linux.git/kernel/trace, branch v5.11.8

ring-buffer: Force before_stamp and write_stamp to be different on discard

2021-03-09T10:21:20+00:00

commit 6f6be606e763f2da9fc21de00538c97fe4ca1492 upstream.

Part of the logic of the new time stamp code depends on the before_stamp and
the write_stamp to be different if the write_stamp does not match the last
event on the buffer, as it will be used to calculate the delta of the next
event written on the buffer.

The discard logic depends on this, as the next event to come in needs to
inject a full timestamp as it can not rely on the last event timestamp in
the buffer because it is unknown due to events after it being discarded. But
by changing the write_stamp back to the time before it, it forces the next
event to use a full time stamp, instead of relying on it.

The issue came when a full time stamp was used for the event, and
rb_time_delta() returns zero in that case. The update to the write_stamp
(which subtracts delta) made it not change. Then when the event is removed
from the buffer, because the before_stamp and write_stamp still match, the
next event written would calculate its delta from the write_stamp, but that
would be wrong as the write_stamp is of the time of the event that was
discarded.

In the case that the delta change being made to write_stamp is zero, set the
before_stamp to zero as well, and this will force the next event to inject a
full timestamp and not use the current write_stamp.

Cc: stable@vger.kernel.org
Fixes: a389d86f7fd09 ("ring-buffer: Have nested events still record running time stamp")
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'trace-v5.11-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2021-02-12T19:16:17+00:00

Pull tracing fix from Steven Rostedt:
 "Fix buffer overflow in trace event filter.

  It was reported that if an trace event was larger than a page and was
  filtered, that it caused memory corruption. The reason is that
  filtered events first go into a buffer to test the filter before being
  written into the ring buffer. Unfortunately, this write did not check
  the size"

* tag 'trace-v5.11-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Check length before giving out the filter buffer

tracing: Check length before giving out the filter buffer

2021-02-11T19:23:37+00:00

When filters are used by trace events, a page is allocated on each CPU and
used to copy the trace event fields to this page before writing to the ring
buffer. The reason to use the filter and not write directly into the ring
buffer is because a filter may discard the event and there's more overhead
on discarding from the ring buffer than the extra copy.

The problem here is that there is no check against the size being allocated
when using this page. If an event asks for more than a page size while being
filtered, it will get only a page, leading to the caller writing more that
what was allocated.

Check the length of the request, and if it is more than PAGE_SIZE minus the
header default back to allocating from the ring buffer directly. The ring
buffer may reject the event if its too big anyway, but it wont overflow.

Link: https://lore.kernel.org/ath10k/1612839593-2308-1-git-send-email-wgong@codeaurora.org/

Cc: stable@vger.kernel.org
Fixes: 0fc1b09ff1ff4 ("tracing: Use temp buffer when filtering events")
Reported-by: Wen Gong 
Signed-off-by: Steven Rostedt (VMware)

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2021-02-10T19:33:39+00:00

Pull networking fixes from David Miller:
 "Another pile of networing fixes:

   1) ath9k build error fix from Arnd Bergmann

   2) dma memory leak fix in mediatec driver from Lorenzo Bianconi.

   3) bpf int3 kprobe fix from Alexei Starovoitov.

   4) bpf stackmap integer overflow fix from Bui Quang Minh.

   5) Add usb device ids for Cinterion MV31 to qmi_qwwan driver, from
      Christoph Schemmel.

   6) Don't update deleted entry in xt_recent netfilter module, from
      Jazsef Kadlecsik.

   7) Use after free in nftables, fix from Pablo Neira Ayuso.

   8) Header checksum fix in flowtable from Sven Auhagen.

   9) Validate user controlled length in qrtr code, from Sabyrzhan
      Tasbolatov.

  10) Fix race in xen/netback, from Juergen Gross,

  11) New device ID in cxgb4, from Raju Rangoju.

  12) Fix ring locking in rxrpc release call, from David Howells.

  13) Don't return LAPB error codes from x25_open(), from Xie He.

  14) Missing error returns in gsi_channel_setup() from Alex Elder.

  15) Get skb_copy_and_csum_datagram working properly with odd segment
      sizes, from Willem de Bruijn.

  16) Missing RFS/RSS table init in enetc driver, from Vladimir Oltean.

  17) Do teardown on probe failure in DSA, from Vladimir Oltean.

  18) Fix compilation failures of txtimestamp selftest, from Vadim
      Fedorenko.

  19) Limit rx per-napi gro queue size to fix latency regression, from
      Eric Dumazet.

  20) dpaa_eth xdp fixes from Camelia Groza.

  21) Missing txq mode update when switching CBS off, in stmmac driver,
      from Mohammad Athari Bin Ismail.

  22) Failover pending logic fix in ibmvnic driver, from Sukadev
      Bhattiprolu.

  23) Null deref fix in vmw_vsock, from Norbert Slusarek.

  24) Missing verdict update in xdp paths of ena driver, from Shay
      Agroskin.

  25) seq_file iteration fix in sctp from Neil Brown.

  26) bpf 32-bit src register truncation fix on div/mod, from Daniel
      Borkmann.

  27) Fix jmp32 pruning in bpf verifier, from Daniel Borkmann.

  28) Fix locking in vsock_shutdown(), from Stefano Garzarella.

  29) Various missing index bound checks in hns3 driver, from Yufeng Mo.

  30) Flush ports on .phylink_mac_link_down() in dsa felix driver, from
      Vladimir Oltean.

  31) Don't mix up stp and mrp port states in bridge layer, from Horatiu
      Vultur.

  32) Fix locking during netif_tx_disable(), from Edwin Peer"

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (45 commits)
  bpf: Fix 32 bit src register truncation on div/mod
  bpf: Fix verifier jmp32 pruning decision logic
  bpf: Fix verifier jsgt branch analysis on max bound
  vsock: fix locking in vsock_shutdown()
  net: hns3: add a check for index in hclge_get_rss_key()
  net: hns3: add a check for tqp_index in hclge_get_ring_chain_from_mbx()
  net: hns3: add a check for queue_id in hclge_reset_vf_queue()
  net: dsa: felix: implement port flushing on .phylink_mac_link_down
  switchdev: mrp: Remove SWITCHDEV_ATTR_ID_MRP_PORT_STAT
  bridge: mrp: Fix the usage of br_mrp_port_switchdev_set_state
  net: watchdog: hold device global xmit lock during tx disable
  netfilter: nftables: relax check for stateful expressions in set definition
  netfilter: conntrack: skip identical origin tuple in same zone only
  vsock/virtio: update credit only if socket is not closed
  net: fix iteration for sctp transport seq_files
  net: ena: Update XDP verdict upon failure
  net/vmw_vsock: improve locking in vsock_connect_timeout()
  net/vmw_vsock: fix NULL pointer dereference
  ibmvnic: Clear failover_pending if unable to schedule
  net: stmmac: set TxQ mode back to DCB after disabling CBS
  ...

tracing: Do not count ftrace events in top level enable output

2021-02-05T20:40:04+00:00

The file /sys/kernel/tracing/events/enable is used to enable all events by
echoing in "1", or disabling all events when echoing in "0". To know if all
events are enabled, disabled, or some are enabled but not all of them,
cating the file should show either "1" (all enabled), "0" (all disabled), or
"X" (some enabled but not all of them). This works the same as the "enable"
files in the individule system directories (like tracing/events/sched/enable).

But when all events are enabled, the top level "enable" file shows "X". The
reason is that its checking the "ftrace" events, which are special events
that only exist for their format files. These include the format for the
function tracer events, that are enabled when the function tracer is
enabled, but not by the "enable" file. The check includes these events,
which will always be disabled, and even though all true events are enabled,
the top level "enable" file will show "X" instead of "1".

To fix this, have the check test the event's flags to see if it has the
"IGNORE_ENABLE" flag set, and if so, not test it.

Cc: stable@vger.kernel.org
Fixes: 553552ce1796c ("tracing: Combine event filter_active and enable into single flags field")
Reported-by: "Yordan Karadzhov (VMware)" 
Signed-off-by: Steven Rostedt (VMware)

bpf: Unbreak BPF_PROG_TYPE_KPROBE when kprobe is called via do_int3

2021-02-03T14:54:22+00:00

The commit 0d00449c7a28 ("x86: Replace ist_enter() with nmi_enter()")
converted do_int3 handler to be "NMI-like".
That made old if (in_nmi()) check abort execution of bpf programs
attached to kprobe when kprobe is firing via int3
(For example when kprobe is placed in the middle of the function).
Remove the check to restore user visible behavior.

Fixes: 0d00449c7a28 ("x86: Replace ist_enter() with nmi_enter()")
Reported-by: Nikolay Borisov 
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Daniel Borkmann 
Tested-by: Nikolay Borisov 
Reviewed-by: Masami Hiramatsu 
Link: https://lore.kernel.org/bpf/20210203070636.70926-1-alexei.starovoitov@gmail.com

tracing/kprobe: Fix to support kretprobe events on unloaded modules

2021-01-29T20:39:48+00:00

Fix kprobe_on_func_entry() returns error code instead of false so that
register_kretprobe() can return an appropriate error code.

append_trace_kprobe() expects the kprobe registration returns -ENOENT
when the target symbol is not found, and it checks whether the target
module is unloaded or not. If the target module doesn't exist, it
defers to probe the target symbol until the module is loaded.

However, since register_kretprobe() returns -EINVAL instead of -ENOENT
in that case, it always fail on putting the kretprobe event on unloaded
modules. e.g.

Kprobe event:
/sys/kernel/debug/tracing # echo p xfs:xfs_end_io >> kprobe_events
[   16.515574] trace_kprobe: This probe might be able to register after target module is loaded. Continue.

Kretprobe event: (p -> r)
/sys/kernel/debug/tracing # echo r xfs:xfs_end_io >> kprobe_events
sh: write error: Invalid argument
/sys/kernel/debug/tracing # cat error_log
[   41.122514] trace_kprobe: error: Failed to register probe event
  Command: r xfs:xfs_end_io
             ^

To fix this bug, change kprobe_on_func_entry() to detect symbol lookup
failure and return -ENOENT in that case. Otherwise it returns -EINVAL
or 0 (succeeded, given address is on the entry).

Link: https://lkml.kernel.org/r/161176187132.1067016.8118042342894378981.stgit@devnote2

Cc: stable@vger.kernel.org
Fixes: 59158ec4aef7 ("tracing/kprobes: Check the probe on unloaded module correctly")
Reported-by: Jianlin Lv 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

tracing: Use pause-on-trace with the latency tracers

2021-01-29T20:35:33+00:00

Eaerlier, tracing was disabled when reading the trace file. This behavior
was changed with:

commit 06e0a548bad0 ("tracing: Do not disable tracing when reading the
trace file").

This doesn't seem to work with the latency tracers.

The above mentioned commit dit not only change the behavior but also added
an option to emulate the old behavior. The idea with this patch is to
enable this pause-on-trace option when the latency tracers are used.

Link: https://lkml.kernel.org/r/20210119164344.37500-2-Viktor.Rosendahl@bmw.de

Cc: stable@vger.kernel.org
Fixes: 06e0a548bad0 ("tracing: Do not disable tracing when reading the trace file")
Signed-off-by: Viktor Rosendahl 
Signed-off-by: Steven Rostedt (VMware)

fgraph: Initialize tracing_graph_pause at task creation

2021-01-29T20:07:32+00:00

On some archs, the idle task can call into cpu_suspend(). The cpu_suspend()
will disable or pause function graph tracing, as there's some paths in
bringing down the CPU that can have issues with its return address being
modified. The task_struct structure has a "tracing_graph_pause" atomic
counter, that when set to something other than zero, the function graph
tracer will not modify the return address.

The problem is that the tracing_graph_pause counter is initialized when the
function graph tracer is enabled. This can corrupt the counter for the idle
task if it is suspended in these architectures.

   CPU 1				CPU 2
   -----				-----
  do_idle()
    cpu_suspend()
      pause_graph_tracing()
          task_struct->tracing_graph_pause++ (0 -> 1)

				start_graph_tracing()
				  for_each_online_cpu(cpu) {
				    ftrace_graph_init_idle_task(cpu)
				      task-struct->tracing_graph_pause = 0 (1 -> 0)

      unpause_graph_tracing()
          task_struct->tracing_graph_pause-- (0 -> -1)

The above should have gone from 1 to zero, and enabled function graph
tracing again. But instead, it is set to -1, which keeps it disabled.

There's no reason that the field tracing_graph_pause on the task_struct can
not be initialized at boot up.

Cc: stable@vger.kernel.org
Fixes: 380c4b1411ccd ("tracing/function-graph-tracer: append the tracing_graph_flag")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211339
Reported-by: pierre.gondois@arm.com
Signed-off-by: Steven Rostedt (VMware)

tracing/kprobes: Do the notrace functions check without kprobes on ftrace

2021-01-11T21:09:53+00:00

Enable the notrace function check on the architecture which doesn't
support kprobes on ftrace but support dynamic ftrace. This notrace
function check is not only for the kprobes on ftrace but also
sw-breakpoint based kprobes.
Thus there is no reason to limit this check for the arch which
supports kprobes on ftrace.

This also changes the dependency of Kconfig. Because kprobe event
uses the function tracer's address list for identifying notrace
function, if the CONFIG_DYNAMIC_FTRACE=n, it can not check whether
the target function is notrace or not.

Link: https://lkml.kernel.org/r/20210105065730.2634785-1-naveen.n.rao@linux.vnet.ibm.com
Link: https://lkml.kernel.org/r/161007957862.114704.4512260007555399463.stgit@devnote2

Cc: stable@vger.kernel.org
Fixes: 45408c4f92506 ("tracing: kprobes: Prohibit probing on notrace function")
Acked-by: Naveen N. Rao 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)