Package: src:linux
Version: 6.1.174-1
Severity: important
Dear Maintainer,
After booting into 6.1.0-49-amd64, commands that access /proc or the
kernel ring buffer (dmesg -T, ps -ef, systemctl status) block
indefinitely, making the SSH session unresponsive.
The issue is triggered by:
sync; echo 3 > /proc/sys/vm/drop_caches
(run via cronjob every hour)
This is a regression. Kernel 6.1.0-37-amd64 ran for 396 days with the
identical cronjob and configuration without any issues.
Steps to reproduce:
1. Boot 6.1.0-49-amd64
2. Run: sync; echo 3 > /proc/sys/vm/drop_caches
3. Run: dmesg -T (or ps -ef, or systemctl status ssh)
4. Command blocks indefinitely, SSH session becomes unresponsive
Expected: Commands complete normally (as with 6.1.0-37)
Actual: Commands block, require new SSH session or reboot
Workaround: Boot 6.1.0-37-amd64 or disable drop_caches cronjob.
Environment:
- Hypervisor: KVM/QEMU (i440FX + PIIX)
- Block device: virtio_blk (vda, 1.5 TB ext4)
- RAM: 20 GB (524 MB used at time of issue)
- CPUs: 6
- Docker installed (containers running)
- tinc VPN running
- No D-state processes visible during hang
- No filesystem errors (errors_count = 0)
- /proc/stat, /proc/loadavg still readable durin
-- Package-specific info:
** Kernel log: boot messages should be attached
** Model information
sys_vendor: QEMU
product_name: Standard PC (i440FX + PIIX, 1996)
product_version: pc-i440fx-9.0
chassis_vendor: QEMU
chassis_version: pc-i440fx-9.0
bios_vendor: SeaBIOS
bios_version: rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org
** PCI devices:
00:00.0 Host bridge [0600]: Intel Corporation 440FX - 82441FX PMC [Natoma]
[8086:1237] (rev 02)
Subsystem: Red Hat, Inc. Qemu virtual machine [1af4:1100]
Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx-
Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- >SERR- <PERR- INTx-
00:01.0 ISA bridge [0601]: Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton
II] [8086:7000]
Subsystem: Red Hat, Inc. Qemu virtual machine [1af4:1100]
Physical Slot: 1
Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx-
Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort-
<TAbort- <MAbort- >SERR- <PERR- INTx-
00:01.1 IDE interface [0101]: Intel Corporation 82371SB PIIX3 IDE
[Natoma/Triton II] [8086:7010] (prog-if 80 [ISA Compatibility mode-only
controller, supports bus mastering])
Subsystem: Red Hat, Inc. Qemu virtual machine [1af4:1100]
Physical Slot: 1
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx-
Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort-
<TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 0
Region 0: I/O ports at 01f0 [size=8]
Region 1: I/O ports at 03f4
Region 2: I/O ports at 0170 [size=8]
Region 3: I/O ports at 0374
Region 4: I/O ports at e100 [size=16]
Kernel driver in use: ata_piix
Kernel modules: ata_piix, ata_generic
00:01.2 USB controller [0c03]: Intel Corporation 82371SB PIIX3 USB
[Natoma/Triton II] [8086:7020] (rev 01) (prog-if 00 [UHCI])
Subsystem: Red Hat, Inc. QEMU Virtual Machine [1af4:1100]
Physical Slot: 1
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx-
Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- >SERR- <PERR- INTx-
Latency: 0
Interrupt: pin D routed to IRQ 11
Region 4: I/O ports at e0c0 [size=32]
Kernel driver in use: uhci_hcd
Kernel modules: uhci_hcd
00:01.3 Bridge [0680]: Intel Corporation 82371AB/EB/MB PIIX4 ACPI [8086:7113]
(rev 03)
Subsystem: Red Hat, Inc. Qemu virtual machine [1af4:1100]
Physical Slot: 1
Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx-
Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort-
<TAbort- <MAbort- >SERR- <PERR- INTx-
Interrupt: pin A routed to IRQ 9
Kernel driver in use: piix4_smbus
Kernel modules: i2c_piix4
00:02.0 VGA compatible controller [0300]: Device [1234:1111] (rev 02) (prog-if
00 [VGA controller])
Subsystem: Red Hat, Inc. Device [1af4:1100]
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B- DisINTx-
Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- >SERR- <PERR- INTx-
Latency: 0
Region 0: Memory at fd000000 (32-bit, prefetchable) [size=16M]
Region 2: Memory at fea50000 (32-bit, non-prefetchable) [size=4K]
Expansion ROM at 000c0000 [disabled] [size=128K]
Kernel driver in use: bochs-drm
Kernel modules: bochs
00:03.0 Unclassified device [00ff]: Red Hat, Inc. Virtio memory balloon
[1af4:1002]
Subsystem: Red Hat, Inc. Virtio memory balloon [1af4:0005]
Physical Slot: 3
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- >SERR- <PERR- INTx-
Latency: 0
Interrupt: pin A routed to IRQ 10
Region 0: I/O ports at e080 [size=64]
Region 4: Memory at 381800000000 (64-bit, prefetchable) [size=16K]
Capabilities: <access denied>
Kernel driver in use: virtio-pci
Kernel modules: virtio_pci
00:0a.0 SCSI storage controller [0100]: Red Hat, Inc. Virtio block device
[1af4:1001]
Subsystem: Red Hat, Inc. Virtio block device [1af4:0002]
Physical Slot: 10
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx+
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- >SERR- <PERR- INTx-
Latency: 0
Interrupt: pin A routed to IRQ 10
Region 0: I/O ports at e000 [size=128]
Region 1: Memory at fea51000 (32-bit, non-prefetchable) [size=4K]
Region 4: Memory at 381800004000 (64-bit, prefetchable) [size=16K]
Capabilities: <access denied>
Kernel driver in use: virtio-pci
Kernel modules: virtio_pci
00:12.0 Ethernet controller [0200]: Red Hat, Inc. Virtio network device
[1af4:1000]
Subsystem: Red Hat, Inc. Virtio network device [1af4:0001]
Physical Slot: 18
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx+
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- >SERR- <PERR- INTx-
Latency: 0
Interrupt: pin A routed to IRQ 10
Region 0: I/O ports at e0e0 [size=32]
Region 1: Memory at fea52000 (32-bit, non-prefetchable) [size=4K]
Region 4: Memory at 381800008000 (64-bit, prefetchable) [size=16K]
Expansion ROM at fea00000 [disabled] [size=256K]
Capabilities: <access denied>
Kernel driver in use: virtio-pci
Kernel modules: virtio_pci
00:1e.0 PCI bridge [0604]: Red Hat, Inc. QEMU PCI-PCI bridge [1b36:0001]
(prog-if 00 [Normal decode])
Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx-
Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- >SERR- <PERR- INTx-
Interrupt: pin A routed to IRQ 10
Region 0: Memory at 380000000000 (64-bit, non-prefetchable) [size=256]
Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
I/O behind bridge: d000-dfff [size=4K] [16-bit]
Memory behind bridge: fe800000-fe9fffff [size=2M] [32-bit]
Prefetchable memory behind bridge: 381000000000-3817ffffffff [size=32G]
[32-bit]
Secondary status: 66MHz+ FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- <SERR- <PERR-
BridgeCtl: Parity- SERR+ NoISA- VGA- VGA16- MAbort- >Reset- FastB2B-
PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn-
Capabilities: <access denied>
00:1f.0 PCI bridge [0604]: Red Hat, Inc. QEMU PCI-PCI bridge [1b36:0001]
(prog-if 00 [Normal decode])
Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B- DisINTx-
Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- >SERR- <PERR- INTx-
Interrupt: pin A routed to IRQ 11
Region 0: Memory at 380000001000 (64-bit, non-prefetchable) [size=256]
Bus: primary=00, secondary=02, subordinate=02, sec-latency=0
I/O behind bridge: c000-cfff [size=4K] [16-bit]
Memory behind bridge: fe600000-fe7fffff [size=2M] [32-bit]
Prefetchable memory behind bridge: 380800000000-380fffffffff [size=32G]
[32-bit]
Secondary status: 66MHz+ FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- <SERR- <PERR-
BridgeCtl: Parity- SERR+ NoISA- VGA- VGA16- MAbort- >Reset- FastB2B-
PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn-
Capabilities: <access denied>
** USB devices:
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
-- System Information:
Debian Release: 12.14
APT prefers oldstable-updates
APT policy: (500, 'oldstable-updates'), (500, 'oldstable-security'), (500,
'oldstable')
Architecture: amd64 (x86_64)
Kernel: Linux 6.1.0-37-amd64 (SMP w/6 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages linux-image-6.1.0-49-amd64 depends on:
ii initramfs-tools [linux-initramfs-tool] 0.142+deb12u3
ii kmod 30+20221128-1
ii linux-base 4.12.1~deb12u1
Versions of packages linux-image-6.1.0-49-amd64 recommends:
ii apparmor 3.0.8-3
ii firmware-linux-free 20200122-1
Versions of packages linux-image-6.1.0-49-amd64 suggests:
pn debian-kernel-handbook <none>
ii grub-pc 2.06-13+deb12u2
pn linux-doc-6.1 <none>
Versions of packages linux-image-6.1.0-49-amd64 is related to:
pn firmware-amd-graphics <none>
pn firmware-atheros <none>
pn firmware-bnx2 <none>
pn firmware-bnx2x <none>
pn firmware-brcm80211 <none>
pn firmware-cavium <none>
pn firmware-intel-sound <none>
pn firmware-intelwimax <none>
pn firmware-ipw2x00 <none>
pn firmware-ivtv <none>
pn firmware-iwlwifi <none>
pn firmware-libertas <none>
pn firmware-linux-nonfree <none>
pn firmware-misc-nonfree <none>
pn firmware-myricom <none>
pn firmware-netxen <none>
pn firmware-qlogic <none>
pn firmware-realtek <none>
pn firmware-samsung <none>
pn firmware-siano <none>
pn firmware-ti-connectivity <none>
pn xen-hypervisor <none>
-- debconf-show failed
