linux.git/kernel, branch v5.17.6

perf/core: Fix perf_mmap fail when CONFIG_PERF_USE_VMALLOC enabled

2022-04-27T12:41:12+00:00

[ Upstream commit 60490e7966659b26d74bf1fa4aa8693d9a94ca88 ]

This problem can be reproduced with CONFIG_PERF_USE_VMALLOC enabled on
both x86_64 and aarch64 arch when using sysdig -B(using ebpf)[1].
sysdig -B works fine after rebuilding the kernel with
CONFIG_PERF_USE_VMALLOC disabled.

I tracked it down to the if condition event->rb->nr_pages != nr_pages
in perf_mmap is true when CONFIG_PERF_USE_VMALLOC is enabled where
event->rb->nr_pages = 1 and nr_pages = 2048 resulting perf_mmap to
return -EINVAL. This is because when CONFIG_PERF_USE_VMALLOC is
enabled, rb->nr_pages is always equal to 1.

Arch with CONFIG_PERF_USE_VMALLOC enabled by default:
	arc/arm/csky/mips/sh/sparc/xtensa

Arch with CONFIG_PERF_USE_VMALLOC disabled by default:
	x86_64/aarch64/...

Fix this problem by using data_page_nr()

[1] https://github.com/draios/sysdig

Fixes: 906010b2134e ("perf_event: Provide vmalloc() based mmap() backing")
Signed-off-by: Zhipeng Xie 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20220209145417.6495-1-xiezhipeng1@huawei.com
Signed-off-by: Sasha Levin

sched/pelt: Fix attach_entity_load_avg() corner case

2022-04-27T12:41:12+00:00

[ Upstream commit 40f5aa4c5eaebfeaca4566217cb9c468e28ed682 ]

The warning in cfs_rq_is_decayed() triggered:

    SCHED_WARN_ON(cfs_rq->avg.load_avg ||
		  cfs_rq->avg.util_avg ||
		  cfs_rq->avg.runnable_avg)

There exists a corner case in attach_entity_load_avg() which will
cause load_sum to be zero while load_avg will not be.

Consider se_weight is 88761 as per the sched_prio_to_weight[] table.
Further assume the get_pelt_divider() is 47742, this gives:
se->avg.load_avg is 1.

However, calculating load_sum:

  se->avg.load_sum = div_u64(se->avg.load_avg * se->avg.load_sum, se_weight(se));
  se->avg.load_sum = 1*47742/88761 = 0.

Then enqueue_load_avg() adds this to the cfs_rq totals:

  cfs_rq->avg.load_avg += se->avg.load_avg;
  cfs_rq->avg.load_sum += se_weight(se) * se->avg.load_sum;

Resulting in load_avg being 1 with load_sum is 0, which will trigger
the WARN.

Fixes: f207934fb79d ("sched/fair: Align PELT windows between cfs_rq and its se")
Signed-off-by: kuyo chang 
[peterz: massage changelog]
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Vincent Guittot 
Tested-by: Dietmar Eggemann 
Link: https://lkml.kernel.org/r/20220414090229.342-1-kuyo.chang@mediatek.com
Signed-off-by: Sasha Levin

irq_work: use kasan_record_aux_stack_noalloc() record callstack

2022-04-27T12:41:10+00:00

[ Upstream commit 25934fcfb93c4687ad32fd3d062bcf03457129d4 ]

On PREEMPT_RT kernel and KASAN is enabled.  the kasan_record_aux_stack()
may call alloc_pages(), and the rt-spinlock will be acquired, if currently
in atomic context, will trigger warning:

  BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
  in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 239, name: bootlogd
  Preemption disabled at:
  [] rt_mutex_slowunlock+0xa1/0x4e0
  CPU: 3 PID: 239 Comm: bootlogd Tainted: G        W 5.17.1-rt17-yocto-preempt-rt+ #105
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
  Call Trace:
     __might_resched.cold+0x13b/0x173
     rt_spin_lock+0x5b/0xf0
     get_page_from_freelist+0x20c/0x1610
     __alloc_pages+0x25e/0x5e0
     __stack_depot_save+0x3c0/0x4a0
     kasan_save_stack+0x3a/0x50
     __kasan_record_aux_stack+0xb6/0xc0
     kasan_record_aux_stack+0xe/0x10
     irq_work_queue_on+0x6a/0x1c0
     pull_rt_task+0x631/0x6b0
     do_balance_callbacks+0x56/0x80
     __balance_callbacks+0x63/0x90
     rt_mutex_setprio+0x349/0x880
     rt_mutex_slowunlock+0x22a/0x4e0
     rt_spin_unlock+0x49/0x80
     uart_write+0x186/0x2b0
     do_output_char+0x2e9/0x3a0
     n_tty_write+0x306/0x800
     file_tty_write.isra.0+0x2af/0x450
     tty_write+0x22/0x30
     new_sync_write+0x27c/0x3a0
     vfs_write+0x3f7/0x5d0
     ksys_write+0xd9/0x180
     __x64_sys_write+0x43/0x50
     do_syscall_64+0x44/0x90
     entry_SYSCALL_64_after_hwframe+0x44/0xae

Fix it by using kasan_record_aux_stack_noalloc() to avoid the call to
alloc_pages().

Link: https://lkml.kernel.org/r/20220402142555.2699582-1-qiang1.zhang@intel.com
Signed-off-by: Zqiang 
Cc: Andrey Ryabinin 
Cc: Alexander Potapenko 
Cc: Andrey Konovalov 
Cc: Dmitry Vyukov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

cpu/hotplug: Remove the 'cpu' member of cpuhp_cpu_state

2022-04-20T07:36:28+00:00

commit b7ba6d8dc3569e49800ef0136799f26f43e237e8 upstream.

Currently the setting of the 'cpu' member of struct cpuhp_cpu_state in
cpuhp_create() is too late as it is used earlier in _cpu_up().

If kzalloc_node() in __smpboot_create_thread() fails then the rollback will
be done with st->cpu==0 causing CPU0 to be erroneously set to be dying,
causing the scheduler to get mightily confused and throw its toys out of
the pram.

However the cpu number is actually available directly, so simply remove
the 'cpu' member and avoid the problem in the first place.

Fixes: 2ea46c6fc945 ("cpumask/hotplug: Fix cpu_dying() state tracking")
Signed-off-by: Steven Price 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20220411152233.474129-2-steven.price@arm.com
Signed-off-by: Greg Kroah-Hartman

dma-direct: avoid redundant memory sync for swiotlb

2022-04-20T07:36:27+00:00

commit 9e02977bfad006af328add9434c8bffa40e053bb upstream.

When we looked into FIO performance with swiotlb enabled in VM, we found
swiotlb_bounce() is always called one more time than expected for each DMA
read request.

It turns out that the bounce buffer is copied to original DMA buffer twice
after the completion of a DMA request (one is done by in
dma_direct_sync_single_for_cpu(), the other by swiotlb_tbl_unmap_single()).
But the content in bounce buffer actually doesn't change between the two
rounds of copy. So, one round of copy is redundant.

Pass DMA_ATTR_SKIP_CPU_SYNC flag to swiotlb_tbl_unmap_single() to
skip the memory copy in it.

This fix increases FIO 64KB sequential read throughput in a guest with
swiotlb=force by 5.6%.

Fixes: 55897af63091 ("dma-direct: merge swiotlb_dma_ops into the dma_direct code")
Reported-by: Wang Zhaoyang1 
Reported-by: Gao Liang 
Signed-off-by: Chao Gao 
Reviewed-by: Kevin Tian 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Greg Kroah-Hartman

timers: Fix warning condition in __run_timers()

2022-04-20T07:36:27+00:00

commit c54bc0fc84214b203f7a0ebfd1bd308ce2abe920 upstream.

When the timer base is empty, base::next_expiry is set to base::clk +
NEXT_TIMER_MAX_DELTA and base::next_expiry_recalc is false. When no timer
is queued until jiffies reaches base::next_expiry value, the warning for
not finding any expired timer and base::next_expiry_recalc is false in
__run_timers() triggers.

To prevent triggering the warning in this valid scenario
base::timers_pending needs to be added to the warning condition.

Fixes: 31cd0e119d50 ("timers: Recalculate next timer interrupt only when necessary")
Reported-by: Johannes Berg 
Signed-off-by: Anna-Maria Behnsen 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Frederic Weisbecker 
Link: https://lore.kernel.org/r/20220405191732.7438-3-anna-maria@linutronix.de
Signed-off-by: Greg Kroah-Hartman

smp: Fix offline cpu check in flush_smp_call_function_queue()

2022-04-20T07:36:27+00:00

commit 9e949a3886356fe9112c6f6f34a6e23d1d35407f upstream.

The check in flush_smp_call_function_queue() for callbacks that are sent
to offline CPUs currently checks whether the queue is empty.

However, flush_smp_call_function_queue() has just deleted all the
callbacks from the queue and moved all the entries into a local list.
This checks would only be positive if some callbacks were added in the
short time after llist_del_all() was called. This does not seem to be
the intention of this check.

Change the check to look at the local list to which the entries were
moved instead of the queue from which all the callbacks were just
removed.

Fixes: 8d056c48e4862 ("CPU hotplug, smp: flush any pending IPI callbacks before CPU offline")
Signed-off-by: Nadav Amit 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20220319072015.1495036-1-namit@vmware.com
Signed-off-by: Greg Kroah-Hartman

tick/nohz: Use WARN_ON_ONCE() to prevent console saturation

2022-04-20T07:36:26+00:00

commit 40e97e42961f8c6cc7bd5fe67cc18417e02d78f1 upstream.

While running some testing on code that happened to allow the variable
tick_nohz_full_running to get set but with no "possible" NOHZ cores to
back up that setting, this warning triggered:

        if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
                WARN_ON(tick_nohz_full_running);

The console was overwhemled with an endless stream of one WARN per tick
per core and there was no way to even see what was going on w/o using a
serial console to capture it and then trace it back to this.

Change it to WARN_ON_ONCE().

Fixes: 08ae95f4fd3b ("nohz_full: Allow the boot CPU to be nohz_full")
Signed-off-by: Paul Gortmaker 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211206145950.10927-3-paul.gortmaker@windriver.com
Signed-off-by: Greg Kroah-Hartman

genirq/affinity: Consider that CPUs on nodes can be unbalanced

2022-04-20T07:36:26+00:00

commit 08d835dff916bfe8f45acc7b92c7af6c4081c8a7 upstream.

If CPUs on a node are offline at boot time, the number of nodes is
different when building affinity masks for present cpus and when building
affinity masks for possible cpus. This causes the following problem:

In the case that the number of vectors is less than the number of nodes
there are cases where bits of masks for present cpus are overwritten when
building masks for possible cpus.

Fix this by excluding CPUs, which are not part of the current build mask
(present/possible).

[ tglx: Massaged changelog and added comment ]

Fixes: b82592199032 ("genirq/affinity: Spread IRQs to all available NUMA nodes")
Signed-off-by: Rei Yamamoto 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Ming Lei 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220331003309.10891-1-yamamoto.rei@jp.fujitsu.com
Signed-off-by: Greg Kroah-Hartman

static_call: Don't make __static_call_return0 static

2022-04-13T17:27:43+00:00

commit 8fd4ddda2f49a66bf5dd3d0c01966c4b1971308b upstream.

System.map shows that vmlinux contains several instances of
__static_call_return0():

	c0004fc0 t __static_call_return0
	c0011518 t __static_call_return0
	c00d8160 t __static_call_return0

arch_static_call_transform() uses the middle one to check whether we are
setting a call to __static_call_return0 or not:

	c0011520 :
	c0011520:       3d 20 c0 01     lis     r9,-16383	<== r9 =  0xc001 << 16
	c0011524:       39 29 15 18     addi    r9,r9,5400	<== r9 += 0x1518
	c0011528:       7c 05 48 00     cmpw    r5,r9		<== r9 has value 0xc0011518 here

So if static_call_update() is called with one of the other instances of
__static_call_return0(), arch_static_call_transform() won't recognise it.

In order to work properly, global single instance of __static_call_return0() is required.

Fixes: 3f2a8fc4b15d ("static_call/x86: Add __static_call_return0()")
Signed-off-by: Christophe Leroy 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Josh Poimboeuf 
Link: https://lkml.kernel.org/r/30821468a0e7d28251954b578e5051dc09300d04.1647258493.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman