linux-stable.git/kernel, branch v5.4.49

kretprobe: Prevent triggering kretprobe from within kprobe_flush_task

2020-06-24T15:50:52+00:00

commit 9b38cc704e844e41d9cf74e647bff1d249512cb3 upstream.

Ziqian reported lockup when adding retprobe on _raw_spin_lock_irqsave.
My test was also able to trigger lockdep output:

 ============================================
 WARNING: possible recursive locking detected
 5.6.0-rc6+ #6 Not tainted
 --------------------------------------------
 sched-messaging/2767 is trying to acquire lock:
 ffffffff9a492798 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_hash_lock+0x52/0xa0

 but task is already holding lock:
 ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&(kretprobe_table_locks[i].lock));
   lock(&(kretprobe_table_locks[i].lock));

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 1 lock held by sched-messaging/2767:
  #0: ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50

 stack backtrace:
 CPU: 3 PID: 2767 Comm: sched-messaging Not tainted 5.6.0-rc6+ #6
 Call Trace:
  dump_stack+0x96/0xe0
  __lock_acquire.cold.57+0x173/0x2b7
  ? native_queued_spin_lock_slowpath+0x42b/0x9e0
  ? lockdep_hardirqs_on+0x590/0x590
  ? __lock_acquire+0xf63/0x4030
  lock_acquire+0x15a/0x3d0
  ? kretprobe_hash_lock+0x52/0xa0
  _raw_spin_lock_irqsave+0x36/0x70
  ? kretprobe_hash_lock+0x52/0xa0
  kretprobe_hash_lock+0x52/0xa0
  trampoline_handler+0xf8/0x940
  ? kprobe_fault_handler+0x380/0x380
  ? find_held_lock+0x3a/0x1c0
  kretprobe_trampoline+0x25/0x50
  ? lock_acquired+0x392/0xbc0
  ? _raw_spin_lock_irqsave+0x50/0x70
  ? __get_valid_kprobe+0x1f0/0x1f0
  ? _raw_spin_unlock_irqrestore+0x3b/0x40
  ? finish_task_switch+0x4b9/0x6d0
  ? __switch_to_asm+0x34/0x70
  ? __switch_to_asm+0x40/0x70

The code within the kretprobe handler checks for probe reentrancy,
so we won't trigger any _raw_spin_lock_irqsave probe in there.

The problem is in outside kprobe_flush_task, where we call:

  kprobe_flush_task
    kretprobe_table_lock
      raw_spin_lock_irqsave
        _raw_spin_lock_irqsave

where _raw_spin_lock_irqsave triggers the kretprobe and installs
kretprobe_trampoline handler on _raw_spin_lock_irqsave return.

The kretprobe_trampoline handler is then executed with already
locked kretprobe_table_locks, and first thing it does is to
lock kretprobe_table_locks ;-) the whole lockup path like:

  kprobe_flush_task
    kretprobe_table_lock
      raw_spin_lock_irqsave
        _raw_spin_lock_irqsave ---> probe triggered, kretprobe_trampoline installed

        ---> kretprobe_table_locks locked

        kretprobe_trampoline
          trampoline_handler
            kretprobe_hash_lock(current, &head, &flags);  <--- deadlock

Adding kprobe_busy_begin/end helpers that mark code with fake
probe installed to prevent triggering of another kprobe within
this code.

Using these helpers in kprobe_flush_task, so the probe recursion
protection check is hit and the probe is never set to prevent
above lockup.

Link: http://lkml.kernel.org/r/158927059835.27680.7011202830041561604.stgit@devnote2

Fixes: ef53d9c5e4da ("kprobes: improve kretprobe scalability with hashed locking")
Cc: Ingo Molnar 
Cc: "Gustavo A . R . Silva" 
Cc: Anders Roxell 
Cc: "Naveen N . Rao" 
Cc: Anil S Keshavamurthy 
Cc: David Miller 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: stable@vger.kernel.org
Reported-by: "Ziqian SUN (Zamir)" 
Acked-by: Masami Hiramatsu 
Signed-off-by: Jiri Olsa 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex

2020-06-24T15:50:51+00:00

commit 1a0aa991a6274161c95a844c58cfb801d681eb59 upstream.

In kprobe_optimizer() kick_kprobe_optimizer() is called
without kprobe_mutex, but this can race with other caller
which is protected by kprobe_mutex.

To fix that, expand kprobe_mutex protected area to protect
kick_kprobe_optimizer() call.

Link: http://lkml.kernel.org/r/158927057586.27680.5036330063955940456.stgit@devnote2

Fixes: cd7ebe2298ff ("kprobes: Use text_poke_smp_batch for optimizing")
Cc: Ingo Molnar 
Cc: "Gustavo A . R . Silva" 
Cc: Anders Roxell 
Cc: "Naveen N . Rao" 
Cc: Anil S Keshavamurthy 
Cc: David Miller 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Ziqian SUN 
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing/probe: Fix memleak in fetch_op_data operations

2020-06-24T15:50:51+00:00

commit 3aa8fdc37d16735e8891035becf25b3857d3efe0 upstream.

kmemleak report:
    [<57dcc2ca>] __kmalloc_track_caller+0x139/0x2b0
    [] kstrndup+0x37/0x80
    [] parse_probe_arg.isra.7+0x3cc/0x630
    [<055bf2ba>] traceprobe_parse_probe_arg+0x2f5/0x810
    [<655a7766>] trace_kprobe_create+0x2ca/0x950
    [<4fc6a02a>] create_or_delete_trace_kprobe+0xf/0x30
    [<6d1c8a52>] trace_run_command+0x67/0x80
    [] trace_parse_run_command+0xa7/0x140
    [] probes_write+0x10/0x20
    [<2027641c>] __vfs_write+0x30/0x1e0
    [<6a4aeee1>] vfs_write+0x96/0x1b0
    [<3517fb7d>] ksys_write+0x53/0xc0
    [] __ia32_sys_write+0x15/0x20
    [] do_syscall_32_irqs_on+0x3d/0x260
    [] do_fast_syscall_32+0x39/0xb0
    [] entry_SYSENTER_32+0xaf/0x102

Post parse_probe_arg(), the FETCH_OP_DATA operation type is overwritten
to FETCH_OP_ST_STRING, as a result memory is never freed since
traceprobe_free_probe_arg() iterates only over SYMBOL and DATA op types

Setup fetch string operation correctly after fetch_op_data operation.

Link: https://lkml.kernel.org/r/20200615143034.GA1734@cosmos

Cc: stable@vger.kernel.org
Fixes: a42e3c4de964 ("tracing/probe: Add immediate string parameter support")
Acked-by: Masami Hiramatsu 
Signed-off-by: Vamshi K Sthambamkadi 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing/probe: Fix bpf_task_fd_query() for kprobes and uprobes

2020-06-24T15:50:43+00:00

[ Upstream commit 22d5bd6867364b41576a712755271a7d6161abd6 ]

Commit 60d53e2c3b75 ("tracing/probe: Split trace_event related data from
trace_probe") removed the trace_[ku]probe structure from the
trace_event_call->data pointer. As bpf_get_[ku]probe_info() were
forgotten in that change, fix them now. These functions are currently
only used by the bpf_task_fd_query() syscall handler to collect
information about a perf event.

Fixes: 60d53e2c3b75 ("tracing/probe: Split trace_event related data from trace_probe")
Signed-off-by: Jean-Philippe Brucker 
Signed-off-by: Alexei Starovoitov 
Acked-by: Yonghong Song 
Acked-by: Masami Hiramatsu 
Link: https://lore.kernel.org/bpf/20200608124531.819838-1-jean-philippe@linaro.org
Signed-off-by: Sasha Levin

blktrace: fix endianness for blk_log_remap()

2020-06-24T15:50:39+00:00

[ Upstream commit 5aec598c456fe3c1b71a1202cbb42bdc2a643277 ]

The function blk_log_remap() can be simplified by removing the
call to get_pdu_remap() that copies the values into extra variable to
print the data, which also fixes the endiannness warning reported by
sparse.

Signed-off-by: Chaitanya Kulkarni 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

blktrace: fix endianness in get_pdu_int()

2020-06-24T15:50:39+00:00

[ Upstream commit 71df3fd82e7cccec7b749a8607a4662d9f7febdd ]

In function get_pdu_len() replace variable type from __u64 to
__be64. This fixes sparse warning.

Signed-off-by: Chaitanya Kulkarni 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

blktrace: use errno instead of bi_status

2020-06-24T15:50:39+00:00

[ Upstream commit 48bc3cd3e07a1486f45d9971c75d6090976c3b1b ]

In blk_add_trace_spliti() blk_add_trace_bio_remap() use
blk_status_to_errno() to pass the error instead of pasing the bi_status.
This fixes the sparse warning.

Signed-off-by: Chaitanya Kulkarni 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

/dev/mem: Revoke mappings when a driver claims the region

2020-06-24T15:50:35+00:00

[ Upstream commit 3234ac664a870e6ea69ae3a57d824cd7edbeacc5 ]

Close the hole of holding a mapping over kernel driver takeover event of
a given address range.

Commit 90a545e98126 ("restrict /dev/mem to idle io memory ranges")
introduced CONFIG_IO_STRICT_DEVMEM with the goal of protecting the
kernel against scenarios where a /dev/mem user tramples memory that a
kernel driver owns. However, this protection only prevents *new* read(),
write() and mmap() requests. Established mappings prior to the driver
calling request_mem_region() are left alone.

Especially with persistent memory, and the core kernel metadata that is
stored there, there are plentiful scenarios for a /dev/mem user to
violate the expectations of the driver and cause amplified damage.

Teach request_mem_region() to find and shoot down active /dev/mem
mappings that it believes it has successfully claimed for the exclusive
use of the driver. Effectively a driver call to request_mem_region()
becomes a hole-punch on the /dev/mem device.

The typical usage of unmap_mapping_range() is part of
truncate_pagecache() to punch a hole in a file, but in this case the
implementation is only doing the "first half" of a hole punch. Namely it
is just evacuating current established mappings of the "hole", and it
relies on the fact that /dev/mem establishes mappings in terms of
absolute physical address offsets. Once existing mmap users are
invalidated they can attempt to re-establish the mapping, or attempt to
continue issuing read(2) / write(2) to the invalidated extent, but they
will then be subject to the CONFIG_IO_STRICT_DEVMEM checking that can
block those subsequent accesses.

Cc: Arnd Bergmann 
Cc: Ingo Molnar 
Cc: Kees Cook 
Cc: Matthew Wilcox 
Cc: Russell King 
Cc: Andrew Morton 
Cc: Greg Kroah-Hartman 
Fixes: 90a545e98126 ("restrict /dev/mem to idle io memory ranges")
Signed-off-by: Dan Williams 
Reviewed-by: Kees Cook 
Link: https://lore.kernel.org/r/159009507306.847224.8502634072429766747.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

kernel/cpu_pm: Fix uninitted local in cpu_pm

2020-06-22T07:31:22+00:00

commit b5945214b76a1f22929481724ffd448000ede914 upstream.

cpu_pm_notify() is basically a wrapper of notifier_call_chain().
notifier_call_chain() doesn't initialize *nr_calls to 0 before it
starts incrementing it--presumably it's up to the callers to do this.

Unfortunately the callers of cpu_pm_notify() don't init *nr_calls.
This potentially means you could get too many or two few calls to
CPU_PM_ENTER_FAILED or CPU_CLUSTER_PM_ENTER_FAILED depending on the
luck of the stack.

Let's fix this.

Fixes: ab10023e0088 ("cpu_pm: Add cpu power management notifiers")
Cc: stable@vger.kernel.org
Cc: Rafael J. Wysocki 
Reviewed-by: Stephen Boyd 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Douglas Anderson 
Link: https://lore.kernel.org/r/20200504104917.v6.3.I2d44fc0053d019f239527a4e5829416714b7e299@changeid
Signed-off-by: Bjorn Andersson 
Signed-off-by: Greg Kroah-Hartman

bpf: Fix map permissions check

2020-06-22T07:31:11+00:00

[ Upstream commit 1ea0f9120c8ce105ca181b070561df5cbd6bc049 ]

The map_lookup_and_delete_elem() function should check for both FMODE_CAN_WRITE
and FMODE_CAN_READ permissions because it returns a map element to user space.

Fixes: bd513cd08f10 ("bpf: add MAP_LOOKUP_AND_DELETE_ELEM syscall")
Signed-off-by: Anton Protopopov 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20200527185700.14658-5-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin