- 19 Apr, 2021 13 commits
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Kan Liang authored
Each Hybrid PMU has to check and update its own extra registers before registration. The intel_pmu_check_extra_regs will be reused later to check the extra registers of each hybrid PMU. Signed-off-by:
Kan Liang <kan.liang@linux.intel.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Andi Kleen <ak@linux.intel.com> Link: https://lkml.kernel.org/r/1618237865-33448-14-git-send-email-kan.liang@linux.intel.com
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Kan Liang authored
Each Hybrid PMU has to check and update its own event constraints before registration. The intel_pmu_check_event_constraints will be reused later to check the event constraints of each hybrid PMU. Signed-off-by:
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Kan Liang authored
Each Hybrid PMU has to check its own number of counters and mask fixed counters before registration. The intel_pmu_check_num_counters will be reused later to check the number of the counters for each hybrid PMU. Signed-off-by:
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Kan Liang authored
Different hybrid PMU may have different extra registers, e.g. Core PMU may have offcore registers, frontend register and ldlat register. Atom core may only have offcore registers and ldlat register. Each hybrid PMU should use its own extra_regs. An Intel Hybrid system should always have extra registers. Unconditionally allocate shared_regs for Intel Hybrid system. Signed-off-by:
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Kan Liang authored
The events are different among hybrid PMUs. Each hybrid PMU should use its own event constraints. Signed-off-by:
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Kan Liang authored
The hardware cache events are different among hybrid PMUs. Each hybrid PMU should have its own hw cache event table. Suggested-by:
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Kan Liang authored
The unconstrained value depends on the number of GP and fixed counters. Each hybrid PMU should use its own unconstrained. Suggested-by:
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Kan Liang authored
The number of GP and fixed counters are different among hybrid PMUs. Each hybrid PMU should use its own counter related information. When handling a certain hybrid PMU, apply the number of counters from the corresponding hybrid PMU. When reserving the counters in the initialization of a new event, reserve all possible counters. The number of counter recored in the global x86_pmu is for the architecture counters which are available for all hybrid PMUs. KVM doesn't support the hybrid PMU yet. Return the number of the architecture counters for now. For the functions only available for the old platforms, e.g., intel_pmu_drain_pebs_nhm(), nothing is changed. Signed-off-by:
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Kan Liang authored
The intel_ctrl is the counter mask of a PMU. The PMU counter information may be different among hybrid PMUs, each hybrid PMU should use its own intel_ctrl to check and access the counters. When handling a certain hybrid PMU, apply the intel_ctrl from the corresponding hybrid PMU. When checking the HW existence, apply the PMU and number of counters from the corresponding hybrid PMU as well. Perf will check the HW existence for each Hybrid PMU before registration. Expose the check_hw_exists() for a later patch. Signed-off-by:
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Kan Liang authored
Some platforms, e.g. Alder Lake, have hybrid architecture. Although most PMU capabilities are the same, there are still some unique PMU capabilities for different hybrid PMUs. Perf should register a dedicated pmu for each hybrid PMU. Add a new struct x86_hybrid_pmu, which saves the dedicated pmu and capabilities for each hybrid PMU. The architecture MSR, MSR_IA32_PERF_CAPABILITIES, only indicates the architecture features which are available on all hybrid PMUs. The architecture features are stored in the global x86_pmu.intel_cap. For Alder Lake, the model-specific features are perf metrics and PEBS-via-PT. The corresponding bits of the global x86_pmu.intel_cap should be 0 for these two features. Perf should not use the global intel_cap to check the features on a hybrid system. Add a dedicated intel_cap in the x86_hybrid_pmu to store the model-specific capabilities. Use the dedicated intel_cap to replace the global intel_cap for thse two features. The dedicated intel_cap will be set in the following "Add Alder Lake Hybrid support" patch. Add is_hybrid() to distinguish a hybrid system. ADL may have an alternative configuration. With that configuration, the X86_FEATURE_HYBRID_CPU is not set. Perf cannot rely on the feature bit. Add a new static_key_false, perf_is_hybrid, to indicate a hybrid system. It will be assigned in the following "Add Alder Lake Hybrid support" patch as well. Suggested-by:
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Kan Liang authored
Some platforms, e.g. Alder Lake, have hybrid architecture. In the same package, there may be more than one type of CPU. The PMU capabilities are different among different types of CPU. Perf will register a dedicated PMU for each type of CPU. Add a 'pmu' variable in the struct cpu_hw_events to track the dedicated PMU of the current CPU. Current x86_get_pmu() use the global 'pmu', which will be broken on a hybrid platform. Modify it to apply the 'pmu' of the specific CPU. Initialize the per-CPU 'pmu' variable with the global 'pmu'. There is nothing changed for the non-hybrid platforms. The is_x86_event() will be updated in the later patch ("perf/x86: Register hybrid PMUs") for hybrid platforms. For the non-hybrid platforms, nothing is changed here. Suggested-by: -
Ricardo Neri authored
On processors with Intel Hybrid Technology (i.e., one having more than one type of CPU in the same package), all CPUs support the same instruction set and enumerate the same features on CPUID. Thus, all software can run on any CPU without restrictions. However, there may be model-specific differences among types of CPUs. For instance, each type of CPU may support a different number of performance counters. Also, machine check error banks may be wired differently. Even though most software will not care about these differences, kernel subsystems dealing with these differences must know. Add and expose a new helper function get_this_hybrid_cpu_type() to query the type of the current hybrid CPU. The function will be used later in the perf subsystem. The Intel Software Developer's Manual defines the CPU type as 8-bit identifier. Signed-off-by:
Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by:
Tony Luck <tony.luck@intel.com> Reviewed-by:
Len Brown <len.brown@intel.com> Acked-by:
Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/1618237865-33448-3-git-send-email-kan.liang@linux.intel.com
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Ricardo Neri authored
Add feature enumeration to identify a processor with Intel Hybrid Technology: one in which CPUs of more than one type are the same package. On a hybrid processor, all CPUs support the same homogeneous (i.e., symmetric) instruction set. All CPUs enumerate the same features in CPUID. Thus, software (user space and kernel) can run and migrate to any CPU in the system as well as utilize any of the enumerated features without any change or special provisions. The main difference among CPUs in a hybrid processor are power and performance properties. Signed-off-by:
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- 16 Apr, 2021 15 commits
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Nathan Chancellor authored
dev_attr_show() calls the __uncore_*_show() functions via an indirect call but their type does not currently match the type of the show() member in 'struct device_attribute', resulting in a Control Flow Integrity violation. $ cat /sys/devices/amd_l3/format/umask config:8-15 $ dmesg | grep "CFI failure" [ 1258.174653] CFI failure (target: __uncore_umask_show...): Update the type in the DEFINE_UNCORE_FORMAT_ATTR macro to match 'struct device_attribute' so that there is no more CFI violation. Fixes: 06f2c245 ("perf/amd/uncore: Prepare to scale for more attributes that vary per family") Signed-off-by:
Nathan Chancellor <nathan@kernel.org> Signed-off-by:
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Nathan Chancellor authored
dev_attr_show() calls _iommu_event_show() via an indirect call but _iommu_event_show()'s type does not currently match the type of the show() member in 'struct device_attribute', resulting in a Control Flow Integrity violation. $ cat /sys/devices/amd_iommu_1/events/mem_dte_hit csource=0x0a $ dmesg | grep "CFI failure" [ 3526.735140] CFI failure (target: _iommu_event_show...): Change _iommu_event_show() and 'struct amd_iommu_event_desc' to 'struct device_attribute' so that there is no more CFI violation. Fixes: 7be6296f ("perf/x86/amd: AMD IOMMU Performance Counter PERF uncore PMU implementation") Signed-off-by:
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Namhyung Kim authored
This patch adds a new software event to count context switches involving cgroup switches. So it's counted only if cgroups of previous and next tasks are different. Note that it only checks the cgroups in the perf_event subsystem. For cgroup v2, it shouldn't matter anyway. One can argue that we can do this by using existing sched_switch event with eBPF. But some systems might not have eBPF for some reason so I'd like to add this as a simple way. Signed-off-by:
Namhyung Kim <namhyung@kernel.org> Signed-off-by:
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Namhyung Kim authored
In some cases, we need to check more than whether the software event is enabled. So split the condition check and the actual event handling. This is a preparation for the next change. Suggested-by:
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Kan Liang authored
The 'running' variable is only used in the P4 PMU. Current perf sets the variable in the critical function x86_pmu_start(), which wastes cycles for everybody not running on P4. Move cpuc->running into the P4 specific p4_pmu_enable_event(). Add a static per-CPU 'p4_running' variable to replace the 'running' variable in the struct cpu_hw_events. Saves space for the generic structure. The p4_pmu_enable_all() also invokes the p4_pmu_enable_event(), but it should not set cpuc->running. Factor out __p4_pmu_enable_event() for p4_pmu_enable_all(). Suggested-by:
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Marco Elver authored
Add kselftest to test that remove_on_exec removes inherited events from child tasks. Signed-off-by:
Marco Elver <elver@google.com> Signed-off-by:
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Marco Elver authored
Add a kselftest for testing process-wide perf events with synchronous SIGTRAP on events (using breakpoints). In particular, we want to test that changes to the event propagate to all children, and the SIGTRAPs are in fact synchronously sent to the thread where the event occurred. Note: The "signal_stress" test case is also added later in the series to perf tool's built-in tests. The test here is more elaborate in that respect, which on one hand avoids bloating the perf tool unnecessarily, but we also benefit from structured tests with TAP-compliant output that the kselftest framework provides. Signed-off-by:
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Marco Elver authored
Adds bit perf_event_attr::sigtrap, which can be set to cause events to send SIGTRAP (with si_code TRAP_PERF) to the task where the event occurred. The primary motivation is to support synchronous signals on perf events in the task where an event (such as breakpoints) triggered. To distinguish perf events based on the event type, the type is set in si_errno. For events that are associated with an address, si_addr is copied from perf_sample_data. The new field perf_event_attr::sig_data is copied to si_perf, which allows user space to disambiguate which event (of the same type) triggered the signal. For example, user space could encode the relevant information it cares about in sig_data. We note that the choice of an opaque u64 provides the simplest and most flexible option. Alternatives where a reference to some user space data is passed back suffer from the problem that modification of referenced data (be it the event fd, or the perf_event_attr) can race with the signal being delivered (of course, the same caveat applies if user space decides to store a pointer in sig_data, but the ABI explicitly avoids prescribing such a design). Suggested-by:
Dmitry Vyukov <dvyukov@google.com> Link: https://lore.kernel.org/lkml/YBv3rAT566k+6zjg@hirez.programming.kicks-ass.net/
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Marco Elver authored
Introduces the TRAP_PERF si_code, and associated siginfo_t field si_perf. These will be used by the perf event subsystem to send signals (if requested) to the task where an event occurred. Signed-off-by:
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Marco Elver authored
Adds bit perf_event_attr::remove_on_exec, to support removing an event from a task on exec. This option supports the case where an event is supposed to be process-wide only, and should not propagate beyond exec, to limit monitoring to the original process image only. Suggested-by:
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Marco Elver authored
Adds bit perf_event_attr::inherit_thread, to restricting inheriting events only if the child was cloned with CLONE_THREAD. This option supports the case where an event is supposed to be process-wide only (including subthreads), but should not propagate beyond the current process's shared environment. Suggested-by:
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Marco Elver authored
As with other ioctls (such as PERF_EVENT_IOC_{ENABLE,DISABLE}), fix up handling of PERF_EVENT_IOC_MODIFY_ATTRIBUTES to also apply to children. Suggested-by: -
Peter Zijlstra authored
Make perf_event_exit_event() more robust, such that we can use it from other contexts. Specifically the up and coming remove_on_exec. For this to work we need to address a few issues. Remove_on_exec will not destroy the entire context, so we cannot rely on TASK_TOMBSTONE to disable event_function_call() and we thus have to use perf_remove_from_context(). When using perf_remove_from_context(), there's two races to consider. The first is against close(), where we can have concurrent tear-down of the event. The second is against child_list iteration, which should not find a half baked event. To address this, teach perf_remove_from_context() to special case !ctx->is_active and about DETACH_CHILD. [ elver@google.com: fix racing parent/child exit in sync_child_event(). ] Signed-off-by:
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Alexander Shishkin authored
Turns out, the default setting of attr.aux_watermark to half of the total buffer size is not very useful, especially with smaller buffers. The problem is that, after half of the buffer is filled up, the kernel updates ->aux_head and sets up the next "transaction", while observing that ->aux_tail is still zero (as userspace haven't had the chance to update it), meaning that the trace will have to stop at the end of this second "transaction". This means, for example, that the second PERF_RECORD_AUX in every trace comes with TRUNCATED flag set. Setting attr.aux_watermark to quarter of the buffer gives enough space for the ->aux_tail update to be observed and prevents the data loss. The obligatory before/after showcase: > # perf_before record -e intel_pt//u -m,8 uname > Linux > [ perf record: Woken up 6 times to write data ] > Warning: > AUX data lost 4 times out of 10! > > [ perf record: Captured and wrote 0.099 MB perf.data ] > # perf record -e intel_pt//u -m,8 uname > Linux > [ perf record: Woken up 4 times to write data ] > [ perf record: Captured and wrote 0.039 MB perf.data ] The effect is still visible with large workloads and large buffers, although less pronounced. Signed-off-by:
Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by:
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Alexander Shishkin authored
Currently, we start allocating AUX pages half the size of the total requested AUX buffer size, ignoring the attr.aux_watermark setting. This, in turn, makes intel_pt driver disregard the watermark also, as it uses page order for its SG (ToPA) configuration. Now, this can be fixed in the intel_pt PMU driver, but seeing as it's the only one currently making use of high order allocations, there is no reason not to fix the allocator instead. This way, any other driver wishing to add this support would not have to worry about this. Signed-off-by:
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- 02 Apr, 2021 6 commits
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Alexander Antonov authored
IIO stacks to PMON mapping on Skylake servers is exposed through introduced early attributes /sys/devices/uncore_iio_<pmu_idx>/dieX, where dieX is a file which holds "Segment:Root Bus" for PCIe root port which can be monitored by that IIO PMON block. These sysfs attributes are disabled for multiple segment topologies except VMD domains which start at 0x10000. This patch removes the limitation and enables IIO stacks to PMON mapping for multi-segment Skylake servers by introducing segment-aware intel_uncore_topology structure and attributing the topology configuration to the segment in skx_iio_get_topology() function. Reported-by:
kernel test robot <lkp@intel.com> Signed-off-by:
Alexander Antonov <alexander.antonov@linux.intel.com> Signed-off-by:
Kyle Meyer <kyle.meyer@hpe.com> Link: https://lkml.kernel.org/r/20210323150507.2013-1-alexander.antonov@linux.intel.com
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Kan Liang authored
The discovery table provides the generic uncore block information for the MMIO type of uncore blocks, which is good enough to provide basic uncore support. The box control field is composed of the BAR address and box control offset. When initializing the uncore blocks, perf should ioremap the address from the box control field. Implement the generic support for the MMIO type of uncore block. Signed-off-by:
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Kan Liang authored
The discovery table provides the generic uncore block information for the PCI type of uncore blocks, which is good enough to provide basic uncore support. The PCI BUS and DEVFN information can be retrieved from the box control field. Introduce the uncore_pci_pmus_register() to register all the PCICFG type of uncore blocks. The old PCI probe/remove way is dropped. The PCI BUS and DEVFN information are different among dies. Add box_ctls to store the box control field of each die. Add a new BUS notifier for the PCI type of uncore block to support the hotplug. If the device is "hot remove", the corresponding registered PMU has to be unregistered. Perf cannot locate the PMU by searching a const pci_device_id table, because the discovery tables don't provide such information. Introduce uncore_pci_find_dev_pmu_from_types() to search the whole uncore_pci_uncores for the PMU. Implement generic support for the PCI type of uncore block. Signed-off-by:
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Kan Liang authored
Perf will use a similar method to the PCI sub driver to register the PMUs for the PCI type of uncore blocks. The method requires a BUS notifier to support hotplug. The current BUS notifier cannot be reused, because it searches a const id_table for the corresponding registered PMU. The PCI type of uncore blocks in the discovery tables doesn't provide an id_table. Factor out uncore_bus_notify() and add the pointer of an id_table as a parameter. The uncore_bus_notify() will be reused in the following patch. The current BUS notifier is only used by the PCI sub driver. Its name is too generic. Rename it to uncore_pci_sub_notifier, which is specific for the PCI sub driver. Signed-off-by:
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Kan Liang authored
The discovery table provides the generic uncore block information for the MSR type of uncore blocks, e.g., the counter width, the number of counters, the location of control/counter registers, which is good enough to provide basic uncore support. It can be used as a fallback solution when the kernel doesn't support a platform. The name of the uncore box cannot be retrieved from the discovery table. uncore_type_&typeID_&boxID will be used as its name. Save the type ID and the box ID information in the struct intel_uncore_type. Factor out uncore_get_pmu_name() to handle different naming methods. Implement generic support for the MSR type of uncore block. Some advanced features, such as filters and constraints, cannot be retrieved from discovery tables. Features that rely on that information are not be supported here. Signed-off-by:
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Kan Liang authored
A self-describing mechanism for the uncore PerfMon hardware has been introduced with the latest Intel platforms. By reading through an MMIO page worth of information, perf can 'discover' all the standard uncore PerfMon registers in a machine. The discovery mechanism relies on BIOS's support. With a proper BIOS, a PCI device with the unique capability ID 0x23 can be found on each die. Perf can retrieve the information of all available uncore PerfMons from the device via MMIO. The information is composed of one global discovery table and several unit discovery tables. - The global discovery table includes global uncore information of the die, e.g., the address of the global control register, the offset of the global status register, the number of uncore units, the offset of unit discovery tables, etc. - The unit discovery table includes generic uncore unit information, e.g., the access type, the counter width, the address of counters, the address of the counter control, the unit ID, the unit type, etc. The unit is also called "box" in the code. Perf can provide basic uncore support based on this information with the following patches. To locate the PCI device with the discovery tables, check the generic PCI ID first. If it doesn't match, go through the entire PCI device tree and locate the device with the unique capability ID. The uncore information is similar among dies. To save parsing time and space, only completely parse and store the discovery tables on the first die and the first box of each die. The parsed information is stored in an RB tree structure, intel_uncore_discovery_type. The size of the stored discovery tables varies among platforms. It's around 4KB for a Sapphire Rapids server. If a BIOS doesn't support the 'discovery' mechanism, the uncore driver will exit with -ENODEV. There is nothing changed. Add a module parameter to disable the discovery feature. If a BIOS gets the discovery tables wrong, users can have an option to disable the feature. For the current patchset, the uncore driver will exit with -ENODEV. In the future, it may fall back to the hardcode uncore driver on a known platform. Signed-off-by:
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- 16 Mar, 2021 4 commits
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Ondrej Mosnacek authored
Currently, the lockdown state is queried unconditionally, even though its result is used only if the PERF_SAMPLE_REGS_INTR bit is set in attr.sample_type. While that doesn't matter in case of the Lockdown LSM, it causes trouble with the SELinux's lockdown hook implementation. SELinux implements the locked_down hook with a check whether the current task's type has the corresponding "lockdown" class permission ("integrity" or "confidentiality") allowed in the policy. This means that calling the hook when the access control decision would be ignored generates a bogus permission check and audit record. Fix this by checking sample_type first and only calling the hook when its result would be honored. Fixes: b0c8fdc7 ("lockdown: Lock down perf when in confidentiality mode") Signed-off-by:Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by:
Paul Moore <paul@paul-moore.com> Link: https://lkml.kernel.org/r/20210224215628.192519-1-omosnace@redhat.com
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Namhyung Kim authored
For cpu events, it'd better allocating them in the corresponding node memory as they would be mostly accessed by the target cpu. Although perf tools sets the cpu affinity before calling perf_event_open, there are places it doesn't (notably perf record) and we should consider other external users too. Signed-off-by:
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Namhyung Kim authored
The kernel can allocate a lot of struct perf_event when profiling. For example, 256 cpu x 8 events x 20 cgroups = 40K instances of the struct would be allocated on a large system. The size of struct perf_event in my setup is 1152 byte. As it's allocated by kmalloc, the actual allocation size would be rounded up to 2K. Then there's 896 byte (~43%) of waste per instance resulting in total ~35MB with 40K instances. We can create a dedicated kmem_cache to avoid such a big unnecessary memory consumption. With this change, I can see below (note this machine has 112 cpus). # grep perf_event /proc/slabinfo perf_event 224 784 1152 7 2 : tunables 24 12 8 : slabdata 112 112 0 The sixth column is pages-per-slab which is 2, and the fifth column is obj-per-slab which is 7. Thus actually it can use 1152 x 7 = 8064 byte in the 8K, and wasted memory is (8192 - 8064) / 7 = ~18 byte per instance. Signed-off-by:
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Namhyung Kim authored
I found the ring buffer pages are allocated in the node but the ring buffer itself is not. Let's convert it to use kzalloc_node() too. Signed-off-by:
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- 14 Mar, 2021 2 commits
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Linus Torvalds authored
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Alexey Dobriyan authored
Doing a prctl(PR_SET_MM, PR_SET_MM_AUXV, addr, 1); will copy 1 byte from userspace to (quite big) on-stack array and then stash everything to mm->saved_auxv. AT_NULL terminator will be inserted at the very end. /proc/*/auxv handler will find that AT_NULL terminator and copy original stack contents to userspace. This devious scheme requires CAP_SYS_RESOURCE. Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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