linux-stable.git/kernel, branch v6.3.4

rethook: use preempt_{disable, enable}_notrace in rethook_trampoline_handler

2023-05-24T16:30:24+00:00

commit be243bacfb25f5219f2396d787408e8cf1301dd1 upstream.

This patch replaces preempt_{disable, enable} with its corresponding
notrace version in rethook_trampoline_handler so no worries about stack
recursion or overflow introduced by preempt_count_{add, sub} under
fprobe + rethook context.

Link: https://lore.kernel.org/all/20230517034510.15639-2-zegao@tencent.com/

Fixes: 54ecbe6f1ed5 ("rethook: Add a generic return hook")
Signed-off-by: Ze Gao 
Acked-by: Masami Hiramatsu (Google) 
Cc: 
Signed-off-by: Masami Hiramatsu (Google) 
Signed-off-by: Greg Kroah-Hartman

bpf: Add preempt_count_{sub,add} into btf id deny list

2023-05-24T16:30:06+00:00

[ Upstream commit c11bd046485d7bf1ca200db0e7d0bdc4bafdd395 ]

The recursion check in __bpf_prog_enter* and __bpf_prog_exit*
leave preempt_count_{sub,add} unprotected. When attaching trampoline to
them we get panic as follows,

[  867.843050] BUG: TASK stack guard page was hit at 0000000009d325cf (stack is 0000000046a46a15..00000000537e7b28)
[  867.843064] stack guard page: 0000 [#1] PREEMPT SMP NOPTI
[  867.843067] CPU: 8 PID: 11009 Comm: trace Kdump: loaded Not tainted 6.2.0+ #4
[  867.843100] Call Trace:
[  867.843101]  
[  867.843104]  asm_exc_int3+0x3a/0x40
[  867.843108] RIP: 0010:preempt_count_sub+0x1/0xa0
[  867.843135]  __bpf_prog_enter_recur+0x17/0x90
[  867.843148]  bpf_trampoline_6442468108_0+0x2e/0x1000
[  867.843154]  ? preempt_count_sub+0x1/0xa0
[  867.843157]  preempt_count_sub+0x5/0xa0
[  867.843159]  ? migrate_enable+0xac/0xf0
[  867.843164]  __bpf_prog_exit_recur+0x2d/0x40
[  867.843168]  bpf_trampoline_6442468108_0+0x55/0x1000
...
[  867.843788]  preempt_count_sub+0x5/0xa0
[  867.843793]  ? migrate_enable+0xac/0xf0
[  867.843829]  __bpf_prog_exit_recur+0x2d/0x40
[  867.843837] BUG: IRQ stack guard page was hit at 0000000099bd8228 (stack is 00000000b23e2bc4..000000006d95af35)
[  867.843841] BUG: IRQ stack guard page was hit at 000000005ae07924 (stack is 00000000ffd69623..0000000014eb594c)
[  867.843843] BUG: IRQ stack guard page was hit at 00000000028320f0 (stack is 00000000034b6438..0000000078d1bcec)
[  867.843842]  bpf_trampoline_6442468108_0+0x55/0x1000
...

That is because in __bpf_prog_exit_recur, the preempt_count_{sub,add} are
called after prog->active is decreased.

Fixing this by adding these two functions into btf ids deny list.

Suggested-by: Steven Rostedt 
Signed-off-by: Yafang 
Cc: Masami Hiramatsu 
Cc: Steven Rostedt 
Cc: Jiri Olsa 
Acked-by: Hao Luo 
Link: https://lore.kernel.org/r/20230413025248.79764-1-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

bpf: Annotate data races in bpf_local_storage

2023-05-24T16:30:04+00:00

[ Upstream commit 0a09a2f933c73dc76ab0b72da6855f44342a8903 ]

There are a few cases where hlist_node is checked to be unhashed without
holding the lock protecting its modification. In this case, one must use
hlist_unhashed_lockless to avoid load tearing and KCSAN reports. Fix
this by using lockless variant in places not protected by the lock.

Since this is not prompted by any actual KCSAN reports but only from
code review, I have not included a fixes tag.

Cc: Martin KaFai Lau 
Cc: KP Singh 
Signed-off-by: Kumar Kartikeya Dwivedi 
Link: https://lore.kernel.org/r/20230221200646.2500777-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access

2023-05-24T16:30:00+00:00

[ Upstream commit 3c1566bca3f8349f12b75d0a2d5e4a20ad6262ec ]

For kernels built with CONFIG_PREEMPT_RCU=y, the following scenario can
result in a NULL-pointer dereference:

           CPU1                                           CPU2
rcu_preempt_deferred_qs_irqrestore                rcu_print_task_exp_stall
  if (special.b.blocked)                            READ_ONCE(rnp->exp_tasks) != NULL
    raw_spin_lock_rcu_node
    np = rcu_next_node_entry(t, rnp)
    if (&t->rcu_node_entry == rnp->exp_tasks)
      WRITE_ONCE(rnp->exp_tasks, np)
      ....
      raw_spin_unlock_irqrestore_rcu_node
                                                    raw_spin_lock_irqsave_rcu_node
                                                    t = list_entry(rnp->exp_tasks->prev,
                                                        struct task_struct, rcu_node_entry)
                                                    (if rnp->exp_tasks is NULL, this
                                                       will dereference a NULL pointer)

The problem is that CPU2 accesses the rcu_node structure's->exp_tasks
field without holding the rcu_node structure's ->lock and CPU2 did
not observe CPU1's change to rcu_node structure's ->exp_tasks in time.
Therefore, if CPU1 sets rcu_node structure's->exp_tasks pointer to NULL,
then CPU2 might dereference that NULL pointer.

This commit therefore holds the rcu_node structure's ->lock while
accessing that structure's->exp_tasks field.

[ paulmck: Apply Frederic Weisbecker feedback. ]

Acked-by: Joel Fernandes (Google) 
Signed-off-by: Zqiang 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Joel Fernandes (Google) 
Signed-off-by: Sasha Levin

refscale: Move shutdown from wait_event() to wait_event_idle()

2023-05-24T16:30:00+00:00

[ Upstream commit 6bc6e6b27524304aadb9c04611ddb1c84dd7617a ]

The ref_scale_shutdown() kthread/function uses wait_event() to wait for
the refscale test to complete.  However, although the read-side tests
are normally extremely fast, there is no law against specifying a very
large value for the refscale.loops module parameter or against having
a slow read-side primitive.  Either way, this might well trigger the
hung-task timeout.

This commit therefore replaces those wait_event() calls with calls to
wait_event_idle(), which do not trigger the hung-task timeout.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Boqun Feng 
Signed-off-by: Sasha Levin

tick/broadcast: Make broadcast device replacement work correctly

2023-05-24T16:29:58+00:00

[ Upstream commit f9d36cf445ffff0b913ba187a3eff78028f9b1fb ]

When a tick broadcast clockevent device is initialized for one shot mode
then tick_broadcast_setup_oneshot() OR's the periodic broadcast mode
cpumask into the oneshot broadcast cpumask.

This is required when switching from periodic broadcast mode to oneshot
broadcast mode to ensure that CPUs which are waiting for periodic
broadcast are woken up on the next tick.

But it is subtly broken, when an active broadcast device is replaced and
the system is already in oneshot (NOHZ/HIGHRES) mode. Victor observed
this and debugged the issue.

Then the OR of the periodic broadcast CPU mask is wrong as the periodic
cpumask bits are sticky after tick_broadcast_enable() set it for a CPU
unless explicitly cleared via tick_broadcast_disable().

That means that this sets all other CPUs which have tick broadcasting
enabled at that point unconditionally in the oneshot broadcast mask.

If the affected CPUs were already idle and had their bits set in the
oneshot broadcast mask then this does no harm. But for non idle CPUs
which were not set this corrupts their state.

On their next invocation of tick_broadcast_enable() they observe the bit
set, which indicates that the broadcast for the CPU is already set up.
As a consequence they fail to update the broadcast event even if their
earliest expiring timer is before the actually programmed broadcast
event.

If the programmed broadcast event is far in the future, then this can
cause stalls or trigger the hung task detector.

Avoid this by telling tick_broadcast_setup_oneshot() explicitly whether
this is the initial switch over from periodic to oneshot broadcast which
must take the periodic broadcast mask into account. In the case of
initialization of a replacement device this prevents that the broadcast
oneshot mask is modified.

There is a second problem with broadcast device replacement in this
function. The broadcast device is only armed when the previous state of
the device was periodic.

That is correct for the switch from periodic broadcast mode to oneshot
broadcast mode as the underlying broadcast device could operate in
oneshot state already due to lack of periodic state in hardware. In that
case it is already armed to expire at the next tick.

For the replacement case this is wrong as the device is in shutdown
state. That means that any already pending broadcast event will not be
armed.

This went unnoticed because any CPU which goes idle will observe that
the broadcast device has an expiry time of KTIME_MAX and therefore any
CPUs next timer event will be earlier and cause a reprogramming of the
broadcast device. But that does not guarantee that the events of the
CPUs which were already in idle are delivered on time.

Fix this by arming the newly installed device for an immediate event
which will reevaluate the per CPU expiry times and reprogram the
broadcast device accordingly. This is simpler than caching the last
expiry time in yet another place or saving it before the device exchange
and handing it down to the setup function. Replacement of broadcast
devices is not a frequent operation and usually happens once somewhere
late in the boot process.

Fixes: 9c336c9935cf ("tick/broadcast: Allow late registered device to enter oneshot mode")
Reported-by: Victor Hassan
Signed-off-by: Thomas Gleixner
Reviewed-by: Frederic Weisbecker
Link: https://lore.kernel.org/r/87pm7d2z1i.ffs@tglx
Signed-off-by: Sasha Levin

perf/core: Fix perf_sample_data not properly initialized for different swevents in perf_tp_event()

2023-05-24T16:29:58+00:00

[ Upstream commit 1d1bfe30dad50d4bea83cd38d73c441972ea0173 ]

data->sample_flags may be modified in perf_prepare_sample(),
in perf_tp_event(), different swevents use the same on-stack
perf_sample_data, the previous swevent may change sample_flags in
perf_prepare_sample(), as a result, some members of perf_sample_data are
not correctly initialized when next swevent_event preparing sample
(for example data->id, the value varies according to swevent).

A simple scenario triggers this problem is as follows:

  # perf record -e sched:sched_switch --switch-output-event sched:sched_switch -a sleep 1
  [ perf record: dump data: Woken up 0 times ]
  [ perf record: Dump perf.data.2023041209014396 ]
  [ perf record: dump data: Woken up 0 times ]
  [ perf record: Dump perf.data.2023041209014662 ]
  [ perf record: dump data: Woken up 0 times ]
  [ perf record: Dump perf.data.2023041209014910 ]
  [ perf record: Woken up 0 times to write data ]
  [ perf record: Dump perf.data.2023041209015164 ]
  [ perf record: Captured and wrote 0.069 MB perf.data. ]
  # ls -l
  total 860
  -rw------- 1 root root  95694 Apr 12 09:01 perf.data.2023041209014396
  -rw------- 1 root root 606430 Apr 12 09:01 perf.data.2023041209014662
  -rw------- 1 root root  82246 Apr 12 09:01 perf.data.2023041209014910
  -rw------- 1 root root  82342 Apr 12 09:01 perf.data.2023041209015164
  # perf script -i perf.data.2023041209014396
  0x11d58 [0x80]: failed to process type: 9 [Bad address]

Solution: Re-initialize perf_sample_data after each event is processed.
Note that data->raw->frag.data may be accessed in perf_tp_event_match().
Therefore, need to init sample_data and then go through swevent hlist to prevent
reference of NULL pointer, reported by [1].

After fix:

  # perf record -e sched:sched_switch --switch-output-event sched:sched_switch -a sleep 1
  [ perf record: dump data: Woken up 0 times ]
  [ perf record: Dump perf.data.2023041209442259 ]
  [ perf record: dump data: Woken up 0 times ]
  [ perf record: Dump perf.data.2023041209442514 ]
  [ perf record: dump data: Woken up 0 times ]
  [ perf record: Dump perf.data.2023041209442760 ]
  [ perf record: Woken up 0 times to write data ]
  [ perf record: Dump perf.data.2023041209443003 ]
  [ perf record: Captured and wrote 0.069 MB perf.data. ]
  # ls -l
  total 864
  -rw------- 1 root root 100166 Apr 12 09:44 perf.data.2023041209442259
  -rw------- 1 root root 606438 Apr 12 09:44 perf.data.2023041209442514
  -rw------- 1 root root  82246 Apr 12 09:44 perf.data.2023041209442760
  -rw------- 1 root root  82342 Apr 12 09:44 perf.data.2023041209443003
  # perf script -i perf.data.2023041209442259 | head -n 5
              perf   232 [000]    66.846217: sched:sched_switch: prev_comm=perf prev_pid=232 prev_prio=120 prev_state=D ==> next_comm=perf next_pid=234 next_prio=120
              perf   234 [000]    66.846449: sched:sched_switch: prev_comm=perf prev_pid=234 prev_prio=120 prev_state=S ==> next_comm=perf next_pid=232 next_prio=120
              perf   232 [000]    66.846546: sched:sched_switch: prev_comm=perf prev_pid=232 prev_prio=120 prev_state=R ==> next_comm=perf next_pid=234 next_prio=120
              perf   234 [000]    66.846606: sched:sched_switch: prev_comm=perf prev_pid=234 prev_prio=120 prev_state=S ==> next_comm=perf next_pid=232 next_prio=120
              perf   232 [000]    66.846646: sched:sched_switch: prev_comm=perf prev_pid=232 prev_prio=120 prev_state=R ==> next_comm=perf next_pid=234 next_prio=120

[1] Link: https://lore.kernel.org/oe-lkp/202304250929.efef2caa-yujie.liu@intel.com

Fixes: bb447c27a467 ("perf/core: Set data->sample_flags in perf_prepare_sample()")
Signed-off-by: Yang Jihong 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20230425103217.130600-1-yangjihong1@huawei.com
Signed-off-by: Sasha Levin

locking/rwsem: Add __always_inline annotation to __down_read_common() and inlined callers

2023-05-17T12:02:05+00:00

commit 92cc5d00a431e96e5a49c0b97e5ad4fa7536bd4b upstream.

Apparently despite it being marked inline, the compiler
may not inline __down_read_common() which makes it difficult
to identify the cause of lock contention, as the blocked
function in traceevents will always be listed as
__down_read_common().

So this patch adds __always_inline annotation to the common
function (as well as the inlined helper callers) to force it to
be inlined so the blocking function will be listed (via Wchan)
in traceevents.

Fixes: c995e638ccbb ("locking/rwsem: Fold __down_{read,write}*()")
Reported-by: Tim Murray 
Signed-off-by: John Stultz 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Waiman Long 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20230503023351.2832796-1-jstultz@google.com
Signed-off-by: Greg Kroah-Hartman

PM: hibernate: Do not get block device exclusively in test_resume mode

2023-05-11T14:17:36+00:00

[ Upstream commit 5904de0d735bbb3b4afe9375c5b4f9748f882945 ]

The system refused to do a test_resume because it found that the
swap device has already been taken by someone else. Specifically,
the swsusp_check()->blkdev_get_by_dev(FMODE_EXCL) is supposed to
do this check.

Steps to reproduce:
 dd if=/dev/zero of=/swapfile bs=$(cat /proc/meminfo |
       awk '/MemTotal/ {print $2}') count=1024 conv=notrunc
 mkswap /swapfile
 swapon /swapfile
 swap-offset /swapfile
 echo 34816 > /sys/power/resume_offset
 echo test_resume > /sys/power/disk
 echo disk > /sys/power/state

 PM: Using 3 thread(s) for compression
 PM: Compressing and saving image data (293150 pages)...
 PM: Image saving progress:   0%
 PM: Image saving progress:  10%
 ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
 ata1.00: configured for UDMA/100
 ata2: SATA link down (SStatus 0 SControl 300)
 ata5: SATA link down (SStatus 0 SControl 300)
 ata6: SATA link down (SStatus 0 SControl 300)
 ata3: SATA link down (SStatus 0 SControl 300)
 ata4: SATA link down (SStatus 0 SControl 300)
 PM: Image saving progress:  20%
 PM: Image saving progress:  30%
 PM: Image saving progress:  40%
 PM: Image saving progress:  50%
 pcieport 0000:00:02.5: pciehp: Slot(0-5): No device found
 PM: Image saving progress:  60%
 PM: Image saving progress:  70%
 PM: Image saving progress:  80%
 PM: Image saving progress:  90%
 PM: Image saving done
 PM: hibernation: Wrote 1172600 kbytes in 2.70 seconds (434.29 MB/s)
 PM: S|
 PM: hibernation: Basic memory bitmaps freed
 PM: Image not found (code -16)

This is because when using the swapfile as the hibernation storage,
the block device where the swapfile is located has already been mounted
by the OS distribution(usually mounted as the rootfs). This is not
an issue for normal hibernation, because software_resume()->swsusp_check()
happens before the block device(rootfs) mount. But it is a problem for the
test_resume mode. Because when test_resume happens, the block device has
been mounted already.

Thus remove the FMODE_EXCL for test_resume mode. This would not be a
problem because in test_resume stage, the processes have already been
frozen, and the race condition described in
Commit 39fbef4b0f77 ("PM: hibernate: Get block device exclusively in swsusp_check()")
is unlikely to happen.

Fixes: 39fbef4b0f77 ("PM: hibernate: Get block device exclusively in swsusp_check()")
Reported-by: Yifan Li 
Suggested-by: Pavankumar Kondeti 
Tested-by: Pavankumar Kondeti 
Tested-by: Wendy Wang 
Signed-off-by: Chen Yu 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

PM: hibernate: Turn snapshot_test into global variable

2023-05-11T14:17:36+00:00

[ Upstream commit 08169a162f97819d3e5b4a342bb9cf5137787154 ]

There is need to check snapshot_test and open block device
in different mode, so as to avoid the race condition.

No functional changes intended.

Suggested-by: Pavankumar Kondeti 
Signed-off-by: Chen Yu 
Signed-off-by: Rafael J. Wysocki 
Stable-dep-of: 5904de0d735b ("PM: hibernate: Do not get block device exclusively in test_resume mode")
Signed-off-by: Sasha Levin