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[pull] master from torvalds:master #346

Merged
merged 2 commits into from
Dec 7, 2020
Merged

[pull] master from torvalds:master #346

merged 2 commits into from
Dec 7, 2020

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rostedt and others added 2 commits December 4, 2020 16:36
When the instances were able to use their own options, the userstacktrace
option was left hardcoded for the top level. This made the instance
userstacktrace option bascially into a nop, and will confuse users that set
it, but nothing happens (I was confused when it happened to me!)

Cc: stable@vger.kernel.org
Fixes: 1627014 ("tracing: Add trace options for core options to instances")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
…nel/git/rostedt/linux-trace

Pull tracing fix from Steven Rostedt:
 "Fix userstacktrace option for instances

  While writing an application that requires user stack trace option to
  work in instances, I found that the instance option has a bug that
  makes it a nop. The check for performing the user stack trace in an
  instance, checks the top level options (not the instance options) to
  determine if a user stack trace should be performed or not.

  This is not only incorrect, but also confusing for users. It confused
  me for a bit!"

* tag 'trace-v5.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix userstacktrace option for instances
@pull pull bot added the ⤵️ pull label Dec 7, 2020
@pull pull bot merged commit cd796ed into bergwolf:master Dec 7, 2020
pull bot pushed a commit that referenced this pull request Dec 18, 2020
Internally, UBD treats each physical IO segment as a separate command to
be submitted in the execution pipe.  If the pipe returns a transient
error after a few segments have already been written, UBD will tell the
block layer to requeue the request, but there is no way to reclaim the
segments already submitted.  When a new attempt to dispatch the request
is done, those segments already submitted will get duplicated, causing
the WARN_ON below in the best case, and potentially data corruption.

In my system, running a UML instance with 2GB of RAM and a 50M UBD disk,
I can reproduce the WARN_ON by simply running mkfs.fvat against the
disk on a freshly booted system.

There are a few ways to around this, like reducing the pressure on
the pipe by reducing the queue depth, which almost eliminates the
occurrence of the problem, increasing the pipe buffer size on the host
system, or by limiting the request to one physical segment, which causes
the block layer to submit way more requests to resolve a single
operation.

Instead, this patch modifies the format of a UBD command, such that all
segments are sent through a single element in the communication pipe,
turning the command submission atomic from the point of view of the
block layer.  The new format has a variable size, depending on the
number of elements, and looks like this:

+------------+-----------+-----------+------------
| cmd_header | segment 0 | segment 1 | segment ...
+------------+-----------+-----------+------------

With this format, we push a pointer to cmd_header in the submission
pipe.

This has the advantage of reducing the memory footprint of executing a
single request, since it allow us to merge some fields in the header.
It is possible to reduce even further each segment memory footprint, by
merging bitmap_words and cow_offset, for instance, but this is not the
focus of this patch and is left as future work.  One issue with the
patch is that for a big number of segments, we now perform one big
memory allocation instead of multiple small ones, but I wasn't able to
trigger any real issues or -ENOMEM because of this change, that wouldn't
be reproduced otherwise.

This was tested using fio with the verify-crc32 option, and by running
an ext4 filesystem over this UBD device.

The original WARN_ON was:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at lib/refcount.c:28 refcount_warn_saturate+0x13f/0x141
refcount_t: underflow; use-after-free.
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 5.5.0-rc6-00002-g2a5bb2cf75c8 #346
Stack:
 6084eed0 6063dc77 00000009 6084ef60
 00000000 604b8d9f 6084eee0 6063dcbc
 6084ef40 6006ab8d e013d780 1c00000000
Call Trace:
 [<600a0c1c>] ? printk+0x0/0x94
 [<6004a888>] show_stack+0x13b/0x155
 [<6063dc77>] ? dump_stack_print_info+0xdf/0xe8
 [<604b8d9f>] ? refcount_warn_saturate+0x13f/0x141
 [<6063dcbc>] dump_stack+0x2a/0x2c
 [<6006ab8d>] __warn+0x107/0x134
 [<6008da6c>] ? wake_up_process+0x17/0x19
 [<60487628>] ? blk_queue_max_discard_sectors+0x0/0xd
 [<6006b05f>] warn_slowpath_fmt+0xd1/0xdf
 [<6006af8e>] ? warn_slowpath_fmt+0x0/0xdf
 [<600acc14>] ? raw_read_seqcount_begin.constprop.0+0x0/0x15
 [<600619ae>] ? os_nsecs+0x1d/0x2b
 [<604b8d9f>] refcount_warn_saturate+0x13f/0x141
 [<6048bc8f>] refcount_sub_and_test.constprop.0+0x2f/0x37
 [<6048c8de>] blk_mq_free_request+0xf1/0x10d
 [<6048ca06>] __blk_mq_end_request+0x10c/0x114
 [<6005ac0f>] ubd_intr+0xb5/0x169
 [<600a1a37>] __handle_irq_event_percpu+0x6b/0x17e
 [<600a1b70>] handle_irq_event_percpu+0x26/0x69
 [<600a1bd9>] handle_irq_event+0x26/0x34
 [<600a1bb3>] ? handle_irq_event+0x0/0x34
 [<600a5186>] ? unmask_irq+0x0/0x37
 [<600a57e6>] handle_edge_irq+0xbc/0xd6
 [<600a131a>] generic_handle_irq+0x21/0x29
 [<60048f6e>] do_IRQ+0x39/0x54
 [...]
---[ end trace c6e7444e55386c0f ]---

Cc: Christopher Obbard <chris.obbard@collabora.com>
Reported-by: Martyn Welch <martyn@collabora.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Tested-by: Christopher Obbard <chris.obbard@collabora.com>
Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
pull bot pushed a commit that referenced this pull request May 17, 2024
Recent additions in BPF like cpu v4 instructions, test_bpf module
exhibits the following failures:

  test_bpf: #82 ALU_MOVSX | BPF_B jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times)
  test_bpf: #83 ALU_MOVSX | BPF_H jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times)
  test_bpf: #84 ALU64_MOVSX | BPF_B jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times)
  test_bpf: #85 ALU64_MOVSX | BPF_H jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times)
  test_bpf: #86 ALU64_MOVSX | BPF_W jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times)

  test_bpf: #165 ALU_SDIV_X: -6 / 2 = -3 jited:1 ret 2147483645 != -3 (0x7ffffffd != 0xfffffffd)FAIL (1 times)
  test_bpf: #166 ALU_SDIV_K: -6 / 2 = -3 jited:1 ret 2147483645 != -3 (0x7ffffffd != 0xfffffffd)FAIL (1 times)

  test_bpf: #169 ALU_SMOD_X: -7 % 2 = -1 jited:1 ret 1 != -1 (0x1 != 0xffffffff)FAIL (1 times)
  test_bpf: #170 ALU_SMOD_K: -7 % 2 = -1 jited:1 ret 1 != -1 (0x1 != 0xffffffff)FAIL (1 times)

  test_bpf: #172 ALU64_SMOD_K: -7 % 2 = -1 jited:1 ret 1 != -1 (0x1 != 0xffffffff)FAIL (1 times)

  test_bpf: #313 BSWAP 16: 0x0123456789abcdef -> 0xefcd
  eBPF filter opcode 00d7 (@2) unsupported
  jited:0 301 PASS
  test_bpf: #314 BSWAP 32: 0x0123456789abcdef -> 0xefcdab89
  eBPF filter opcode 00d7 (@2) unsupported
  jited:0 555 PASS
  test_bpf: #315 BSWAP 64: 0x0123456789abcdef -> 0x67452301
  eBPF filter opcode 00d7 (@2) unsupported
  jited:0 268 PASS
  test_bpf: #316 BSWAP 64: 0x0123456789abcdef >> 32 -> 0xefcdab89
  eBPF filter opcode 00d7 (@2) unsupported
  jited:0 269 PASS
  test_bpf: #317 BSWAP 16: 0xfedcba9876543210 -> 0x1032
  eBPF filter opcode 00d7 (@2) unsupported
  jited:0 460 PASS
  test_bpf: #318 BSWAP 32: 0xfedcba9876543210 -> 0x10325476
  eBPF filter opcode 00d7 (@2) unsupported
  jited:0 320 PASS
  test_bpf: #319 BSWAP 64: 0xfedcba9876543210 -> 0x98badcfe
  eBPF filter opcode 00d7 (@2) unsupported
  jited:0 222 PASS
  test_bpf: #320 BSWAP 64: 0xfedcba9876543210 >> 32 -> 0x10325476
  eBPF filter opcode 00d7 (@2) unsupported
  jited:0 273 PASS

  test_bpf: #344 BPF_LDX_MEMSX | BPF_B
  eBPF filter opcode 0091 (@5) unsupported
  jited:0 432 PASS
  test_bpf: #345 BPF_LDX_MEMSX | BPF_H
  eBPF filter opcode 0089 (@5) unsupported
  jited:0 381 PASS
  test_bpf: #346 BPF_LDX_MEMSX | BPF_W
  eBPF filter opcode 0081 (@5) unsupported
  jited:0 505 PASS

  test_bpf: #490 JMP32_JA: Unconditional jump: if (true) return 1
  eBPF filter opcode 0006 (@1) unsupported
  jited:0 261 PASS

  test_bpf: Summary: 1040 PASSED, 10 FAILED, [924/1038 JIT'ed]

Fix them by adding missing processing.

Fixes: daabb2b ("bpf/tests: add tests for cpuv4 instructions")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/91de862dda99d170697eb79ffb478678af7e0b27.1709652689.git.christophe.leroy@csgroup.eu
pull bot pushed a commit that referenced this pull request Jun 1, 2024
Add a test case to assert that the skb->pkt_type which was set from the BPF
program is retained from the netkit xmit side to the peer's device at tcx
ingress location.

  # ./vmtest.sh -- ./test_progs -t netkit
  [...]
  ./test_progs -t netkit
  [    1.140780] bpf_testmod: loading out-of-tree module taints kernel.
  [    1.141127] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
  [    1.284601] tsc: Refined TSC clocksource calibration: 3408.006 MHz
  [    1.286672] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fd9b189d, max_idle_ns: 440795225691 ns
  [    1.290384] clocksource: Switched to clocksource tsc
  #345     tc_netkit_basic:OK
  #346     tc_netkit_device:OK
  #347     tc_netkit_multi_links:OK
  #348     tc_netkit_multi_opts:OK
  #349     tc_netkit_neigh_links:OK
  #350     tc_netkit_pkt_type:OK
  Summary: 6/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20240524163619.26001-4-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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2 participants