This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
* Removed macros from proc handler converters
Replace the proc converter macros with "regular" functions. Though it is more
verbose than the macro version, it helps when debugging and better aligns with
coding-style.rst.
* General cleanup
Remove superfluous ctl_table forward declarations. Const qualify the
memory_allocation_profiling_sysctl and loadpin_sysctl_table arrays. Add
missing kernel doc to proc_dointvec_conv.
* Testing
This series was run through sysctl selftests/kunit test suite in
x86_64. And went into linux-next after rc4, giving it a good 3 weeks of
testing
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Merge tag 'sysctl-7.00-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl
Pull sysctl updates from Joel Granados:
- Remove macros from proc handler converters
Replace the proc converter macros with "regular" functions. Though it
is more verbose than the macro version, it helps when debugging and
better aligns with coding-style.rst.
- General cleanup
Remove superfluous ctl_table forward declarations. Const qualify the
memory_allocation_profiling_sysctl and loadpin_sysctl_table arrays.
Add missing kernel doc to proc_dointvec_conv.
- Testing
This series was run through sysctl selftests/kunit test suite in
x86_64. And went into linux-next after rc4, giving it a good 3 weeks
of testing
* tag 'sysctl-7.00-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl:
sysctl: replace SYSCTL_INT_CONV_CUSTOM macro with functions
sysctl: Replace unidirectional INT converter macros with functions
sysctl: Add kernel doc to proc_douintvec_conv
sysctl: Replace UINT converter macros with functions
sysctl: Add CONFIG_PROC_SYSCTL guards for converter macros
sysctl: clarify proc_douintvec_minmax doc
sysctl: Return -ENOSYS from proc_douintvec_conv when CONFIG_PROC_SYSCTL=n
sysctl: Remove unused ctl_table forward declarations
loadpin: Implement custom proc_handler for enforce
alloc_tag: move memory_allocation_profiling_sysctls into .rodata
sysctl: Add missing kernel-doc for proc_dointvec_conv
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 8d91f8b153 ("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: 5f53ca3ff8 ("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>
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
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-next-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
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()
...
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>
Lock debugging:
- Implement compiler-driven static analysis locking context
checking, using the upcoming Clang 22 compiler's context
analysis features. (Marco Elver)
We removed Sparse context analysis support, because prior to
removal even a defconfig kernel produced 1,700+ context
tracking Sparse warnings, the overwhelming majority of which
are false positives. On an allmodconfig kernel the number of
false positive context tracking Sparse warnings grows to
over 5,200... On the plus side of the balance actual locking
bugs found by Sparse context analysis is also rather ... sparse:
I found only 3 such commits in the last 3 years. So the
rate of false positives and the maintenance overhead is
rather high and there appears to be no active policy in
place to achieve a zero-warnings baseline to move the
annotations & fixers to developers who introduce new code.
Clang context analysis is more complete and more aggressive
in trying to find bugs, at least in principle. Plus it has
a different model to enabling it: it's enabled subsystem by
subsystem, which results in zero warnings on all relevant
kernel builds (as far as our testing managed to cover it).
Which allowed us to enable it by default, similar to other
compiler warnings, with the expectation that there are no
warnings going forward. This enforces a zero-warnings baseline
on clang-22+ builds. (Which are still limited in distribution,
admittedly.)
Hopefully the Clang approach can lead to a more maintainable
zero-warnings status quo and policy, with more and more
subsystems and drivers enabling the feature. Context tracking
can be enabled for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y
(default disabled), but this will generate a lot of false positives.
( Having said that, Sparse support could still be added back,
if anyone is interested - the removal patch is still
relatively straightforward to revert at this stage. )
Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng)
- Add support for Atomic<i8/i16/bool> and replace most Rust native
AtomicBool usages with Atomic<bool>
- Clean up LockClassKey and improve its documentation
- Add missing Send and Sync trait implementation for SetOnce
- Make ARef Unpin as it is supposed to be
- Add __rust_helper to a few Rust helpers as a preparation for
helper LTO
- Inline various lock related functions to avoid additional
function calls.
WW mutexes:
- Extend ww_mutex tests and other test-ww_mutex updates (John Stultz)
Misc fixes and cleanups:
- rcu: Mark lockdep_assert_rcu_helper() __always_inline
(Arnd Bergmann)
- locking/local_lock: Include more missing headers (Peter Zijlstra)
- seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap)
- rust: sync: Replace `kernel::c_str!` with C-Strings
(Tamir Duberstein)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"Lock debugging:
- Implement compiler-driven static analysis locking context checking,
using the upcoming Clang 22 compiler's context analysis features
(Marco Elver)
We removed Sparse context analysis support, because prior to
removal even a defconfig kernel produced 1,700+ context tracking
Sparse warnings, the overwhelming majority of which are false
positives. On an allmodconfig kernel the number of false positive
context tracking Sparse warnings grows to over 5,200... On the plus
side of the balance actual locking bugs found by Sparse context
analysis is also rather ... sparse: I found only 3 such commits in
the last 3 years. So the rate of false positives and the
maintenance overhead is rather high and there appears to be no
active policy in place to achieve a zero-warnings baseline to move
the annotations & fixers to developers who introduce new code.
Clang context analysis is more complete and more aggressive in
trying to find bugs, at least in principle. Plus it has a different
model to enabling it: it's enabled subsystem by subsystem, which
results in zero warnings on all relevant kernel builds (as far as
our testing managed to cover it). Which allowed us to enable it by
default, similar to other compiler warnings, with the expectation
that there are no warnings going forward. This enforces a
zero-warnings baseline on clang-22+ builds (Which are still limited
in distribution, admittedly)
Hopefully the Clang approach can lead to a more maintainable
zero-warnings status quo and policy, with more and more subsystems
and drivers enabling the feature. Context tracking can be enabled
for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y (default
disabled), but this will generate a lot of false positives.
( Having said that, Sparse support could still be added back,
if anyone is interested - the removal patch is still
relatively straightforward to revert at this stage. )
Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng)
- Add support for Atomic<i8/i16/bool> and replace most Rust native
AtomicBool usages with Atomic<bool>
- Clean up LockClassKey and improve its documentation
- Add missing Send and Sync trait implementation for SetOnce
- Make ARef Unpin as it is supposed to be
- Add __rust_helper to a few Rust helpers as a preparation for
helper LTO
- Inline various lock related functions to avoid additional function
calls
WW mutexes:
- Extend ww_mutex tests and other test-ww_mutex updates (John
Stultz)
Misc fixes and cleanups:
- rcu: Mark lockdep_assert_rcu_helper() __always_inline (Arnd
Bergmann)
- locking/local_lock: Include more missing headers (Peter Zijlstra)
- seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap)
- rust: sync: Replace `kernel::c_str!` with C-Strings (Tamir
Duberstein)"
* tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits)
locking/rwlock: Fix write_trylock_irqsave() with CONFIG_INLINE_WRITE_TRYLOCK
rcu: Mark lockdep_assert_rcu_helper() __always_inline
compiler-context-analysis: Remove __assume_ctx_lock from initializers
tomoyo: Use scoped init guard
crypto: Use scoped init guard
kcov: Use scoped init guard
compiler-context-analysis: Introduce scoped init guards
cleanup: Make __DEFINE_LOCK_GUARD handle commas in initializers
seqlock: fix scoped_seqlock_read kernel-doc
tools: Update context analysis macros in compiler_types.h
rust: sync: Replace `kernel::c_str!` with C-Strings
rust: sync: Inline various lock related methods
rust: helpers: Move #define __rust_helper out of atomic.c
rust: wait: Add __rust_helper to helpers
rust: time: Add __rust_helper to helpers
rust: task: Add __rust_helper to helpers
rust: sync: Add __rust_helper to helpers
rust: refcount: Add __rust_helper to helpers
rust: rcu: Add __rust_helper to helpers
rust: processor: Add __rust_helper to helpers
...
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Merge tag 'printk-for-6.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk fix from Petr Mladek:
- Prevent softlockup by restoring IRQs in atomic flush after each
record
* tag 'printk-for-6.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk/nbcon: Restore IRQ in atomic flush after each emitted record
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
Remove superfluous forward declarations of ctl_table from header files
where they are no longer needed. These declarations were left behind
after sysctl code refactoring and cleanup.
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Muchun Song <muchun.song@linux.dev>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Joel Granados <joel.granados@kernel.org>
The commit d5d399efff ("printk/nbcon: Release nbcon consoles ownership
in atomic flush after each emitted record") prevented stall of a CPU
which lost nbcon console ownership because another CPU entered
an emergency flush.
But there is still the problem that the CPU doing the emergency flush
might cause a stall on its own.
Let's go even further and restore IRQ in the atomic flush after
each emitted record.
It is not a complete solution. The interrupts and/or scheduling might
still be blocked when the emergency atomic flush was called with
IRQs and/or scheduling disabled. But it should remove the following
lockup:
mlx5_core 0000:03:00.0: Shutdown was called
kvm: exiting hardware virtualization
arm-smmu-v3 arm-smmu-v3.10.auto: CMD_SYNC timeout at 0x00000103 [hwprod 0x00000104, hwcons 0x00000102]
smp: csd: Detected non-responsive CSD lock (#1) on CPU#4, waiting 5000000032 ns for CPU#00 do_nothing (kernel/smp.c:1057)
smp: csd: CSD lock (#1) unresponsive.
[...]
Call trace:
pl011_console_write_atomic (./arch/arm64/include/asm/vdso/processor.h:12 drivers/tty/serial/amba-pl011.c:2540) (P)
nbcon_emit_next_record (kernel/printk/nbcon.c:1049)
__nbcon_atomic_flush_pending_con (kernel/printk/nbcon.c:1517)
__nbcon_atomic_flush_pending.llvm.15488114865160659019 (./arch/arm64/include/asm/alternative-macros.h:254 ./arch/arm64/include/asm/cpufeature.h:808 ./arch/arm64/include/asm/irqflags.h:192 kernel/printk/nbcon.c:1562 kernel/printk/nbcon.c:1612)
nbcon_atomic_flush_pending (kernel/printk/nbcon.c:1629)
printk_kthreads_shutdown (kernel/printk/printk.c:?)
syscore_shutdown (drivers/base/syscore.c:120)
kernel_kexec (kernel/kexec_core.c:1045)
__arm64_sys_reboot (kernel/reboot.c:794 kernel/reboot.c:722 kernel/reboot.c:722)
invoke_syscall (arch/arm64/kernel/syscall.c:50)
el0_svc_common.llvm.14158405452757855239 (arch/arm64/kernel/syscall.c:?)
do_el0_svc (arch/arm64/kernel/syscall.c:152)
el0_svc (./arch/arm64/include/asm/alternative-macros.h:254 ./arch/arm64/include/asm/cpufeature.h:808 ./arch/arm64/include/asm/irqflags.h:73 arch/arm64/kernel/entry-common.c:169 arch/arm64/kernel/entry-common.c:182 arch/arm64/kernel/entry-common.c:749)
el0t_64_sync_handler (arch/arm64/kernel/entry-common.c:820)
el0t_64_sync (arch/arm64/kernel/entry.S:600)
In this case, nbcon_atomic_flush_pending() is called from
printk_kthreads_shutdown() with IRQs and scheduling enabled.
Note that __nbcon_atomic_flush_pending_con() is directly called also from
nbcon_device_release() where the disabled IRQs might break PREEMPT_RT
guarantees. But the atomic flush is called only in emergency or panic
situations where the latencies are irrelevant anyway.
An ultimate solution would be a touching of watchdogs. But it would hide
all problems. Let's do it later when anyone reports a stall which does
not have a better solution.
Closes: https://lore.kernel.org/r/sqwajvt7utnt463tzxgwu2yctyn5m6bjwrslsnupfexeml6hkd@v6sqmpbu3vvu
Tested-by: Breno Leitao <leitao@debian.org>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20251212124520.244483-1-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
These callbacks are necessary to synchronize ->write_thread callback
against other operations using the same device.
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20251208-nbcon-device-cb-fix-v2-1-36be8d195123@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
This is the first half of the driver changes:
- A treewide interface change to the "syscore" operations for
power management, as a preparation for future Tegra specific
changes.
- Reset controller updates with added drivers for LAN969x, eic770
and RZ/G3S SoCs.
- Protection of system controller registers on Renesas and Google SoCs,
to prevent trivially triggering a system crash from e.g. debugfs
access.
- soc_device identification updates on Nvidia, Exynos and Mediatek
- debugfs support in the ST STM32 firewall driver
- Minor updates for SoC drivers on AMD/Xilinx, Renesas, Allwinner, TI
- Cleanups for memory controller support on Nvidia and Renesas
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Merge tag 'soc-drivers-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc
Pull SoC driver updates from Arnd Bergmann:
"This is the first half of the driver changes:
- A treewide interface change to the "syscore" operations for power
management, as a preparation for future Tegra specific changes
- Reset controller updates with added drivers for LAN969x, eic770 and
RZ/G3S SoCs
- Protection of system controller registers on Renesas and Google
SoCs, to prevent trivially triggering a system crash from e.g.
debugfs access
- soc_device identification updates on Nvidia, Exynos and Mediatek
- debugfs support in the ST STM32 firewall driver
- Minor updates for SoC drivers on AMD/Xilinx, Renesas, Allwinner, TI
- Cleanups for memory controller support on Nvidia and Renesas"
* tag 'soc-drivers-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (114 commits)
memory: tegra186-emc: Fix missing put_bpmp
Documentation: reset: Remove reset_controller_add_lookup()
reset: fix BIT macro reference
reset: rzg2l-usbphy-ctrl: Fix a NULL vs IS_ERR() bug in probe
reset: th1520: Support reset controllers in more subsystems
reset: th1520: Prepare for supporting multiple controllers
dt-bindings: reset: thead,th1520-reset: Add controllers for more subsys
dt-bindings: reset: thead,th1520-reset: Remove non-VO-subsystem resets
reset: remove legacy reset lookup code
clk: davinci: psc: drop unused reset lookup
reset: rzg2l-usbphy-ctrl: Add support for RZ/G3S SoC
reset: rzg2l-usbphy-ctrl: Add support for USB PWRRDY
dt-bindings: reset: renesas,rzg2l-usbphy-ctrl: Document RZ/G3S support
reset: eswin: Add eic7700 reset driver
dt-bindings: reset: eswin: Documentation for eic7700 SoC
reset: sparx5: add LAN969x support
dt-bindings: reset: microchip: Add LAN969x support
soc: rockchip: grf: Add select correct PWM implementation on RK3368
soc/tegra: pmc: Add USB wake events for Tegra234
amba: tegra-ahb: Fix device leak on SMMU enable
...
The macro for_each_console_srcu iterates over all registered consoles. It's
implied that all registered consoles have CON_ENABLED flag set, making
the check for the flag unnecessary. Call console_is_usable function to
fully verify if the given console is usable before calling the ->unblank
callback.
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://patch.msgid.link/20251121-printk-cleanup-part2-v2-3-57b8b78647f4@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
With commit ("printk: Avoid scheduling irq_work on suspend") the
implementation of printk_get_console_flush_type() was modified to
avoid offloading when irq_work should be blocked during suspend.
Since printk uses the returned flush type to determine what
flushing methods are used, this was thought to be sufficient for
avoiding irq_work usage during the suspend phase.
However, vprintk_emit() implements a hack to support
printk_deferred(). In this hack, the returned flush type is
adjusted to make sure no legacy direct printing occurs when
printk_deferred() was used.
Because of this hack, the legacy offloading flushing method can
still be used, causing irq_work to be queued when it should not
be.
Adjust the vprintk_emit() hack to also consider
@console_irqwork_blocked so that legacy offloading will not be
chosen when irq_work should be blocked.
Link: https://lore.kernel.org/lkml/87fra90xv4.fsf@jogness.linutronix.de
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Fixes: 26873e3e7f ("printk: Avoid scheduling irq_work on suspend")
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Allowing irq_work to be scheduled while trying to suspend has shown
to cause problems as some architectures interpret the pending
interrupts as a reason to not suspend. This became a problem for
printk() with the introduction of NBCON consoles. With every
printk() call, NBCON console printing kthreads are woken by queueing
irq_work. This means that irq_work continues to be queued due to
printk() calls late in the suspend procedure.
Avoid this problem by preventing printk() from queueing irq_work
once console suspending has begun. This applies to triggering NBCON
and legacy deferred printing as well as klogd waiters.
Since triggering of NBCON threaded printing relies on irq_work, the
pr_flush() within console_suspend_all() is used to perform the final
flushing before suspending consoles and blocking irq_work queueing.
NBCON consoles that are not suspended (due to the usage of the
"no_console_suspend" boot argument) transition to atomic flushing.
Introduce a new global variable @console_irqwork_blocked to flag
when irq_work queueing is to be avoided. The flag is used by
printk_get_console_flush_type() to avoid allowing deferred printing
and switch NBCON consoles to atomic flushing. It is also used by
vprintk_emit() to avoid klogd waking.
Add WARN_ON_ONCE(console_irqwork_blocked) to the irq_work queuing
functions to catch any code that attempts to queue printk irq_work
during the suspending/resuming procedure.
Cc: stable@vger.kernel.org # 6.13.x because no drivers in 6.12.x
Fixes: 6b93bb41f6 ("printk: Add non-BKL (nbcon) console basic infrastructure")
Closes: https://lore.kernel.org/lkml/DB9PR04MB8429E7DDF2D93C2695DE401D92C4A@DB9PR04MB8429.eurprd04.prod.outlook.com
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://patch.msgid.link/20251113160351.113031-3-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
Currently printk_trigger_flush() only triggers legacy offloaded
flushing, even if that may not be the appropriate method to flush
for currently registered consoles. (The function predates the
NBCON consoles.)
Since commit 6690d6b527 ("printk: Add helper for flush type
logic") there is printk_get_console_flush_type(), which also
considers NBCON consoles and reports all the methods of flushing
appropriate based on the system state and consoles available.
Update printk_trigger_flush() to use
printk_get_console_flush_type() to appropriately flush registered
consoles.
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/stable/20251113160351.113031-2-john.ogness%40linutronix.de
Tested-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://patch.msgid.link/20251113160351.113031-2-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
Several drivers can benefit from registering per-instance data along
with the syscore operations. To achieve this, move the modifiable fields
out of the syscore_ops structure and into a separate struct syscore that
can be registered with the framework. Add a void * driver data field for
drivers to store contextual data that will be passed to the syscore ops.
Acked-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
The decision whether some more space is needed is tricky in the printk
ring buffer code:
1. The given lpos values might overflow. A subtraction must be used
instead of a simple "lower than" check.
2. Another CPU might reuse the space in the mean time. It can be
detected when the subtraction is bigger than DATA_SIZE(data_ring).
3. There is exactly enough space when the result of the subtraction
is zero. But more space is needed when the result is exactly
DATA_SIZE(data_ring).
Add a helper function to make sure that the check is done correctly
in all situations. Also it helps to make the code consistent and
better documented.
Suggested-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/87tsz7iea2.fsf@jogness.linutronix.de
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20251107194720.1231457-3-pmladek@suse.com
[pmladek@suse.com: Updated wording as suggested by John]
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>
printk() tries to flush messages with NBCON_PRIO_EMERGENCY on
nbcon consoles immediately. It might take seconds to flush all
pending lines on slow serial consoles. Note that there might be
hundreds of messages, for example:
[ 3.771531][ T1] pci 0000:3e:08.1: [8086:324
** replaying previous printk message **
[ 3.771531][ T1] pci 0000:3e:08.1: [8086:3246] type 00 class 0x088000 PCIe Root Complex Integrated Endpoint
[ ... more than 2000 lines, about 200kB messages ... ]
[ 3.837752][ T1] pci 0000:20:01.0: Adding to iommu group 18
[ 3.837851][ T
** replaying previous printk message **
[ 3.837851][ T1] pci 0000:20:03.0: Adding to iommu group 19
[ 3.837946][ T1] pci 0000:20:05.0: Adding to iommu group 20
[ ... more than 500 messages for iommu groups 21-590 ...]
[ 3.912932][ T1] pci 0000:f6:00.1: Adding to iommu group 591
[ 3.913070][ T1] pci 0000:f6:00.2: Adding to iommu group 592
[ 3.913243][ T1] DMAR: Intel(R) Virtualization Technology for Directed I/O
[ 3.913245][ T1] PCI-DMA: Using software bounce buffering for IO (SWIOTLB)
[ 3.913245][ T1] software IO TLB: mapped [mem 0x000000004f000000-0x0000000053000000] (64MB)
[ 3.913324][ T1] RAPL PMU: API unit is 2^-32 Joules, 3 fixed counters, 655360 ms ovfl timer
[ 3.913325][ T1] RAPL PMU: hw unit of domain package 2^-14 Joules
[ 3.913326][ T1] RAPL PMU: hw unit of domain dram 2^-14 Joules
[ 3.913327][ T1] RAPL PMU: hw unit of domain psys 2^-0 Joules
[ 3.933486][ T1] ------------[ cut here ]------------
[ 3.933488][ T1] WARNING: CPU: 2 PID: 1 at arch/x86/events/intel/uncore.c:1156 uncore_pci_pmu_register+0x15e/0x180
[ 3.930291][ C0] watchdog: Watchdog detected hard LOCKUP on cpu 0
[ 3.930291][ C0] Kernel panic - not syncing: Hard LOCKUP
[...]
[ 3.930291][ C0] CPU: 0 UID: 0 PID: 18 Comm: pr/ttyS0 Not tainted...
[...]
[ 3.930291][ C0] RIP: 0010:nbcon_reacquire_nobuf+0x11/0x50
[ 3.930291][ C0] Call Trace:
[...]
[ 3.930291][ C0] <TASK>
[ 3.930291][ C0] serial8250_console_write+0x16d/0x5c0
[ 3.930291][ C0] nbcon_emit_next_record+0x22c/0x250
[ 3.930291][ C0] nbcon_emit_one+0x93/0xe0
[ 3.930291][ C0] nbcon_kthread_func+0x13c/0x1c0
The are visible two takeovers of the console ownership:
- The 1st one is triggered by the "WARNING: CPU: 2 PID: 1 at
arch/x86/..." line printed with NBCON_PRIO_EMERGENCY.
- The 2nd one is triggered by the "Kernel panic - not syncing:
Hard LOCKUP" line printed with NBCON_PRIO_PANIC.
There are more than 2500 lines, at about 240kB, emitted between
the takeover and the 1st "WARNING" line in the emergency context.
This amount of pending messages had to be flushed by
nbcon_atomic_flush_pending() when WARN() printed its first line.
The atomic flush was holding the nbcon console context for too long so
that it triggered hard lockup on the CPU running the printk kthread
"pr/ttyS0". The kthread needed to reacquire the console ownership
for restoring the original serial port state in serial8250_console_write().
Prevent the hardlockup by releasing the nbcon console ownership after
each emitted record.
Note that __nbcon_atomic_flush_pending_con() used to hold the console
ownership all the time because it blocked the printk kthread. Otherwise
the kthread tried to flush the messages in parallel which caused repeated
takeovers and more replayed messages.
It is not longer a problem because the repeated takeovers are blocked
by the counter of emergency contexts, see nbcon_cpu_emergency_cnt.
Link: https://lore.kernel.org/all/aNQO-zl3k1l4ENfy@pathway.suse.cz
Reviewed-by: Andrew Murray <amurray@thegoodpenguin.co.uk>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20250926124912.243464-4-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
The printk kthread might be running when there is a panic in progress.
But it is not able to acquire the console ownership any longer.
Prevent the desperate attempts to acquire the ownership and allow sleeping
in panic. It would make it behave the same as when there is any CPU
in an emergency context.
Reviewed-by: Andrew Murray <amurray@thegoodpenguin.co.uk>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20250926124912.243464-3-pmladek@suse.com
[pmladek@suse.com: Rebased on top of 6.18-rc1 (panic_in_progress() moved to panic.c)]
Signed-off-by: Petr Mladek <pmladek@suse.com>
In emergency contexts, printk() tries to flush messages directly even
on nbcon consoles. And it is allowed to takeover the console ownership
and interrupt the printk kthread in the middle of a message.
Only one takeover and one repeated message should be enough in most
situations. The first emergency message flushes the backlog and printk
kthreads get to sleep. Next emergency messages are flushed directly
and printk() does not wake up the kthreads.
However, the one takeover is not guaranteed. Any printk() in normal
context on another CPU could wake up the kthreads. Or a new emergency
message might be added before the kthreads get to sleep. Note that
the interrupted .write_thread() callbacks usually have to call
nbcon_reacquire_nobuf() and restore the original device setting
before checking for pending messages.
The risk of the repeated takeovers will be even bigger because
__nbcon_atomic_flush_pending_con is going to release the console
ownership after each emitted record. It will be needed to prevent
hardlockup reports on other CPUs which are busy waiting for
the context ownership, for example, by nbcon_reacquire_nobuf() or
__uart_port_nbcon_acquire().
The repeated takeovers break the output, for example:
[ 5042.650211][ T2220] Call Trace:
[ 5042.6511
** replaying previous printk message **
[ 5042.651192][ T2220] <TASK>
[ 5042.652160][ T2220] kunit_run_
** replaying previous printk message **
[ 5042.652160][ T2220] kunit_run_tests+0x72/0x90
[ 5042.653340][ T22
** replaying previous printk message **
[ 5042.653340][ T2220] ? srso_alias_return_thunk+0x5/0xfbef5
[ 5042.654628][ T2220] ? stack_trace_save+0x4d/0x70
[ 5042.6553
** replaying previous printk message **
[ 5042.655394][ T2220] ? srso_alias_return_thunk+0x5/0xfbef5
[ 5042.656713][ T2220] ? save_trace+0x5b/0x180
A more robust solution is to block the printk kthread entirely whenever
*any* CPU enters an emergency context. This ensures that critical messages
can be flushed without contention from the normal, non-atomic printing
path.
Link: https://lore.kernel.org/all/aNQO-zl3k1l4ENfy@pathway.suse.cz
Reviewed-by: Andrew Murray <amurray@thegoodpenguin.co.uk>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20250926124912.243464-2-pmladek@suse.com
[pmladek@suse.com: Added changes proposed by John Ogness]
Signed-off-by: Petr Mladek <pmladek@suse.com>
printk_legacy_map is used to hide lock nesting violations caused by
legacy drivers and is using the wrong override type. LD_WAIT_SLEEP is
for always sleeping lock types such as mutex_t. LD_WAIT_CONFIG is for
lock type which are sleeping while spinning on PREEMPT_RT such as
spinlock_t.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20251026150726.GA23223@redhat.com
[pmladek@suse.com: Fixed indentation.]
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>
KDB can interrupt any console to execute the "mirrored printing" at any
time, so add an exception to nbcon_context_try_acquire_direct to allow
to get the context if the current CPU is the same as kdb_printf_cpu.
This change will be necessary for the next patch, which fixes
kdb_msg_write to work with NBCON consoles by calling ->write_atomic on
such consoles. But to print it first needs to acquire the ownership of
the console, so nbcon_context_try_acquire_direct is fixed here.
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://patch.msgid.link/20251016-nbcon-kgdboc-v6-3-866aac60a80e@suse.com
[pmladek@suse.com: Fix compilation with !CONFIG_KGDB_KDB.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
These helpers will be used when calling console->write_atomic on
KDB code in the next patch. It's basically the same implementation
as nbcon_device_try_acquire, but using NBCON_PRIO_EMERGENCY when
acquiring the context.
If the acquire succeeds, the message and message length are assigned to
nbcon_write_context so ->write_atomic can print the message.
After release try to flush the console since there may be a backlog of
messages in the ringbuffer. The kthread console printers do not get a
chance to run while kdb is active.
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-v6-2-866aac60a80e@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
The helper will be used on KDB code in the next commits.
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-v6-1-866aac60a80e@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
The legacy printer kthread uses console_lock and
__console_flush_and_unlock to flush records to the console. This
approach results in the console_lock being held for the entire
duration of a flush. This can result in large waiting times for
those waiting for console_lock especially where there is a large
volume of records or where the console is slow (e.g. serial). This
contention is observed during boot, as the call to filp_open in
console_on_rootfs will delay progression to userspace until any
in-flight flush is completed.
Let's instead use console_flush_one_record and release/reacquire
the console_lock between records.
On a PocketBeagle 2, with the following boot args:
"console=ttyS2,9600 initcall_debug=1 loglevel=10"
Without this patch:
[ 5.613166] +console_on_rootfs/filp_open
[ 5.643473] mmc1: SDHCI controller on fa00000.mmc [fa00000.mmc] using ADMA 64-bit
[ 5.643823] probe of fa00000.mmc returned 0 after 258244 usecs
[ 5.710520] mmc1: new UHS-I speed SDR104 SDHC card at address 5048
[ 5.721976] mmcblk1: mmc1:5048 SD32G 29.7 GiB
[ 5.747258] mmcblk1: p1 p2
[ 5.753324] probe of mmc1:5048 returned 0 after 40002 usecs
[ 15.595240] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to 30040000.pruss
[ 15.595282] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to e010000.watchdog
[ 15.595297] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to e000000.watchdog
[ 15.595437] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to 30300000.crc
[ 146.275961] -console_on_rootfs/filp_open ...
and with:
[ 5.477122] +console_on_rootfs/filp_open
[ 5.595814] mmc1: SDHCI controller on fa00000.mmc [fa00000.mmc] using ADMA 64-bit
[ 5.596181] probe of fa00000.mmc returned 0 after 312757 usecs
[ 5.662813] mmc1: new UHS-I speed SDR104 SDHC card at address 5048
[ 5.674367] mmcblk1: mmc1:5048 SD32G 29.7 GiB
[ 5.699320] mmcblk1: p1 p2
[ 5.705494] probe of mmc1:5048 returned 0 after 39987 usecs
[ 6.418682] -console_on_rootfs/filp_open ...
...
[ 15.593509] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to 30040000.pruss
[ 15.593551] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to e010000.watchdog
[ 15.593566] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to e000000.watchdog
[ 15.593704] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to 30300000.crc
Where I've added a printk surrounding the call in console_on_rootfs
to filp_open.
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andrew Murray <amurray@thegoodpenguin.co.uk>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20251020-printk_legacy_thread_console_lock-v3-3-00f1f0ac055a@thegoodpenguin.co.uk
[pmladek@suse.com: Fixed ordering of variable definition suggested by John.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
console_flush_one_record() and console_flush_all() duplicate several
checks. They both want to tell the caller that consoles are not
longer usable in this context because it has lost the lock or
the lock has to be reserved for the panic CPU.
Remove the duplication by changing the semantic of the function
console_flush_one_record() return value and parameters.
The function will return true when it is able to do the job. It means
that there is at least one usable console. And the flushing was
not interrupted by a takeover or panic_on_other_cpu().
Also replace the @any_usable parameter with @try_again. The @try_again
parameter will be set to true when the function could do the job
and at least one console made a progress.
Motivation:
The callers need to know when
+ they should continue flushing => @try_again
+ when the console is flushed => can_do_the_job(return) && !@try_again
+ when @next_seq is valid => same as flushed
+ when lost console_lock => @takeover
The proposed change makes it clear when the function can do
the job. It simplifies the answer for the other questions.
Also the return value from console_flush_one_record() can
be used as return value from console_flush_all().
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20251020-printk_legacy_thread_console_lock-v3-2-00f1f0ac055a@thegoodpenguin.co.uk
[pmladek@suse.com: Fixed type of any_usable variable reported by John]
Signed-off-by: Petr Mladek <pmladek@suse.com>
console_flush_all prints all remaining records to all usable consoles
whilst its caller holds console_lock. This can result in large waiting
times for those waiting for console_lock especially where there is a
large volume of records or where the console is slow (e.g. serial).
Let's extract the parts of this function which print a single record
into a new function named console_flush_one_record. This can later
be used for functions that will release and reacquire console_lock
between records.
This commit should not change existing functionality.
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andrew Murray <amurray@thegoodpenguin.co.uk>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20251020-printk_legacy_thread_console_lock-v3-1-00f1f0ac055a@thegoodpenguin.co.uk
Signed-off-by: Petr Mladek <pmladek@suse.com>
Previously, data blocks that perfectly fit the data ring buffer would
get wrapped around to the beginning for no reason since the calculated
offset of the next data block would belong to the next wrap. Since this
offset is not actually part of the data block, but rather the offset of
where the next data block is going to start, there is no reason to
include it when deciding whether the current block fits the buffer.
Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Tested-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20250905144152.9137-2-d-tatianin@yandex-team.ru
[pmladek@suse.com: Updated indentation.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
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Merge tag 'printk-for-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk updates from Petr Mladek:
- Add KUnit test for the printk ring buffer
- Fix the check of the maximal record size which is allowed to be
stored into the printk ring buffer. It prevents corruptions of the
ring buffer.
Note that printk() is on the safe side. The messages are limited by
1kB buffer and are always small enough for the minimal log buffer
size 4kB, see CONFIG_LOG_BUF_SHIFT definition.
* tag 'printk-for-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk: ringbuffer: Fix data block max size check
printk: kunit: support offstack cpumask
printk: kunit: Fix __counted_by() in struct prbtest_rbdata
printk: ringbuffer: Explain why the KUnit test ignores failed writes
printk: ringbuffer: Add KUnit test
Currently data_check_size() limits data blocks to a maximum size of
the full buffer minus an ID (long integer):
max_size <= DATA_SIZE(data_ring) - sizeof(long)
However, this is not an appropriate limit due to the nature of
wrapping data blocks. For example, if a data block is larger than
half the buffer:
size = (DATA_SIZE(data_ring) / 2) + 8
and begins exactly in the middle of the buffer, then:
- the data block will wrap
- the ID will be stored at exactly half of the buffer
- the record data begins at the beginning of the buffer
- the record data ends 8 bytes _past_ exactly half of the buffer
The record overwrites itself, i.e. needs more space than the full
buffer!
Luckily printk() is not vulnerable to this problem because
truncate_msg() limits printk-messages to 1/4 of the ringbuffer.
Indeed, by adjusting the printk_ringbuffer KUnit test, which does not
use printk() and its truncate_msg() check, it is easy to see that the
ringbuffer becomes corrupted for records larger than half the buffer
size.
The corruption occurs because data_push_tail() expects it will never
be requested to push the tail beyond the head.
Avoid this problem by adjusting data_check_size() to limit record
sizes to half the buffer size. Also add WARN_ON_ONCE() before
relevant data_push_tail() calls to validate that there are no such
illegal requests. WARN_ON_ONCE() is used, rather than just adding
extra checks to data_push_tail() because it is considered a bug to
attempt such illegal actions.
Link: https://lore.kernel.org/lkml/aMLrGCQSyC8odlFZ@pathway.suse.cz
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Replace quoted includes of panic.h with `#include <linux/panic.h>` for
consistency across the kernel.
Link: https://lkml.kernel.org/r/20250829051312.33773-1-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The helper this_cpu_in_panic() duplicated logic already provided by
panic_on_this_cpu().
Remove this_cpu_in_panic() and switch all users to panic_on_this_cpu().
This simplifies the code and avoids having two helpers for the same check.
Link: https://lkml.kernel.org/r/20250825022947.1596226-8-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Kees Cook <kees@kernel.org>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Luo Gengkun <luogengkun@huaweicloud.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Nam Cao <namcao@linutronix.de>
Cc: oushixiong <oushixiong@kylinos.cn>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Yunhui Cui <cuiyunhui@bytedance.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
nbcon_context_try_acquire() compared panic_cpu directly with
smp_processor_id(). This open-coded check is now provided by
panic_on_this_cpu().
Switch to panic_on_this_cpu() to simplify the code and improve readability.
Link: https://lkml.kernel.org/r/20250825022947.1596226-7-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Kees Cook <kees@kernel.org>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Luo Gengkun <luogengkun@huaweicloud.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Nam Cao <namcao@linutronix.de>
Cc: oushixiong <oushixiong@kylinos.cn>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Yunhui Cui <cuiyunhui@bytedance.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "panic: introduce panic status function family", v2.
This series introduces a family of helper functions to manage panic state
and updates existing code to use them.
Before this series, panic state helpers were scattered and inconsistent.
For example, panic_in_progress() was defined in printk/printk.c, not in
panic.c or panic.h. As a result, developers had to look in unexpected
places to understand or re-use panic state logic. Other checks were open-
coded, duplicating logic across panic, crash, and watchdog paths.
The new helpers centralize the functionality in panic.c/panic.h:
- panic_try_start()
- panic_reset()
- panic_in_progress()
- panic_on_this_cpu()
- panic_on_other_cpu()
Patches 1–8 add the helpers and convert panic/crash and printk/nbcon
code to use them.
Patch 9 fixes a bug in the watchdog subsystem by skipping checks when a
panic is in progress, avoiding interference with the panic CPU.
Together, this makes panic state handling simpler, more discoverable, and
more robust.
This patch (of 9):
This patch introduces four new helper functions to abstract the management
of the panic_cpu variable. These functions will be used in subsequent
patches to refactor existing code.
The direct use of panic_cpu can be error-prone and ambiguous, as it
requires manual checks to determine which CPU is handling the panic. The
new helpers clarify intent:
panic_try_start():
Atomically sets the current CPU as the panicking CPU.
panic_reset():
Reset panic_cpu to PANIC_CPU_INVALID.
panic_in_progress():
Checks if a panic has been triggered.
panic_on_this_cpu():
Returns true if the current CPU is the panic originator.
panic_on_other_cpu():
Returns true if a panic is on another CPU.
This change lays the groundwork for improved code readability
and robustness in the panic handling subsystem.
Link: https://lkml.kernel.org/r/20250825022947.1596226-1-wangjinchao600@gmail.com
Link: https://lkml.kernel.org/r/20250825022947.1596226-2-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Kees Cook <kees@kernel.org>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Luo Gengkun <luogengkun@huaweicloud.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Nam Cao <namcao@linutronix.de>
Cc: oushixiong <oushixiong@kylinos.cn>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Yunhui Cui <cuiyunhui@bytedance.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>b
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
For large values of CONFIG_NR_CPUS, the newly added kunit test fails
to build:
kernel/printk/printk_ringbuffer_kunit_test.c: In function 'test_readerwriter':
kernel/printk/printk_ringbuffer_kunit_test.c:279:1: error: the frame size of 1432 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]
Change this to use cpumask_var_t and allocate it dynamically when
CONFIG_CPUMASK_OFFSTACK is set.
The variable has to be released via a KUnit action wrapper so that it is
freed when the test fails and gets aborted. The parameter type is hardcoded
to "struct cpumask *" because the macro KUNIT_DEFINE_ACTION_WRAPPER()
does not accept an array. But the function does nothing when
CONFIG_CPUMASK_OFFSTACK is not set anyway.
Fixes: 5ea2bcdfbf ("printk: ringbuffer: Add KUnit test")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/all/20250620192554.2234184-1-arnd@kernel.org # v1
[pmladek@suse.com: Correctly handle allocation failures and freeing using KUnit test API.]
Link: https://lore.kernel.org/all/20250702095157.110916-3-pmladek@suse.com # v2
Signed-off-by: Petr Mladek <pmladek@suse.com>
