<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/arch/powerpc/kernel/smp.c, branch linux-rolling-stable</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>Convert 'alloc_obj' family to use the new default GFP_KERNEL argument</title>
<updated>2026-02-22T01:09:51+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-02-22T00:37:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43'/>
<id>bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43</id>
<content type='text'>
This was done entirely with mindless brute force, using

    git grep -l '\&lt;k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This was done entirely with mindless brute force, using

    git grep -l '\&lt;k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>treewide: Replace kmalloc with kmalloc_obj for non-scalar types</title>
<updated>2026-02-21T09:02:28+00:00</updated>
<author>
<name>Kees Cook</name>
<email>kees@kernel.org</email>
</author>
<published>2026-02-21T07:49:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=69050f8d6d075dc01af7a5f2f550a8067510366f'/>
<id>69050f8d6d075dc01af7a5f2f550a8067510366f</id>
<content type='text'>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook &lt;kees@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook &lt;kees@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/smp: Add check for kcalloc() failure in parse_thread_groups()</title>
<updated>2026-01-29T03:36:01+00:00</updated>
<author>
<name>Guangshuo Li</name>
<email>lgs201920130244@gmail.com</email>
</author>
<published>2025-09-23T13:32:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=33c1c6d8a28a2761ac74b0380b2563cf546c2a3a'/>
<id>33c1c6d8a28a2761ac74b0380b2563cf546c2a3a</id>
<content type='text'>
As kcalloc() may fail, check its return value to avoid a NULL pointer
dereference when passing it to of_property_read_u32_array().

Fixes: 790a1662d3a26 ("powerpc/smp: Parse ibm,thread-groups with multiple properties")
Cc: stable@vger.kernel.org
Reviewed-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Signed-off-by: Guangshuo Li &lt;lgs201920130244@gmail.com&gt;
Signed-off-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Link: https://patch.msgid.link/20250923133235.1862108-1-lgs201920130244@gmail.com

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
As kcalloc() may fail, check its return value to avoid a NULL pointer
dereference when passing it to of_property_read_u32_array().

Fixes: 790a1662d3a26 ("powerpc/smp: Parse ibm,thread-groups with multiple properties")
Cc: stable@vger.kernel.org
Reviewed-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Signed-off-by: Guangshuo Li &lt;lgs201920130244@gmail.com&gt;
Signed-off-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Link: https://patch.msgid.link/20250923133235.1862108-1-lgs201920130244@gmail.com

</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/smp: Expose die_id and die_cpumask</title>
<updated>2025-11-14T05:42:56+00:00</updated>
<author>
<name>Srikar Dronamraju</name>
<email>srikar@linux.ibm.com</email>
</author>
<published>2025-11-12T07:48:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fb2ff9fa72e20a75cab0ffc9dc8735de68ed4d0d'/>
<id>fb2ff9fa72e20a75cab0ffc9dc8735de68ed4d0d</id>
<content type='text'>
&gt;From Power10 processors onwards, each chip has 2 hemispheres. For LPARs
running on PowerVM Hypervisor, hypervisor determines the allocation of
CPU groups to each LPAR, resulting in two LPARs with the same number of
CPUs potentially having different numbers of CPUs from each hemisphere.
Additionally, it is not feasible to ascertain the hemisphere based
solely on the CPU number.

Users wishing to assign their workload to all CPUs, or a subset of CPUs
within a specific hemisphere, encounter difficulties in identifying the
cpumask. To address this, it is proposed to expose hemisphere
information as a die in sysfs. This aligns with other architectures
and facilitates the identification of CPUs within the same hemisphere.
Tools such as lstopo can also access this information.

Please note: The hypervisor reveals the locality of the CPUs to
hemispheres only in dedicated mode. Consequently, in systems where
hemisphere information is unavailable, such as shared LPARs, the
die_cpus information in sysfs will mirror package_cpus, with
die_id set to -1.

Without this change.
$ grep . /sys/devices/system/cpu/cpu16/topology/{die*,package*} 2&gt;/dev/null
/sys/devices/system/cpu/cpu16/topology/package_cpus:000000,000000ff,ffff0000
/sys/devices/system/cpu/cpu16/topology/package_cpus_list:16-39

With this change.
$ grep . /sys/devices/system/cpu/cpu16/topology/{die*,package*} 2&gt;/dev/null
/sys/devices/system/cpu/cpu16/topology/die_cpus:000000,00000000,00ff0000
/sys/devices/system/cpu/cpu16/topology/die_cpus_list:16-23
/sys/devices/system/cpu/cpu16/topology/die_id:2
/sys/devices/system/cpu/cpu16/topology/package_cpus:000000,000000ff,ffff0000
/sys/devices/system/cpu/cpu16/topology/package_cpus_list:16-39

snipped lstopo-no-graphics o/p
  Group0 L#0 (total=8747584KB)
    Package L#0 (total=3564096KB CPUModel="POWER10 (architected), altivec supported" CPURevision="2.0 (pvr 0080 0200)")
      NUMANode L#0 (P#0 local=3564096KB total=3564096KB)
      Die L#0 (P#0)
        Core L#0 (P#0)
&lt;snipped&gt;
    Package L#1 (total=5183488KB CPUModel="POWER10 (architected), altivec supported" CPURevision="2.0 (pvr 0080 0200)")
      NUMANode L#1 (P#1 local=5183488KB total=5183488KB)
      Die L#2 (P#2)
        Core L#2 (P#16)
          L3Cache L#4 (size=4096KB linesize=128 ways=16)
            L2Cache L#4 (size=1024KB linesize=128 ways=8)
              L1dCache L#4 (size=32KB linesize=128 ways=8)
                L1iCache L#4 (size=48KB linesize=128 ways=6)
                  PU L#16 (P#16)
                  PU L#17 (P#18)
                  PU L#18 (P#20)
                  PU L#19 (P#22)
          L3Cache L#5 (size=4096KB linesize=128 ways=16)
            L2Cache L#5 (size=1024KB linesize=128 ways=8)
              L1dCache L#5 (size=32KB linesize=128 ways=8)
                L1iCache L#5 (size=48KB linesize=128 ways=6)
                  PU L#20 (P#17)
                  PU L#21 (P#19)
                  PU L#22 (P#21)
                  PU L#23 (P#23)
      Die L#3 (P#3)
        Core L#3 (P#24)
          L3Cache L#6 (size=4096KB linesize=128 ways=16)
            L2Cache L#6 (size=1024KB linesize=128 ways=8)
              L1dCache L#6 (size=32KB linesize=128 ways=8)
                L1iCache L#6 (size=48KB linesize=128 ways=6)
                  PU L#24 (P#24)
                  PU L#25 (P#26)
                  PU L#26 (P#28)
                  PU L#27 (P#30)
          L3Cache L#7 (size=4096KB linesize=128 ways=16)
            L2Cache L#7 (size=1024KB linesize=128 ways=8)
              L1dCache L#7 (size=32KB linesize=128 ways=8)
                L1iCache L#7 (size=48KB linesize=128 ways=6)
                  PU L#28 (P#25)
                  PU L#29 (P#27)
                  PU L#30 (P#29)
                  PU L#31 (P#31)
        Core L#4 (P#32)
          L3Cache L#8 (size=4096KB linesize=128 ways=16)
            L2Cache L#8 (size=1024KB linesize=128 ways=8)
              L1dCache L#8 (size=32KB linesize=128 ways=8)
                L1iCache L#8 (size=48KB linesize=128 ways=6)
                  PU L#32 (P#32)
                  PU L#33 (P#34)
                  PU L#34 (P#36)
                  PU L#35 (P#38)
          L3Cache L#9 (size=4096KB linesize=128 ways=16)
            L2Cache L#9 (size=1024KB linesize=128 ways=8)
              L1dCache L#9 (size=32KB linesize=128 ways=8)
                L1iCache L#9 (size=48KB linesize=128 ways=6)
                  PU L#36 (P#33)
                  PU L#37 (P#35)
                  PU L#38 (P#37)
                  PU L#39 (P#39)
  Group0 L#1 (total=7736896KB)
    Package L#2 (total=5170880KB CPUModel="POWER10 (architected), altivec supported" CPURevision="2.0 (pvr 0080 0200)")
      NUMANode L#2 (P#2 local=5170880KB total=5170880KB)
      Die L#4 (P#4)
&lt;snipped&gt;

Reviewed-by: Shrikanth Hegde &lt;sshegde@linux.ibm.com&gt;
Signed-off-by: Srikar Dronamraju &lt;srikar@linux.ibm.com&gt;
Signed-off-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Link: https://patch.msgid.link/20251112074859.814087-1-srikar@linux.ibm.com

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
&gt;From Power10 processors onwards, each chip has 2 hemispheres. For LPARs
running on PowerVM Hypervisor, hypervisor determines the allocation of
CPU groups to each LPAR, resulting in two LPARs with the same number of
CPUs potentially having different numbers of CPUs from each hemisphere.
Additionally, it is not feasible to ascertain the hemisphere based
solely on the CPU number.

Users wishing to assign their workload to all CPUs, or a subset of CPUs
within a specific hemisphere, encounter difficulties in identifying the
cpumask. To address this, it is proposed to expose hemisphere
information as a die in sysfs. This aligns with other architectures
and facilitates the identification of CPUs within the same hemisphere.
Tools such as lstopo can also access this information.

Please note: The hypervisor reveals the locality of the CPUs to
hemispheres only in dedicated mode. Consequently, in systems where
hemisphere information is unavailable, such as shared LPARs, the
die_cpus information in sysfs will mirror package_cpus, with
die_id set to -1.

Without this change.
$ grep . /sys/devices/system/cpu/cpu16/topology/{die*,package*} 2&gt;/dev/null
/sys/devices/system/cpu/cpu16/topology/package_cpus:000000,000000ff,ffff0000
/sys/devices/system/cpu/cpu16/topology/package_cpus_list:16-39

With this change.
$ grep . /sys/devices/system/cpu/cpu16/topology/{die*,package*} 2&gt;/dev/null
/sys/devices/system/cpu/cpu16/topology/die_cpus:000000,00000000,00ff0000
/sys/devices/system/cpu/cpu16/topology/die_cpus_list:16-23
/sys/devices/system/cpu/cpu16/topology/die_id:2
/sys/devices/system/cpu/cpu16/topology/package_cpus:000000,000000ff,ffff0000
/sys/devices/system/cpu/cpu16/topology/package_cpus_list:16-39

snipped lstopo-no-graphics o/p
  Group0 L#0 (total=8747584KB)
    Package L#0 (total=3564096KB CPUModel="POWER10 (architected), altivec supported" CPURevision="2.0 (pvr 0080 0200)")
      NUMANode L#0 (P#0 local=3564096KB total=3564096KB)
      Die L#0 (P#0)
        Core L#0 (P#0)
&lt;snipped&gt;
    Package L#1 (total=5183488KB CPUModel="POWER10 (architected), altivec supported" CPURevision="2.0 (pvr 0080 0200)")
      NUMANode L#1 (P#1 local=5183488KB total=5183488KB)
      Die L#2 (P#2)
        Core L#2 (P#16)
          L3Cache L#4 (size=4096KB linesize=128 ways=16)
            L2Cache L#4 (size=1024KB linesize=128 ways=8)
              L1dCache L#4 (size=32KB linesize=128 ways=8)
                L1iCache L#4 (size=48KB linesize=128 ways=6)
                  PU L#16 (P#16)
                  PU L#17 (P#18)
                  PU L#18 (P#20)
                  PU L#19 (P#22)
          L3Cache L#5 (size=4096KB linesize=128 ways=16)
            L2Cache L#5 (size=1024KB linesize=128 ways=8)
              L1dCache L#5 (size=32KB linesize=128 ways=8)
                L1iCache L#5 (size=48KB linesize=128 ways=6)
                  PU L#20 (P#17)
                  PU L#21 (P#19)
                  PU L#22 (P#21)
                  PU L#23 (P#23)
      Die L#3 (P#3)
        Core L#3 (P#24)
          L3Cache L#6 (size=4096KB linesize=128 ways=16)
            L2Cache L#6 (size=1024KB linesize=128 ways=8)
              L1dCache L#6 (size=32KB linesize=128 ways=8)
                L1iCache L#6 (size=48KB linesize=128 ways=6)
                  PU L#24 (P#24)
                  PU L#25 (P#26)
                  PU L#26 (P#28)
                  PU L#27 (P#30)
          L3Cache L#7 (size=4096KB linesize=128 ways=16)
            L2Cache L#7 (size=1024KB linesize=128 ways=8)
              L1dCache L#7 (size=32KB linesize=128 ways=8)
                L1iCache L#7 (size=48KB linesize=128 ways=6)
                  PU L#28 (P#25)
                  PU L#29 (P#27)
                  PU L#30 (P#29)
                  PU L#31 (P#31)
        Core L#4 (P#32)
          L3Cache L#8 (size=4096KB linesize=128 ways=16)
            L2Cache L#8 (size=1024KB linesize=128 ways=8)
              L1dCache L#8 (size=32KB linesize=128 ways=8)
                L1iCache L#8 (size=48KB linesize=128 ways=6)
                  PU L#32 (P#32)
                  PU L#33 (P#34)
                  PU L#34 (P#36)
                  PU L#35 (P#38)
          L3Cache L#9 (size=4096KB linesize=128 ways=16)
            L2Cache L#9 (size=1024KB linesize=128 ways=8)
              L1dCache L#9 (size=32KB linesize=128 ways=8)
                L1iCache L#9 (size=48KB linesize=128 ways=6)
                  PU L#36 (P#33)
                  PU L#37 (P#35)
                  PU L#38 (P#37)
                  PU L#39 (P#39)
  Group0 L#1 (total=7736896KB)
    Package L#2 (total=5170880KB CPUModel="POWER10 (architected), altivec supported" CPURevision="2.0 (pvr 0080 0200)")
      NUMANode L#2 (P#2 local=5170880KB total=5170880KB)
      Die L#4 (P#4)
&lt;snipped&gt;

Reviewed-by: Shrikanth Hegde &lt;sshegde@linux.ibm.com&gt;
Signed-off-by: Srikar Dronamraju &lt;srikar@linux.ibm.com&gt;
Signed-off-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Link: https://patch.msgid.link/20251112074859.814087-1-srikar@linux.ibm.com

</pre>
</div>
</content>
</entry>
<entry>
<title>sched/fair: Get rid of sched_domains_curr_level hack for tl-&gt;cpumask()</title>
<updated>2025-09-03T08:03:12+00:00</updated>
<author>
<name>Peter Zijlstra</name>
<email>peterz@infradead.org</email>
</author>
<published>2025-08-25T12:02:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=661f951e371cc134ea31c84238dbdc9a898b8403'/>
<id>661f951e371cc134ea31c84238dbdc9a898b8403</id>
<content type='text'>
Leon [1] and Vinicius [2] noted a topology_span_sane() warning during
their testing starting from v6.16-rc1. Debug that followed pointed to
the tl-&gt;mask() for the NODE domain being incorrectly resolved to that of
the highest NUMA domain.

tl-&gt;mask() for NODE is set to the sd_numa_mask() which depends on the
global "sched_domains_curr_level" hack. "sched_domains_curr_level" is
set to the "tl-&gt;numa_level" during tl traversal in build_sched_domains()
calling sd_init() but was not reset before topology_span_sane().

Since "tl-&gt;numa_level" still reflected the old value from
build_sched_domains(), topology_span_sane() for the NODE domain trips
when the span of the last NUMA domain overlaps.

Instead of replicating the "sched_domains_curr_level" hack, get rid of
it entirely and instead, pass the entire "sched_domain_topology_level"
object to tl-&gt;cpumask() function to prevent such mishap in the future.

sd_numa_mask() now directly references "tl-&gt;numa_level" instead of
relying on the global "sched_domains_curr_level" hack to index into
sched_domains_numa_masks[].

The original warning was reproducible on the following NUMA topology
reported by Leon:

    $ sudo numactl -H
    available: 5 nodes (0-4)
    node 0 cpus: 0 1
    node 0 size: 2927 MB
    node 0 free: 1603 MB
    node 1 cpus: 2 3
    node 1 size: 3023 MB
    node 1 free: 3008 MB
    node 2 cpus: 4 5
    node 2 size: 3023 MB
    node 2 free: 3007 MB
    node 3 cpus: 6 7
    node 3 size: 3023 MB
    node 3 free: 3002 MB
    node 4 cpus: 8 9
    node 4 size: 3022 MB
    node 4 free: 2718 MB
    node distances:
    node   0   1   2   3   4
      0:  10  39  38  37  36
      1:  39  10  38  37  36
      2:  38  38  10  37  36
      3:  37  37  37  10  36
      4:  36  36  36  36  10

The above topology can be mimicked using the following QEMU cmd that was
used to reproduce the warning and test the fix:

     sudo qemu-system-x86_64 -enable-kvm -cpu host \
     -m 20G -smp cpus=10,sockets=10 -machine q35 \
     -object memory-backend-ram,size=4G,id=m0 \
     -object memory-backend-ram,size=4G,id=m1 \
     -object memory-backend-ram,size=4G,id=m2 \
     -object memory-backend-ram,size=4G,id=m3 \
     -object memory-backend-ram,size=4G,id=m4 \
     -numa node,cpus=0-1,memdev=m0,nodeid=0 \
     -numa node,cpus=2-3,memdev=m1,nodeid=1 \
     -numa node,cpus=4-5,memdev=m2,nodeid=2 \
     -numa node,cpus=6-7,memdev=m3,nodeid=3 \
     -numa node,cpus=8-9,memdev=m4,nodeid=4 \
     -numa dist,src=0,dst=1,val=39 \
     -numa dist,src=0,dst=2,val=38 \
     -numa dist,src=0,dst=3,val=37 \
     -numa dist,src=0,dst=4,val=36 \
     -numa dist,src=1,dst=0,val=39 \
     -numa dist,src=1,dst=2,val=38 \
     -numa dist,src=1,dst=3,val=37 \
     -numa dist,src=1,dst=4,val=36 \
     -numa dist,src=2,dst=0,val=38 \
     -numa dist,src=2,dst=1,val=38 \
     -numa dist,src=2,dst=3,val=37 \
     -numa dist,src=2,dst=4,val=36 \
     -numa dist,src=3,dst=0,val=37 \
     -numa dist,src=3,dst=1,val=37 \
     -numa dist,src=3,dst=2,val=37 \
     -numa dist,src=3,dst=4,val=36 \
     -numa dist,src=4,dst=0,val=36 \
     -numa dist,src=4,dst=1,val=36 \
     -numa dist,src=4,dst=2,val=36 \
     -numa dist,src=4,dst=3,val=36 \
     ...

  [ prateek: Moved common functions to include/linux/sched/topology.h,
    reuse the common bits for s390 and ppc, commit message ]

Closes: https://lore.kernel.org/lkml/20250610110701.GA256154@unreal/ [1]
Fixes: ccf74128d66c ("sched/topology: Assert non-NUMA topology masks don't (partially) overlap") # ce29a7da84cd, f55dac1dafb3
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reported-by: Leon Romanovsky &lt;leon@kernel.org&gt;
Signed-off-by: K Prateek Nayak &lt;kprateek.nayak@amd.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Valentin Schneider &lt;vschneid@redhat.com&gt;
Reviewed-by: Shrikanth Hegde &lt;sshegde@linux.ibm.com&gt;
Tested-by: Valentin Schneider &lt;vschneid@redhat.com&gt; # x86
Tested-by: Shrikanth Hegde &lt;sshegde@linux.ibm.com&gt; # powerpc
Link: https://lore.kernel.org/lkml/a3de98387abad28592e6ab591f3ff6107fe01dc1.1755893468.git.tim.c.chen@linux.intel.com/ [2]
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Leon [1] and Vinicius [2] noted a topology_span_sane() warning during
their testing starting from v6.16-rc1. Debug that followed pointed to
the tl-&gt;mask() for the NODE domain being incorrectly resolved to that of
the highest NUMA domain.

tl-&gt;mask() for NODE is set to the sd_numa_mask() which depends on the
global "sched_domains_curr_level" hack. "sched_domains_curr_level" is
set to the "tl-&gt;numa_level" during tl traversal in build_sched_domains()
calling sd_init() but was not reset before topology_span_sane().

Since "tl-&gt;numa_level" still reflected the old value from
build_sched_domains(), topology_span_sane() for the NODE domain trips
when the span of the last NUMA domain overlaps.

Instead of replicating the "sched_domains_curr_level" hack, get rid of
it entirely and instead, pass the entire "sched_domain_topology_level"
object to tl-&gt;cpumask() function to prevent such mishap in the future.

sd_numa_mask() now directly references "tl-&gt;numa_level" instead of
relying on the global "sched_domains_curr_level" hack to index into
sched_domains_numa_masks[].

The original warning was reproducible on the following NUMA topology
reported by Leon:

    $ sudo numactl -H
    available: 5 nodes (0-4)
    node 0 cpus: 0 1
    node 0 size: 2927 MB
    node 0 free: 1603 MB
    node 1 cpus: 2 3
    node 1 size: 3023 MB
    node 1 free: 3008 MB
    node 2 cpus: 4 5
    node 2 size: 3023 MB
    node 2 free: 3007 MB
    node 3 cpus: 6 7
    node 3 size: 3023 MB
    node 3 free: 3002 MB
    node 4 cpus: 8 9
    node 4 size: 3022 MB
    node 4 free: 2718 MB
    node distances:
    node   0   1   2   3   4
      0:  10  39  38  37  36
      1:  39  10  38  37  36
      2:  38  38  10  37  36
      3:  37  37  37  10  36
      4:  36  36  36  36  10

The above topology can be mimicked using the following QEMU cmd that was
used to reproduce the warning and test the fix:

     sudo qemu-system-x86_64 -enable-kvm -cpu host \
     -m 20G -smp cpus=10,sockets=10 -machine q35 \
     -object memory-backend-ram,size=4G,id=m0 \
     -object memory-backend-ram,size=4G,id=m1 \
     -object memory-backend-ram,size=4G,id=m2 \
     -object memory-backend-ram,size=4G,id=m3 \
     -object memory-backend-ram,size=4G,id=m4 \
     -numa node,cpus=0-1,memdev=m0,nodeid=0 \
     -numa node,cpus=2-3,memdev=m1,nodeid=1 \
     -numa node,cpus=4-5,memdev=m2,nodeid=2 \
     -numa node,cpus=6-7,memdev=m3,nodeid=3 \
     -numa node,cpus=8-9,memdev=m4,nodeid=4 \
     -numa dist,src=0,dst=1,val=39 \
     -numa dist,src=0,dst=2,val=38 \
     -numa dist,src=0,dst=3,val=37 \
     -numa dist,src=0,dst=4,val=36 \
     -numa dist,src=1,dst=0,val=39 \
     -numa dist,src=1,dst=2,val=38 \
     -numa dist,src=1,dst=3,val=37 \
     -numa dist,src=1,dst=4,val=36 \
     -numa dist,src=2,dst=0,val=38 \
     -numa dist,src=2,dst=1,val=38 \
     -numa dist,src=2,dst=3,val=37 \
     -numa dist,src=2,dst=4,val=36 \
     -numa dist,src=3,dst=0,val=37 \
     -numa dist,src=3,dst=1,val=37 \
     -numa dist,src=3,dst=2,val=37 \
     -numa dist,src=3,dst=4,val=36 \
     -numa dist,src=4,dst=0,val=36 \
     -numa dist,src=4,dst=1,val=36 \
     -numa dist,src=4,dst=2,val=36 \
     -numa dist,src=4,dst=3,val=36 \
     ...

  [ prateek: Moved common functions to include/linux/sched/topology.h,
    reuse the common bits for s390 and ppc, commit message ]

Closes: https://lore.kernel.org/lkml/20250610110701.GA256154@unreal/ [1]
Fixes: ccf74128d66c ("sched/topology: Assert non-NUMA topology masks don't (partially) overlap") # ce29a7da84cd, f55dac1dafb3
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reported-by: Leon Romanovsky &lt;leon@kernel.org&gt;
Signed-off-by: K Prateek Nayak &lt;kprateek.nayak@amd.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Valentin Schneider &lt;vschneid@redhat.com&gt;
Reviewed-by: Shrikanth Hegde &lt;sshegde@linux.ibm.com&gt;
Tested-by: Valentin Schneider &lt;vschneid@redhat.com&gt; # x86
Tested-by: Shrikanth Hegde &lt;sshegde@linux.ibm.com&gt; # powerpc
Link: https://lore.kernel.org/lkml/a3de98387abad28592e6ab591f3ff6107fe01dc1.1755893468.git.tim.c.chen@linux.intel.com/ [2]
</pre>
</div>
</content>
</entry>
<entry>
<title>smpboot: introduce SDTL_INIT() helper to tidy sched topology setup</title>
<updated>2025-07-14T08:59:34+00:00</updated>
<author>
<name>Li Chen</name>
<email>chenl311@chinatelecom.cn</email>
</author>
<published>2025-07-10T10:57:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e075f4360931263f5ec006ea5dadc065e5e98eb8'/>
<id>e075f4360931263f5ec006ea5dadc065e5e98eb8</id>
<content type='text'>
Define a small SDTL_INIT(maskfn, flagsfn, name) macro and use it to build the
sched_domain_topology_level array. Purely a cleanup; behaviour is unchanged.

Suggested-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Li Chen &lt;chenl311@chinatelecom.cn&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: K Prateek Nayak &lt;kprateek.nayak@amd.com&gt;
Tested-by: K Prateek Nayak &lt;kprateek.nayak@amd.com&gt;
Link: https://lore.kernel.org/r/20250710105715.66594-2-me@linux.beauty
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Define a small SDTL_INIT(maskfn, flagsfn, name) macro and use it to build the
sched_domain_topology_level array. Purely a cleanup; behaviour is unchanged.

Suggested-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Li Chen &lt;chenl311@chinatelecom.cn&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: K Prateek Nayak &lt;kprateek.nayak@amd.com&gt;
Tested-by: K Prateek Nayak &lt;kprateek.nayak@amd.com&gt;
Link: https://lore.kernel.org/r/20250710105715.66594-2-me@linux.beauty
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc: Split systemcfg struct definitions out from vdso</title>
<updated>2024-11-02T11:37:36+00:00</updated>
<author>
<name>Thomas Weißschuh</name>
<email>thomas.weissschuh@linutronix.de</email>
</author>
<published>2024-10-10T07:01:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6142be7ed7f3b0a8a0d6e7c2bb34598b4e7196a1'/>
<id>6142be7ed7f3b0a8a0d6e7c2bb34598b4e7196a1</id>
<content type='text'>
The systemcfg data has nothing to do anymore with the vdso.
Split it into a dedicated header file.

Signed-off-by: Thomas Weißschuh &lt;thomas.weissschuh@linutronix.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-27-b64f0842d512@linutronix.de

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The systemcfg data has nothing to do anymore with the vdso.
Split it into a dedicated header file.

Signed-off-by: Thomas Weißschuh &lt;thomas.weissschuh@linutronix.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-27-b64f0842d512@linutronix.de

</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc: Split systemcfg data out of vdso data page</title>
<updated>2024-11-02T11:37:36+00:00</updated>
<author>
<name>Thomas Weißschuh</name>
<email>thomas.weissschuh@linutronix.de</email>
</author>
<published>2024-10-10T07:01:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1184674d6ef9368b9377213caad3aeb0d97ee1d5'/>
<id>1184674d6ef9368b9377213caad3aeb0d97ee1d5</id>
<content type='text'>
The systemcfg data only has minimal overlap with the vdso data.
Splitting the two avoids mapping the implementation-defined vdso data
into /proc/ppc64/systemcfg.
It is also a preparation for the standardization of vdso data storage.

The only field actually used by both systemcfg and vdso is
tb_ticks_per_sec and it is only changed once during time_init().
Initialize it in both structures there.

Signed-off-by: Thomas Weißschuh &lt;thomas.weissschuh@linutronix.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-26-b64f0842d512@linutronix.de

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The systemcfg data only has minimal overlap with the vdso data.
Splitting the two avoids mapping the implementation-defined vdso data
into /proc/ppc64/systemcfg.
It is also a preparation for the standardization of vdso data storage.

The only field actually used by both systemcfg and vdso is
tb_ticks_per_sec and it is only changed once during time_init().
Initialize it in both structures there.

Signed-off-by: Thomas Weißschuh &lt;thomas.weissschuh@linutronix.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-26-b64f0842d512@linutronix.de

</pre>
</div>
</content>
</entry>
<entry>
<title>smp: Mark smp_prepare_boot_cpu() __init</title>
<updated>2024-09-08T14:01:10+00:00</updated>
<author>
<name>Bibo Mao</name>
<email>maobibo@loongson.cn</email>
</author>
<published>2024-09-07T08:27:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1d07085402d122f223bda3f8b72bea37a46ee0c9'/>
<id>1d07085402d122f223bda3f8b72bea37a46ee0c9</id>
<content type='text'>
smp_prepare_boot_cpu() is only called during boot, hence mark it as
__init.

Signed-off-by: Bibo Mao &lt;maobibo@loongson.cn&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Huacai Chen &lt;chenhuacai@loongson.cn&gt;
Link: https://lore.kernel.org/all/20240907082720.452148-1-maobibo@loongson.cn
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
smp_prepare_boot_cpu() is only called during boot, hence mark it as
__init.

Signed-off-by: Bibo Mao &lt;maobibo@loongson.cn&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Huacai Chen &lt;chenhuacai@loongson.cn&gt;
Link: https://lore.kernel.org/all/20240907082720.452148-1-maobibo@loongson.cn
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc: Fix typos</title>
<updated>2024-05-07T14:21:30+00:00</updated>
<author>
<name>Bjorn Helgaas</name>
<email>bhelgaas@google.com</email>
</author>
<published>2024-01-03T23:16:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0ddbbb8960eaf91c7b432ec80566dfa60a8d79e4'/>
<id>0ddbbb8960eaf91c7b432ec80566dfa60a8d79e4</id>
<content type='text'>
Fix typos, most reported by "codespell arch/powerpc".  Only touches
comments, no code changes.

Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20240103231605.1801364-8-helgaas@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix typos, most reported by "codespell arch/powerpc".  Only touches
comments, no code changes.

Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20240103231605.1801364-8-helgaas@kernel.org
</pre>
</div>
</content>
</entry>
</feed>
