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2022-02-14kernel/fork: Initialize mm's PASIDFenghua Yu
A new mm doesn't have a PASID yet when it's created. Initialize the mm's PASID on fork() or for init_mm to INVALID_IOASID (-1). INIT_PASID (0) is reserved for kernel legacy DMA PASID. It cannot be allocated to a user process. Initializing the process's PASID to 0 may cause confusion that's why the process uses the reserved kernel legacy DMA PASID. Initializing the PASID to INVALID_IOASID (-1) explicitly tells the process doesn't have a valid PASID yet. Even though the only user of mm_pasid_init() is in fork.c, define it in <linux/sched/mm.h> as the first of three mm/pasid life cycle functions (init/set/drop) to keep these all together. Suggested-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20220207230254.3342514-5-fenghua.yu@intel.com
2022-02-14rcu: Replace cpumask_weight with cpumask_empty where appropriateYury Norov
In some places, RCU code calls cpumask_weight() to check if any bit of a given cpumask is set. We can do it more efficiently with cpumask_empty() because cpumask_empty() stops traversing the cpumask as soon as it finds first set bit, while cpumask_weight() counts all bits unconditionally. Signed-off-by: Yury Norov <yury.norov@gmail.com> Acked-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-02-14rcu: Uninline multi-use function: finish_rcuwait()Ingo Molnar
This is a rarely used function, so uninlining its 3 instructions is probably a win or a wash - but the main motivation is to make <linux/rcuwait.h> independent of task_struct details. Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-02-14rcu: Mark writes to the rcu_segcblist structure's ->flags fieldPaul E. McKenney
KCSAN reports data races between the rcu_segcblist_clear_flags() and rcu_segcblist_set_flags() functions, though misreporting the latter as a call to rcu_segcblist_is_enabled() from call_rcu(). This commit converts the updates of this field to WRITE_ONCE(), relying on the resulting unmarked reads to continue to detect buggy concurrent writes to this field. Reported-by: Zhouyi Zhou <zhouzhouyi@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Frederic Weisbecker <frederic@kernel.org>
2022-02-14kasan: Record work creation stack trace with interrupts enabledZqiang
Recording the work creation stack trace for KASAN reports in call_rcu() is expensive, due to unwinding the stack, but also due to acquiring depot_lock inside stackdepot (which may be contended). Because calling kasan_record_aux_stack_noalloc() does not require interrupts to already be disabled, this may unnecessarily extend the time with interrupts disabled. Therefore, move calling kasan_record_aux_stack() before the section with interrupts disabled. Acked-by: Marco Elver <elver@google.com> Signed-off-by: Zqiang <qiang1.zhang@intel.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-02-14rcu: Inline __call_rcu() into call_rcu()Paul E. McKenney
Because __call_rcu() is invoked only by call_rcu(), this commit inlines the former into the latter. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-02-14rcu: Add mutex for rcu boost kthread spawning and affinity settingDavid Woodhouse
As we handle parallel CPU bringup, we will need to take care to avoid spawning multiple boost threads, or race conditions when setting their affinity. Spotted by Paul McKenney. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-02-14mm: Change CONFIG option for mm->pasid fieldFenghua Yu
This currently depends on CONFIG_IOMMU_SUPPORT. But it is only needed when CONFIG_IOMMU_SVA option is enabled. Change the CONFIG guards around definition and initialization of mm->pasid field. Suggested-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/20220207230254.3342514-3-fenghua.yu@intel.com
2022-02-14printk: Drop console_sem during panicStephen Brennan
If another CPU is in panic, we are about to be halted. Try to gracefully abandon the console_sem, leaving it free for the panic CPU to grab. Suggested-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20220202171821.179394-5-stephen.s.brennan@oracle.com
2022-02-14printk: Avoid livelock with heavy printk during panicStephen Brennan
During panic(), if another CPU is writing heavily the kernel log (e.g. via /dev/kmsg), then the panic CPU may livelock writing out its messages to the console. Note when too many messages are dropped during panic and suppress further printk, except from the panic CPU. This could result in some important messages being dropped. However, messages are already being dropped, so this approach at least prevents a livelock. Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20220202171821.179394-4-stephen.s.brennan@oracle.com
2022-02-14printk: disable optimistic spin during panicStephen Brennan
A CPU executing with console lock spinning enabled might be halted during a panic. Before the panicking CPU calls console_flush_on_panic(), it may call console_trylock(), which attempts to optimistically spin, deadlocking the panic CPU: CPU 0 (panic CPU) CPU 1 ----------------- ------ printk() { vprintk_func() { vprintk_default() { vprintk_emit() { console_unlock() { console_lock_spinning_enable(); ... printing to console ... panic() { crash_smp_send_stop() { NMI -------------------> HALT } atomic_notifier_call_chain() { printk() { ... console_trylock_spinnning() { // optimistic spin infinitely This hang during panic can be induced when a kdump kernel is loaded, and crash_kexec_post_notifiers=1 is present on the kernel command line. The following script which concurrently writes to /dev/kmsg, and triggers a panic, can result in this hang: #!/bin/bash date # 991 chars (based on log buffer size): chars="$(printf 'a%.0s' {1..991})" while :; do echo $chars > /dev/kmsg done & echo c > /proc/sysrq-trigger & date exit To avoid this deadlock, ensure that console_trylock_spinning() does not allow spinning once a panic has begun. Fixes: dbdda842fe96 ("printk: Add console owner and waiter logic to load balance console writes") Suggested-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20220202171821.179394-3-stephen.s.brennan@oracle.com
2022-02-14printk: Add panic_in_progress helperStephen Brennan
This will be used help avoid deadlocks during panics. Although it would be better to include this in linux/panic.h, it would require that header to include linux/atomic.h as well. On some architectures, this results in a circular dependency as well. So instead add the helper directly to printk.c. Suggested-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20220202171821.179394-2-stephen.s.brennan@oracle.com
2022-02-14swiotlb: fix info leak with DMA_FROM_DEVICEHalil Pasic
The problem I'm addressing was discovered by the LTP test covering cve-2018-1000204. A short description of what happens follows: 1) The test case issues a command code 00 (TEST UNIT READY) via the SG_IO interface with: dxfer_len == 524288, dxdfer_dir == SG_DXFER_FROM_DEV and a corresponding dxferp. The peculiar thing about this is that TUR is not reading from the device. 2) In sg_start_req() the invocation of blk_rq_map_user() effectively bounces the user-space buffer. As if the device was to transfer into it. Since commit a45b599ad808 ("scsi: sg: allocate with __GFP_ZERO in sg_build_indirect()") we make sure this first bounce buffer is allocated with GFP_ZERO. 3) For the rest of the story we keep ignoring that we have a TUR, so the device won't touch the buffer we prepare as if the we had a DMA_FROM_DEVICE type of situation. My setup uses a virtio-scsi device and the buffer allocated by SG is mapped by the function virtqueue_add_split() which uses DMA_FROM_DEVICE for the "in" sgs (here scatter-gather and not scsi generics). This mapping involves bouncing via the swiotlb (we need swiotlb to do virtio in protected guest like s390 Secure Execution, or AMD SEV). 4) When the SCSI TUR is done, we first copy back the content of the second (that is swiotlb) bounce buffer (which most likely contains some previous IO data), to the first bounce buffer, which contains all zeros. Then we copy back the content of the first bounce buffer to the user-space buffer. 5) The test case detects that the buffer, which it zero-initialized, ain't all zeros and fails. One can argue that this is an swiotlb problem, because without swiotlb we leak all zeros, and the swiotlb should be transparent in a sense that it does not affect the outcome (if all other participants are well behaved). Copying the content of the original buffer into the swiotlb buffer is the only way I can think of to make swiotlb transparent in such scenarios. So let's do just that if in doubt, but allow the driver to tell us that the whole mapped buffer is going to be overwritten, in which case we can preserve the old behavior and avoid the performance impact of the extra bounce. Signed-off-by: Halil Pasic <pasic@linux.ibm.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2022-02-13Merge tag 'sched_urgent_for_v5.17_rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fix from Borislav Petkov: "Fix a NULL-ptr dereference when recalculating a sched entity's weight" * tag 'sched_urgent_for_v5.17_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/fair: Fix fault in reweight_entity
2022-02-13Merge tag 'perf_urgent_for_v5.17_rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fix from Borislav Petkov: "Prevent cgroup event list corruption when switching events" * tag 'perf_urgent_for_v5.17_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Fix list corruption in perf_cgroup_switch()
2022-02-12ARM: ixp4xx: Drop custom DMA coherency and bouncingLinus Walleij
The new PCI driver does not need any of this stuff, so just drop it. Cc: iommu@lists.linux-foundation.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Link: https://lore.kernel.org/r/20220211223238.648934-12-linus.walleij@linaro.org Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2022-02-12Merge tag 'seccomp-v5.17-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull seccomp fixes from Kees Cook: "This fixes a corner case of fatal SIGSYS being ignored since v5.15. Along with the signal fix is a change to seccomp so that seeing another syscall after a fatal filter result will cause seccomp to kill the process harder. Summary: - Force HANDLER_EXIT even for SIGNAL_UNKILLABLE - Make seccomp self-destruct after fatal filter results - Update seccomp samples for easier behavioral demonstration" * tag 'seccomp-v5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: samples/seccomp: Adjust sample to also provide kill option seccomp: Invalidate seccomp mode to catch death failures signal: HANDLER_EXIT should clear SIGNAL_UNKILLABLE
2022-02-11sched/fair: Adjust the allowed NUMA imbalance when SD_NUMA spans multiple LLCsMel Gorman
Commit 7d2b5dd0bcc4 ("sched/numa: Allow a floating imbalance between NUMA nodes") allowed an imbalance between NUMA nodes such that communicating tasks would not be pulled apart by the load balancer. This works fine when there is a 1:1 relationship between LLC and node but can be suboptimal for multiple LLCs if independent tasks prematurely use CPUs sharing cache. Zen* has multiple LLCs per node with local memory channels and due to the allowed imbalance, it's far harder to tune some workloads to run optimally than it is on hardware that has 1 LLC per node. This patch allows an imbalance to exist up to the point where LLCs should be balanced between nodes. On a Zen3 machine running STREAM parallelised with OMP to have on instance per LLC the results and without binding, the results are 5.17.0-rc0 5.17.0-rc0 vanilla sched-numaimb-v6 MB/sec copy-16 162596.94 ( 0.00%) 580559.74 ( 257.05%) MB/sec scale-16 136901.28 ( 0.00%) 374450.52 ( 173.52%) MB/sec add-16 157300.70 ( 0.00%) 564113.76 ( 258.62%) MB/sec triad-16 151446.88 ( 0.00%) 564304.24 ( 272.61%) STREAM can use directives to force the spread if the OpenMP is new enough but that doesn't help if an application uses threads and it's not known in advance how many threads will be created. Coremark is a CPU and cache intensive benchmark parallelised with threads. When running with 1 thread per core, the vanilla kernel allows threads to contend on cache. With the patch; 5.17.0-rc0 5.17.0-rc0 vanilla sched-numaimb-v5 Min Score-16 368239.36 ( 0.00%) 389816.06 ( 5.86%) Hmean Score-16 388607.33 ( 0.00%) 427877.08 * 10.11%* Max Score-16 408945.69 ( 0.00%) 481022.17 ( 17.62%) Stddev Score-16 15247.04 ( 0.00%) 24966.82 ( -63.75%) CoeffVar Score-16 3.92 ( 0.00%) 5.82 ( -48.48%) It can also make a big difference for semi-realistic workloads like specjbb which can execute arbitrary numbers of threads without advance knowledge of how they should be placed. Even in cases where the average performance is neutral, the results are more stable. 5.17.0-rc0 5.17.0-rc0 vanilla sched-numaimb-v6 Hmean tput-1 71631.55 ( 0.00%) 73065.57 ( 2.00%) Hmean tput-8 582758.78 ( 0.00%) 556777.23 ( -4.46%) Hmean tput-16 1020372.75 ( 0.00%) 1009995.26 ( -1.02%) Hmean tput-24 1416430.67 ( 0.00%) 1398700.11 ( -1.25%) Hmean tput-32 1687702.72 ( 0.00%) 1671357.04 ( -0.97%) Hmean tput-40 1798094.90 ( 0.00%) 2015616.46 * 12.10%* Hmean tput-48 1972731.77 ( 0.00%) 2333233.72 ( 18.27%) Hmean tput-56 2386872.38 ( 0.00%) 2759483.38 ( 15.61%) Hmean tput-64 2909475.33 ( 0.00%) 2925074.69 ( 0.54%) Hmean tput-72 2585071.36 ( 0.00%) 2962443.97 ( 14.60%) Hmean tput-80 2994387.24 ( 0.00%) 3015980.59 ( 0.72%) Hmean tput-88 3061408.57 ( 0.00%) 3010296.16 ( -1.67%) Hmean tput-96 3052394.82 ( 0.00%) 2784743.41 ( -8.77%) Hmean tput-104 2997814.76 ( 0.00%) 2758184.50 ( -7.99%) Hmean tput-112 2955353.29 ( 0.00%) 2859705.09 ( -3.24%) Hmean tput-120 2889770.71 ( 0.00%) 2764478.46 ( -4.34%) Hmean tput-128 2871713.84 ( 0.00%) 2750136.73 ( -4.23%) Stddev tput-1 5325.93 ( 0.00%) 2002.53 ( 62.40%) Stddev tput-8 6630.54 ( 0.00%) 10905.00 ( -64.47%) Stddev tput-16 25608.58 ( 0.00%) 6851.16 ( 73.25%) Stddev tput-24 12117.69 ( 0.00%) 4227.79 ( 65.11%) Stddev tput-32 27577.16 ( 0.00%) 8761.05 ( 68.23%) Stddev tput-40 59505.86 ( 0.00%) 2048.49 ( 96.56%) Stddev tput-48 168330.30 ( 0.00%) 93058.08 ( 44.72%) Stddev tput-56 219540.39 ( 0.00%) 30687.02 ( 86.02%) Stddev tput-64 121750.35 ( 0.00%) 9617.36 ( 92.10%) Stddev tput-72 223387.05 ( 0.00%) 34081.13 ( 84.74%) Stddev tput-80 128198.46 ( 0.00%) 22565.19 ( 82.40%) Stddev tput-88 136665.36 ( 0.00%) 27905.97 ( 79.58%) Stddev tput-96 111925.81 ( 0.00%) 99615.79 ( 11.00%) Stddev tput-104 146455.96 ( 0.00%) 28861.98 ( 80.29%) Stddev tput-112 88740.49 ( 0.00%) 58288.23 ( 34.32%) Stddev tput-120 186384.86 ( 0.00%) 45812.03 ( 75.42%) Stddev tput-128 78761.09 ( 0.00%) 57418.48 ( 27.10%) Similarly, for embarassingly parallel problems like NPB-ep, there are improvements due to better spreading across LLC when the machine is not fully utilised. vanilla sched-numaimb-v6 Min ep.D 31.79 ( 0.00%) 26.11 ( 17.87%) Amean ep.D 31.86 ( 0.00%) 26.17 * 17.86%* Stddev ep.D 0.07 ( 0.00%) 0.05 ( 24.41%) CoeffVar ep.D 0.22 ( 0.00%) 0.20 ( 7.97%) Max ep.D 31.93 ( 0.00%) 26.21 ( 17.91%) Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com> Tested-by: K Prateek Nayak <kprateek.nayak@amd.com> Link: https://lore.kernel.org/r/20220208094334.16379-3-mgorman@techsingularity.net
2022-02-11sched/fair: Improve consistency of allowed NUMA balance calculationsMel Gorman
There are inconsistencies when determining if a NUMA imbalance is allowed that should be corrected. o allow_numa_imbalance changes types and is not always examining the destination group so both the type should be corrected as well as the naming. o find_idlest_group uses the sched_domain's weight instead of the group weight which is different to find_busiest_group o find_busiest_group uses the source group instead of the destination which is different to task_numa_find_cpu o Both find_idlest_group and find_busiest_group should account for the number of running tasks if a move was allowed to be consistent with task_numa_find_cpu Fixes: 7d2b5dd0bcc4 ("sched/numa: Allow a floating imbalance between NUMA nodes") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com> Link: https://lore.kernel.org/r/20220208094334.16379-2-mgorman@techsingularity.net
2022-02-11lockdep: Correct lock_classes index mappingCheng Jui Wang
A kernel exception was hit when trying to dump /proc/lockdep_chains after lockdep report "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!": Unable to handle kernel paging request at virtual address 00054005450e05c3 ... 00054005450e05c3] address between user and kernel address ranges ... pc : [0xffffffece769b3a8] string+0x50/0x10c lr : [0xffffffece769ac88] vsnprintf+0x468/0x69c ... Call trace: string+0x50/0x10c vsnprintf+0x468/0x69c seq_printf+0x8c/0xd8 print_name+0x64/0xf4 lc_show+0xb8/0x128 seq_read_iter+0x3cc/0x5fc proc_reg_read_iter+0xdc/0x1d4 The cause of the problem is the function lock_chain_get_class() will shift lock_classes index by 1, but the index don't need to be shifted anymore since commit 01bb6f0af992 ("locking/lockdep: Change the range of class_idx in held_lock struct") already change the index to start from 0. The lock_classes[-1] located at chain_hlocks array. When printing lock_classes[-1] after the chain_hlocks entries are modified, the exception happened. The output of lockdep_chains are incorrect due to this problem too. Fixes: f611e8cf98ec ("lockdep: Take read/write status in consideration when generate chainkey") Signed-off-by: Cheng Jui Wang <cheng-jui.wang@mediatek.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20220210105011.21712-1-cheng-jui.wang@mediatek.com
2022-02-11bpf: Emit bpf_timer in vmlinux BTFYonghong Song
Currently the following code in check_and_init_map_value() *(struct bpf_timer *)(dst + map->timer_off) = (struct bpf_timer){}; can help generate bpf_timer definition in vmlinuxBTF. But the code above may not zero the whole structure due to anonymour members and that code will be replaced by memset in the subsequent patch and bpf_timer definition will disappear from vmlinuxBTF. Let us emit the type explicitly so bpf program can continue to use it from vmlinux.h. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220211194948.3141529-1-yhs@fb.com
2022-02-11Merge tag 'acpi-5.17-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull ACPI fixes from Rafael Wysocki: "These revert two commits that turned out to be problematic and fix two issues related to wakeup from suspend-to-idle on x86. Specifics: - Revert a recent change that attempted to avoid issues with conflicting address ranges during PCI initialization, because it turned out to introduce a regression (Hans de Goede). - Revert a change that limited EC GPE wakeups from suspend-to-idle to systems based on Intel hardware, because it turned out that systems based on hardware from other vendors depended on that functionality too (Mario Limonciello). - Fix two issues related to the handling of wakeup interrupts and wakeup events signaled through the EC GPE during suspend-to-idle on x86 (Rafael Wysocki)" * tag 'acpi-5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: x86/PCI: revert "Ignore E820 reservations for bridge windows on newer systems" PM: s2idle: ACPI: Fix wakeup interrupts handling ACPI: PM: s2idle: Cancel wakeup before dispatching EC GPE ACPI: PM: Revert "Only mark EC GPE for wakeup on Intel systems"
2022-02-11Merge tag 'trace-v5.17-rc2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: - Fixes to the RTLA tooling - A fix to a tp_printk overriding tp_printk_stop_on_boot on the command line * tag 'trace-v5.17-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Fix tp_printk option related with tp_printk_stop_on_boot MAINTAINERS: Add RTLA entry rtla: Fix segmentation fault when failing to enable -t rtla/trace: Error message fixup rtla/utils: Fix session duration parsing rtla: Follow kernel version
2022-02-11locking: Add missing __sched attributesMinchan Kim
This patch adds __sched attributes to a few missing places to show blocked function rather than locking function in get_wchan. Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220115231657.84828-1-minchan@kernel.org
2022-02-11copy_process(): Move fd_install() out of sighand->siglock critical sectionWaiman Long
I was made aware of the following lockdep splat: [ 2516.308763] ===================================================== [ 2516.309085] WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected [ 2516.309433] 5.14.0-51.el9.aarch64+debug #1 Not tainted [ 2516.309703] ----------------------------------------------------- [ 2516.310149] stress-ng/153663 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: [ 2516.310512] ffff0000e422b198 (&newf->file_lock){+.+.}-{2:2}, at: fd_install+0x368/0x4f0 [ 2516.310944] and this task is already holding: [ 2516.311248] ffff0000c08140d8 (&sighand->siglock){-.-.}-{2:2}, at: copy_process+0x1e2c/0x3e80 [ 2516.311804] which would create a new lock dependency: [ 2516.312066] (&sighand->siglock){-.-.}-{2:2} -> (&newf->file_lock){+.+.}-{2:2} [ 2516.312446] but this new dependency connects a HARDIRQ-irq-safe lock: [ 2516.312983] (&sighand->siglock){-.-.}-{2:2} : [ 2516.330700] Possible interrupt unsafe locking scenario: [ 2516.331075] CPU0 CPU1 [ 2516.331328] ---- ---- [ 2516.331580] lock(&newf->file_lock); [ 2516.331790] local_irq_disable(); [ 2516.332231] lock(&sighand->siglock); [ 2516.332579] lock(&newf->file_lock); [ 2516.332922] <Interrupt> [ 2516.333069] lock(&sighand->siglock); [ 2516.333291] *** DEADLOCK *** [ 2516.389845] stack backtrace: [ 2516.390101] CPU: 3 PID: 153663 Comm: stress-ng Kdump: loaded Not tainted 5.14.0-51.el9.aarch64+debug #1 [ 2516.390756] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 2516.391155] Call trace: [ 2516.391302] dump_backtrace+0x0/0x3e0 [ 2516.391518] show_stack+0x24/0x30 [ 2516.391717] dump_stack_lvl+0x9c/0xd8 [ 2516.391938] dump_stack+0x1c/0x38 [ 2516.392247] print_bad_irq_dependency+0x620/0x710 [ 2516.392525] check_irq_usage+0x4fc/0x86c [ 2516.392756] check_prev_add+0x180/0x1d90 [ 2516.392988] validate_chain+0x8e0/0xee0 [ 2516.393215] __lock_acquire+0x97c/0x1e40 [ 2516.393449] lock_acquire.part.0+0x240/0x570 [ 2516.393814] lock_acquire+0x90/0xb4 [ 2516.394021] _raw_spin_lock+0xe8/0x154 [ 2516.394244] fd_install+0x368/0x4f0 [ 2516.394451] copy_process+0x1f5c/0x3e80 [ 2516.394678] kernel_clone+0x134/0x660 [ 2516.394895] __do_sys_clone3+0x130/0x1f4 [ 2516.395128] __arm64_sys_clone3+0x5c/0x7c [ 2516.395478] invoke_syscall.constprop.0+0x78/0x1f0 [ 2516.395762] el0_svc_common.constprop.0+0x22c/0x2c4 [ 2516.396050] do_el0_svc+0xb0/0x10c [ 2516.396252] el0_svc+0x24/0x34 [ 2516.396436] el0t_64_sync_handler+0xa4/0x12c [ 2516.396688] el0t_64_sync+0x198/0x19c [ 2517.491197] NET: Registered PF_ATMPVC protocol family [ 2517.491524] NET: Registered PF_ATMSVC protocol family [ 2591.991877] sched: RT throttling activated One way to solve this problem is to move the fd_install() call out of the sighand->siglock critical section. Before commit 6fd2fe494b17 ("copy_process(): don't use ksys_close() on cleanups"), the pidfd installation was done without holding both the task_list lock and the sighand->siglock. Obviously, holding these two locks are not really needed to protect the fd_install() call. So move the fd_install() call down to after the releases of both locks. Link: https://lore.kernel.org/r/20220208163912.1084752-1-longman@redhat.com Fixes: 6fd2fe494b17 ("copy_process(): don't use ksys_close() on cleanups") Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2022-02-10user_events: Validate user payloads for size and null terminationBeau Belgrave
Add validation to ensure data is at or greater than the min size for the fields of the event. If a dynamic array is used and is a type of char, ensure null termination of the array exists. Link: https://lkml.kernel.org/r/20220118204326.2169-7-beaub@linux.microsoft.com Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-10user_events: Optimize writing events by only copying data onceBeau Belgrave
Pass iterator through to probes to allow copying data directly to the probe buffers instead of taking multiple copies. Enables eBPF user and raw iterator types out to programs for no-copy scenarios. Link: https://lkml.kernel.org/r/20220118204326.2169-6-beaub@linux.microsoft.com Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-10user_events: Add basic perf and eBPF supportBeau Belgrave
Adds support to write out user_event data to perf_probe/perf files as well as to any attached eBPF program. Link: https://lkml.kernel.org/r/20220118204326.2169-5-beaub@linux.microsoft.com Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-10user_events: Handle matching arguments from dyn_eventsBeau Belgrave
Ensures that when dynamic events requests a match with arguments that they match what is in the user_event. Link: https://lkml.kernel.org/r/20220118204326.2169-4-beaub@linux.microsoft.com Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-10user_events: Add print_fmt generation support for basic typesBeau Belgrave
Addes print_fmt format generation for basic types that are supported for user processes. Only supports sizes that are the same on 32 and 64 bit. Link: https://lkml.kernel.org/r/20220118204326.2169-3-beaub@linux.microsoft.com Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-10user_events: Add minimal support for trace_event into ftraceBeau Belgrave
Minimal support for interacting with dynamic events, trace_event and ftrace. Core outline of flow between user process, ioctl and trace_event APIs. User mode processes that wish to use trace events to get data into ftrace, perf, eBPF, etc are limited to uprobes today. The user events features enables an ABI for user mode processes to create and write to trace events that are isolated from kernel level trace events. This enables a faster path for tracing from user mode data as well as opens managed code to participate in trace events, where stub locations are dynamic. User processes often want to trace only when it's useful. To enable this a set of pages are mapped into the user process space that indicate the current state of the user events that have been registered. User processes can check if their event is hooked to a trace/probe, and if it is, emit the event data out via the write() syscall. Two new files are introduced into tracefs to accomplish this: user_events_status - This file is mmap'd into participating user mode processes to indicate event status. user_events_data - This file is opened and register/delete ioctl's are issued to create/open/delete trace events that can be used for tracing. The typical scenario is on process start to mmap user_events_status. Processes then register the events they plan to use via the REG ioctl. The ioctl reads and updates the passed in user_reg struct. The status_index of the struct is used to know the byte in the status page to check for that event. The write_index of the struct is used to describe that event when writing out to the fd that was used for the ioctl call. The data must always include this index first when writing out data for an event. Data can be written either by write() or by writev(). For example, in memory: int index; char data[]; Psuedo code example of typical usage: struct user_reg reg; int page_fd = open("user_events_status", O_RDWR); char *page_data = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, page_fd, 0); close(page_fd); int data_fd = open("user_events_data", O_RDWR); reg.size = sizeof(reg); reg.name_args = (__u64)"test"; ioctl(data_fd, DIAG_IOCSREG, &reg); int status_id = reg.status_index; int write_id = reg.write_index; struct iovec io[2]; io[0].iov_base = &write_id; io[0].iov_len = sizeof(write_id); io[1].iov_base = payload; io[1].iov_len = sizeof(payload); if (page_data[status_id]) writev(data_fd, io, 2); User events are also exposed via the dynamic_events tracefs file for both create and delete. Current status is exposed via the user_events_status tracefs file. Simple example to register a user event via dynamic_events: echo u:test >> dynamic_events cat dynamic_events u:test If an event is hooked to a probe, the probe hooked shows up: echo 1 > events/user_events/test/enable cat user_events_status 1:test # Used by ftrace Active: 1 Busy: 1 Max: 4096 If an event is not hooked to a probe, no probe status shows up: echo 0 > events/user_events/test/enable cat user_events_status 1:test Active: 1 Busy: 0 Max: 4096 Users can describe the trace event format via the following format: name[:FLAG1[,FLAG2...] [field1[;field2...]] Each field has the following format: type name Example for char array with a size of 20 named msg: echo 'u:detailed char[20] msg' >> dynamic_events cat dynamic_events u:detailed char[20] msg Data offsets are based on the data written out via write() and will be updated to reflect the correct offset in the trace_event fields. For dynamic data it is recommended to use the new __rel_loc data type. This type will be the same as __data_loc, but the offset is relative to this entry. This allows user_events to not worry about what common fields are being inserted before the data. The above format is valid for both the ioctl and the dynamic_events file. Link: https://lkml.kernel.org/r/20220118204326.2169-2-beaub@linux.microsoft.com Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-10tracing: Save both wakee and current on wakeup eventsSteven Rostedt (Google)
Use the sched_switch function to save both the wakee and the waker comms in the saved cmdlines list when sched_wakeup is done. Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-10tracing: Remove size restriction on synthetic event cmd error loggingTom Zanussi
Currently, synthetic event command error strings are restricted to a length of MAX_FILTER_STR_VAL (256), which is too short for some commands already seen in the wild (with cmd strings longer than that showing up truncated in err_log). Remove the restriction so that no synthetic event command error string is ever truncated. Link: https://lkml.kernel.org/r/0376692396a81d0b795127c66ea92ca5bf60f481.1643399022.git.zanussi@kernel.org Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-10tracing: Remove size restriction on hist trigger cmd error loggingTom Zanussi
Currently, hist trigger command error strings are restricted to a length of MAX_FILTER_STR_VAL (256), which is too short for some commands already seen in the wild (with cmd strings longer than that showing up truncated in err_log). Remove the restriction so that no hist trigger command error string is ever truncated. Link: https://lkml.kernel.org/r/0f9d46407222eaf6632cd3b417bc50a11f401b71.1643399022.git.zanussi@kernel.org Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-10tracing: Remove size restriction on tracing_log_err cmd stringsTom Zanussi
Currently, tracing_log_err.cmd strings are restricted to a length of MAX_FILTER_STR_VAL (256), which is too short for some commands already seen in the wild (with cmd strings longer than that showing up truncated). Remove the restriction so that no command string is ever truncated. Link: https://lkml.kernel.org/r/ca965f23256b350ebd94b3dc1a319f28e8267f5f.1643319703.git.zanussi@kernel.org Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-10seccomp: Invalidate seccomp mode to catch death failuresKees Cook
If seccomp tries to kill a process, it should never see that process again. To enforce this proactively, switch the mode to something impossible. If encountered: WARN, reject all syscalls, and attempt to kill the process again even harder. Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will Drewry <wad@chromium.org> Fixes: 8112c4f140fa ("seccomp: remove 2-phase API") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
2022-02-10signal: HANDLER_EXIT should clear SIGNAL_UNKILLABLEKees Cook
Fatal SIGSYS signals (i.e. seccomp RET_KILL_* syscall filter actions) were not being delivered to ptraced pid namespace init processes. Make sure the SIGNAL_UNKILLABLE doesn't get set for these cases. Reported-by: Robert Święcki <robert@swiecki.net> Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com> Fixes: 00b06da29cf9 ("signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Link: https://lore.kernel.org/lkml/878rui8u4a.fsf@email.froward.int.ebiederm.org
2022-02-10bpf: Fix bpf_prog_pack build for ppc64_defconfigSong Liu
bpf_prog_pack causes build error with powerpc ppc64_defconfig: kernel/bpf/core.c:830:23: error: variably modified 'bitmap' at file scope 830 | unsigned long bitmap[BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)]; | ^~~~~~ This is because the marco expands as: unsigned long bitmap[((((((1UL) << (16 + __pte_index_size)) / (1 << 6))) \ + ((sizeof(long) * 8)) - 1) / ((sizeof(long) * 8)))]; where __pte_index_size is a global variable. Fix it by turning bitmap into a 0-length array. Fixes: 57631054fae6 ("bpf: Introduce bpf_prog_pack allocator") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Song Liu <song@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220211024939.2962537-1-song@kernel.org
2022-02-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-10bpf: Convert bpf_preload.ko to use light skeleton.Alexei Starovoitov
The main change is a move of the single line #include "iterators.lskel.h" from iterators/iterators.c to bpf_preload_kern.c. Which means that generated light skeleton can be used from user space or user mode driver like iterators.c or from the kernel module or the kernel itself. The direct use of light skeleton from the kernel module simplifies the code, since UMD is no longer necessary. The libbpf.a required user space and UMD. The CO-RE in the kernel and generated "loader bpf program" used by the light skeleton are capable to perform complex loading operations traditionally provided by libbpf. In addition UMD approach was launching UMD process every time bpffs has to be mounted. With light skeleton in the kernel the bpf_preload kernel module loads bpf iterators once and pins them multiple times into different bpffs mounts. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209232001.27490-6-alexei.starovoitov@gmail.com
2022-02-10bpf: Update iterators.lskel.h.Alexei Starovoitov
Light skeleton and skel_internal.h have changed. Update iterators.lskel.h. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209232001.27490-5-alexei.starovoitov@gmail.com
2022-02-10bpf: Extend sys_bpf commands for bpf_syscall programs.Alexei Starovoitov
bpf_sycall programs can be used directly by the kernel modules to load programs and create maps via kernel skeleton. . Export bpf_sys_bpf syscall wrapper to be used in kernel skeleton. . Export bpf_map_get to be used in kernel skeleton. . Allow prog_run cmd for bpf_syscall programs with recursion check. . Enable link_create and raw_tp_open cmds. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209232001.27490-2-alexei.starovoitov@gmail.com
2022-02-10Merge tag 'audit-pr-20220209' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit Pull audit fix from Paul Moore: "Another audit fix, this time a single rather small but important fix for an oops/page-fault caused by improperly accessing userspace memory" * tag 'audit-pr-20220209' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit: audit: don't deref the syscall args when checking the openat2 open_how::flags
2022-02-10genirq: Kill irq_chip::parent_deviceMarc Zyngier
Now that noone is using irq_chip::parent_device in the tree, get rid of it. Signed-off-by: Marc Zyngier <maz@kernel.org> Acked-by: Bartosz Golaszewski <brgl@bgdev.pl> Link: https://lore.kernel.org/r/20220201120310.878267-13-maz@kernel.org
2022-02-09Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski
Daniel Borkmann says: ==================== pull-request: bpf-next 2022-02-09 We've added 126 non-merge commits during the last 16 day(s) which contain a total of 201 files changed, 4049 insertions(+), 2215 deletions(-). The main changes are: 1) Add custom BPF allocator for JITs that pack multiple programs into a huge page to reduce iTLB pressure, from Song Liu. 2) Add __user tagging support in vmlinux BTF and utilize it from BPF verifier when generating loads, from Yonghong Song. 3) Add per-socket fast path check guarding from cgroup/BPF overhead when used by only some sockets, from Pavel Begunkov. 4) Continued libbpf deprecation work of APIs/features and removal of their usage from samples, selftests, libbpf & bpftool, from Andrii Nakryiko and various others. 5) Improve BPF instruction set documentation by adding byte swap instructions and cleaning up load/store section, from Christoph Hellwig. 6) Switch BPF preload infra to light skeleton and remove libbpf dependency from it, from Alexei Starovoitov. 7) Fix architecture-agnostic macros in libbpf for accessing syscall arguments from BPF progs for non-x86 architectures, from Ilya Leoshkevich. 8) Rework port members in struct bpf_sk_lookup and struct bpf_sock to be of 16-bit field with anonymous zero padding, from Jakub Sitnicki. 9) Add new bpf_copy_from_user_task() helper to read memory from a different task than current. Add ability to create sleepable BPF iterator progs, from Kenny Yu. 10) Implement XSK batching for ice's zero-copy driver used by AF_XDP and utilize TX batching API from XSK buffer pool, from Maciej Fijalkowski. 11) Generate temporary netns names for BPF selftests to avoid naming collisions, from Hangbin Liu. 12) Implement bpf_core_types_are_compat() with limited recursion for in-kernel usage, from Matteo Croce. 13) Simplify pahole version detection and finally enable CONFIG_DEBUG_INFO_DWARF5 to be selected with CONFIG_DEBUG_INFO_BTF, from Nathan Chancellor. 14) Misc minor fixes to libbpf and selftests from various folks. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (126 commits) selftests/bpf: Cover 4-byte load from remote_port in bpf_sk_lookup bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide libbpf: Fix compilation warning due to mismatched printf format selftests/bpf: Test BPF_KPROBE_SYSCALL macro libbpf: Add BPF_KPROBE_SYSCALL macro libbpf: Fix accessing the first syscall argument on s390 libbpf: Fix accessing the first syscall argument on arm64 libbpf: Allow overriding PT_REGS_PARM1{_CORE}_SYSCALL selftests/bpf: Skip test_bpf_syscall_macro's syscall_arg1 on arm64 and s390 libbpf: Fix accessing syscall arguments on riscv libbpf: Fix riscv register names libbpf: Fix accessing syscall arguments on powerpc selftests/bpf: Use PT_REGS_SYSCALL_REGS in bpf_syscall_macro libbpf: Add PT_REGS_SYSCALL_REGS macro selftests/bpf: Fix an endianness issue in bpf_syscall_macro test bpf: Fix bpf_prog_pack build HPAGE_PMD_SIZE bpf: Fix leftover header->pages in sparc and powerpc code. libbpf: Fix signedness bug in btf_dump_array_data() selftests/bpf: Do not export subtest as standalone test bpf, x86_64: Fail gracefully on bpf_jit_binary_pack_finalize failures ... ==================== Link: https://lore.kernel.org/r/20220209210050.8425-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-09audit: don't deref the syscall args when checking the openat2 open_how::flagsPaul Moore
As reported by Jeff, dereferencing the openat2 syscall argument in audit_match_perm() to obtain the open_how::flags can result in an oops/page-fault. This patch fixes this by using the open_how struct that we store in the audit_context with audit_openat2_how(). Independent of this patch, Richard Guy Briggs posted a similar patch to the audit mailing list roughly 40 minutes after this patch was posted. Cc: stable@vger.kernel.org Fixes: 1c30e3af8a79 ("audit: add support for the openat2 syscall") Reported-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-02-09genirq: Allow the PM device to originate from irq domainMarc Zyngier
As a preparation to moving the reference to the device used for runtime power management, add a new 'dev' field to the irqdomain structure for that exact purpose. The irq_chip_pm_{get,put}() helpers are made aware of the dual location via a new private helper. No functional change intended. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Tony Lindgren <tony@atomide.com> Acked-by: Bartosz Golaszewski <brgl@bgdev.pl> Link: https://lore.kernel.org/r/20220201120310.878267-2-maz@kernel.org
2022-02-08bpf: Fix bpf_prog_pack build HPAGE_PMD_SIZESong Liu
Fix build with CONFIG_TRANSPARENT_HUGEPAGE=n with BPF_PROG_PACK_SIZE as PAGE_SIZE. Fixes: 57631054fae6 ("bpf: Introduce bpf_prog_pack allocator") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Song Liu <song@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220208220509.4180389-3-song@kernel.org
2022-02-08tracing: Fix tp_printk option related with tp_printk_stop_on_bootJaeSang Yoo
The kernel parameter "tp_printk_stop_on_boot" starts with "tp_printk" which is the same as another kernel parameter "tp_printk". If "tp_printk" setup is called before the "tp_printk_stop_on_boot", it will override the latter and keep it from being set. This is similar to other kernel parameter issues, such as: Commit 745a600cf1a6 ("um: console: Ignore console= option") or init/do_mounts.c:45 (setup function of "ro" kernel param) Fix it by checking for a "_" right after the "tp_printk" and if that exists do not process the parameter. Link: https://lkml.kernel.org/r/20220208195421.969326-1-jsyoo5b@gmail.com Signed-off-by: JaeSang Yoo <jsyoo5b@gmail.com> [ Fixed up change log and added space after if condition ] Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-08rcu-tasks: Set ->percpu_enqueue_shift to zero upon contentionPaul E. McKenney
Currently, call_rcu_tasks_generic() sets ->percpu_enqueue_shift to order_base_2(nr_cpu_ids) upon encountering sufficient contention. This does not shift to use of non-CPU-0 callback queues as intended, but rather continues using only CPU 0's queue. Although this does provide some decrease in contention due to spreading work over multiple locks, it is not the dramatic decrease that was intended. This commit therefore makes call_rcu_tasks_generic() set ->percpu_enqueue_shift to 0. Reported-by: Neeraj Upadhyay <quic_neeraju@quicinc.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>