<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/kernel, branch v5.18-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'perf_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2022-04-10T17:08:22+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-04-10T17:08:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b51f86e9900ab1ff05fb5674c17fd3cb858c4500'/>
<id>b51f86e9900ab1ff05fb5674c17fd3cb858c4500</id>
<content type='text'>
Pull perf fixes from Borislav Petkov:

 - A couple of fixes to cgroup-related handling of perf events

 - A couple of fixes to event encoding on Sapphire Rapids

 - Pass event caps of inherited events so that perf doesn't fail wrongly
   at fork()

 - Add support for a new Raptor Lake CPU

* tag 'perf_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Always set cpuctx cgrp when enable cgroup event
  perf/core: Fix perf_cgroup_switch()
  perf/core: Use perf_cgroup_info-&gt;active to check if cgroup is active
  perf/core: Don't pass task around when ctx sched in
  perf/x86/intel: Update the FRONTEND MSR mask on Sapphire Rapids
  perf/x86/intel: Don't extend the pseudo-encoding to GP counters
  perf/core: Inherit event_caps
  perf/x86/uncore: Add Raptor Lake uncore support
  perf/x86/msr: Add Raptor Lake CPU support
  perf/x86/cstate: Add Raptor Lake support
  perf/x86: Add Intel Raptor Lake support
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull perf fixes from Borislav Petkov:

 - A couple of fixes to cgroup-related handling of perf events

 - A couple of fixes to event encoding on Sapphire Rapids

 - Pass event caps of inherited events so that perf doesn't fail wrongly
   at fork()

 - Add support for a new Raptor Lake CPU

* tag 'perf_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Always set cpuctx cgrp when enable cgroup event
  perf/core: Fix perf_cgroup_switch()
  perf/core: Use perf_cgroup_info-&gt;active to check if cgroup is active
  perf/core: Don't pass task around when ctx sched in
  perf/x86/intel: Update the FRONTEND MSR mask on Sapphire Rapids
  perf/x86/intel: Don't extend the pseudo-encoding to GP counters
  perf/core: Inherit event_caps
  perf/x86/uncore: Add Raptor Lake uncore support
  perf/x86/msr: Add Raptor Lake CPU support
  perf/x86/cstate: Add Raptor Lake support
  perf/x86: Add Intel Raptor Lake support
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'locking_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2022-04-10T16:56:46+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-04-10T16:56:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=50c94de67cfcf858d32a868dcc4e40d8581137c1'/>
<id>50c94de67cfcf858d32a868dcc4e40d8581137c1</id>
<content type='text'>
Pull locking fixes from Borislav Petkov:

 - Allow the compiler to optimize away unused percpu accesses and change
   the local_lock_* macros back to inline functions

 - A couple of fixes to static call insn patching

* tag 'locking_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "mm/page_alloc: mark pagesets as __maybe_unused"
  Revert "locking/local_lock: Make the empty local_lock_*() function a macro."
  x86/percpu: Remove volatile from arch_raw_cpu_ptr().
  static_call: Remove __DEFINE_STATIC_CALL macro
  static_call: Properly initialise DEFINE_STATIC_CALL_RET0()
  static_call: Don't make __static_call_return0 static
  x86,static_call: Fix __static_call_return0 for i386
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull locking fixes from Borislav Petkov:

 - Allow the compiler to optimize away unused percpu accesses and change
   the local_lock_* macros back to inline functions

 - A couple of fixes to static call insn patching

* tag 'locking_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "mm/page_alloc: mark pagesets as __maybe_unused"
  Revert "locking/local_lock: Make the empty local_lock_*() function a macro."
  x86/percpu: Remove volatile from arch_raw_cpu_ptr().
  static_call: Remove __DEFINE_STATIC_CALL macro
  static_call: Properly initialise DEFINE_STATIC_CALL_RET0()
  static_call: Don't make __static_call_return0 static
  x86,static_call: Fix __static_call_return0 for i386
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'sched_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2022-04-10T16:47:49+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-04-10T16:47:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7136849ea95280685dc6a00a893501e61983b6b9'/>
<id>7136849ea95280685dc6a00a893501e61983b6b9</id>
<content type='text'>
Pull scheduler fixes from Borislav Petkov:

 - Use the correct static key checking primitive on the IRQ exit path

 - Two fixes for the new forceidle balancer

* tag 'sched_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  entry: Fix compile error in dynamic_irqentry_exit_cond_resched()
  sched: Teach the forced-newidle balancer about CPU affinity limitation.
  sched/core: Fix forceidle balancing
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull scheduler fixes from Borislav Petkov:

 - Use the correct static key checking primitive on the IRQ exit path

 - Two fixes for the new forceidle balancer

* tag 'sched_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  entry: Fix compile error in dynamic_irqentry_exit_cond_resched()
  sched: Teach the forced-newidle balancer about CPU affinity limitation.
  sched/core: Fix forceidle balancing
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'net-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net</title>
<updated>2022-04-08T05:01:47+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-04-08T05:01:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=73b193f265096080eac866b9a852627b475384fc'/>
<id>73b193f265096080eac866b9a852627b475384fc</id>
<content type='text'>
Pull networking fixes from Paolo Abeni:
 "Including fixes from bpf and netfilter.

  Current release - new code bugs:

   - mctp: correct mctp_i2c_header_create result

   - eth: fungible: fix reference to __udivdi3 on 32b builds

   - eth: micrel: remove latencies support lan8814

  Previous releases - regressions:

   - bpf: resolve to prog-&gt;aux-&gt;dst_prog-&gt;type only for BPF_PROG_TYPE_EXT

   - vrf: fix packet sniffing for traffic originating from ip tunnels

   - rxrpc: fix a race in rxrpc_exit_net()

   - dsa: revert "net: dsa: stop updating master MTU from master.c"

   - eth: ice: fix MAC address setting

  Previous releases - always broken:

   - tls: fix slab-out-of-bounds bug in decrypt_internal

   - bpf: support dual-stack sockets in bpf_tcp_check_syncookie

   - xdp: fix coalescing for page_pool fragment recycling

   - ovs: fix leak of nested actions

   - eth: sfc:
      - add missing xdp queue reinitialization
      - fix using uninitialized xdp tx_queue

   - eth: ice:
      - clear default forwarding VSI during VSI release
      - fix broken IFF_ALLMULTI handling
      - synchronize_rcu() when terminating rings

   - eth: qede: confirm skb is allocated before using

   - eth: aqc111: fix out-of-bounds accesses in RX fixup

   - eth: slip: fix NPD bug in sl_tx_timeout()"

* tag 'net-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (61 commits)
  drivers: net: slip: fix NPD bug in sl_tx_timeout()
  bpf: Adjust bpf_tcp_check_syncookie selftest to test dual-stack sockets
  bpf: Support dual-stack sockets in bpf_tcp_check_syncookie
  myri10ge: fix an incorrect free for skb in myri10ge_sw_tso
  net: usb: aqc111: Fix out-of-bounds accesses in RX fixup
  qede: confirm skb is allocated before using
  net: ipv6mr: fix unused variable warning with CONFIG_IPV6_PIMSM_V2=n
  net: phy: mscc-miim: reject clause 45 register accesses
  net: axiemac: use a phandle to reference pcs_phy
  dt-bindings: net: add pcs-handle attribute
  net: axienet: factor out phy_node in struct axienet_local
  net: axienet: setup mdio unconditionally
  net: sfc: fix using uninitialized xdp tx_queue
  rxrpc: fix a race in rxrpc_exit_net()
  net: openvswitch: fix leak of nested actions
  net: ethernet: mv643xx: Fix over zealous checking of_get_mac_address()
  net: openvswitch: don't send internal clone attribute to the userspace.
  net: micrel: Fix KS8851 Kconfig
  ice: clear cmd_type_offset_bsz for TX rings
  ice: xsk: fix VSI state check in ice_xsk_wakeup()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull networking fixes from Paolo Abeni:
 "Including fixes from bpf and netfilter.

  Current release - new code bugs:

   - mctp: correct mctp_i2c_header_create result

   - eth: fungible: fix reference to __udivdi3 on 32b builds

   - eth: micrel: remove latencies support lan8814

  Previous releases - regressions:

   - bpf: resolve to prog-&gt;aux-&gt;dst_prog-&gt;type only for BPF_PROG_TYPE_EXT

   - vrf: fix packet sniffing for traffic originating from ip tunnels

   - rxrpc: fix a race in rxrpc_exit_net()

   - dsa: revert "net: dsa: stop updating master MTU from master.c"

   - eth: ice: fix MAC address setting

  Previous releases - always broken:

   - tls: fix slab-out-of-bounds bug in decrypt_internal

   - bpf: support dual-stack sockets in bpf_tcp_check_syncookie

   - xdp: fix coalescing for page_pool fragment recycling

   - ovs: fix leak of nested actions

   - eth: sfc:
      - add missing xdp queue reinitialization
      - fix using uninitialized xdp tx_queue

   - eth: ice:
      - clear default forwarding VSI during VSI release
      - fix broken IFF_ALLMULTI handling
      - synchronize_rcu() when terminating rings

   - eth: qede: confirm skb is allocated before using

   - eth: aqc111: fix out-of-bounds accesses in RX fixup

   - eth: slip: fix NPD bug in sl_tx_timeout()"

* tag 'net-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (61 commits)
  drivers: net: slip: fix NPD bug in sl_tx_timeout()
  bpf: Adjust bpf_tcp_check_syncookie selftest to test dual-stack sockets
  bpf: Support dual-stack sockets in bpf_tcp_check_syncookie
  myri10ge: fix an incorrect free for skb in myri10ge_sw_tso
  net: usb: aqc111: Fix out-of-bounds accesses in RX fixup
  qede: confirm skb is allocated before using
  net: ipv6mr: fix unused variable warning with CONFIG_IPV6_PIMSM_V2=n
  net: phy: mscc-miim: reject clause 45 register accesses
  net: axiemac: use a phandle to reference pcs_phy
  dt-bindings: net: add pcs-handle attribute
  net: axienet: factor out phy_node in struct axienet_local
  net: axienet: setup mdio unconditionally
  net: sfc: fix using uninitialized xdp tx_queue
  rxrpc: fix a race in rxrpc_exit_net()
  net: openvswitch: fix leak of nested actions
  net: ethernet: mv643xx: Fix over zealous checking of_get_mac_address()
  net: openvswitch: don't send internal clone attribute to the userspace.
  net: micrel: Fix KS8851 Kconfig
  ice: clear cmd_type_offset_bsz for TX rings
  ice: xsk: fix VSI state check in ice_xsk_wakeup()
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf</title>
<updated>2022-04-07T04:58:50+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2022-04-07T04:58:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8e9d0d7a76c556e8b73289555950917db13d2077'/>
<id>8e9d0d7a76c556e8b73289555950917db13d2077</id>
<content type='text'>
Alexei Starovoitov says:

====================
pull-request: bpf 2022-04-06

We've added 8 non-merge commits during the last 8 day(s) which contain
a total of 9 files changed, 139 insertions(+), 36 deletions(-).

The main changes are:

1) rethook related fixes, from Jiri and Masami.

2) Fix the case when tracing bpf prog is attached to struct_ops, from Martin.

3) Support dual-stack sockets in bpf_tcp_check_syncookie, from Maxim.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf: Adjust bpf_tcp_check_syncookie selftest to test dual-stack sockets
  bpf: Support dual-stack sockets in bpf_tcp_check_syncookie
  bpf: selftests: Test fentry tracing a struct_ops program
  bpf: Resolve to prog-&gt;aux-&gt;dst_prog-&gt;type only for BPF_PROG_TYPE_EXT
  rethook: Fix to use WRITE_ONCE() for rethook:: Handler
  selftests/bpf: Fix warning comparing pointer to 0
  bpf: Fix sparse warnings in kprobe_multi_resolve_syms
  bpftool: Explicit errno handling in skeletons
====================

Link: https://lore.kernel.org/r/20220407031245.73026-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Alexei Starovoitov says:

====================
pull-request: bpf 2022-04-06

We've added 8 non-merge commits during the last 8 day(s) which contain
a total of 9 files changed, 139 insertions(+), 36 deletions(-).

The main changes are:

1) rethook related fixes, from Jiri and Masami.

2) Fix the case when tracing bpf prog is attached to struct_ops, from Martin.

3) Support dual-stack sockets in bpf_tcp_check_syncookie, from Maxim.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf: Adjust bpf_tcp_check_syncookie selftest to test dual-stack sockets
  bpf: Support dual-stack sockets in bpf_tcp_check_syncookie
  bpf: selftests: Test fentry tracing a struct_ops program
  bpf: Resolve to prog-&gt;aux-&gt;dst_prog-&gt;type only for BPF_PROG_TYPE_EXT
  rethook: Fix to use WRITE_ONCE() for rethook:: Handler
  selftests/bpf: Fix warning comparing pointer to 0
  bpf: Fix sparse warnings in kprobe_multi_resolve_syms
  bpftool: Explicit errno handling in skeletons
====================

Link: https://lore.kernel.org/r/20220407031245.73026-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf/core: Always set cpuctx cgrp when enable cgroup event</title>
<updated>2022-04-05T07:59:45+00:00</updated>
<author>
<name>Chengming Zhou</name>
<email>zhouchengming@bytedance.com</email>
</author>
<published>2022-03-29T15:45:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e19cd0b6fa5938c51d7b928010d584f0de93913a'/>
<id>e19cd0b6fa5938c51d7b928010d584f0de93913a</id>
<content type='text'>
When enable a cgroup event, cpuctx-&gt;cgrp setting is conditional
on the current task cgrp matching the event's cgroup, so have to
do it for every new event. It brings complexity but no advantage.

To keep it simple, this patch would always set cpuctx-&gt;cgrp
when enable the first cgroup event, and reset to NULL when disable
the last cgroup event.

Signed-off-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20220329154523.86438-5-zhouchengming@bytedance.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When enable a cgroup event, cpuctx-&gt;cgrp setting is conditional
on the current task cgrp matching the event's cgroup, so have to
do it for every new event. It brings complexity but no advantage.

To keep it simple, this patch would always set cpuctx-&gt;cgrp
when enable the first cgroup event, and reset to NULL when disable
the last cgroup event.

Signed-off-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20220329154523.86438-5-zhouchengming@bytedance.com
</pre>
</div>
</content>
</entry>
<entry>
<title>perf/core: Fix perf_cgroup_switch()</title>
<updated>2022-04-05T07:59:45+00:00</updated>
<author>
<name>Chengming Zhou</name>
<email>zhouchengming@bytedance.com</email>
</author>
<published>2022-03-29T15:45:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=96492a6c558acb56124844d1409d9ef8624a0322'/>
<id>96492a6c558acb56124844d1409d9ef8624a0322</id>
<content type='text'>
There is a race problem that can trigger WARN_ON_ONCE(cpuctx-&gt;cgrp)
in perf_cgroup_switch().

CPU1						CPU2
perf_cgroup_sched_out(prev, next)
  cgrp1 = perf_cgroup_from_task(prev)
  cgrp2 = perf_cgroup_from_task(next)
  if (cgrp1 != cgrp2)
    perf_cgroup_switch(prev, PERF_CGROUP_SWOUT)
						cgroup_migrate_execute()
						  task-&gt;cgroups = ?
						  perf_cgroup_attach()
						    task_function_call(task, __perf_cgroup_move)
perf_cgroup_sched_in(prev, next)
  cgrp1 = perf_cgroup_from_task(prev)
  cgrp2 = perf_cgroup_from_task(next)
  if (cgrp1 != cgrp2)
    perf_cgroup_switch(next, PERF_CGROUP_SWIN)
						__perf_cgroup_move()
						  perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN)

The commit a8d757ef076f ("perf events: Fix slow and broken cgroup
context switch code") want to skip perf_cgroup_switch() when the
perf_cgroup of "prev" and "next" are the same.

But task-&gt;cgroups can change in concurrent with context_switch()
in cgroup_migrate_execute(). If cgrp1 == cgrp2 in sched_out(),
cpuctx won't do sched_out. Then task-&gt;cgroups changed cause
cgrp1 != cgrp2 in sched_in(), cpuctx will do sched_in. So trigger
WARN_ON_ONCE(cpuctx-&gt;cgrp).

Even though __perf_cgroup_move() will be synchronized as the context
switch disables the interrupt, context_switch() still can see the
task-&gt;cgroups is changing in the middle, since task-&gt;cgroups changed
before sending IPI.

So we have to combine perf_cgroup_sched_in() into perf_cgroup_sched_out(),
unified into perf_cgroup_switch(), to fix the incosistency between
perf_cgroup_sched_out() and perf_cgroup_sched_in().

But we can't just compare prev-&gt;cgroups with next-&gt;cgroups to decide
whether to skip cpuctx sched_out/in since the prev-&gt;cgroups is changing
too. For example:

CPU1					CPU2
					cgroup_migrate_execute()
					  prev-&gt;cgroups = ?
					  perf_cgroup_attach()
					    task_function_call(task, __perf_cgroup_move)
perf_cgroup_switch(task)
  cgrp1 = perf_cgroup_from_task(prev)
  cgrp2 = perf_cgroup_from_task(next)
  if (cgrp1 != cgrp2)
    cpuctx sched_out/in ...
					task_function_call() will return -ESRCH

In the above example, prev-&gt;cgroups changing cause (cgrp1 == cgrp2)
to be true, so skip cpuctx sched_out/in. And later task_function_call()
would return -ESRCH since the prev task isn't running on cpu anymore.
So we would leave perf_events of the old prev-&gt;cgroups still sched on
the CPU, which is wrong.

The solution is that we should use cpuctx-&gt;cgrp to compare with
the next task's perf_cgroup. Since cpuctx-&gt;cgrp can only be changed
on local CPU, and we have irq disabled, we can read cpuctx-&gt;cgrp to
compare without holding ctx lock.

Fixes: a8d757ef076f ("perf events: Fix slow and broken cgroup context switch code")
Signed-off-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20220329154523.86438-4-zhouchengming@bytedance.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is a race problem that can trigger WARN_ON_ONCE(cpuctx-&gt;cgrp)
in perf_cgroup_switch().

CPU1						CPU2
perf_cgroup_sched_out(prev, next)
  cgrp1 = perf_cgroup_from_task(prev)
  cgrp2 = perf_cgroup_from_task(next)
  if (cgrp1 != cgrp2)
    perf_cgroup_switch(prev, PERF_CGROUP_SWOUT)
						cgroup_migrate_execute()
						  task-&gt;cgroups = ?
						  perf_cgroup_attach()
						    task_function_call(task, __perf_cgroup_move)
perf_cgroup_sched_in(prev, next)
  cgrp1 = perf_cgroup_from_task(prev)
  cgrp2 = perf_cgroup_from_task(next)
  if (cgrp1 != cgrp2)
    perf_cgroup_switch(next, PERF_CGROUP_SWIN)
						__perf_cgroup_move()
						  perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN)

The commit a8d757ef076f ("perf events: Fix slow and broken cgroup
context switch code") want to skip perf_cgroup_switch() when the
perf_cgroup of "prev" and "next" are the same.

But task-&gt;cgroups can change in concurrent with context_switch()
in cgroup_migrate_execute(). If cgrp1 == cgrp2 in sched_out(),
cpuctx won't do sched_out. Then task-&gt;cgroups changed cause
cgrp1 != cgrp2 in sched_in(), cpuctx will do sched_in. So trigger
WARN_ON_ONCE(cpuctx-&gt;cgrp).

Even though __perf_cgroup_move() will be synchronized as the context
switch disables the interrupt, context_switch() still can see the
task-&gt;cgroups is changing in the middle, since task-&gt;cgroups changed
before sending IPI.

So we have to combine perf_cgroup_sched_in() into perf_cgroup_sched_out(),
unified into perf_cgroup_switch(), to fix the incosistency between
perf_cgroup_sched_out() and perf_cgroup_sched_in().

But we can't just compare prev-&gt;cgroups with next-&gt;cgroups to decide
whether to skip cpuctx sched_out/in since the prev-&gt;cgroups is changing
too. For example:

CPU1					CPU2
					cgroup_migrate_execute()
					  prev-&gt;cgroups = ?
					  perf_cgroup_attach()
					    task_function_call(task, __perf_cgroup_move)
perf_cgroup_switch(task)
  cgrp1 = perf_cgroup_from_task(prev)
  cgrp2 = perf_cgroup_from_task(next)
  if (cgrp1 != cgrp2)
    cpuctx sched_out/in ...
					task_function_call() will return -ESRCH

In the above example, prev-&gt;cgroups changing cause (cgrp1 == cgrp2)
to be true, so skip cpuctx sched_out/in. And later task_function_call()
would return -ESRCH since the prev task isn't running on cpu anymore.
So we would leave perf_events of the old prev-&gt;cgroups still sched on
the CPU, which is wrong.

The solution is that we should use cpuctx-&gt;cgrp to compare with
the next task's perf_cgroup. Since cpuctx-&gt;cgrp can only be changed
on local CPU, and we have irq disabled, we can read cpuctx-&gt;cgrp to
compare without holding ctx lock.

Fixes: a8d757ef076f ("perf events: Fix slow and broken cgroup context switch code")
Signed-off-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20220329154523.86438-4-zhouchengming@bytedance.com
</pre>
</div>
</content>
</entry>
<entry>
<title>perf/core: Use perf_cgroup_info-&gt;active to check if cgroup is active</title>
<updated>2022-04-05T07:59:45+00:00</updated>
<author>
<name>Chengming Zhou</name>
<email>zhouchengming@bytedance.com</email>
</author>
<published>2022-03-29T15:45:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6875186aea5ce09a644758d9193265da1cc187c7'/>
<id>6875186aea5ce09a644758d9193265da1cc187c7</id>
<content type='text'>
Since we use perf_cgroup_set_timestamp() to start cgroup time and
set active to 1, then use update_cgrp_time_from_cpuctx() to stop
cgroup time and set active to 0.

We can use info-&gt;active directly to check if cgroup is active.

Signed-off-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20220329154523.86438-3-zhouchengming@bytedance.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Since we use perf_cgroup_set_timestamp() to start cgroup time and
set active to 1, then use update_cgrp_time_from_cpuctx() to stop
cgroup time and set active to 0.

We can use info-&gt;active directly to check if cgroup is active.

Signed-off-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20220329154523.86438-3-zhouchengming@bytedance.com
</pre>
</div>
</content>
</entry>
<entry>
<title>perf/core: Don't pass task around when ctx sched in</title>
<updated>2022-04-05T07:59:44+00:00</updated>
<author>
<name>Chengming Zhou</name>
<email>zhouchengming@bytedance.com</email>
</author>
<published>2022-03-29T15:45:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a0827713e298d021d3c79ae7423aea408f3f7c3a'/>
<id>a0827713e298d021d3c79ae7423aea408f3f7c3a</id>
<content type='text'>
The current code pass task around for ctx_sched_in(), only
to get perf_cgroup of the task, then update the timestamp
of it and its ancestors and set them to active.

But we can use cpuctx-&gt;cgrp to get active perf_cgroup and
its ancestors since cpuctx-&gt;cgrp has been set before
ctx_sched_in().

This patch remove the task argument in ctx_sched_in()
and cleanup related code.

Signed-off-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20220329154523.86438-2-zhouchengming@bytedance.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The current code pass task around for ctx_sched_in(), only
to get perf_cgroup of the task, then update the timestamp
of it and its ancestors and set them to active.

But we can use cpuctx-&gt;cgrp to get active perf_cgroup and
its ancestors since cpuctx-&gt;cgrp has been set before
ctx_sched_in().

This patch remove the task argument in ctx_sched_in()
and cleanup related code.

Signed-off-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20220329154523.86438-2-zhouchengming@bytedance.com
</pre>
</div>
</content>
</entry>
<entry>
<title>perf/core: Inherit event_caps</title>
<updated>2022-04-05T07:59:44+00:00</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2022-03-28T20:01:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e3265a4386428d3d157d9565bb520aabff8b4bf0'/>
<id>e3265a4386428d3d157d9565bb520aabff8b4bf0</id>
<content type='text'>
It was reported that some perf event setup can make fork failed on
ARM64.  It was the case of a group of mixed hw and sw events and it
failed in perf_event_init_task() due to armpmu_event_init().

The ARM PMU code checks if all the events in a group belong to the
same PMU except for software events.  But it didn't set the event_caps
of inherited events and no longer identify them as software events.
Therefore the test failed in a child process.

A simple reproducer is:

  $ perf stat -e '{cycles,cs,instructions}' perf bench sched messaging
  # Running 'sched/messaging' benchmark:
  perf: fork(): Invalid argument

The perf stat was fine but the perf bench failed in fork().  Let's
inherit the event caps from the parent.

Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lkml.kernel.org/r/20220328200112.457740-1-namhyung@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It was reported that some perf event setup can make fork failed on
ARM64.  It was the case of a group of mixed hw and sw events and it
failed in perf_event_init_task() due to armpmu_event_init().

The ARM PMU code checks if all the events in a group belong to the
same PMU except for software events.  But it didn't set the event_caps
of inherited events and no longer identify them as software events.
Therefore the test failed in a child process.

A simple reproducer is:

  $ perf stat -e '{cycles,cs,instructions}' perf bench sched messaging
  # Running 'sched/messaging' benchmark:
  perf: fork(): Invalid argument

The perf stat was fine but the perf bench failed in fork().  Let's
inherit the event caps from the parent.

Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lkml.kernel.org/r/20220328200112.457740-1-namhyung@kernel.org
</pre>
</div>
</content>
</entry>
</feed>
