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2023-01-18kheaders: explicitly validate existence of cpio commandThomas Weißschuh
If the cpio command is not available the error emitted by gen_kheaders.so is not clear as all output of the call to cpio is discarded: GNU make 4.4: GEN kernel/kheaders_data.tar.xz find: 'standard output': Broken pipe find: write error make[2]: *** [kernel/Makefile:157: kernel/kheaders_data.tar.xz] Error 127 make[1]: *** [scripts/Makefile.build:504: kernel] Error 2 GNU make < 4.4: GEN kernel/kheaders_data.tar.xz make[2]: *** [kernel/Makefile:157: kernel/kheaders_data.tar.xz] Error 127 make[2]: *** Waiting for unfinished jobs.... make[1]: *** [scripts/Makefile.build:504: kernel] Error 2 Add an explicit check that will trigger a clear message about the issue: CHK kernel/kheaders_data.tar.xz ./kernel/gen_kheaders.sh: line 17: type: cpio: not found The other commands executed by gen_kheaders.sh are part of a standard installation, so they are not checked. Reported-by: Amy Parker <apark0006@student.cerritos.edu> Link: https://lore.kernel.org/lkml/CAPOgqxFva=tOuh1UitCSN38+28q3BNXKq19rEsVNPRzRqKqZ+g@mail.gmail.com/ Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Reviewed-by: Nicolas Schier <n.schier@avm.de> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2023-01-17rcu: Track laziness during boot and suspendJoel Fernandes (Google)
Boot and suspend/resume should not be slowed down in kernels built with CONFIG_RCU_LAZY=y. In particular, suspend can sometimes fail in such kernels. This commit therefore adds rcu_async_hurry(), rcu_async_relax(), and rcu_async_should_hurry() functions that track whether or not either a boot or a suspend/resume operation is in progress. This will enable a later commit to refrain from laziness during those times. Export rcu_async_should_hurry(), rcu_async_hurry(), and rcu_async_relax() for later use by rcutorture. [ paulmck: Apply feedback from Steve Rostedt. ] Fixes: 3cb278e73be5 ("rcu: Make call_rcu() lazy to save power") Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2023-01-17Merge tag 'for-netdev' of ↵Jakub Kicinski
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf Daniel Borkmann says: ==================== bpf 2023-01-16 We've added 6 non-merge commits during the last 8 day(s) which contain a total of 6 files changed, 22 insertions(+), 24 deletions(-). The main changes are: 1) Mitigate a Spectre v4 leak in unprivileged BPF from speculative pointer-as-scalar type confusion, from Luis Gerhorst. 2) Fix a splat when pid 1 attaches a BPF program that attempts to send killing signal to itself, from Hao Sun. 3) Fix BPF program ID information in BPF_AUDIT_UNLOAD as well as PERF_BPF_EVENT_PROG_UNLOAD events, from Paul Moore. 4) Fix BPF verifier warning triggered from invalid kfunc call in backtrack_insn, also from Hao Sun. 5) Fix potential deadlock in htab_lock_bucket from same bucket index but different map_locked index, from Tonghao Zhang. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: bpf: Fix pointer-leak due to insufficient speculative store bypass mitigation bpf: hash map, avoid deadlock with suitable hash mask bpf: remove the do_idr_lock parameter from bpf_prog_free_id() bpf: restore the ebpf program ID for BPF_AUDIT_UNLOAD and PERF_BPF_EVENT_PROG_UNLOAD bpf: Skip task with pid=1 in send_signal_common() bpf: Skip invalid kfunc call in backtrack_insn ==================== Link: https://lore.kernel.org/r/20230116230745.21742-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-01-17bpf: Do not allow to load sleepable BPF_TRACE_RAW_TP programJiri Olsa
Currently we allow to load any tracing program as sleepable, but BPF_TRACE_RAW_TP can't sleep. Making the check explicit for tracing programs attach types, so sleepable BPF_TRACE_RAW_TP will fail to load. Updating the verifier error to mention iter programs as well. Acked-by: Song Liu <song@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230117223705.440975-1-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-17genirq/msi: Free the fwnode created by msi_create_device_irq_domain()Jason Gunthorpe
msi_create_device_irq_domain() creates a firmware node for the new domain, which is never freed. kmemleak reports: unreferenced object 0xffff888120ba9a00 (size 96): comm "systemd-modules", pid 221, jiffies 4294893411 (age 635.732s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 e0 19 8b 83 ff ff ff ff ................ 00 00 00 00 00 00 00 00 18 9a ba 20 81 88 ff ff ........... .... backtrace: [<000000008cdbc98d>] __irq_domain_alloc_fwnode+0x51/0x2b0 [<00000000c57acf9d>] msi_create_device_irq_domain+0x283/0x670 [<000000009b567982>] __pci_enable_msix_range+0x49e/0xdb0 [<0000000077cc1445>] pci_alloc_irq_vectors_affinity+0x11f/0x1c0 [<00000000532e9ef5>] mlx5_irq_table_create+0x24c/0x940 [mlx5_core] [<00000000fabd2b80>] mlx5_load+0x1fa/0x680 [mlx5_core] [<000000006bb22ae4>] mlx5_init_one+0x485/0x670 [mlx5_core] [<00000000eaa5e1ad>] probe_one+0x4c2/0x720 [mlx5_core] [<00000000df8efb43>] local_pci_probe+0xd6/0x170 [<0000000085cb9924>] pci_device_probe+0x231/0x6e0 Use the proper free operation for the firmware wnode so the name is freed during error unwind of msi_create_device_irq_domain() and also free the node in msi_remove_device_irq_domain() if it was automatically allocated. To avoid extra NULL pointer checks make irq_domain_free_fwnode() tolerant of NULL. Fixes: 27a6dea3ebaa ("genirq/msi: Provide msi_create/free_device_irq_domain()") Reported-by: Omri Barazi <obarazi@nvidia.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Kalle Valo <kvalo@kernel.org> Tested-by: Leon Romanovsky <leonro@nvidia.com> Link: https://lore.kernel.org/r/0-v2-24af6665e2da+c9-msi_leak_jgg@nvidia.com
2023-01-17genirq/affinity: Move group_cpus_evenly() into lib/Ming Lei
group_cpus_evenly() has become a generic function which can be used for other subsystems than the interrupt subsystem, so move it into lib/. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/20221227022905.352674-6-ming.lei@redhat.com
2023-01-17genirq/affinity: Rename irq_build_affinity_masks as group_cpus_evenlyMing Lei
Map irq vector into group, which allows to abstract the algorithm for a generic use case outside of the interrupt core. Rename irq_build_affinity_masks as group_cpus_evenly, so the API can be reused for blk-mq to make default queue mapping even though irq vectors aren't involved. No functional change, just rename vector as group. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/20221227022905.352674-5-ming.lei@redhat.com
2023-01-17genirq/affinity: Don't pass irq_affinity_desc array to irq_build_affinity_masksMing Lei
Prepare for abstracting irq_build_affinity_masks() into a public function for assigning all CPUs evenly into several groups. Don't pass irq_affinity_desc array to irq_build_affinity_masks, instead return a cpumask array by storing each assigned group into one element of the array. This allows to provide a generic interface for grouping all CPUs evenly from a NUMA and CPU locality viewpoint, and the cost is one extra allocation in irq_build_affinity_masks(), which should be fine since it is done via GFP_KERNEL and irq_build_affinity_masks() is a slow path anyway. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/20221227022905.352674-4-ming.lei@redhat.com
2023-01-17genirq/affinity: Pass affinity managed mask array to irq_build_affinity_masksMing Lei
Pass affinity managed mask array to irq_build_affinity_masks() so that the index of the first affinity managed vector is always zero. This allows to simplify the implementation a bit. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/20221227022905.352674-3-ming.lei@redhat.com
2023-01-17genirq/affinity: Remove the 'firstvec' parameter from irq_build_affinity_masksMing Lei
The 'firstvec' parameter is always same with the parameter of 'startvec', so use 'startvec' directly inside irq_build_affinity_masks(). Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/20221227022905.352674-2-ming.lei@redhat.com
2023-01-16kernel/printk/printk.c: Fix W=1 kernel-doc warningAnuradha Weeraman
Fix W=1 kernel-doc warning: kernel/printk/printk.c: - Include function parameter in console_lock_spinning_disable_and_check() Signed-off-by: Anuradha Weeraman <anuradha@debian.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20230116125635.374567-1-anuradha@debian.org
2023-01-16tty: serial: kgdboc: fix mutex locking order for configure_kgdboc()John Ogness
Several mutexes are taken while setting up console serial ports. In particular, the tty_port->mutex and @console_mutex are taken: serial_pnp_probe serial8250_register_8250_port uart_add_one_port (locks tty_port->mutex) uart_configure_port register_console (locks @console_mutex) In order to synchronize kgdb's tty_find_polling_driver() with register_console(), commit 6193bc90849a ("tty: serial: kgdboc: synchronize tty_find_polling_driver() and register_console()") takes the @console_mutex. However, this leads to the following call chain (with locking): platform_probe kgdboc_probe configure_kgdboc (locks @console_mutex) tty_find_polling_driver uart_poll_init (locks tty_port->mutex) uart_set_options This is clearly deadlock potential due to the reverse lock ordering. Since uart_set_options() requires holding @console_mutex in order to serialize early initialization of the serial-console lock, take the @console_mutex in uart_poll_init() instead of configure_kgdboc(). Since configure_kgdboc() was using @console_mutex for safe traversal of the console list, change it to use the SRCU iterator instead. Add comments to uart_set_options() kerneldoc mentioning that it requires holding @console_mutex (aka the console_list_lock). Fixes: 6193bc90849a ("tty: serial: kgdboc: synchronize tty_find_polling_driver() and register_console()") Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Reviewed-by: Petr Mladek <pmladek@suse.com> [pmladek@suse.com: Export console_srcu_read_lock_is_held() to fix build kgdboc as a module.] Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20230112161213.1434854-1-john.ogness@linutronix.de
2023-01-16sched/core: Fix NULL pointer access fault in sched_setaffinity() with ↵Waiman Long
non-SMP configs The kernel commit 9a5418bc48ba ("sched/core: Use kfree_rcu() in do_set_cpus_allowed()") introduces a bug for kernels built with non-SMP configs. Calling sched_setaffinity() on such a uniprocessor kernel will cause cpumask_copy() to be called with a NULL pointer leading to general protection fault. This is not really a problem in real use cases as there aren't that many uniprocessor kernel configs in use and calling sched_setaffinity() on such a uniprocessor system doesn't make sense. Fix this problem by making sure cpumask_copy() will not be called in such a case. Fixes: 9a5418bc48ba ("sched/core: Use kfree_rcu() in do_set_cpus_allowed()") Reported-by: kernel test robot <yujie.liu@intel.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20230115193122.563036-1-longman@redhat.com
2023-01-15sched/fair: Limit sched slice durationVincent Guittot
In presence of a lot of small weight tasks like sched_idle tasks, normal or high weight tasks can see their ideal runtime (sched_slice) to increase to hundreds ms whereas it normally stays below sysctl_sched_latency. 2 normal tasks running on a CPU will have a max sched_slice of 12ms (half of the sched_period). This means that they will make progress every sysctl_sched_latency period. If we now add 1000 idle tasks on the CPU, the sched_period becomes 3006 ms and the ideal runtime of the normal tasks becomes 609 ms. It will even become 1500ms if the idle tasks belongs to an idle cgroup. This means that the scheduler will look for picking another waiting task after 609ms running time (1500ms respectively). The idle tasks change significantly the way the 2 normal tasks interleave their running time slot whereas they should have a small impact. Such long sched_slice can delay significantly the release of resources as the tasks can wait hundreds of ms before the next running slot just because of idle tasks queued on the rq. Cap the ideal_runtime to sysctl_sched_latency to make sure that tasks will regularly make progress and will not be significantly impacted by idle/background tasks queued on the rq. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lore.kernel.org/r/20230113133613.257342-1-vincent.guittot@linaro.org
2023-01-14Merge tag 'modules-6.2-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux Pull module fix from Luis Chamberlain: "Just one fix for modules by Nick" * tag 'modules-6.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: kallsyms: Fix scheduling with interrupts disabled in self-test
2023-01-13seccomp: fix kernel-doc function name warningRandy Dunlap
Move the ACTION_ONLY() macro so that it is not between the kernel-doc notation and the function definition for seccomp_run_filters(), eliminating a kernel-doc warning: kernel/seccomp.c:400: warning: expecting prototype for seccomp_run_filters(). Prototype was for ACTION_ONLY() instead Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will Drewry <wad@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20230108021228.15975-1-rdunlap@infradead.org
2023-01-13kallsyms: Fix scheduling with interrupts disabled in self-testNicholas Piggin
kallsyms_on_each* may schedule so must not be called with interrupts disabled. The iteration function could disable interrupts, but this also changes lookup_symbol() to match the change to the other timing code. Reported-by: Erhard F. <erhard_f@mailbox.org> Link: https://lore.kernel.org/all/bug-216902-206035@https.bugzilla.kernel.org%2F/ Reported-by: kernel test robot <oliver.sang@intel.com> Link: https://lore.kernel.org/oe-lkp/202212251728.8d0872ff-oliver.sang@intel.com Fixes: 30f3bb09778d ("kallsyms: Add self-test facility") Tested-by: "Erhard F." <erhard_f@mailbox.org> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-01-13workqueue: Fold rebind_worker() within rebind_workers()Valentin Schneider
!CONFIG_SMP builds complain about rebind_worker() being unused. Its only user, rebind_workers() is indeed only defined for CONFIG_SMP, so just fold the two lines back up there. Link: http://lore.kernel.org/r/20230113143102.2e94d74f@canb.auug.org.au Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Valentin Schneider <vschneid@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2023-01-13bpf: Fix pointer-leak due to insufficient speculative store bypass mitigationLuis Gerhorst
To mitigate Spectre v4, 2039f26f3aca ("bpf: Fix leakage due to insufficient speculative store bypass mitigation") inserts lfence instructions after 1) initializing a stack slot and 2) spilling a pointer to the stack. However, this does not cover cases where a stack slot is first initialized with a pointer (subject to sanitization) but then overwritten with a scalar (not subject to sanitization because the slot was already initialized). In this case, the second write may be subject to speculative store bypass (SSB) creating a speculative pointer-as-scalar type confusion. This allows the program to subsequently leak the numerical pointer value using, for example, a branch-based cache side channel. To fix this, also sanitize scalars if they write a stack slot that previously contained a pointer. Assuming that pointer-spills are only generated by LLVM on register-pressure, the performance impact on most real-world BPF programs should be small. The following unprivileged BPF bytecode drafts a minimal exploit and the mitigation: [...] // r6 = 0 or 1 (skalar, unknown user input) // r7 = accessible ptr for side channel // r10 = frame pointer (fp), to be leaked // r9 = r10 # fp alias to encourage ssb *(u64 *)(r9 - 8) = r10 // fp[-8] = ptr, to be leaked // lfence added here because of pointer spill to stack. // // Ommitted: Dummy bpf_ringbuf_output() here to train alias predictor // for no r9-r10 dependency. // *(u64 *)(r10 - 8) = r6 // fp[-8] = scalar, overwrites ptr // 2039f26f3aca: no lfence added because stack slot was not STACK_INVALID, // store may be subject to SSB // // fix: also add an lfence when the slot contained a ptr // r8 = *(u64 *)(r9 - 8) // r8 = architecturally a scalar, speculatively a ptr // // leak ptr using branch-based cache side channel: r8 &= 1 // choose bit to leak if r8 == 0 goto SLOW // no mispredict // architecturally dead code if input r6 is 0, // only executes speculatively iff ptr bit is 1 r8 = *(u64 *)(r7 + 0) # encode bit in cache (0: slow, 1: fast) SLOW: [...] After running this, the program can time the access to *(r7 + 0) to determine whether the chosen pointer bit was 0 or 1. Repeat this 64 times to recover the whole address on amd64. In summary, sanitization can only be skipped if one scalar is overwritten with another scalar. Scalar-confusion due to speculative store bypass can not lead to invalid accesses because the pointer bounds deducted during verification are enforced using branchless logic. See 979d63d50c0c ("bpf: prevent out of bounds speculation on pointer arithmetic") for details. Do not make the mitigation depend on !env->allow_{uninit_stack,ptr_leaks} because speculative leaks are likely unexpected if these were enabled. For example, leaking the address to a protected log file may be acceptable while disabling the mitigation might unintentionally leak the address into the cached-state of a map that is accessible to unprivileged processes. Fixes: 2039f26f3aca ("bpf: Fix leakage due to insufficient speculative store bypass mitigation") Signed-off-by: Luis Gerhorst <gerhorst@cs.fau.de> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Henriette Hofmeier <henriette.hofmeier@rub.de> Link: https://lore.kernel.org/bpf/edc95bad-aada-9cfc-ffe2-fa9bb206583c@cs.fau.de Link: https://lore.kernel.org/bpf/20230109150544.41465-1-gerhorst@cs.fau.de
2023-01-13context_tracking: Fix noinstr vs KASANPeter Zijlstra
Low level noinstr context-tracking code is calling out to instrumented code on KASAN: vmlinux.o: warning: objtool: __ct_user_enter+0x72: call to __kasan_check_write() leaves .noinstr.text section vmlinux.o: warning: objtool: __ct_user_exit+0x47: call to __kasan_check_write() leaves .noinstr.text section Use even lower level atomic methods to avoid the instrumentation. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230112195542.458034262@infradead.org
2023-01-13tracing, hardirq: No moar _rcuidle() tracingPeter Zijlstra
Robot reported that trace_hardirqs_{on,off}() tickle the forbidden _rcuidle() tracepoint through local_irq_{en,dis}able(). For 'sane' configs, these calls will only happen with RCU enabled and as such can use the regular tracepoint. This also means it's possible to trace them from NMI context again. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230112195541.477416709@infradead.org
2023-01-13tracing: WARN on rcuidlePeter Zijlstra
ARCH_WANTS_NO_INSTR (a superset of CONFIG_GENERIC_ENTRY) disallows any and all tracing when RCU isn't enabled. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20230112195541.416110581@infradead.org
2023-01-13tracing: Remove trace_hardirqs_{on,off}_caller()Peter Zijlstra
Per commit 56e62a737028 ("s390: convert to generic entry") the last and only callers of trace_hardirqs_{on,off}_caller() went away, clean up. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230112195541.355283994@infradead.org
2023-01-13time/tick-broadcast: Remove RCU_NONIDLE() usagePeter Zijlstra
No callers left that have already disabled RCU. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20230112195540.927904612@infradead.org
2023-01-13printk: Remove trace_.*_rcuidle() usagePeter Zijlstra
The problem, per commit fc98c3c8c9dc ("printk: use rcuidle console tracepoint"), was printk usage from the cpuidle path where RCU was already disabled. Per the patches earlier in this series, this is no longer the case. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Acked-by: Petr Mladek <pmladek@suse.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20230112195540.865735001@infradead.org
2023-01-13arch/idle: Change arch_cpu_idle() behavior: always exit with IRQs disabledPeter Zijlstra
Current arch_cpu_idle() is called with IRQs disabled, but will return with IRQs enabled. However, the very first thing the generic code does after calling arch_cpu_idle() is raw_local_irq_disable(). This means that architectures that can idle with IRQs disabled end up doing a pointless 'enable-disable' dance. Therefore, push this IRQ disabling into the idle function, meaning that those architectures can avoid the pointless IRQ state flipping. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com> Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64] Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Guo Ren <guoren@kernel.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20230112195540.618076436@infradead.org
2023-01-13cpuidle, cpu_pm: Remove RCU fiddling from cpu_pm_{enter,exit}()Peter Zijlstra
All callers should still have RCU enabled. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20230112195540.190860672@infradead.org
2023-01-13cpuidle: Fix ct_idle_*() usagePeter Zijlstra
The whole disable-RCU, enable-IRQS dance is very intricate since changing IRQ state is traced, which depends on RCU. Add two helpers for the cpuidle case that mirror the entry code: ct_cpuidle_enter() ct_cpuidle_exit() And fix all the cases where the enter/exit dance was buggy. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20230112195540.130014793@infradead.org
2023-01-13sched/fair: Fixes for capacity inversion detectionQais Yousef
Traversing the Perf Domains requires rcu_read_lock() to be held and is conditional on sched_energy_enabled(). Ensure right protections applied. Also skip capacity inversion detection for our own pd; which was an error. Fixes: 44c7b80bffc3 ("sched/fair: Detect capacity inversion") Reported-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lore.kernel.org/r/20230112122708.330667-3-qyousef@layalina.io
2023-01-13sched/uclamp: Fix a uninitialized variable warningsQais Yousef
Addresses the following warnings: > config: riscv-randconfig-m031-20221111 > compiler: riscv64-linux-gcc (GCC) 12.1.0 > > smatch warnings: > kernel/sched/fair.c:7263 find_energy_efficient_cpu() error: uninitialized symbol 'util_min'. > kernel/sched/fair.c:7263 find_energy_efficient_cpu() error: uninitialized symbol 'util_max'. Fixes: 244226035a1f ("sched/uclamp: Fix fits_capacity() check in feec()") Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lore.kernel.org/r/20230112122708.330667-2-qyousef@layalina.io
2023-01-12Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
drivers/net/usb/r8152.c be53771c87f4 ("r8152: add vendor/device ID pair for Microsoft Devkit") ec51fbd1b8a2 ("r8152: add USB device driver for config selection") https://lore.kernel.org/all/20230113113339.658c4723@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-01-12bpf: hash map, avoid deadlock with suitable hash maskTonghao Zhang
The deadlock still may occur while accessed in NMI and non-NMI context. Because in NMI, we still may access the same bucket but with different map_locked index. For example, on the same CPU, .max_entries = 2, we update the hash map, with key = 4, while running bpf prog in NMI nmi_handle(), to update hash map with key = 20, so it will have the same bucket index but have different map_locked index. To fix this issue, using min mask to hash again. Fixes: 20b6cc34ea74 ("bpf: Avoid hashtab deadlock with map_locked") Signed-off-by: Tonghao Zhang <tong@infragraf.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <martin.lau@linux.dev> Cc: Song Liu <song@kernel.org> Cc: Yonghong Song <yhs@fb.com> Cc: John Fastabend <john.fastabend@gmail.com> Cc: KP Singh <kpsingh@kernel.org> Cc: Stanislav Fomichev <sdf@google.com> Cc: Hao Luo <haoluo@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Hou Tao <houtao1@huawei.com> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/20230111092903.92389-1-tong@infragraf.org Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-01-12Merge tag 'timers-urgent-2023-01-12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer doc fixes from Ingo Molnar: - Fix various DocBook formatting errors in kernel/time/ that generated (justified) warnings during a kernel-doc build. * tag 'timers-urgent-2023-01-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: time: Fix various kernel-doc problems
2023-01-12Merge tag 'sched-urgent-2023-01-12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: - Fix scheduler frequency invariance bug related to overly long tickless periods triggering an integer overflow and disabling the feature. - Fix use-after-free bug in dup_user_cpus_ptr(). - Fix do_set_cpus_allowed() deadlock scenarios related to calling kfree() with the pi_lock held. NOTE: the rcu_free() is the 'lazy' solution here - we looked at patches to free the structure after the pi_lock got dropped, but that looked quite a bit messier - and none of this is truly performance critical. We can revisit this if it's too lazy of a solution ... * tag 'sched-urgent-2023-01-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/core: Use kfree_rcu() in do_set_cpus_allowed() sched/core: Fix use-after-free bug in dup_user_cpus_ptr() sched/core: Fix arch_scale_freq_tick() on tickless systems
2023-01-12rcu: Remove redundant call to rcu_boost_kthread_setaffinity()Zqiang
The rcu_boost_kthread_setaffinity() function is invoked at rcutree_online_cpu() and rcutree_offline_cpu() time, early in the online timeline and late in the offline timeline, respectively. It is also invoked from rcutree_dead_cpu(), however, in the absence of userspace manipulations (for which userspace must take responsibility), this call is redundant with that from rcutree_offline_cpu(). This redundancy can be demonstrated by printing out the relevant cpumasks This commit therefore removes the call to rcu_boost_kthread_setaffinity() from rcutree_dead_cpu(). Signed-off-by: Zqiang <qiang1.zhang@intel.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
2023-01-12workqueue: Unbind kworkers before sending them to exit()Valentin Schneider
It has been reported that isolated CPUs can suffer from interference due to per-CPU kworkers waking up just to die. A surge of workqueue activity during initial setup of a latency-sensitive application (refresh_vm_stats() being one of the culprits) can cause extra per-CPU kworkers to be spawned. Then, said latency-sensitive task can be running merrily on an isolated CPU only to be interrupted sometime later by a kworker marked for death (cf. IDLE_WORKER_TIMEOUT, 5 minutes after last kworker activity). Prevent this by affining kworkers to the wq_unbound_cpumask (which doesn't contain isolated CPUs, cf. HK_TYPE_WQ) before waking them up after marking them with WORKER_DIE. Changing the affinity does require a sleepable context, leverage the newly introduced pool->idle_cull_work to get that. Remove dying workers from pool->workers and keep track of them in a separate list. This intentionally prevents for_each_loop_worker() from iterating over workers that are marked for death. Rename destroy_worker() to set_working_dying() to better reflect its effects and relationship with wake_dying_workers(). Signed-off-by: Valentin Schneider <vschneid@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2023-01-12workqueue: Don't hold any lock while rcuwait'ing for !POOL_MANAGER_ACTIVEValentin Schneider
put_unbound_pool() currently passes wq_manager_inactive() as exit condition to rcuwait_wait_event(), which grabs pool->lock to check for pool->flags & POOL_MANAGER_ACTIVE A later patch will require destroy_worker() to be invoked with wq_pool_attach_mutex held, which needs to be acquired before pool->lock. A mutex cannot be acquired within rcuwait_wait_event(), as it could clobber the task state set by rcuwait_wait_event() Instead, restructure the waiting logic to acquire any necessary lock outside of rcuwait_wait_event(). Since further work cannot be inserted into unbound pwqs that have reached ->refcnt==0, this is bound to make forward progress as eventually the worklist will be drained and need_more_worker(pool) will remain false, preventing any worker from stealing the manager position from us. Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Valentin Schneider <vschneid@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2023-01-12workqueue: Convert the idle_timer to a timer + work_structValentin Schneider
A later patch will require a sleepable context in the idle worker timeout function. Converting worker_pool.idle_timer to a delayed_work gives us just that, however this would imply turning all idle_timer expiries into scheduler events (waking up a worker to handle the dwork). Instead, implement a "custom dwork" where the timer callback does some extra checks before queuing the associated work. No change in functionality intended. Signed-off-by: Valentin Schneider <vschneid@redhat.com> Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2023-01-12workqueue: Factorize unbind/rebind_workers() logicValentin Schneider
Later patches will reuse this code, move it into reusable functions. Signed-off-by: Valentin Schneider <vschneid@redhat.com> Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2023-01-12workqueue: Protects wq_unbound_cpumask with wq_pool_attach_mutexLai Jiangshan
When unbind_workers() reads wq_unbound_cpumask to set the affinity of freshly-unbound kworkers, it only holds wq_pool_attach_mutex. This isn't sufficient as wq_unbound_cpumask is only protected by wq_pool_mutex. Make wq_unbound_cpumask protected with wq_pool_attach_mutex and also remove the need of temporary saved_cpumask. Fixes: 10a5a651e3af ("workqueue: Restrict kworker in the offline CPU pool running on housekeeping CPUs") Reported-by: Valentin Schneider <vschneid@redhat.com> Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2023-01-11irq/s390: Add arch_is_isolated_msi() for s390Jason Gunthorpe
s390 doesn't use irq_domains, so it has no place to set IRQ_DOMAIN_FLAG_ISOLATED_MSI. Instead of continuing to abuse the iommu subsystem to convey this information add a simple define which s390 can make statically true. The define will cause msi_device_has_isolated() to return true. Remove IOMMU_CAP_INTR_REMAP from the s390 iommu driver. Link: https://lore.kernel.org/r/8-v3-3313bb5dd3a3+10f11-secure_msi_jgg@nvidia.com Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2023-01-11genirq/msi: Rename IRQ_DOMAIN_MSI_REMAP to IRQ_DOMAIN_ISOLATED_MSIJason Gunthorpe
What x86 calls "interrupt remapping" is one way to achieve isolated MSI, make it clear this is talking about isolated MSI, no matter how it is achieved. This matches the new driver facing API name of msi_device_has_isolated_msi() No functional change. Link: https://lore.kernel.org/r/6-v3-3313bb5dd3a3+10f11-secure_msi_jgg@nvidia.com Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2023-01-11genirq/irqdomain: Remove unused irq_domain_check_msi_remap() codeJason Gunthorpe
After converting the users of irq_domain_check_msi_remap() it and the helpers are no longer needed. The new version does not require all the #ifdef helpers and inlines because CONFIG_GENERIC_MSI_IRQ always requires CONFIG_IRQ_DOMAIN and IRQ_DOMAIN_HIERARCHY. Link: https://lore.kernel.org/r/5-v3-3313bb5dd3a3+10f11-secure_msi_jgg@nvidia.com Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2023-01-11genirq/msi: Add msi_device_has_isolated_msi()Jason Gunthorpe
This will replace irq_domain_check_msi_remap() in following patches. The new API makes it more clear what "msi_remap" actually means from a functional perspective instead of identifying an implementation specific HW feature. Isolated MSI means that HW modeled by an irq_domain on the path from the initiating device to the CPU will validate that the MSI message specifies an interrupt number that the device is authorized to trigger. This must block devices from triggering interrupts they are not authorized to trigger. Currently authorization means the MSI vector is one assigned to the device. This is interesting for securing VFIO use cases where a rouge MSI (eg created by abusing a normal PCI MemWr DMA) must not allow the VFIO userspace to impact outside its security domain, eg userspace triggering interrupts on kernel drivers, a VM triggering interrupts on the hypervisor, or a VM triggering interrupts on another VM. As this is actually modeled as a per-irq_domain property, not a global platform property, correct the interface to accept the device parameter and scan through only the part of the irq_domains hierarchy originating from the source device. Locate the new code in msi.c as it naturally only works with CONFIG_GENERIC_MSI_IRQ, which also requires CONFIG_IRQ_DOMAIN and IRQ_DOMAIN_HIERARCHY. Link: https://lore.kernel.org/r/1-v3-3313bb5dd3a3+10f11-secure_msi_jgg@nvidia.com Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2023-01-11genirq: Add might_sleep() to disable_irq()Manfred Spraul
With the introduction of threaded interrupt handlers, it is virtually never safe to call disable_irq() from non-premptible context. Thus: Update the documentation, add an explicit might_sleep() to catch any offenders. This is more obvious and straight forward than the implicit might_sleep() check deeper down in the disable_irq() call chain. Fixes: 3aa551c9b4c4 ("genirq: add threaded interrupt handler support") Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20221216150441.200533-3-manfred@colorfullife.com
2023-01-11timers: Prevent union confusion from unexpected restart_syscall()Jann Horn
The nanosleep syscalls use the restart_block mechanism, with a quirk: The `type` and `rmtp`/`compat_rmtp` fields are set up unconditionally on syscall entry, while the rest of the restart_block is only set up in the unlikely case that the syscall is actually interrupted by a signal (or pseudo-signal) that doesn't have a signal handler. If the restart_block was set up by a previous syscall (futex(..., FUTEX_WAIT, ...) or poll()) and hasn't been invalidated somehow since then, this will clobber some of the union fields used by futex_wait_restart() and do_restart_poll(). If userspace afterwards wrongly calls the restart_syscall syscall, futex_wait_restart()/do_restart_poll() will read struct fields that have been clobbered. This doesn't actually lead to anything particularly interesting because none of the union fields contain trusted kernel data, and futex(..., FUTEX_WAIT, ...) and poll() aren't syscalls where it makes much sense to apply seccomp filters to their arguments. So the current consequences are just of the "if userspace does bad stuff, it can damage itself, and that's not a problem" flavor. But still, it seems like a hazard for future developers, so invalidate the restart_block when partly setting it up in the nanosleep syscalls. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230105134403.754986-1-jannh@google.com
2023-01-11printk: adjust string limit macrosJohn Ogness
The various internal size limit macros have names and/or values that do not fit well to their current usage. Rename the macros so that their purpose is clear and, if needed, provide a more appropriate value. In general, the new macros and values will lead to less memory usage. The new macros are... PRINTK_MESSAGE_MAX: This is the maximum size for a formatted message on a console, devkmsg, or syslog. It does not matter which format the message has (normal or extended). It replaces the use of CONSOLE_EXT_LOG_MAX for console and devkmsg. It replaces the use of CONSOLE_LOG_MAX for syslog. Historically, normal messages have been allowed to print up to 1kB, whereas extended messages have been allowed to print up to 8kB. However, the difference in lengths of these message types is not significant and in multi-line records, normal messages are probably larger. Also, because 1kB is only slightly above the allowed record size, multi-line normal messages could be easily truncated during formatting. This new macro should be significantly larger than the allowed record size to allow sufficient space for extended or multi-line prefix text. A value of 2kB should be plenty of space. For normal messages this represents a doubling of the historically allowed amount. For extended messages it reduces the excessive 8kB size, thus reducing memory usage needed for message formatting. PRINTK_PREFIX_MAX: This is the maximum size allowed for a record prefix (used by console and syslog). It replaces PREFIX_MAX. The value is left unchanged. PRINTKRB_RECORD_MAX: This is the maximum size allowed to be reserved for a record in the ringbuffer. It is used by all readers and writers with the printk ringbuffer. It replaces LOG_LINE_MAX. Previously this was set to "1kB - PREFIX_MAX", which makes some sense if 1kB is the limit for normal message output and prefixes are enabled. However, with the allowance of larger output and the existence of multi-line records, the value is rather bizarre. Round the value up to 1kB. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20230109100800.1085541-9-john.ogness@linutronix.de
2023-01-11printk: use printk_buffers for devkmsgJohn Ogness
Replace the buffers in struct devkmsg_user with a struct printk_buffers. This reduces the number of buffers to keep track of. As a side-effect, @text_buf was 8kB large, even though it only needed to be the max size of a ringbuffer record. By switching to struct printk_buffers, ~7kB less memory is allocated when opening /dev/kmsg. And since struct printk_buffers will be used now, reduce duplicate code by calling printk_get_next_message() to handle the record reading and formatting. Note that since /dev/kmsg never suppresses records based on loglevel, printk_get_next_message() is extended with an extra bool argument to specify if suppression is allowed. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20230109100800.1085541-8-john.ogness@linutronix.de
2023-01-11printk: introduce console_prepend_dropped() for dropped messagesJohn Ogness
Currently "dropped messages" are separately printed immediately before printing the printk message. Since normal consoles are now using an output buffer that is much larger than previously, the "dropped message" could be prepended to the printk message and then output everything in a single write() call. Introduce a helper function console_prepend_dropped() to prepend an existing message with a "dropped message". This simplifies the code by allowing all message formatting to be handled together and then only requires a single write() call to output the full message. And since this helper does not require any locking, it can be used in the future for other console printing contexts as well. Note that console_prepend_dropped() is defined as a NOP for !CONFIG_PRINTK. Although the function will never be called for !CONFIG_PRINTK, compiling the function can lead to warnings of "always true" conditionals due to the size macro values used in !CONFIG_PRINTK. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20230109100800.1085541-7-john.ogness@linutronix.de
2023-01-11printk: introduce printk_get_next_message() and printk_messageJohn Ogness
Code for performing the console output is intermixed with code that is formatting the output for that console. Introduce a new helper function printk_get_next_message() to handle the reading and formatting of the printk text. The helper does not require any locking so that in the future it can be used for other printing contexts as well. This also introduces a new struct printk_message to wrap the struct printk_buffers, adding metadata about its contents. This allows users of printk_get_next_message() to receive all relevant information about the message that was read and formatted. Why is struct printk_message a wrapper struct? It is intentional that a wrapper struct is introduced instead of adding the metadata directly to struct printk_buffers. The upcoming atomic consoles support multiple printing contexts per CPU. This means that while a CPU is formatting a message, it can be interrupted and the interrupting context may also format a (possibly different) message. Since the printk buffers are rather large, there will only be one struct printk_buffers per CPU and it must be shared by the possible contexts of that CPU. If the metadata was part of struct printk_buffers, interrupting contexts would clobber the metadata being prepared by the interrupted context. This could be handled by robustifying the message formatting functions to cope with metadata unexpectedly changing. However, this would require significant amounts of extra data copying, also adding significant complexity to the code. Instead, the metadata can live on the stack of the formatting context and the message formatting functions do not need to be concerned about the metadata changing underneath them. Note that the message formatting functions can handle unexpected text buffer changes. So it is perfectly OK if a shared text buffer is clobbered by an interrupting context. The atomic console implementation will recognize the interruption and avoid printing the (probably garbage) text buffer. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20230109100800.1085541-6-john.ogness@linutronix.de