On Wed, Aug 09, 2023 at 02:35:59PM -0400, Joel Fernandes wrote:
On Wed, Aug 9, 2023 at 12:18 PM Guenter Roeck linux@roeck-us.net wrote:
On 8/9/23 06:53, Joel Fernandes wrote:
On Wed, Aug 09, 2023 at 12:40:36PM +0200, Greg Kroah-Hartman wrote:
This is the start of the stable review cycle for the 5.15.126 release. There are 92 patches in this series, all will be posted as a response to this one. If anyone has any issues with these being applied, please let me know.
Responses should be made by Fri, 11 Aug 2023 10:36:10 +0000. Anything received after that time might be too late.
The whole patch series can be found in one patch at: https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.15.126-rc... or in the git tree and branch at: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.15.y and the diffstat can be found below.
Not necesscarily new with 5.15 stable but 3 of the 19 rcutorture scenarios hang with this -rc: TREE04, TREE07, TASKS03.
5.15 has a known stop machine issue where it hangs after 1.5 hours with cpu hotplug rcutorture testing. Me and tglx are continuing to debug this. The issue does not show up on anything but 5.15 stable kernels and neither on mainline.
Do you by any have a crash pattern that we could possibly use to find the crash in ChromeOS crash logs ? No idea if that would help, but it could provide some additional data points.
The pattern shows as a hard hang, the system is unresponsive and all CPUs are stuck in stop_machine. Sometimes it recovers on its own from the hang and then RCU immediately gives stall warnings. It takes 1.5 hour to reproduce and sometimes never happens for several hours.
It appears related to CPU hotplug since gdb showed me most of the CPUs are spinning in multi_cpu_stop() / stop machine after the hang.
Hmm, we do see lots of soft lockups with multi_cpu_stop() in the backtrace, but not with v5.15.y but with v5.4.y. The actual hang is in stop_machine_yield(). Example:
<0>[63298.624328] watchdog: BUG: soft lockup - CPU#0 stuck for 11s! [migration/0:11] <4>[63298.624331] Modules linked in: 8021q ccm snd_seq_dummy snd_seq snd_seq_device bridge stp llc tun nf_nat_tftp nf_conntrack_tftp nf_nat_ftp nf_conntrack_ftp esp6 ah6 ip6t_REJECT ip6t_ipv6header vhost_vsock vhost vmw_vsock_virtio_transport_common vsock veth rfcomm xt_cgroup cmac algif_hash algif_skcipher af_alg xt_MASQUERADE uinput iwlmvm snd_soc_skl_ssp_clk iwl7000_mac80211 btusb snd_soc_kbl_da7219_max98357a btrtl btintel snd_soc_hdac_hdmi btbcm bluetooth snd_soc_dmic snd_soc_skl ecdh_generic ecc snd_soc_sst_ipc snd_soc_sst_dsp snd_soc_hdac_hda uvcvideo snd_soc_acpi_intel_match snd_soc_acpi snd_hda_ext_core videobuf2_vmalloc videobuf2_v4l2 videobuf2_common snd_intel_dspcfg videobuf2_memops snd_hda_codec snd_hwdep snd_hda_core iwlwifi snd_soc_da7219 snd_soc_max98357a fuse ip6table_nat cfg80211 lzo_rle lzo_compress zram joydev <4>[63298.624357] CPU: 0 PID: 11 Comm: migration/0 Tainted: G U W 5.4.180-17902-g44152654f29b #1 <4>[63298.624358] Hardware name: Google Nami/Nami, BIOS Google_Nami.10775.145.0 09/19/2019 <4>[63298.624363] RIP: 0010:stop_machine_yield+0xb/0xd <4>[63298.624366] Code: ff 74 b6 f0 ff 0f 75 b1 48 83 c7 08 e8 1f cb f9 ff eb a6 e8 a0 20 e3 ff eb bc e8 50 4b f5 ff 0f 1f 44 00 00 55 48 89 e5 f3 90 <5d> c3 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 81 <4>[63298.624368] RSP: 0000:ffffbaf90006fe38 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 <4>[63298.624370] RAX: 0000000000000000 RBX: ffffbaf90300bca8 RCX: 0000000000000000 <4>[63298.624371] RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffffb0d46920 <4>[63298.624373] RBP: ffffbaf90006fe38 R08: 0000000000000002 R09: 0000398ecf9a0ac5 <4>[63298.624374] R10: 0000000000000171 R11: ffffffffaf9cfb11 R12: 0000000000000001 <4>[63298.624376] R13: ffff9b09baa22201 R14: ffffffffb0d46920 R15: 0000000000000001 <4>[63298.624377] FS: 0000000000000000(0000) GS:ffff9b09baa00000(0000) knlGS:0000000000000000 <4>[63298.624379] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[63298.624380] CR2: 0000153c00724820 CR3: 0000000171ab8005 CR4: 00000000003606f0 <4>[63298.624382] Call Trace: <4>[63298.624386] multi_cpu_stop+0x89/0x119 <4>[63298.624389] ? stop_two_cpus+0x24d/0x24d <4>[63298.624391] cpu_stopper_thread+0x8f/0x111 <4>[63298.624394] smpboot_thread_fn+0x174/0x212 <4>[63298.624397] kthread+0x147/0x156 <4>[63298.624399] ? cpu_report_death+0x43/0x43 <4>[63298.624401] ? kthread_blkcg+0x2e/0x2e <4>[63298.624404] ret_from_fork+0x35/0x40 <0>[63298.624407] Kernel panic - not syncing: softlockup: hung tasks
I guess that is something different ?
Guenter