linux-toradex.git/include/linux/console.h, branch v7.0-rc5 Linux kernel for Apalis and Colibri modules printk, vt, fbcon: Remove console_conditional_schedule() 2026-02-14T10:09:47+00:00 Sebastian Andrzej Siewior bigeasy@linutronix.de 2026-01-26T18:08:36+00:00 8e9bf8b9e8c0a3e1ef16dd48260a113f65ed01d2 do_con_write(), fbcon_redraw.*() invoke console_conditional_schedule() which is a conditional scheduling point based on printk's internal variables console_may_schedule. It may only be used if the console lock is acquired for instance via console_lock() or console_trylock(). Prinkt sets the internal variable to 1 (and allows to schedule) if the console lock has been acquired via console_lock(). The trylock does not allow it. The console_conditional_schedule() invocation in do_con_write() is invoked shortly before console_unlock(). The console_conditional_schedule() invocation in fbcon_redraw.*() original from fbcon_scroll() / vt's con_scroll() which originate from a line feed. In console_unlock() the variable is set to 0 (forbids to schedule) and it tries to schedule while making progress printing. This is brand new compared to when console_conditional_schedule() was added in v2.4.9.11. In v2.6.38-rc3, console_unlock() (started its existence) iterated over all consoles and flushed them with disabled interrupts. A scheduling attempt here was not possible, it relied that a long print scheduled before console_unlock(). Since commit 8d91f8b15361d ("printk: do cond_resched() between lines while outputting to consoles"), which appeared in v4.5-rc1, console_unlock() attempts to schedule if it was allowed to schedule while during console_lock(). Each record is idealy one line so after every line feed. This console_conditional_schedule() is also only relevant on PREEMPT_NONE and PREEMPT_VOLUNTARY builds. In other configurations cond_resched() becomes a nop and has no impact. I'm bringing this all up just proof that it is not required anymore. It becomes a problem on a PREEMPT_RT build with debug code enabled because that might_sleep() in cond_resched() remains and triggers a warnings. This is due to legacy_kthread_func-> console_flush_one_record -> vt_console_print-> lf -> con_scroll -> fbcon_scroll and vt_console_print() acquires a spinlock_t which does not allow a voluntary schedule. There is no need to fb_scroll() to schedule since console_flush_one_record() attempts to schedule after each line. !PREEMPT_RT is not affected because the legacy printing thread is only enabled on PREEMPT_RT builds. Therefore I suggest to remove console_conditional_schedule(). Cc: Simona Vetter <simona@ffwll.ch> Cc: Helge Deller <deller@gmx.de> Cc: linux-fbdev@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Fixes: 5f53ca3ff83b4 ("printk: Implement legacy printer kthread for PREEMPT_RT") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Petr Mladek <pmladek@suse.com> # from printk() POV Signed-off-by: Helge Deller <deller@gmx.de> 
do_con_write(), fbcon_redraw.*() invoke console_conditional_schedule()
which is a conditional scheduling point based on printk's internal
variables console_may_schedule. It may only be used if the console lock
is acquired for instance via console_lock() or console_trylock().

Prinkt sets the internal variable to 1 (and allows to schedule)
if the console lock has been acquired via console_lock(). The trylock
does not allow it.

The console_conditional_schedule() invocation in do_con_write() is
invoked shortly before console_unlock().
The console_conditional_schedule() invocation in fbcon_redraw.*()
original from fbcon_scroll() / vt's con_scroll() which originate from a
line feed.

In console_unlock() the variable is set to 0 (forbids to schedule) and
it tries to schedule while making progress printing. This is brand new
compared to when console_conditional_schedule() was added in v2.4.9.11.

In v2.6.38-rc3, console_unlock() (started its existence) iterated over
all consoles and flushed them with disabled interrupts. A scheduling
attempt here was not possible, it relied that a long print scheduled
before console_unlock().

Since commit 8d91f8b15361d ("printk: do cond_resched() between lines
while outputting to consoles"), which appeared in v4.5-rc1,
console_unlock() attempts to schedule if it was allowed to schedule
while during console_lock(). Each record is idealy one line so after
every line feed.

This console_conditional_schedule() is also only relevant on
PREEMPT_NONE and PREEMPT_VOLUNTARY builds. In other configurations
cond_resched() becomes a nop and has no impact.

I'm bringing this all up just proof that it is not required anymore. It
becomes a problem on a PREEMPT_RT build with debug code enabled because
that might_sleep() in cond_resched() remains and triggers a warnings.
This is due to

 legacy_kthread_func-> console_flush_one_record ->  vt_console_print-> lf
   -> con_scroll -> fbcon_scroll

and vt_console_print() acquires a spinlock_t which does not allow a
voluntary schedule. There is no need to fb_scroll() to schedule since
console_flush_one_record() attempts to schedule after each line.
!PREEMPT_RT is not affected because the legacy printing thread is only
enabled on PREEMPT_RT builds.

Therefore I suggest to remove console_conditional_schedule().

Cc: Simona Vetter <simona@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Fixes: 5f53ca3ff83b4 ("printk: Implement legacy printer kthread for PREEMPT_RT")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Petr Mladek <pmladek@suse.com> # from printk() POV
Signed-off-by: Helge Deller <deller@gmx.de>
Merge tag 'net-next-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2026-02-12T03:31:52+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-02-12T03:31:52+00:00 37a93dd5c49b5fda807fd204edf2547c3493319c Pull networking updates from Paolo Abeni: "Core & protocols: - A significant effort all around the stack to guide the compiler to make the right choice when inlining code, to avoid unneeded calls for small helper and stack canary overhead in the fast-path. This generates better and faster code with very small or no text size increases, as in many cases the call generated more code than the actual inlined helper. - Extend AccECN implementation so that is now functionally complete, also allow the user-space enabling it on a per network namespace basis. - Add support for memory providers with large (above 4K) rx buffer. Paired with hw-gro, larger rx buffer sizes reduce the number of buffers traversing the stack, dincreasing single stream CPU usage by up to ~30%. - Do not add HBH header to Big TCP GSO packets. This simplifies the RX path, the TX path and the NIC drivers, and is possible because user-space taps can now interpret correctly such packets without the HBH hint. - Allow IPv6 routes to be configured with a gateway address that is resolved out of a different interface than the one specified, aligning IPv6 to IPv4 behavior. - Multi-queue aware sch_cake. This makes it possible to scale the rate shaper of sch_cake across multiple CPUs, while still enforcing a single global rate on the interface. - Add support for the nbcon (new buffer console) infrastructure to netconsole, enabling lock-free, priority-based console operations that are safer in crash scenarios. - Improve the TCP ipv6 output path to cache the flow information, saving cpu cycles, reducing cache line misses and stack use. - Improve netfilter packet tracker to resolve clashes for most protocols, avoiding unneeded drops on rare occasions. - Add IP6IP6 tunneling acceleration to the flowtable infrastructure. - Reduce tcp socket size by one cache line. - Notify neighbour changes atomically, avoiding inconsistencies between the notification sequence and the actual states sequence. - Add vsock namespace support, allowing complete isolation of vsocks across different network namespaces. - Improve xsk generic performances with cache-alignment-oriented optimizations. - Support netconsole automatic target recovery, allowing netconsole to reestablish targets when underlying low-level interface comes back online. Driver API: - Support for switching the working mode (automatic vs manual) of a DPLL device via netlink. - Introduce PHY ports representation to expose multiple front-facing media ports over a single MAC. - Introduce "rx-polarity" and "tx-polarity" device tree properties, to generalize polarity inversion requirements for differential signaling. - Add helper to create, prepare and enable managed clocks. Device drivers: - Add Huawei hinic3 PF etherner driver. - Add DWMAC glue driver for Motorcomm YT6801 PCIe ethernet controller. - Add ethernet driver for MaxLinear MxL862xx switches - Remove parallel-port Ethernet driver. - Convert existing driver timestamp configuration reporting to hwtstamp_get and remove legacy ioctl(). - Convert existing drivers to .get_rx_ring_count(), simplifing the RX ring count retrieval. Also remove the legacy fallback path. - Ethernet high-speed NICs: - Broadcom (bnxt, bng): - bnxt: add FW interface update to support FEC stats histogram and NVRAM defragmentation - bng: add TSO and H/W GRO support - nVidia/Mellanox (mlx5): - improve latency of channel restart operations, reducing the used H/W resources - add TSO support for UDP over GRE over VLAN - add flow counters support for hardware steering (HWS) rules - use a static memory area to store headers for H/W GRO, leading to 12% RX tput improvement - Intel (100G, ice, idpf): - ice: reorganizes layout of Tx and Rx rings for cacheline locality and utilizes __cacheline_group* macros on the new layouts - ice: introduces Synchronous Ethernet (SyncE) support - Meta (fbnic): - adds debugfs for firmware mailbox and tx/rx rings vectors - Ethernet virtual: - geneve: introduce GRO/GSO support for double UDP encapsulation - Ethernet NICs consumer, and embedded: - Synopsys (stmmac): - some code refactoring and cleanups - RealTek (r8169): - add support for RTL8127ATF (10G Fiber SFP) - add dash and LTR support - Airoha: - AN8811HB 2.5 Gbps phy support - Freescale (fec): - add XDP zero-copy support - Thunderbolt: - add get link setting support to allow bonding - Renesas: - add support for RZ/G3L GBETH SoC - Ethernet switches: - Maxlinear: - support R(G)MII slow rate configuration - add support for Intel GSW150 - Motorcomm (yt921x): - add DCB/QoS support - TI: - icssm-prueth: support bridging (STP/RSTP) via the switchdev framework - Ethernet PHYs: - Realtek: - enable SGMII and 2500Base-X in-band auto-negotiation - simplify and reunify C22/C45 drivers - Micrel: convert bindings to DT schema - CAN: - move skb headroom content into skb extensions, making CAN metadata access more robust - CAN drivers: - rcar_canfd: - add support for FD-only mode - add support for the RZ/T2H SoC - sja1000: cleanup the CAN state handling - WiFi: - implement EPPKE/802.1X over auth frames support - split up drop reasons better, removing generic RX_DROP - additional FTM capabilities: 6 GHz support, supported number of spatial streams and supported number of LTF repetitions - better mac80211 iterators to enumerate resources - initial UHR (Wi-Fi 8) support for cfg80211/mac80211 - WiFi drivers: - Qualcomm/Atheros: - ath11k: support for Channel Frequency Response measurement - ath12k: a significant driver refactor to support multi-wiphy devices and and pave the way for future device support in the same driver (rather than splitting to ath13k) - ath12k: support for the QCC2072 chipset - Intel: - iwlwifi: partial Neighbor Awareness Networking (NAN) support - iwlwifi: initial support for U-NII-9 and IEEE 802.11bn - RealTek (rtw89): - preparations for RTL8922DE support - Bluetooth: - implement setsockopt(BT_PHY) to set the connection packet type/PHY - set link_policy on incoming ACL connections - Bluetooth drivers: - btusb: add support for MediaTek7920, Realtek RTL8761BU and 8851BE - btqca: add WCN6855 firmware priority selection feature" * tag 'net-next-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1254 commits) bnge/bng_re: Add a new HSI net: macb: Fix tx/rx malfunction after phy link down and up af_unix: Fix memleak of newsk in unix_stream_connect(). net: ti: icssg-prueth: Add optional dependency on HSR net: dsa: add basic initial driver for MxL862xx switches net: mdio: add unlocked mdiodev C45 bus accessors net: dsa: add tag format for MxL862xx switches dt-bindings: net: dsa: add MaxLinear MxL862xx selftests: drivers: net: hw: Modify toeplitz.c to poll for packets octeontx2-pf: Unregister devlink on probe failure net: renesas: rswitch: fix forwarding offload statemachine ionic: Rate limit unknown xcvr type messages tcp: inet6_csk_xmit() optimization tcp: populate inet->cork.fl.u.ip6 in tcp_v6_syn_recv_sock() tcp: populate inet->cork.fl.u.ip6 in tcp_v6_connect() ipv6: inet6_csk_xmit() and inet6_csk_update_pmtu() use inet->cork.fl.u.ip6 ipv6: use inet->cork.fl.u.ip6 and np->final in ip6_datagram_dst_update() ipv6: use np->final in inet6_sk_rebuild_header() ipv6: add daddr/final storage in struct ipv6_pinfo net: stmmac: qcom-ethqos: fix qcom_ethqos_serdes_powerup() ... 
Pull networking updates from Paolo Abeni:
 "Core & protocols:

   - A significant effort all around the stack to guide the compiler to
     make the right choice when inlining code, to avoid unneeded calls
     for small helper and stack canary overhead in the fast-path.

     This generates better and faster code with very small or no text
     size increases, as in many cases the call generated more code than
     the actual inlined helper.

   - Extend AccECN implementation so that is now functionally complete,
     also allow the user-space enabling it on a per network namespace
     basis.

   - Add support for memory providers with large (above 4K) rx buffer.
     Paired with hw-gro, larger rx buffer sizes reduce the number of
     buffers traversing the stack, dincreasing single stream CPU usage
     by up to ~30%.

   - Do not add HBH header to Big TCP GSO packets. This simplifies the
     RX path, the TX path and the NIC drivers, and is possible because
     user-space taps can now interpret correctly such packets without
     the HBH hint.

   - Allow IPv6 routes to be configured with a gateway address that is
     resolved out of a different interface than the one specified,
     aligning IPv6 to IPv4 behavior.

   - Multi-queue aware sch_cake. This makes it possible to scale the
     rate shaper of sch_cake across multiple CPUs, while still enforcing
     a single global rate on the interface.

   - Add support for the nbcon (new buffer console) infrastructure to
     netconsole, enabling lock-free, priority-based console operations
     that are safer in crash scenarios.

   - Improve the TCP ipv6 output path to cache the flow information,
     saving cpu cycles, reducing cache line misses and stack use.

   - Improve netfilter packet tracker to resolve clashes for most
     protocols, avoiding unneeded drops on rare occasions.

   - Add IP6IP6 tunneling acceleration to the flowtable infrastructure.

   - Reduce tcp socket size by one cache line.

   - Notify neighbour changes atomically, avoiding inconsistencies
     between the notification sequence and the actual states sequence.

   - Add vsock namespace support, allowing complete isolation of vsocks
     across different network namespaces.

   - Improve xsk generic performances with cache-alignment-oriented
     optimizations.

   - Support netconsole automatic target recovery, allowing netconsole
     to reestablish targets when underlying low-level interface comes
     back online.

  Driver API:

   - Support for switching the working mode (automatic vs manual) of a
     DPLL device via netlink.

   - Introduce PHY ports representation to expose multiple front-facing
     media ports over a single MAC.

   - Introduce "rx-polarity" and "tx-polarity" device tree properties,
     to generalize polarity inversion requirements for differential
     signaling.

   - Add helper to create, prepare and enable managed clocks.

  Device drivers:

   - Add Huawei hinic3 PF etherner driver.

   - Add DWMAC glue driver for Motorcomm YT6801 PCIe ethernet
     controller.

   - Add ethernet driver for MaxLinear MxL862xx switches

   - Remove parallel-port Ethernet driver.

   - Convert existing driver timestamp configuration reporting to
     hwtstamp_get and remove legacy ioctl().

   - Convert existing drivers to .get_rx_ring_count(), simplifing the RX
     ring count retrieval. Also remove the legacy fallback path.

   - Ethernet high-speed NICs:
      - Broadcom (bnxt, bng):
         - bnxt: add FW interface update to support FEC stats histogram
           and NVRAM defragmentation
         - bng: add TSO and H/W GRO support
      - nVidia/Mellanox (mlx5):
         - improve latency of channel restart operations, reducing the
           used H/W resources
         - add TSO support for UDP over GRE over VLAN
         - add flow counters support for hardware steering (HWS) rules
         - use a static memory area to store headers for H/W GRO,
           leading to 12% RX tput improvement
      - Intel (100G, ice, idpf):
         - ice: reorganizes layout of Tx and Rx rings for cacheline
           locality and utilizes __cacheline_group* macros on the new
           layouts
         - ice: introduces Synchronous Ethernet (SyncE) support
      - Meta (fbnic):
         - adds debugfs for firmware mailbox and tx/rx rings vectors

   - Ethernet virtual:
      - geneve: introduce GRO/GSO support for double UDP encapsulation

   - Ethernet NICs consumer, and embedded:
      - Synopsys (stmmac):
         - some code refactoring and cleanups
      - RealTek (r8169):
         - add support for RTL8127ATF (10G Fiber SFP)
         - add dash and LTR support
      - Airoha:
         - AN8811HB 2.5 Gbps phy support
      - Freescale (fec):
         - add XDP zero-copy support
      - Thunderbolt:
         - add get link setting support to allow bonding
      - Renesas:
         - add support for RZ/G3L GBETH SoC

   - Ethernet switches:
      - Maxlinear:
         - support R(G)MII slow rate configuration
         - add support for Intel GSW150
      - Motorcomm (yt921x):
         - add DCB/QoS support
      - TI:
         - icssm-prueth: support bridging (STP/RSTP) via the switchdev
           framework

   - Ethernet PHYs:
      - Realtek:
         - enable SGMII and 2500Base-X in-band auto-negotiation
         - simplify and reunify C22/C45 drivers
      - Micrel: convert bindings to DT schema

   - CAN:
      - move skb headroom content into skb extensions, making CAN
        metadata access more robust

   - CAN drivers:
      - rcar_canfd:
         - add support for FD-only mode
         - add support for the RZ/T2H SoC
      - sja1000: cleanup the CAN state handling

   - WiFi:
      - implement EPPKE/802.1X over auth frames support
      - split up drop reasons better, removing generic RX_DROP
      - additional FTM capabilities: 6 GHz support, supported number of
        spatial streams and supported number of LTF repetitions
      - better mac80211 iterators to enumerate resources
      - initial UHR (Wi-Fi 8) support for cfg80211/mac80211

   - WiFi drivers:
      - Qualcomm/Atheros:
         - ath11k: support for Channel Frequency Response measurement
         - ath12k: a significant driver refactor to support multi-wiphy
           devices and and pave the way for future device support in the
           same driver (rather than splitting to ath13k)
         - ath12k: support for the QCC2072 chipset
      - Intel:
         - iwlwifi: partial Neighbor Awareness Networking (NAN) support
         - iwlwifi: initial support for U-NII-9 and IEEE 802.11bn
      - RealTek (rtw89):
         - preparations for RTL8922DE support

   - Bluetooth:
      - implement setsockopt(BT_PHY) to set the connection packet type/PHY
      - set link_policy on incoming ACL connections

   - Bluetooth drivers:
      - btusb: add support for MediaTek7920, Realtek RTL8761BU and 8851BE
      - btqca: add WCN6855 firmware priority selection feature"

* tag 'net-next-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1254 commits)
  bnge/bng_re: Add a new HSI
  net: macb: Fix tx/rx malfunction after phy link down and up
  af_unix: Fix memleak of newsk in unix_stream_connect().
  net: ti: icssg-prueth: Add optional dependency on HSR
  net: dsa: add basic initial driver for MxL862xx switches
  net: mdio: add unlocked mdiodev C45 bus accessors
  net: dsa: add tag format for MxL862xx switches
  dt-bindings: net: dsa: add MaxLinear MxL862xx
  selftests: drivers: net: hw: Modify toeplitz.c to poll for packets
  octeontx2-pf: Unregister devlink on probe failure
  net: renesas: rswitch: fix forwarding offload statemachine
  ionic: Rate limit unknown xcvr type messages
  tcp: inet6_csk_xmit() optimization
  tcp: populate inet->cork.fl.u.ip6 in tcp_v6_syn_recv_sock()
  tcp: populate inet->cork.fl.u.ip6 in tcp_v6_connect()
  ipv6: inet6_csk_xmit() and inet6_csk_update_pmtu() use inet->cork.fl.u.ip6
  ipv6: use inet->cork.fl.u.ip6 and np->final in ip6_datagram_dst_update()
  ipv6: use np->final in inet6_sk_rebuild_header()
  ipv6: add daddr/final storage in struct ipv6_pinfo
  net: stmmac: qcom-ethqos: fix qcom_ethqos_serdes_powerup()
  ...
Merge tag 'drm-next-2026-02-11' of https://gitlab.freedesktop.org/drm/kernel 2026-02-11T20:55:44+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-02-11T20:55:44+00:00 939faf71cf7ca9ab3d1bd2912ac0e203d4d7156a Pull drm updates from Dave Airlie: "Highlights: - amdgpu support for lots of new IP blocks which means newer GPUs - xe has a lot of SR-IOV and SVM improvements - lots of intel display refactoring across i915/xe - msm has more support for gen8 platforms - Given up on kgdb/kms integration, it's too hard on modern hw core: - drop kgdb support - replace system workqueue with percpu - account for property blobs in memcg - MAINTAINERS updates for xe + buddy rust: - Fix documentation for Registration constructors - Use pin_init::zeroed() for fops initialization - Annotate DRM helpers with __rust_helper - Improve safety documentation for gem::Object::new() - Update AlwaysRefCounted imports - mm: Prevent integer overflow in page_align() atomic: - add drm_device pointer to drm_private_obj - introduce gamma/degamma LUT size check buddy: - fix free_trees memory leak - prevent BUG_ON bridge: - introduce drm_bridge_unplug/enter/exit - add connector argument to .hpd_notify - lots of recounting conversions - convert rockchip inno hdmi to bridge - lontium-lt9611uxc: switch to HDMI audio helpers - dw-hdmi-qp: add support for HPD-less setups - Algoltek AG6311 support panels: - edp: CSW MNE007QB3-1, AUO B140HAN06.4, AUO B140QAX01.H - st75751: add SPI support - Sitronix ST7920, Samsung LTL106HL02 - LG LH546WF1-ED01, HannStar HSD156J - BOE NV130WUM-T08 - Innolux G150XGE-L05 - Anbernic RG-DS dma-buf: - improve sg_table debugging - add tracepoints - call clear_page instead of memset - start to introduce cgroup memory accounting in heaps - remove sysfs stats dma-fence: - add new helpers dp: - mst: avoid oob access with vcpi=0 hdmi: - limit infoframes exposure to userspace gem: - reduce page table overhead with THP - fix leak in drm_gem_get_unmapped_area gpuvm: - API sanitation for rust bindings sched: - introduce new helpers panic: - report invalid panic modes - add kunit tests i915/xe display: - Expose sharpness only if num_scalers is >= 2 - Add initial Xe3P_LPD for NVL - BMG FBC support - Add MTL+ platforms to support dpll framework _ fix DIMM_S DRM decoding on ICL - Return to using AUX interrupts - PSR/Panel replay refactoring - use consolidation HDMI tables - Xe3_LPD CD2X dividier changes xe: - vfio: add vfio_pci for intel GPU - multi queue support - dynamic pagemaps and multi-device SVM - expose temp attribs in hwmon - NO_COMPRESSION bo flag - expose MERT OA unit - sysfs survivability refactor - SRIOV PF: add MERT support - enable SR-IOV VF migration - Enable I2C/NVM on Crescent Island - Xe3p page reclaimation support - introduce SRIOV scheduler groups - add SoC remappt support in system controller - insert compiler barriers in GuC code - define NVL GuC firmware - handle GT resume failure - fix drm scheduler layering violations - enable GSC loading and PXP for PTL - disable GuC Power DCC strategy on PTL - unregister drm device on probe error i915: - move to kernel standard fault injection - bump recommended GuC version for DG2 and MTL amdgpu: - SMUIO 15.x, PSP 15.x support - IH 6.1.1/7.1 support - MMHUB 3.4/4.2 support - GC 11.5.4/12.1 support - SDMA 6.1.4/7.1/7.11.4 support - JPEG 5.3 support - UserQ updates - GC 9 gfx queue reset support - TTM memory ops parallelization - convert legacy logging to new helpers - DC analog fixes amdkfd: - GC 11.5.4/12.1 suppport - SDMA 6.1.4/7.1 support - per context support - increase kfd process hash table - Reserved SDMA rework radeon: - convert legacy logging to new helpers - use devm for i2c adapters msm: - GPU - Document a612/RGMU dt bindings - UBWC 6.0 support (for A840 / Kaanapali) - a225 support - DPU: - Switch to use virtual planes by default - Fix DSI CMD panels on DPU 3.x - Rewrite format handling to remove intermediate representation - Fix watchdog on DPU 8.x+ - Fix TE / Vsync source setting on DPU 8.x+ - Add 3D_Mux on SC7280 - Kaanapali platform support - Fix UBWC register programming - Make RM reserve DSPP-enabled mixers for CRTCs with LMs - Gamma correction support - DP: - Enable support for eDP 1.4+ link rate tables - Fix MDSS1 DP indices on SA8775P, making them to work - Fix msm_dp_ctrl_config_msa() to work with LLVM 20 - DSI: - Document QCS8300 as compatible with SA8775P - Kaanapali platform support - DSI PHY: - switch to divider_determine_rate() - MDP5: - Drop support for MSM8998, SDM660 and SDM630 (switch over to DPU) - MDSS: - Kaanapali platform support - Fixed UBWC register programming nova-core: - Prepare for Turing support. This includes parsing and handling Turing-specific firmware headers and sections as well as a Turing Falcon HAL implementation - Get rid of the Result<impl PinInit<T, E>> anti-pattern - Relocate initializer-specific code into the appropriate initializer - Use CStr::from_bytes_until_nul() to remove custom helpers - Improve handling of unexpected firmware values - Clean up redundant debug prints - Replace c_str!() with native Rust C-string literals - Update nova-core task list nova: - Align GEM object size to system page size tyr: - Use generated uAPI bindings for GpuInfo - Replace manual sleeps with read_poll_timeout() - Replace c_str!() with native Rust C-string literals - Suppress warnings for unread fields - Fix incorrect register name in print statement nouveau: - fix big page table support races in PTE management - improve reclocking on tegra 186+ amdxdna: - fix suspend race conditions - improve handling of zero tail pointers - fix cu_idx overwritten during command setup - enable hardware context priority - remove NPU2 support - update message buffer allocation requirements - update firmware version check ast: - support imported cursor buffers - big endian fixes etnaviv: - add PPU flop reset support imagination: - add AM62P support - introduce hw version checks ivpu: - implement warm boot flow panfrost: - add bo sync ioctl - add GPU_PM_RT support for RZ/G3E SoC panthor: - add bo sync ioctl - enable timestamp propagation - scheduler robustness improvements - VM termination fixes - huge page support rockchip: - RK3368 HDMI Support - get rid of atomic_check fixups - RK3506 support - RK3576/RK3588 improved HPD handling rz-du: - RZ/V2H(P) MIPI-DSI Support v3d: - fix DMA segment size - convert to new logging helpers mediatek: - move DP training to hotplug thread - convert logging to new helpers - add support for HS speed DSI - Genio 510/700/1200-EVK, Radxa NIO-12L HDMI support atmel-hlcdc: - switch to drmm resource - support nomodeset - use newer helpers hisilicon: - fix various DP bugs renesas: - fix kernel panic on reboot exynos: - fix vidi_connection_ioctl using wrong device - fix vidi_connection deref user ptr - fix concurrency regression with vidi_context vkms: - add configfs support for display configuration * tag 'drm-next-2026-02-11' of https://gitlab.freedesktop.org/drm/kernel: (1610 commits) drm/xe/pm: Disable D3Cold for BMG only on specific platforms drm/xe: Fix kerneldoc for xe_tlb_inval_job_alloc_dep drm/xe: Fix kerneldoc for xe_gt_tlb_inval_init_early drm/xe: Fix kerneldoc for xe_migrate_exec_queue drm/xe/query: Fix topology query pointer advance drm/xe/guc: Fix kernel-doc warning in GuC scheduler ABI header drm/xe/guc: Fix CFI violation in debugfs access. accel/amdxdna: Move RPM resume into job run function accel/amdxdna: Fix incorrect DPM level after suspend/resume nouveau/vmm: start tracking if the LPT PTE is valid. (v6) nouveau/vmm: increase size of vmm pte tracker struct to u32 (v2) nouveau/vmm: rewrite pte tracker using a struct and bitfields. accel/amdxdna: Fix incorrect error code returned for failed chain command accel/amdxdna: Remove hardware context status drm/bridge: imx8qxp-pixel-combiner: Fix bailout for imx8qxp_pc_bridge_probe() drm/panel: ilitek-ili9882t: Remove duplicate initializers in tianma_il79900a_dsc drm/i915/display: fix the pixel normalization handling for xe3p_lpd drm/exynos: vidi: use ctx->lock to protect struct vidi_context member variables related to memory alloc/free drm/exynos: vidi: fix to avoid directly dereferencing user pointer drm/exynos: vidi: use priv->vidi_dev for ctx lookup in vidi_connection_ioctl() ... 
Pull drm updates from Dave Airlie:
 "Highlights:
   - amdgpu support for lots of new IP blocks which means newer GPUs
   - xe has a lot of SR-IOV and SVM improvements
   - lots of intel display refactoring across i915/xe
   - msm has more support for gen8 platforms
   - Given up on kgdb/kms integration, it's too hard on modern hw

  core:
   - drop kgdb support
   - replace system workqueue with percpu
   - account for property blobs in memcg
   - MAINTAINERS updates for xe + buddy

  rust:
   - Fix documentation for Registration constructors
   - Use pin_init::zeroed() for fops initialization
   - Annotate DRM helpers with __rust_helper
   - Improve safety documentation for gem::Object::new()
   - Update AlwaysRefCounted imports
   - mm: Prevent integer overflow in page_align()

  atomic:
   - add drm_device pointer to drm_private_obj
   - introduce gamma/degamma LUT size check

  buddy:
   - fix free_trees memory leak
   - prevent BUG_ON

  bridge:
   - introduce drm_bridge_unplug/enter/exit
   - add connector argument to .hpd_notify
   - lots of recounting conversions
   - convert rockchip inno hdmi to bridge
   - lontium-lt9611uxc: switch to HDMI audio helpers
   - dw-hdmi-qp: add support for HPD-less setups
   - Algoltek AG6311 support

  panels:
   - edp: CSW MNE007QB3-1, AUO B140HAN06.4, AUO B140QAX01.H
   - st75751: add SPI support
   - Sitronix ST7920, Samsung LTL106HL02
   - LG LH546WF1-ED01, HannStar HSD156J
   - BOE NV130WUM-T08
   - Innolux G150XGE-L05
   - Anbernic RG-DS

  dma-buf:
   - improve sg_table debugging
   - add tracepoints
   - call clear_page instead of memset
   - start to introduce cgroup memory accounting in heaps
   - remove sysfs stats

  dma-fence:
   - add new helpers

  dp:
   - mst: avoid oob access with vcpi=0

  hdmi:
   - limit infoframes exposure to userspace

  gem:
   - reduce page table overhead with THP
   - fix leak in drm_gem_get_unmapped_area

  gpuvm:
   - API sanitation for rust bindings

  sched:
   - introduce new helpers

  panic:
   - report invalid panic modes
   - add kunit tests

  i915/xe display:
   - Expose sharpness only if num_scalers is >= 2
   - Add initial Xe3P_LPD for NVL
   - BMG FBC support
   - Add MTL+ platforms to support dpll framework
   _ fix DIMM_S DRM decoding on ICL
   - Return to using AUX interrupts
   - PSR/Panel replay refactoring
   - use consolidation HDMI tables
   - Xe3_LPD CD2X dividier changes

  xe:
   - vfio: add vfio_pci for intel GPU
   - multi queue support
   - dynamic pagemaps and multi-device SVM
   - expose temp attribs in hwmon
   - NO_COMPRESSION bo flag
   - expose MERT OA unit
   - sysfs survivability refactor
   - SRIOV PF: add MERT support
   - enable SR-IOV VF migration
   - Enable I2C/NVM on Crescent Island
   - Xe3p page reclaimation support
   - introduce SRIOV scheduler groups
   - add SoC remappt support in system controller
   - insert compiler barriers in GuC code
   - define NVL GuC firmware
   - handle GT resume failure
   - fix drm scheduler layering violations
   - enable GSC loading and PXP for PTL
   - disable GuC Power DCC strategy on PTL
   - unregister drm device on probe error

  i915:
   - move to kernel standard fault injection
   - bump recommended GuC version for DG2 and MTL

  amdgpu:
   - SMUIO 15.x, PSP 15.x support
   - IH 6.1.1/7.1 support
   - MMHUB 3.4/4.2 support
   - GC 11.5.4/12.1 support
   - SDMA 6.1.4/7.1/7.11.4 support
   - JPEG 5.3 support
   - UserQ updates
   - GC 9 gfx queue reset support
   - TTM memory ops parallelization
   - convert legacy logging to new helpers
   - DC analog fixes

  amdkfd:
   - GC 11.5.4/12.1 suppport
   - SDMA 6.1.4/7.1 support
   - per context support
   - increase kfd process hash table
   - Reserved SDMA rework

  radeon:
   - convert legacy logging to new helpers
   - use devm for i2c adapters

  msm:
   - GPU
      - Document a612/RGMU dt bindings
      - UBWC 6.0 support (for A840 / Kaanapali)
      - a225 support
   - DPU:
      - Switch to use virtual planes by default
      - Fix DSI CMD panels on DPU 3.x
      - Rewrite format handling to remove intermediate representation
      - Fix watchdog on DPU 8.x+
      - Fix TE / Vsync source setting on DPU 8.x+
      - Add 3D_Mux on SC7280
      - Kaanapali platform support
      - Fix UBWC register programming
      - Make RM reserve DSPP-enabled mixers for CRTCs with LMs
      - Gamma correction support
   - DP:
      - Enable support for eDP 1.4+ link rate tables
      - Fix MDSS1 DP indices on SA8775P, making them to work
      - Fix msm_dp_ctrl_config_msa() to work with LLVM 20
   - DSI:
      - Document QCS8300 as compatible with SA8775P
      - Kaanapali platform support
   - DSI PHY:
      - switch to divider_determine_rate()
   - MDP5:
      - Drop support for MSM8998, SDM660 and SDM630 (switch over to DPU)
   -  MDSS:
      - Kaanapali platform support
      - Fixed UBWC register programming

  nova-core:
   - Prepare for Turing support. This includes parsing and handling
     Turing-specific firmware headers and sections as well as a Turing
     Falcon HAL implementation
   - Get rid of the Result<impl PinInit<T, E>> anti-pattern
   - Relocate initializer-specific code into the appropriate initializer
   - Use CStr::from_bytes_until_nul() to remove custom helpers
   - Improve handling of unexpected firmware values
   - Clean up redundant debug prints
   - Replace c_str!() with native Rust C-string literals
   - Update nova-core task list

  nova:
   - Align GEM object size to system page size

  tyr:
   - Use generated uAPI bindings for GpuInfo
   - Replace manual sleeps with read_poll_timeout()
   - Replace c_str!() with native Rust C-string literals
   - Suppress warnings for unread fields
   - Fix incorrect register name in print statement

  nouveau:
   - fix big page table support races in PTE management
   - improve reclocking on tegra 186+

  amdxdna:
   - fix suspend race conditions
   - improve handling of zero tail pointers
   - fix cu_idx overwritten during command setup
   - enable hardware context priority
   - remove NPU2 support
   - update message buffer allocation requirements
   - update firmware version check

  ast:
   - support imported cursor buffers
   - big endian fixes

  etnaviv:
   - add PPU flop reset support

  imagination:
   - add AM62P support
   - introduce hw version checks

  ivpu:
   - implement warm boot flow

  panfrost:
   - add bo sync ioctl
   - add GPU_PM_RT support for RZ/G3E SoC

  panthor:
   - add bo sync ioctl
   - enable timestamp propagation
   - scheduler robustness improvements
   - VM termination fixes
   - huge page support

  rockchip:
   - RK3368 HDMI Support
   - get rid of atomic_check fixups
   - RK3506 support
   - RK3576/RK3588 improved HPD handling

  rz-du:
   - RZ/V2H(P) MIPI-DSI Support

  v3d:
   - fix DMA segment size
   - convert to new logging helpers

  mediatek:
   - move DP training to hotplug thread
   - convert logging to new helpers
   - add support for HS speed DSI
   - Genio 510/700/1200-EVK, Radxa NIO-12L HDMI support

  atmel-hlcdc:
   - switch to drmm resource
   - support nomodeset
   - use newer helpers

  hisilicon:
   - fix various DP bugs

  renesas:
   - fix kernel panic on reboot

  exynos:
   - fix vidi_connection_ioctl using wrong device
   - fix vidi_connection deref user ptr
   - fix concurrency regression with vidi_context

  vkms:
   - add configfs support for display configuration

* tag 'drm-next-2026-02-11' of https://gitlab.freedesktop.org/drm/kernel: (1610 commits)
  drm/xe/pm: Disable D3Cold for BMG only on specific platforms
  drm/xe: Fix kerneldoc for xe_tlb_inval_job_alloc_dep
  drm/xe: Fix kerneldoc for xe_gt_tlb_inval_init_early
  drm/xe: Fix kerneldoc for xe_migrate_exec_queue
  drm/xe/query: Fix topology query pointer advance
  drm/xe/guc: Fix kernel-doc warning in GuC scheduler ABI header
  drm/xe/guc: Fix CFI violation in debugfs access.
  accel/amdxdna: Move RPM resume into job run function
  accel/amdxdna: Fix incorrect DPM level after suspend/resume
  nouveau/vmm: start tracking if the LPT PTE is valid. (v6)
  nouveau/vmm: increase size of vmm pte tracker struct to u32 (v2)
  nouveau/vmm: rewrite pte tracker using a struct and bitfields.
  accel/amdxdna: Fix incorrect error code returned for failed chain command
  accel/amdxdna: Remove hardware context status
  drm/bridge: imx8qxp-pixel-combiner: Fix bailout for imx8qxp_pc_bridge_probe()
  drm/panel: ilitek-ili9882t: Remove duplicate initializers in tianma_il79900a_dsc
  drm/i915/display: fix the pixel normalization handling for xe3p_lpd
  drm/exynos: vidi: use ctx->lock to protect struct vidi_context member variables related to memory alloc/free
  drm/exynos: vidi: fix to avoid directly dereferencing user pointer
  drm/exynos: vidi: use priv->vidi_dev for ctx lookup in vidi_connection_ioctl()
  ...
printk: Add execution context (task name/CPU) to printk_info 2026-02-11T03:51:56+00:00 Breno Leitao leitao@debian.org 2026-02-06T12:45:29+00:00 60325c27d3cfe13466f6d6aa882b11bdd1c58cc8 Extend struct printk_info to include the task name, pid, and CPU number where printk messages originate. This information is captured at vprintk_store() time and propagated through printk_message to nbcon_write_context, making it available to nbcon console drivers. This is useful for consoles like netconsole that want to include execution context in their output, allowing correlation of messages with specific tasks and CPUs regardless of where the console driver actually runs. The feature is controlled by CONFIG_PRINTK_EXECUTION_CTX, which is automatically selected by CONFIG_NETCONSOLE_DYNAMIC. When disabled, the helper functions compile to no-ops with no overhead. Suggested-by: John Ogness <john.ogness@linutronix.de> Signed-off-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: John Ogness <john.ogness@linutronix.de> Link: https://patch.msgid.link/20260206-nbcon-v7-1-62bda69b1b41@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Extend struct printk_info to include the task name, pid, and CPU
number where printk messages originate. This information is captured
at vprintk_store() time and propagated through printk_message to
nbcon_write_context, making it available to nbcon console drivers.

This is useful for consoles like netconsole that want to include
execution context in their output, allowing correlation of messages
with specific tasks and CPUs regardless of where the console driver
actually runs.

The feature is controlled by CONFIG_PRINTK_EXECUTION_CTX, which is
automatically selected by CONFIG_NETCONSOLE_DYNAMIC. When disabled,
the helper functions compile to no-ops with no overhead.

Suggested-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20260206-nbcon-v7-1-62bda69b1b41@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
printk: Move locking annotation to printk.c 2026-01-05T15:43:36+00:00 Marco Elver elver@google.com 2025-12-19T15:40:22+00:00 8ec56d9aaba9667b0c6429de7aeb4ec691944a5e With Sparse support gone, Clang is a bit more strict and warns: ./include/linux/console.h:492:50: error: use of undeclared identifier 'console_mutex' 492 | extern void console_list_unlock(void) __releases(console_mutex); Since it does not make sense to make console_mutex itself global, move the annotation to printk.c. Context analysis remains disabled for printk.c. This is needed to enable context analysis for modules that include <linux/console.h>. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20251219154418.3592607-34-elver@google.com 
With Sparse support gone, Clang is a bit more strict and warns:

./include/linux/console.h:492:50: error: use of undeclared identifier 'console_mutex'
  492 | extern void console_list_unlock(void) __releases(console_mutex);

Since it does not make sense to make console_mutex itself global, move
the annotation to printk.c. Context analysis remains disabled for
printk.c.

This is needed to enable context analysis for modules that include
<linux/console.h>.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-34-elver@google.com
vt: Remove con_debug_enter/_leave from struct consw 2025-12-21T17:24:53+00:00 Thomas Zimmermann tzimmermann@suse.de 2025-12-08T10:17:34+00:00 c83e42990303c05e60001d636212502ed5a2d48a There are no implementations of con_debug_enter and con_debug_leave. Remove the callbacks from struct consw and clean up the caller. This is a functional revert of commit b45cfba4e900 ("vt,console,kdb: implement atomic console enter/leave functions"). Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://patch.msgid.link/20251208102851.40894-3-tzimmermann@suse.de 
There are no implementations of con_debug_enter and con_debug_leave.
Remove the callbacks from struct consw and clean up the caller.

This is a functional revert of commit b45cfba4e900 ("vt,console,kdb:
implement atomic console enter/leave functions").

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20251208102851.40894-3-tzimmermann@suse.de
Merge tag 'printk-for-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux 2025-12-03T20:42:36+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-12-03T20:42:36+00:00 4d38b88fd17e9989429e65420bf3c33ca53b2085 Pull printk updates from Petr Mladek: - Allow creaing nbcon console drivers with an unsafe write_atomic() callback that can only be called by the final nbcon_atomic_flush_unsafe(). Otherwise, the driver would rely on the kthread. It is going to be used as the-best-effort approach for an experimental nbcon netconsole driver, see https://lore.kernel.org/r/20251121-nbcon-v1-2-503d17b2b4af@debian.org Note that a safe .write_atomic() callback is supposed to work in NMI context. But some networking drivers are not safe even in IRQ context: https://lore.kernel.org/r/oc46gdpmmlly5o44obvmoatfqo5bhpgv7pabpvb6sjuqioymcg@gjsma3ghoz35 In an ideal world, all networking drivers would be fixed first and the atomic flush would be blocked only in NMI context. But it brings the question how reliable networking drivers are when the system is in a bad state. They might block flushing more reliable serial consoles which are more suitable for serious debugging anyway. - Allow to use the last 4 bytes of the printk ring buffer. - Prevent queuing IRQ work and block printk kthreads when consoles are suspended. Otherwise, they create non-necessary churn or even block the suspend. - Release console_lock() between each record in the kthread used for legacy consoles on RT. It might significantly speed up the boot. - Release nbcon context between each record in the atomic flush. It prevents stalls of the related printk kthread after it has lost the ownership in the middle of a record - Add support for NBCON consoles into KDB - Add %ptsP modifier for printing struct timespec64 and use it where possible - Misc code clean up * tag 'printk-for-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (48 commits) printk: Use console_is_usable on console_unblank arch: um: kmsg_dump: Use console_is_usable drivers: serial: kgdboc: Drop checks for CON_ENABLED and CON_BOOT lib/vsprintf: Unify FORMAT_STATE_NUM handlers printk: Avoid irq_work for printk_deferred() on suspend printk: Avoid scheduling irq_work on suspend printk: Allow printk_trigger_flush() to flush all types tracing: Switch to use %ptSp scsi: snic: Switch to use %ptSp scsi: fnic: Switch to use %ptSp s390/dasd: Switch to use %ptSp ptp: ocp: Switch to use %ptSp pps: Switch to use %ptSp PCI: epf-test: Switch to use %ptSp net: dsa: sja1105: Switch to use %ptSp mmc: mmc_test: Switch to use %ptSp media: av7110: Switch to use %ptSp ipmi: Switch to use %ptSp igb: Switch to use %ptSp e1000e: Switch to use %ptSp ... 
Pull printk updates from Petr Mladek:

 - Allow creaing nbcon console drivers with an unsafe write_atomic()
   callback that can only be called by the final nbcon_atomic_flush_unsafe().
   Otherwise, the driver would rely on the kthread.

   It is going to be used as the-best-effort approach for an
   experimental nbcon netconsole driver, see

     https://lore.kernel.org/r/20251121-nbcon-v1-2-503d17b2b4af@debian.org

   Note that a safe .write_atomic() callback is supposed to work in NMI
   context. But some networking drivers are not safe even in IRQ
   context:

     https://lore.kernel.org/r/oc46gdpmmlly5o44obvmoatfqo5bhpgv7pabpvb6sjuqioymcg@gjsma3ghoz35

   In an ideal world, all networking drivers would be fixed first and
   the atomic flush would be blocked only in NMI context. But it brings
   the question how reliable networking drivers are when the system is
   in a bad state. They might block flushing more reliable serial
   consoles which are more suitable for serious debugging anyway.

 - Allow to use the last 4 bytes of the printk ring buffer.

 - Prevent queuing IRQ work and block printk kthreads when consoles are
   suspended. Otherwise, they create non-necessary churn or even block
   the suspend.

 - Release console_lock() between each record in the kthread used for
   legacy consoles on RT. It might significantly speed up the boot.

 - Release nbcon context between each record in the atomic flush. It
   prevents stalls of the related printk kthread after it has lost the
   ownership in the middle of a record

 - Add support for NBCON consoles into KDB

 - Add %ptsP modifier for printing struct timespec64 and use it where
   possible

 - Misc code clean up

* tag 'printk-for-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (48 commits)
  printk: Use console_is_usable on console_unblank
  arch: um: kmsg_dump: Use console_is_usable
  drivers: serial: kgdboc: Drop checks for CON_ENABLED and CON_BOOT
  lib/vsprintf: Unify FORMAT_STATE_NUM handlers
  printk: Avoid irq_work for printk_deferred() on suspend
  printk: Avoid scheduling irq_work on suspend
  printk: Allow printk_trigger_flush() to flush all types
  tracing: Switch to use %ptSp
  scsi: snic: Switch to use %ptSp
  scsi: fnic: Switch to use %ptSp
  s390/dasd: Switch to use %ptSp
  ptp: ocp: Switch to use %ptSp
  pps: Switch to use %ptSp
  PCI: epf-test: Switch to use %ptSp
  net: dsa: sja1105: Switch to use %ptSp
  mmc: mmc_test: Switch to use %ptSp
  media: av7110: Switch to use %ptSp
  ipmi: Switch to use %ptSp
  igb: Switch to use %ptSp
  e1000e: Switch to use %ptSp
  ...
printk: nbcon: Allow unsafe write_atomic() for panic 2025-11-07T13:30:52+00:00 John Ogness john.ogness@linutronix.de 2025-10-27T16:12:03+00:00 187de7c212e5fa87779e1026bf949337bca0cdaa There may be console drivers that have not yet figured out a way to implement safe atomic printing (->write_atomic() callback). These drivers could choose to only implement threaded printing (->write_thread() callback), but then it is guaranteed that _no_ output will be printed during panic. Not even attempted. As a result, developers may be tempted to implement unsafe ->write_atomic() callbacks and/or implement some sort of custom deferred printing trickery to try to make it work. This goes against the principle intention of the nbcon API as well as endangers other nbcon drivers that are doing things correctly (safely). As a compromise, allow nbcon drivers to implement unsafe ->write_atomic() callbacks by providing a new console flag CON_NBCON_ATOMIC_UNSAFE. When specified, the ->write_atomic() callback for that console will _only_ be called during the final "hope and pray" flush attempt at the end of a panic: nbcon_atomic_flush_unsafe(). Signed-off-by: John Ogness <john.ogness@linutronix.de> Link: https://lore.kernel.org/lkml/b2qps3uywhmjaym4mht2wpxul4yqtuuayeoq4iv4k3zf5wdgh3@tocu6c7mj4lt Reviewed-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/all/swdpckuwwlv3uiessmtnf2jwlx3jusw6u7fpk5iggqo4t2vdws@7rpjso4gr7qp/ [1] Link: https://lore.kernel.org/all/20251103-fix_netpoll_aa-v4-1-4cfecdf6da7c@debian.org/ [2] Link: https://patch.msgid.link/20251027161212.334219-2-john.ogness@linutronix.de [pmladek@suse.com: Fix build with rework/nbcon-in-kdb branch.] Signed-off-by: Petr Mladek <pmladek@suse.com> 
There may be console drivers that have not yet figured out a way
to implement safe atomic printing (->write_atomic() callback).
These drivers could choose to only implement threaded printing
(->write_thread() callback), but then it is guaranteed that _no_
output will be printed during panic. Not even attempted.

As a result, developers may be tempted to implement unsafe
->write_atomic() callbacks and/or implement some sort of custom
deferred printing trickery to try to make it work. This goes
against the principle intention of the nbcon API as well as
endangers other nbcon drivers that are doing things correctly
(safely).

As a compromise, allow nbcon drivers to implement unsafe
->write_atomic() callbacks by providing a new console flag
CON_NBCON_ATOMIC_UNSAFE. When specified, the ->write_atomic()
callback for that console will _only_ be called during the
final "hope and pray" flush attempt at the end of a panic:
nbcon_atomic_flush_unsafe().

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/lkml/b2qps3uywhmjaym4mht2wpxul4yqtuuayeoq4iv4k3zf5wdgh3@tocu6c7mj4lt
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/all/swdpckuwwlv3uiessmtnf2jwlx3jusw6u7fpk5iggqo4t2vdws@7rpjso4gr7qp/ [1]
Link: https://lore.kernel.org/all/20251103-fix_netpoll_aa-v4-1-4cfecdf6da7c@debian.org/ [2]
Link: https://patch.msgid.link/20251027161212.334219-2-john.ogness@linutronix.de
[pmladek@suse.com: Fix build with rework/nbcon-in-kdb branch.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
kdb: Adapt kdb_msg_write to work with NBCON consoles 2025-10-24T10:56:20+00:00 Marcos Paulo de Souza mpdesouza@suse.com 2025-10-16T14:47:58+00:00 62627bf0cadf6eae87d92fecf604c42160fe16ef Function kdb_msg_write was calling con->write for any found console, but it won't work on NBCON consoles. In this case we should acquire the ownership of the console using NBCON_PRIO_EMERGENCY, since printing kdb messages should only be interrupted by a panic. At this point, the console is required to use the atomic callback. The console is skipped if the write_atomic callback is not set or if the context could not be acquired. The validation of NBCON is done by the console_is_usable helper. The context is released right after write_atomic finishes. The oops_in_progress handling is only needed in the legacy consoles, so it was moved around the con->write callback. Suggested-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: John Ogness <john.ogness@linutronix.de> Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com> Link: https://patch.msgid.link/20251016-nbcon-kgdboc-v6-5-866aac60a80e@suse.com [pmladek@suse.com: Fixed compilation with !CONFIG_PRINTK.] Signed-off-by: Petr Mladek <pmladek@suse.com> 
Function kdb_msg_write was calling con->write for any found console,
but it won't work on NBCON consoles. In this case we should acquire the
ownership of the console using NBCON_PRIO_EMERGENCY, since printing
kdb messages should only be interrupted by a panic.

At this point, the console is required to use the atomic callback. The
console is skipped if the write_atomic callback is not set or if the
context could not be acquired. The validation of NBCON is done by the
console_is_usable helper. The context is released right after
write_atomic finishes.

The oops_in_progress handling is only needed in the legacy consoles,
so it was moved around the con->write callback.

Suggested-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Link: https://patch.msgid.link/20251016-nbcon-kgdboc-v6-5-866aac60a80e@suse.com
[pmladek@suse.com: Fixed compilation with !CONFIG_PRINTK.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
printk: nbcon: Export nbcon_write_context_set_buf 2025-10-24T10:56:19+00:00 Marcos Paulo de Souza mpdesouza@suse.com 2025-10-16T14:47:57+00:00 4349cf0df34f37d2470d246bc9be8d9836dfa49e This function will be used in the next patch to allow a driver to set both the message and message length of a nbcon_write_context. This is necessary because the function also initializes the ->unsafe_takeover struct member. By using this helper we ensure that the struct is initialized correctly. Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: John Ogness <john.ogness@linutronix.de> Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com> Link: https://patch.msgid.link/20251016-nbcon-kgdboc-v6-4-866aac60a80e@suse.com Signed-off-by: Petr Mladek <pmladek@suse.com> 
This function will be used in the next patch to allow a driver to set
both the message and message length of a nbcon_write_context. This is
necessary because the function also initializes the ->unsafe_takeover
struct member. By using this helper we ensure that the struct is
initialized correctly.

Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Link: https://patch.msgid.link/20251016-nbcon-kgdboc-v6-4-866aac60a80e@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>