unprivileged user to do it.
- Granting the live migration process CAP_SYS_PTRACE gives it this
ability, but *also* the ability to "observe and control the
execution of another process [...], and examine and change [its]
memory and registers" (from ptrace(2)). This isn't something we need
or want to be able to do, so granting this permission violates the
"principle of least privilege".
This is all a long winded way to say: we want a more fine-grained way to
grant access to userfaultfd, without granting other additional permissions
at the same time.
To achieve this, add a /dev/userfaultfd misc device. This device provides
an alternative to the userfaultfd(2) syscall for the creation of new
userfaultfds. The idea is, any userfaultfds created this way will be able
to handle kernel faults, without the caller having any special
capabilities. Access to this mechanism is instead restricted using e.g.
standard filesystem permissions.
[axelrasmussen@google.com: Handle misc_register() failure properly]
Link: https://lkml.kernel.org/r/20220819205201.658693-3-axelrasmussen@google.com
Link: https://lkml.kernel.org/r/20220808175614.3885028-3-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Acked-by: Nadav Amit <namit@vmware.com>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dmitry V. Levin <ldv@altlinux.org>
Cc: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zhang Yi <yi.zhang@huawei.com>
Cc: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This idea was introduced by David Rientjes[1].
Introduce a new madvise mode, MADV_COLLAPSE, that allows users to request
a synchronous collapse of memory at their own expense.
The benefits of this approach are:
* CPU is charged to the process that wants to spend the cycles for the
THP
* Avoid unpredictable timing of khugepaged collapse
Semantics
This call is independent of the system-wide THP sysfs settings, but will
fail for memory marked VM_NOHUGEPAGE. If the ranges provided span
multiple VMAs, the semantics of the collapse over each VMA is independent
from the others. This implies a hugepage cannot cross a VMA boundary. If
collapse of a given hugepage-aligned/sized region fails, the operation may
continue to attempt collapsing the remainder of memory specified.
The memory ranges provided must be page-aligned, but are not required to
be hugepage-aligned. If the memory ranges are not hugepage-aligned, the
start/end of the range will be clamped to the first/last hugepage-aligned
address covered by said range. The memory ranges must span at least one
hugepage-sized region.
All non-resident pages covered by the range will first be
swapped/faulted-in, before being internally copied onto a freshly
allocated hugepage. Unmapped pages will have their data directly
initialized to 0 in the new hugepage. However, for every eligible
hugepage aligned/sized region to-be collapsed, at least one page must
currently be backed by memory (a PMD covering the address range must
already exist).
Allocation for the new hugepage may enter direct reclaim and/or
compaction, regardless of VMA flags. When the system has multiple NUMA
nodes, the hugepage will be allocated from the node providing the most
native pages. This operation operates on the current state of the
specified process and makes no persistent changes or guarantees on how
pages will be mapped, constructed, or faulted in the future
Return Value
If all hugepage-sized/aligned regions covered by the provided range were
either successfully collapsed, or were already PMD-mapped THPs, this
operation will be deemed successful. On success, process_madvise(2)
returns the number of bytes advised, and madvise(2) returns 0. Else, -1
is returned and errno is set to indicate the error for the most-recently
attempted hugepage collapse. Note that many failures might have occurred,
since the operation may continue to collapse in the event a single
hugepage-sized/aligned region fails.
ENOMEM Memory allocation failed or VMA not found
EBUSY Memcg charging failed
EAGAIN Required resource temporarily unavailable. Try again
might succeed.
EINVAL Other error: No PMD found, subpage doesn't have Present
bit set, "Special" page no backed by struct page, VMA
incorrectly sized, address not page-aligned, ...
Most notable here is ENOMEM and EBUSY (new to madvise) which are intended
to provide the caller with actionable feedback so they may take an
appropriate fallback measure.
Use Cases
An immediate user of this new functionality are malloc() implementations
that manage memory in hugepage-sized chunks, but sometimes subrelease
memory back to the system in native-sized chunks via MADV_DONTNEED;
zapping the pmd. Later, when the memory is hot, the implementation could
madvise(MADV_COLLAPSE) to re-back the memory by THPs to regain hugepage
coverage and dTLB performance. TCMalloc is such an implementation that
could benefit from this[2].
Only privately-mapped anon memory is supported for now, but additional
support for file, shmem, and HugeTLB high-granularity mappings[2] is
expected. File and tmpfs/shmem support would permit:
* Backing executable text by THPs. Current support provided by
CONFIG_READ_ONLY_THP_FOR_FS may take a long time on a large system which
might impair services from serving at their full rated load after
(re)starting. Tricks like mremap(2)'ing text onto anonymous memory to
immediately realize iTLB performance prevents page sharing and demand
paging, both of which increase steady state memory footprint. With
MADV_COLLAPSE, we get the best of both worlds: Peak upfront performance
and lower RAM footprints.
* Backing guest memory by hugapages after the memory contents have been
migrated in native-page-sized chunks to a new host, in a
userfaultfd-based live-migration stack.
[1] https://lore.kernel.org/linux-mm/d098c392-273a-36a4-1a29-59731cdf5d3d@google.com/
[2] https://github.com/google/tcmalloc/tree/master/tcmalloc
[jrdr.linux@gmail.com: avoid possible memory leak in failure path]
Link: https://lkml.kernel.org/r/20220713024109.62810-1-jrdr.linux@gmail.com
[zokeefe@google.com add missing kfree() to madvise_collapse()]
Link: https://lore.kernel.org/linux-mm/20220713024109.62810-1-jrdr.linux@gmail.com/
Link: https://lkml.kernel.org/r/20220713161851.1879439-1-zokeefe@google.com
[zokeefe@google.com: delay computation of hpage boundaries until use]]
Link: https://lkml.kernel.org/r/20220720140603.1958773-4-zokeefe@google.com
Link: https://lkml.kernel.org/r/20220706235936.2197195-10-zokeefe@google.com
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: "Souptick Joarder (HPE)" <jrdr.linux@gmail.com>
Suggested-by: David Rientjes <rientjes@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull more hotfixes from Andrew Morton:
"Seventeen hotfixes. Mostly memory management things.
Ten patches are cc:stable, addressing pre-6.0 issues"
* tag 'mm-hotfixes-stable-2022-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
.mailmap: update Luca Ceresoli's e-mail address
mm/mprotect: only reference swap pfn page if type match
squashfs: don't call kmalloc in decompressors
mm/damon/dbgfs: avoid duplicate context directory creation
mailmap: update email address for Colin King
asm-generic: sections: refactor memory_intersects
bootmem: remove the vmemmap pages from kmemleak in put_page_bootmem
ocfs2: fix freeing uninitialized resource on ocfs2_dlm_shutdown
Revert "memcg: cleanup racy sum avoidance code"
mm/zsmalloc: do not attempt to free IS_ERR handle
binder_alloc: add missing mmap_lock calls when using the VMA
mm: re-allow pinning of zero pfns (again)
vmcoreinfo: add kallsyms_num_syms symbol
mailmap: update Guilherme G. Piccoli's email addresses
writeback: avoid use-after-free after removing device
shmem: update folio if shmem_replace_page() updates the page
mm/hugetlb: avoid corrupting page->mapping in hugetlb_mcopy_atomic_pte
There are two problems with the current code of memory_intersects:
First, it doesn't check whether the region (begin, end) falls inside the
region (virt, vend), that is (virt < begin && vend > end).
The second problem is if vend is equal to begin, it will return true but
this is wrong since vend (virt + size) is not the last address of the
memory region but (virt + size -1) is. The wrong determination will
trigger the misreporting when the function check_for_illegal_area calls
memory_intersects to check if the dma region intersects with stext region.
The misreporting is as below (stext is at 0x80100000):
WARNING: CPU: 0 PID: 77 at kernel/dma/debug.c:1073 check_for_illegal_area+0x130/0x168
DMA-API: chipidea-usb2 e0002000.usb: device driver maps memory from kernel text or rodata [addr=800f0000] [len=65536]
Modules linked in:
CPU: 1 PID: 77 Comm: usb-storage Not tainted 5.19.0-yocto-standard #5
Hardware name: Xilinx Zynq Platform
unwind_backtrace from show_stack+0x18/0x1c
show_stack from dump_stack_lvl+0x58/0x70
dump_stack_lvl from __warn+0xb0/0x198
__warn from warn_slowpath_fmt+0x80/0xb4
warn_slowpath_fmt from check_for_illegal_area+0x130/0x168
check_for_illegal_area from debug_dma_map_sg+0x94/0x368
debug_dma_map_sg from __dma_map_sg_attrs+0x114/0x128
__dma_map_sg_attrs from dma_map_sg_attrs+0x18/0x24
dma_map_sg_attrs from usb_hcd_map_urb_for_dma+0x250/0x3b4
usb_hcd_map_urb_for_dma from usb_hcd_submit_urb+0x194/0x214
usb_hcd_submit_urb from usb_sg_wait+0xa4/0x118
usb_sg_wait from usb_stor_bulk_transfer_sglist+0xa0/0xec
usb_stor_bulk_transfer_sglist from usb_stor_bulk_srb+0x38/0x70
usb_stor_bulk_srb from usb_stor_Bulk_transport+0x150/0x360
usb_stor_Bulk_transport from usb_stor_invoke_transport+0x38/0x440
usb_stor_invoke_transport from usb_stor_control_thread+0x1e0/0x238
usb_stor_control_thread from kthread+0xf8/0x104
kthread from ret_from_fork+0x14/0x2c
Refactor memory_intersects to fix the two problems above.
Before the 1d7db834a0 ("dma-debug: use memory_intersects()
directly"), memory_intersects is called only by printk_late_init:
printk_late_init -> init_section_intersects ->memory_intersects.
There were few places where memory_intersects was called.
When commit 1d7db834a0 ("dma-debug: use memory_intersects()
directly") was merged and CONFIG_DMA_API_DEBUG is enabled, the DMA
subsystem uses it to check for an illegal area and the calltrace above
is triggered.
[akpm@linux-foundation.org: fix nearby comment typo]
Link: https://lkml.kernel.org/r/20220819081145.948016-1-quanyang.wang@windriver.com
Fixes: 9795593625 ("asm/sections: add helpers to check for section data")
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thierry Reding <treding@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This reverts commit 96e51ccf1a.
Recently we started running the kernel with rstat infrastructure on
production traffic and begin to see negative memcg stats values.
Particularly the 'sock' stat is the one which we observed having negative
value.
$ grep "sock " /mnt/memory/job/memory.stat
sock 253952
total_sock 18446744073708724224
Re-run after couple of seconds
$ grep "sock " /mnt/memory/job/memory.stat
sock 253952
total_sock 53248
For now we are only seeing this issue on large machines (256 CPUs) and
only with 'sock' stat. I think the networking stack increase the stat on
one cpu and decrease it on another cpu much more often. So, this negative
sock is due to rstat flusher flushing the stats on the CPU that has seen
the decrement of sock but missed the CPU that has increments. A typical
race condition.
For easy stable backport, revert is the most simple solution. For long
term solution, I am thinking of two directions. First is just reduce the
race window by optimizing the rstat flusher. Second is if the reader sees
a negative stat value, force flush and restart the stat collection.
Basically retry but limited.
Link: https://lkml.kernel.org/r/20220817172139.3141101-1-shakeelb@google.com
Fixes: 96e51ccf1a ("memcg: cleanup racy sum avoidance code")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: <stable@vger.kernel.org> [5.15]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull io_uring fixes from Jens Axboe:
- Add missing header file to the MAINTAINERS entry for io_uring (Ammar)
- liburing and the kernel ship the same io_uring.h header, but one
change we've had for a long time only in liburing is to ensure it's
C++ safe. Add extern C around it, so we can more easily sync them in
the future (Ammar)
- Fix an off-by-one in the sync cancel added in this merge window (me)
- Error handling fix for passthrough (Kanchan)
- Fix for address saving for async execution for the zc tx support
(Pavel)
- Fix ordering for TCP zc notifications, so we always have them ordered
correctly between "data was sent" and "data was acked". This isn't
strictly needed with the notification slots, but we've been pondering
disabling the slot support for 6.0 - and if we do, then we do require
the ordering to be sane. Regardless of that, it's the sane thing to
do in terms of API (Pavel)
- Minor cleanup for indentation and lockdep annotation (Pavel)
* tag 'io_uring-6.0-2022-08-26' of git://git.kernel.dk/linux-block:
io_uring/net: save address for sendzc async execution
io_uring: conditional ->async_data allocation
io_uring/notif: order notif vs send CQEs
io_uring/net: fix indentation
io_uring/net: fix zc send link failing
io_uring/net: fix must_hold annotation
io_uring: fix submission-failure handling for uring-cmd
io_uring: fix off-by-one in sync cancelation file check
io_uring: uapi: Add `extern "C"` in io_uring.h for liburing
MAINTAINERS: Add `include/linux/io_uring_types.h`
Pull SCSI fixes from James Bottomley:
"Ten fixes.
Of the three core changes, the two large ones are a complete reversion
of the async rework and an ALUA timing rework (the latter shouldn't
affect non-ALUA paths).
The remaining patches are all small and all but one in drivers"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: sd: Revert "Rework asynchronous resume support"
scsi: core: Fix passthrough retry counter handling
scsi: ufs: core: Reduce the power mode change timeout
scsi: storvsc: Remove WQ_MEM_RECLAIM from storvsc_error_wq
scsi: ufs: host: ufs-exynos: Make fsd_ufs_drvs static
scsi: megaraid_sas: Remove unnecessary kfree()
scsi: megaraid_sas: Fix double kfree()
scsi: ufs: core: Enable link lost interrupt
scsi: core: Allow the ALUA transitioning state enough time
scsi: qla2xxx: Disable ATIO interrupt coalesce for quad port ISP27XX
There are several places in the kernel where wait_on_bit is not followed
by a memory barrier (for example, in drivers/md/dm-bufio.c:new_read).
On architectures with weak memory ordering, it may happen that memory
accesses that follow wait_on_bit are reordered before wait_on_bit and
they may return invalid data.
Fix this class of bugs by introducing a new function "test_bit_acquire"
that works like test_bit, but has acquire memory ordering semantics.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull networking fixes from Jakub Kicinski:
"Including fixes from ipsec and netfilter (with one broken Fixes tag).
Current release - new code bugs:
- dsa: don't dereference NULL extack in dsa_slave_changeupper()
- dpaa: fix <1G ethernet on LS1046ARDB
- neigh: don't call kfree_skb() under spin_lock_irqsave()
Previous releases - regressions:
- r8152: fix the RX FIFO settings when suspending
- dsa: microchip: keep compatibility with device tree blobs with no
phy-mode
- Revert "net: macsec: update SCI upon MAC address change."
- Revert "xfrm: update SA curlft.use_time", comply with RFC 2367
Previous releases - always broken:
- netfilter: conntrack: work around exceeded TCP receive window
- ipsec: fix a null pointer dereference of dst->dev on a metadata dst
in xfrm_lookup_with_ifid
- moxa: get rid of asymmetry in DMA mapping/unmapping
- dsa: microchip: make learning configurable and keep it off while
standalone
- ice: xsk: prohibit usage of non-balanced queue id
- rxrpc: fix locking in rxrpc's sendmsg
Misc:
- another chunk of sysctl data race silencing"
* tag 'net-6.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (87 commits)
net: lantiq_xrx200: restore buffer if memory allocation failed
net: lantiq_xrx200: fix lock under memory pressure
net: lantiq_xrx200: confirm skb is allocated before using
net: stmmac: work around sporadic tx issue on link-up
ionic: VF initial random MAC address if no assigned mac
ionic: fix up issues with handling EAGAIN on FW cmds
ionic: clear broken state on generation change
rxrpc: Fix locking in rxrpc's sendmsg
net: ethernet: mtk_eth_soc: fix hw hash reporting for MTK_NETSYS_V2
MAINTAINERS: rectify file entry in BONDING DRIVER
i40e: Fix incorrect address type for IPv6 flow rules
ixgbe: stop resetting SYSTIME in ixgbe_ptp_start_cyclecounter
net: Fix a data-race around sysctl_somaxconn.
net: Fix a data-race around netdev_unregister_timeout_secs.
net: Fix a data-race around gro_normal_batch.
net: Fix data-races around sysctl_devconf_inherit_init_net.
net: Fix data-races around sysctl_fb_tunnels_only_for_init_net.
net: Fix a data-race around netdev_budget_usecs.
net: Fix data-races around sysctl_max_skb_frags.
net: Fix a data-race around netdev_budget.
...
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
1) Fix crash with malformed ebtables blob which do not provide all
entry points, from Florian Westphal.
2) Fix possible TCP connection clogging up with default 5-days
timeout in conntrack, from Florian.
3) Fix crash in nf_tables tproxy with unsupported chains, also from Florian.
4) Do not allow to update implicit chains.
5) Make table handle allocation per-netns to fix data race.
6) Do not truncated payload length and offset, and checksum offset.
Instead report EINVAl.
7) Enable chain stats update via static key iff no error occurs.
8) Restrict osf expression to ip, ip6 and inet families.
9) Restrict tunnel expression to netdev family.
10) Fix crash when trying to bind again an already bound chain.
11) Flowtable garbage collector might leave behind pending work to
delete entries. This patch comes with a previous preparation patch
as dependency.
12) Allow net.netfilter.nf_conntrack_frag6_high_thresh to be lowered,
from Eric Dumazet.
* git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
netfilter: nf_defrag_ipv6: allow nf_conntrack_frag6_high_thresh increases
netfilter: flowtable: fix stuck flows on cleanup due to pending work
netfilter: flowtable: add function to invoke garbage collection immediately
netfilter: nf_tables: disallow binding to already bound chain
netfilter: nft_tunnel: restrict it to netdev family
netfilter: nft_osf: restrict osf to ipv4, ipv6 and inet families
netfilter: nf_tables: do not leave chain stats enabled on error
netfilter: nft_payload: do not truncate csum_offset and csum_type
netfilter: nft_payload: report ERANGE for too long offset and length
netfilter: nf_tables: make table handle allocation per-netns friendly
netfilter: nf_tables: disallow updates of implicit chain
netfilter: nft_tproxy: restrict to prerouting hook
netfilter: conntrack: work around exceeded receive window
netfilter: ebtables: reject blobs that don't provide all entry points
====================
Link: https://lore.kernel.org/r/20220824220330.64283-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
While reading gro_normal_batch, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.
Fixes: 323ebb61e3 ("net: use listified RX for handling GRO_NORMAL skbs")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While reading sysctl_devconf_inherit_init_net, it can be changed
concurrently. Thus, we need to add READ_ONCE() to its readers.
Fixes: 856c395cfa ("net: introduce a knob to control whether to inherit devconf config")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While reading sysctl_fb_tunnels_only_for_init_net, it can be changed
concurrently. Thus, we need to add READ_ONCE() to its readers.
Fixes: 79134e6ce2 ("net: do not create fallback tunnels for non-default namespaces")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While reading sysctl_net_busy_poll, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.
Fixes: 0602129286 ("net: add low latency socket poll")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Steffen Klassert says:
====================
pull request (net): ipsec 2022-08-24
1) Fix a refcount leak in __xfrm_policy_check.
From Xin Xiong.
2) Revert "xfrm: update SA curlft.use_time". This
violates RFC 2367. From Antony Antony.
3) Fix a comment on XFRMA_LASTUSED.
From Antony Antony.
4) x->lastused is not cloned in xfrm_do_migrate.
Fix from Antony Antony.
5) Serialize the calls to xfrm_probe_algs.
From Herbert Xu.
6) Fix a null pointer dereference of dst->dev on a metadata
dst in xfrm_lookup_with_ifid. From Nikolay Aleksandrov.
Please pull or let me know if there are problems.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
To clear the flow table on flow table free, the following sequence
normally happens in order:
1) gc_step work is stopped to disable any further stats/del requests.
2) All flow table entries are set to teardown state.
3) Run gc_step which will queue HW del work for each flow table entry.
4) Waiting for the above del work to finish (flush).
5) Run gc_step again, deleting all entries from the flow table.
6) Flow table is freed.
But if a flow table entry already has pending HW stats or HW add work
step 3 will not queue HW del work (it will be skipped), step 4 will wait
for the pending add/stats to finish, and step 5 will queue HW del work
which might execute after freeing of the flow table.
To fix the above, this patch flushes the pending work, then it sets the
teardown flag to all flows in the flowtable and it forces a garbage
collector run to queue work to remove the flows from hardware, then it
flushes this new pending work and (finally) it forces another garbage
collector run to remove the entry from the software flowtable.
Stack trace:
[47773.882335] BUG: KASAN: use-after-free in down_read+0x99/0x460
[47773.883634] Write of size 8 at addr ffff888103b45aa8 by task kworker/u20:6/543704
[47773.885634] CPU: 3 PID: 543704 Comm: kworker/u20:6 Not tainted 5.12.0-rc7+ #2
[47773.886745] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)
[47773.888438] Workqueue: nf_ft_offload_del flow_offload_work_handler [nf_flow_table]
[47773.889727] Call Trace:
[47773.890214] dump_stack+0xbb/0x107
[47773.890818] print_address_description.constprop.0+0x18/0x140
[47773.892990] kasan_report.cold+0x7c/0xd8
[47773.894459] kasan_check_range+0x145/0x1a0
[47773.895174] down_read+0x99/0x460
[47773.899706] nf_flow_offload_tuple+0x24f/0x3c0 [nf_flow_table]
[47773.907137] flow_offload_work_handler+0x72d/0xbe0 [nf_flow_table]
[47773.913372] process_one_work+0x8ac/0x14e0
[47773.921325]
[47773.921325] Allocated by task 592159:
[47773.922031] kasan_save_stack+0x1b/0x40
[47773.922730] __kasan_kmalloc+0x7a/0x90
[47773.923411] tcf_ct_flow_table_get+0x3cb/0x1230 [act_ct]
[47773.924363] tcf_ct_init+0x71c/0x1156 [act_ct]
[47773.925207] tcf_action_init_1+0x45b/0x700
[47773.925987] tcf_action_init+0x453/0x6b0
[47773.926692] tcf_exts_validate+0x3d0/0x600
[47773.927419] fl_change+0x757/0x4a51 [cls_flower]
[47773.928227] tc_new_tfilter+0x89a/0x2070
[47773.936652]
[47773.936652] Freed by task 543704:
[47773.937303] kasan_save_stack+0x1b/0x40
[47773.938039] kasan_set_track+0x1c/0x30
[47773.938731] kasan_set_free_info+0x20/0x30
[47773.939467] __kasan_slab_free+0xe7/0x120
[47773.940194] slab_free_freelist_hook+0x86/0x190
[47773.941038] kfree+0xce/0x3a0
[47773.941644] tcf_ct_flow_table_cleanup_work
Original patch description and stack trace by Paul Blakey.
Fixes: c29f74e0df ("netfilter: nf_flow_table: hardware offload support")
Reported-by: Paul Blakey <paulb@nvidia.com>
Tested-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
