linux-stable.git/kernel, branch v4.19.201

workqueue: fix UAF in pwq_unbound_release_workfn()

2021-07-31T06:22:37+00:00

commit b42b0bddcbc87b4c66f6497f66fc72d52b712aa7 upstream.

I got a UAF report when doing fuzz test:

[  152.880091][ T8030] ==================================================================
[  152.881240][ T8030] BUG: KASAN: use-after-free in pwq_unbound_release_workfn+0x50/0x190
[  152.882442][ T8030] Read of size 4 at addr ffff88810d31bd00 by task kworker/3:2/8030
[  152.883578][ T8030]
[  152.883932][ T8030] CPU: 3 PID: 8030 Comm: kworker/3:2 Not tainted 5.13.0+ #249
[  152.885014][ T8030] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[  152.886442][ T8030] Workqueue: events pwq_unbound_release_workfn
[  152.887358][ T8030] Call Trace:
[  152.887837][ T8030]  dump_stack_lvl+0x75/0x9b
[  152.888525][ T8030]  ? pwq_unbound_release_workfn+0x50/0x190
[  152.889371][ T8030]  print_address_description.constprop.10+0x48/0x70
[  152.890326][ T8030]  ? pwq_unbound_release_workfn+0x50/0x190
[  152.891163][ T8030]  ? pwq_unbound_release_workfn+0x50/0x190
[  152.891999][ T8030]  kasan_report.cold.15+0x82/0xdb
[  152.892740][ T8030]  ? pwq_unbound_release_workfn+0x50/0x190
[  152.893594][ T8030]  __asan_load4+0x69/0x90
[  152.894243][ T8030]  pwq_unbound_release_workfn+0x50/0x190
[  152.895057][ T8030]  process_one_work+0x47b/0x890
[  152.895778][ T8030]  worker_thread+0x5c/0x790
[  152.896439][ T8030]  ? process_one_work+0x890/0x890
[  152.897163][ T8030]  kthread+0x223/0x250
[  152.897747][ T8030]  ? set_kthread_struct+0xb0/0xb0
[  152.898471][ T8030]  ret_from_fork+0x1f/0x30
[  152.899114][ T8030]
[  152.899446][ T8030] Allocated by task 8884:
[  152.900084][ T8030]  kasan_save_stack+0x21/0x50
[  152.900769][ T8030]  __kasan_kmalloc+0x88/0xb0
[  152.901416][ T8030]  __kmalloc+0x29c/0x460
[  152.902014][ T8030]  alloc_workqueue+0x111/0x8e0
[  152.902690][ T8030]  __btrfs_alloc_workqueue+0x11e/0x2a0
[  152.903459][ T8030]  btrfs_alloc_workqueue+0x6d/0x1d0
[  152.904198][ T8030]  scrub_workers_get+0x1e8/0x490
[  152.904929][ T8030]  btrfs_scrub_dev+0x1b9/0x9c0
[  152.905599][ T8030]  btrfs_ioctl+0x122c/0x4e50
[  152.906247][ T8030]  __x64_sys_ioctl+0x137/0x190
[  152.906916][ T8030]  do_syscall_64+0x34/0xb0
[  152.907535][ T8030]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[  152.908365][ T8030]
[  152.908688][ T8030] Freed by task 8884:
[  152.909243][ T8030]  kasan_save_stack+0x21/0x50
[  152.909893][ T8030]  kasan_set_track+0x20/0x30
[  152.910541][ T8030]  kasan_set_free_info+0x24/0x40
[  152.911265][ T8030]  __kasan_slab_free+0xf7/0x140
[  152.911964][ T8030]  kfree+0x9e/0x3d0
[  152.912501][ T8030]  alloc_workqueue+0x7d7/0x8e0
[  152.913182][ T8030]  __btrfs_alloc_workqueue+0x11e/0x2a0
[  152.913949][ T8030]  btrfs_alloc_workqueue+0x6d/0x1d0
[  152.914703][ T8030]  scrub_workers_get+0x1e8/0x490
[  152.915402][ T8030]  btrfs_scrub_dev+0x1b9/0x9c0
[  152.916077][ T8030]  btrfs_ioctl+0x122c/0x4e50
[  152.916729][ T8030]  __x64_sys_ioctl+0x137/0x190
[  152.917414][ T8030]  do_syscall_64+0x34/0xb0
[  152.918034][ T8030]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[  152.918872][ T8030]
[  152.919203][ T8030] The buggy address belongs to the object at ffff88810d31bc00
[  152.919203][ T8030]  which belongs to the cache kmalloc-512 of size 512
[  152.921155][ T8030] The buggy address is located 256 bytes inside of
[  152.921155][ T8030]  512-byte region [ffff88810d31bc00, ffff88810d31be00)
[  152.922993][ T8030] The buggy address belongs to the page:
[  152.923800][ T8030] page:ffffea000434c600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10d318
[  152.925249][ T8030] head:ffffea000434c600 order:2 compound_mapcount:0 compound_pincount:0
[  152.926399][ T8030] flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff)
[  152.927515][ T8030] raw: 057ff00000010200 dead000000000100 dead000000000122 ffff888009c42c80
[  152.928716][ T8030] raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
[  152.929890][ T8030] page dumped because: kasan: bad access detected
[  152.930759][ T8030]
[  152.931076][ T8030] Memory state around the buggy address:
[  152.931851][ T8030]  ffff88810d31bc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  152.932967][ T8030]  ffff88810d31bc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  152.934068][ T8030] >ffff88810d31bd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  152.935189][ T8030]                    ^
[  152.935763][ T8030]  ffff88810d31bd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  152.936847][ T8030]  ffff88810d31be00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  152.937940][ T8030] ==================================================================

If apply_wqattrs_prepare() fails in alloc_workqueue(), it will call put_pwq()
which invoke a work queue to call pwq_unbound_release_workfn() and use the 'wq'.
The 'wq' allocated in alloc_workqueue() will be freed in error path when
apply_wqattrs_prepare() fails. So it will lead a UAF.

CPU0                                          CPU1
alloc_workqueue()
alloc_and_link_pwqs()
apply_wqattrs_prepare() fails
apply_wqattrs_cleanup()
schedule_work(&pwq->unbound_release_work)
kfree(wq)
                                              worker_thread()
                                              pwq_unbound_release_workfn() <- trigger uaf here

If apply_wqattrs_prepare() fails, the new pwq are not linked, it doesn't
hold any reference to the 'wq', 'wq' is invalid to access in the worker,
so add check pwq if linked to fix this.

Fixes: 2d5f0764b526 ("workqueue: split apply_workqueue_attrs() into 3 stages")
Cc: stable@vger.kernel.org # v4.2+
Reported-by: Hulk Robot 
Suggested-by: Lai Jiangshan 
Signed-off-by: Yang Yingliang 
Reviewed-by: Lai Jiangshan 
Tested-by: Pavel Skripkin 
Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

tracing: Fix bug in rb_per_cpu_empty() that might cause deadloop.

2021-07-28T09:13:50+00:00

commit 67f0d6d9883c13174669f88adac4f0ee656cc16a upstream.

The "rb_per_cpu_empty()" misinterpret the condition (as not-empty) when
"head_page" and "commit_page" of "struct ring_buffer_per_cpu" points to
the same buffer page, whose "buffer_data_page" is empty and "read" field
is non-zero.

An error scenario could be constructed as followed (kernel perspective):

1. All pages in the buffer has been accessed by reader(s) so that all of
them will have non-zero "read" field.

2. Read and clear all buffer pages so that "rb_num_of_entries()" will
return 0 rendering there's no more data to read. It is also required
that the "read_page", "commit_page" and "tail_page" points to the same
page, while "head_page" is the next page of them.

3. Invoke "ring_buffer_lock_reserve()" with large enough "length"
so that it shot pass the end of current tail buffer page. Now the
"head_page", "commit_page" and "tail_page" points to the same page.

4. Discard current event with "ring_buffer_discard_commit()", so that
"head_page", "commit_page" and "tail_page" points to a page whose buffer
data page is now empty.

When the error scenario has been constructed, "tracing_read_pipe" will
be trapped inside a deadloop: "trace_empty()" returns 0 since
"rb_per_cpu_empty()" returns 0 when it hits the CPU containing such
constructed ring buffer. Then "trace_find_next_entry_inc()" always
return NULL since "rb_num_of_entries()" reports there's no more entry
to read. Finally "trace_seq_to_user()" returns "-EBUSY" spanking
"tracing_read_pipe" back to the start of the "waitagain" loop.

I've also written a proof-of-concept script to construct the scenario
and trigger the bug automatically, you can use it to trace and validate
my reasoning above:

  https://github.com/aegistudio/RingBufferDetonator.git

Tests has been carried out on linux kernel 5.14-rc2
(2734d6c1b1a089fb593ef6a23d4b70903526fe0c), my fixed version
of kernel (for testing whether my update fixes the bug) and
some older kernels (for range of affected kernels). Test result is
also attached to the proof-of-concept repository.

Link: https://lore.kernel.org/linux-trace-devel/YPaNxsIlb2yjSi5Y@aegistudio/
Link: https://lore.kernel.org/linux-trace-devel/YPgrN85WL9VyrZ55@aegistudio

Cc: stable@vger.kernel.org
Fixes: bf41a158cacba ("ring-buffer: make reentrant")
Suggested-by: Linus Torvalds 
Signed-off-by: Haoran Luo 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

sched/fair: Fix CFS bandwidth hrtimer expiry type

2021-07-28T09:13:44+00:00

[ Upstream commit 72d0ad7cb5bad265adb2014dbe46c4ccb11afaba ]

The time remaining until expiry of the refresh_timer can be negative.
Casting the type to an unsigned 64-bit value will cause integer
underflow, making the runtime_refresh_within return false instead of
true. These situations are rare, but they do happen.

This does not cause user-facing issues or errors; other than
possibly unthrottling cfs_rq's using runtime from the previous period(s),
making the CFS bandwidth enforcement less strict in those (special)
situations.

Signed-off-by: Odin Ugedal 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Ben Segall 
Link: https://lore.kernel.org/r/20210629121452.18429-1-odin@uged.al
Signed-off-by: Sasha Levin

tracing: Do not reference char * as a string in histograms

2021-07-20T14:16:07+00:00

commit 704adfb5a9978462cd861f170201ae2b5e3d3a80 upstream.

The histogram logic was allowing events with char * pointers to be used as
normal strings. But it was easy to crash the kernel with:

 # echo 'hist:keys=filename' > events/syscalls/sys_enter_openat/trigger

And open some files, and boom!

 BUG: unable to handle page fault for address: 00007f2ced0c3280
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 1173fa067 P4D 1173fa067 PUD 1171b6067 PMD 1171dd067 PTE 0
 Oops: 0000 [#1] PREEMPT SMP
 CPU: 6 PID: 1810 Comm: cat Not tainted 5.13.0-rc5-test+ #61
 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01
v03.03 07/14/2016
 RIP: 0010:strlen+0x0/0x20
 Code: f6 82 80 2a 0b a9 20 74 11 0f b6 50 01 48 83 c0 01 f6 82 80 2a 0b
a9 20 75 ef c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <80> 3f 00 74
10 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 c3

 RSP: 0018:ffffbdbf81567b50 EFLAGS: 00010246
 RAX: 0000000000000003 RBX: ffff93815cdb3800 RCX: ffff9382401a22d0
 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 00007f2ced0c3280
 RBP: 0000000000000100 R08: ffff9382409ff074 R09: ffffbdbf81567c98
 R10: ffff9382409ff074 R11: 0000000000000000 R12: ffff9382409ff074
 R13: 0000000000000001 R14: ffff93815a744f00 R15: 00007f2ced0c3280
 FS:  00007f2ced0f8580(0000) GS:ffff93825a800000(0000)
knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007f2ced0c3280 CR3: 0000000107069005 CR4: 00000000001706e0
 Call Trace:
  event_hist_trigger+0x463/0x5f0
  ? find_held_lock+0x32/0x90
  ? sched_clock_cpu+0xe/0xd0
  ? lock_release+0x155/0x440
  ? kernel_init_free_pages+0x6d/0x90
  ? preempt_count_sub+0x9b/0xd0
  ? kernel_init_free_pages+0x6d/0x90
  ? get_page_from_freelist+0x12c4/0x1680
  ? __rb_reserve_next+0xe5/0x460
  ? ring_buffer_lock_reserve+0x12a/0x3f0
  event_triggers_call+0x52/0xe0
  ftrace_syscall_enter+0x264/0x2c0
  syscall_trace_enter.constprop.0+0x1ee/0x210
  do_syscall_64+0x1c/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

Where it triggered a fault on strlen(key) where key was the filename.

The reason is that filename is a char * to user space, and the histogram
code just blindly dereferenced it, with obvious bad results.

I originally tried to use strncpy_from_user/kernel_nofault() but found
that there's other places that its dereferenced and not worth the effort.

Just do not allow "char *" to act like strings.

Link: https://lkml.kernel.org/r/20210715000206.025df9d2@rorschach.local.home

Cc: Ingo Molnar 
Cc: Andrew Morton 
Cc: Masami Hiramatsu 
Cc: Tzvetomir Stoyanov 
Cc: stable@vger.kernel.org
Acked-by: Namhyung Kim 
Acked-by: Tom Zanussi 
Fixes: 79e577cbce4c4 ("tracing: Support string type key properly")
Fixes: 5967bd5c4239 ("tracing: Let filter_assign_type() detect FILTER_PTR_STRING")
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing: Resize tgid_map to pid_max, not PID_MAX_DEFAULT

2021-07-20T14:16:05+00:00

commit 4030a6e6a6a4a42ff8c18414c9e0c93e24cc70b8 upstream.

Currently tgid_map is sized at PID_MAX_DEFAULT entries, which means that
on systems where pid_max is configured higher than PID_MAX_DEFAULT the
ftrace record-tgid option doesn't work so well. Any tasks with PIDs
higher than PID_MAX_DEFAULT are simply not recorded in tgid_map, and
don't show up in the saved_tgids file.

In particular since systemd v243 & above configure pid_max to its
highest possible 1<<22 value by default on 64 bit systems this renders
the record-tgids option of little use.

Increase the size of tgid_map to the configured pid_max instead,
allowing it to cover the full range of PIDs up to the maximum value of
PID_MAX_LIMIT if the system is configured that way.

On 64 bit systems with pid_max == PID_MAX_LIMIT this will increase the
size of tgid_map from 256KiB to 16MiB. Whilst this 64x increase in
memory overhead sounds significant 64 bit systems are presumably best
placed to accommodate it, and since tgid_map is only allocated when the
record-tgid option is actually used presumably the user would rather it
spends sufficient memory to actually record the tgids they expect.

The size of tgid_map could also increase for CONFIG_BASE_SMALL=y
configurations, but these seem unlikely to be systems upon which people
are both configuring a large pid_max and running ftrace with record-tgid
anyway.

Of note is that we only allocate tgid_map once, the first time that the
record-tgid option is enabled. Therefore its size is only set once, to
the value of pid_max at the time the record-tgid option is first
enabled. If a user increases pid_max after that point, the saved_tgids
file will not contain entries for any tasks with pids beyond the earlier
value of pid_max.

Link: https://lkml.kernel.org/r/20210701172407.889626-2-paulburton@google.com

Fixes: d914ba37d714 ("tracing: Add support for recording tgid of tasks")
Cc: Ingo Molnar 
Cc: Joel Fernandes 
Cc: 
Signed-off-by: Paul Burton 
[ Fixed comment coding style ]
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing: Simplify & fix saved_tgids logic

2021-07-20T14:16:05+00:00

commit b81b3e959adb107cd5b36c7dc5ba1364bbd31eb2 upstream.

The tgid_map array records a mapping from pid to tgid, where the index
of an entry within the array is the pid & the value stored at that index
is the tgid.

The saved_tgids_next() function iterates over pointers into the tgid_map
array & dereferences the pointers which results in the tgid, but then it
passes that dereferenced value to trace_find_tgid() which treats it as a
pid & does a further lookup within the tgid_map array. It seems likely
that the intent here was to skip over entries in tgid_map for which the
recorded tgid is zero, but instead we end up skipping over entries for
which the thread group leader hasn't yet had its own tgid recorded in
tgid_map.

A minimal fix would be to remove the call to trace_find_tgid, turning:

  if (trace_find_tgid(*ptr))

into:

  if (*ptr)

..but it seems like this logic can be much simpler if we simply let
seq_read() iterate over the whole tgid_map array & filter out empty
entries by returning SEQ_SKIP from saved_tgids_show(). Here we take that
approach, removing the incorrect logic here entirely.

Link: https://lkml.kernel.org/r/20210630003406.4013668-1-paulburton@google.com

Fixes: d914ba37d714 ("tracing: Add support for recording tgid of tasks")
Cc: Ingo Molnar 
Cc: Joel Fernandes 
Cc: 
Signed-off-by: Paul Burton 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

cpu/hotplug: Cure the cpusets trainwreck

2021-07-20T14:16:04+00:00

commit b22afcdf04c96ca58327784e280e10288cfd3303 upstream.

Alexey and Joshua tried to solve a cpusets related hotplug problem which is
user space visible and results in unexpected behaviour for some time after
a CPU has been plugged in and the corresponding uevent was delivered.

cpusets delegate the hotplug work (rebuilding cpumasks etc.) to a
workqueue. This is done because the cpusets code has already a lock
nesting of cgroups_mutex -> cpu_hotplug_lock. A synchronous callback or
waiting for the work to finish with cpu_hotplug_lock held can and will
deadlock because that results in the reverse lock order.

As a consequence the uevent can be delivered before cpusets have consistent
state which means that a user space invocation of sched_setaffinity() to
move a task to the plugged CPU fails up to the point where the scheduled
work has been processed.

The same is true for CPU unplug, but that does not create user observable
failure (yet).

It's still inconsistent to claim that an operation is finished before it
actually is and that's the real issue at hand. uevents just make it
reliably observable.

Obviously the problem should be fixed in cpusets/cgroups, but untangling
that is pretty much impossible because according to the changelog of the
commit which introduced this 8 years ago:

 3a5a6d0c2b03("cpuset: don't nest cgroup_mutex inside get_online_cpus()")

the lock order cgroups_mutex -> cpu_hotplug_lock is a design decision and
the whole code is built around that.

So bite the bullet and invoke the relevant cpuset function, which waits for
the work to finish, in _cpu_up/down() after dropping cpu_hotplug_lock and
only when tasks are not frozen by suspend/hibernate because that would
obviously wait forever.

Waiting there with cpu_add_remove_lock, which is protecting the present
and possible CPU maps, held is not a problem at all because neither work
queues nor cpusets/cgroups have any lockchains related to that lock.

Waiting in the hotplug machinery is not problematic either because there
are already state callbacks which wait for hardware queues to drain. It
makes the operations slightly slower, but hotplug is slow anyway.

This ensures that state is consistent before returning from a hotplug
up/down operation. It's still inconsistent during the operation, but that's
a different story.

Add a large comment which explains why this is done and why this is not a
dump ground for the hack of the day to work around half thought out locking
schemes. Document also the implications vs. hotplug operations and
serialization or the lack of it.

Thanks to Alexy and Joshua for analyzing why this temporary
sched_setaffinity() failure happened.

Fixes: 3a5a6d0c2b03("cpuset: don't nest cgroup_mutex inside get_online_cpus()")
Reported-by: Alexey Klimov 
Reported-by: Joshua Baker 
Signed-off-by: Thomas Gleixner 
Tested-by: Alexey Klimov 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87tuowcnv3.ffs@nanos.tec.linutronix.de
Signed-off-by: Greg Kroah-Hartman

clocksource: Retry clock read if long delays detected

2021-07-20T14:15:46+00:00

[ Upstream commit db3a34e17433de2390eb80d436970edcebd0ca3e ]

When the clocksource watchdog marks a clock as unstable, this might be due
to that clock being unstable or it might be due to delays that happen to
occur between the reads of the two clocks.  Yes, interrupts are disabled
across those two reads, but there are no shortage of things that can delay
interrupts-disabled regions of code ranging from SMI handlers to vCPU
preemption.  It would be good to have some indication as to why the clock
was marked unstable.

Therefore, re-read the watchdog clock on either side of the read from the
clock under test.  If the watchdog clock shows an excessive time delta
between its pair of reads, the reads are retried.

The maximum number of retries is specified by a new kernel boot parameter
clocksource.max_cswd_read_retries, which defaults to three, that is, up to
four reads, one initial and up to three retries.  If more than one retry
was required, a message is printed on the console (the occasional single
retry is expected behavior, especially in guest OSes).  If the maximum
number of retries is exceeded, the clock under test will be marked
unstable.  However, the probability of this happening due to various sorts
of delays is quite small.  In addition, the reason (clock-read delays) for
the unstable marking will be apparent.

Reported-by: Chris Mason 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Thomas Gleixner 
Acked-by: Feng Tang 
Link: https://lore.kernel.org/r/20210527190124.440372-1-paulmck@kernel.org
Signed-off-by: Sasha Levin

sched/fair: Fix ascii art by relpacing tabs

2021-07-20T14:15:44+00:00

[ Upstream commit 08f7c2f4d0e9f4283f5796b8168044c034a1bfcb ]

When using something other than 8 spaces per tab, this ascii art
makes not sense, and the reader might end up wondering what this
advanced equation "is".

Signed-off-by: Odin Ugedal 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Vincent Guittot 
Link: https://lkml.kernel.org/r/20210518125202.78658-4-odin@uged.al
Signed-off-by: Sasha Levin

tracepoint: Add tracepoint_probe_register_may_exist() for BPF tracing

2021-07-20T14:15:42+00:00

commit 9913d5745bd720c4266805c8d29952a3702e4eca upstream.

All internal use cases for tracepoint_probe_register() is set to not ever
be called with the same function and data. If it is, it is considered a
bug, as that means the accounting of handling tracepoints is corrupted.
If the function and data for a tracepoint is already registered when
tracepoint_probe_register() is called, it will call WARN_ON_ONCE() and
return with EEXISTS.

The BPF system call can end up calling tracepoint_probe_register() with
the same data, which now means that this can trigger the warning because
of a user space process. As WARN_ON_ONCE() should not be called because
user space called a system call with bad data, there needs to be a way to
register a tracepoint without triggering a warning.

Enter tracepoint_probe_register_may_exist(), which can be called, but will
not cause a WARN_ON() if the probe already exists. It will still error out
with EEXIST, which will then be sent to the user space that performed the
BPF system call.

This keeps the previous testing for issues with other users of the
tracepoint code, while letting BPF call it with duplicated data and not
warn about it.

Link: https://lore.kernel.org/lkml/20210626135845.4080-1-penguin-kernel@I-love.SAKURA.ne.jp/
Link: https://syzkaller.appspot.com/bug?id=41f4318cf01762389f4d1c1c459da4f542fe5153

Cc: stable@vger.kernel.org
Fixes: c4f6699dfcb85 ("bpf: introduce BPF_RAW_TRACEPOINT")
Reported-by: syzbot 
Reported-by: Tetsuo Handa 
Tested-by: syzbot+721aa903751db87aa244@syzkaller.appspotmail.com
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman