[PATCH 00/16] ptrace: cleanups and calling do_cldstop with only siglock

[Kyle Huey]

On Thu, May 19, 2022 at 11:05 AM Eric W. Biederman
<ebiederm at xmission.com> wrote:
>
> Sebastian Andrzej Siewior <bigeasy at linutronix.de> writes:
>
> > On 2022-05-18 20:26:05 [-0700], Kyle Huey wrote:
> >> Is there a git branch somewhere I can pull to test this? It doesn't apply
> >> cleanly to Linus's tip.
> >
> > https://kernel.googlesource.com/pub/scm/linux/kernel/git/ebiederm/user-namespace.git ptrace_stop-cleanup-for-v5.19
>
> Yes that is the branch this all applies to.
>
> This is my second round of cleanups this cycle for this code.
> I just keep finding little things that deserve to be changed,
> when I am working on the more substantial issues.
>
> Eric

When running the rr test suite, I see hangs like this

[  812.151505] watchdog: BUG: soft lockup - CPU#3 stuck for 548s!
[condvar_stress-:12152]
[  812.151529] Modules linked in: snd_hda_codec_realtek
snd_hda_codec_generic ledtrig_audio rfcomm cmac algif_hash
algif_skcipher af_alg bnep dm_crypt intel_rapl_msr mei_hdcp
snd_hda_codec_
hdmi intel_rapl_common snd_hda_intel x86_pkg_temp_thermal
snd_intel_dspcfg snd_intel_sdw_acpi nls_iso8859_1 intel_powerclamp
snd_hda_codec coretemp snd_hda_core snd_hwdep snd_pcm rtl8723be
btcoexist snd_seq_midi snd_seq_midi_event rtl8723_common kvm_intel
rtl_pci snd_rawmidi rtlwifi btusb btrtl btbcm snd_seq kvm mac80211
btintel btmtk snd_seq_device rapl bluetooth snd_timer i
ntel_cstate hp_wmi cfg80211 serio_raw snd platform_profile
ecdh_generic mei_me sparse_keymap efi_pstore wmi_bmof ee1004 joydev
input_leds ecc libarc4 soundcore mei acpi_pad mac_hid sch_fq_c
odel ipmi_devintf ipmi_msghandler msr vhost_vsock
vmw_vsock_virtio_transport_common vsock vhost_net vhost vhost_iotlb
tap vhci_hcd usbip_core parport_pc ppdev lp parport ip_tables x_tables
autofs4 btrfs blake2b_generic xor raid6_pq zstd_compress
[  812.151570]  libcrc32c hid_generic usbhid hid i915 drm_buddy
i2c_algo_bit ttm drm_dp_helper cec rc_core crct10dif_pclmul
drm_kms_helper crc32_pclmul syscopyarea ghash_clmulni_intel sysfi
llrect sysimgblt fb_sys_fops aesni_intel crypto_simd cryptd r8169
psmouse drm i2c_i801 realtek ahci i2c_smbus xhci_pci libahci
xhci_pci_renesas wmi video
[  812.151584] CPU: 3 PID: 12152 Comm: condvar_stress- Tainted: G
    I  L    5.18.0-rc1+ #2
[  812.151586] Hardware name: HP 750-280st/2B4B, BIOS A0.11 02/24/2016
[  812.151587] RIP: 0010:_raw_spin_unlock_irq+0x15/0x40
[  812.151591] Code: df e8 3f 1f 4a ff 90 5b 5d c3 66 66 2e 0f 1f 84
00 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 c6 07 00 0f 1f 00 fb 0f 1f
44 00 00 <bf> 01 00 00 00 e8 41 95 46 ff 65 8b 05 9
a c1 9a 5f 85 c0 74 02 5d
[  812.151593] RSP: 0018:ffffa863c246bd70 EFLAGS: 00000246
[  812.151594] RAX: ffff8bc0913f6400 RBX: ffff8bc0913f6400 RCX: 0000000000000000
[  812.151595] RDX: 0000000000000002 RSI: 00000000000a0013 RDI: ffff8bc089b63180
[  812.151596] RBP: ffffa863c246bd70 R08: ffff8bc0811d6b40 R09: ffff8bc089b63180
[  812.151597] R10: 0000000000000000 R11: 0000000000000004 R12: ffff8bc0913f6400
[  812.151597] R13: ffff8bc089b63180 R14: ffff8bc0913f6400 R15: ffffa863c246be68
[  812.151598] FS:  00007f612dda5700(0000) GS:ffff8bc7e24c0000(0000)
knlGS:0000000000000000
[  812.151599] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  812.151600] CR2: 000055e70715692e CR3: 000000010b4e8005 CR4: 00000000003706e4
[  812.151601] Call Trace:
[  812.151602]  <TASK>
[  812.151604]  do_signal_stop+0x228/0x260
[  812.151606]  get_signal+0x43a/0x8e0
[  812.151608]  arch_do_signal_or_restart+0x37/0x7d0
[  812.151610]  ? __this_cpu_preempt_check+0x13/0x20
[  812.151612]  ? __perf_event_task_sched_in+0x81/0x230
[  812.151616]  ? __this_cpu_preempt_check+0x13/0x20
[  812.151617]  exit_to_user_mode_prepare+0x130/0x1a0
[  812.151620]  syscall_exit_to_user_mode+0x26/0x40
[  812.151621]  ret_from_fork+0x15/0x30
[  812.151623] RIP: 0033:0x7f612dfcd125
[  812.151625] Code: 48 85 ff 74 3d 48 85 f6 74 38 48 83 ee 10 48 89
4e 08 48 89 3e 48 89 d7 4c 89 c2 4d 89 c8 4c 8b 54 24 08 b8 38 00 00
00 0f 05 <48> 85 c0 7c 13 74 01 c3 31 ed 58 5f ff d
0 48 89 c7 b8 3c 00 00 00
[  812.151626] RSP: 002b:00007f612dda4fb0 EFLAGS: 00000246 ORIG_RAX:
0000000000000038
[  812.151628] RAX: 0000000000000000 RBX: 00007f612dda5700 RCX: ffffffffffffffff
[  812.151628] RDX: 00007f612dda59d0 RSI: 00007f612dda4fb0 RDI: 00000000003d0f00
[  812.151629] RBP: 00007ffd59ad20b0 R08: 00007f612dda5700 R09: 00007f612dda5700
[  812.151630] R10: 00007f612dda59d0 R11: 0000000000000246 R12: 00007ffd59ad20ae
[  812.151631] R13: 00007ffd59ad20af R14: 00007ffd59ad20b0 R15: 00007f612dda4fc0
[  812.151632]  </TASK>

- Kyle