kernel/linux.git/arch/powerpc/perf, branch master

powerpc, perf: Check that current->mm is alive before getting user callchain

2026-03-12T05:32:55+00:00

It may happen that mm is already released, which leads to kernel panic. This adds the NULL check for current->mm, similarly to commit 20afc60f892d ("x86, perf: Check that current->mm is alive before getting user callchain"). I was getting this panic when running a profiling BPF program (profile.py from bcc-tools): [26215.051935] Kernel attempted to read user page (588) - exploit attempt? (uid: 0) [26215.051950] BUG: Kernel NULL pointer dereference on read at 0x00000588 [26215.051952] Faulting instruction address: 0xc00000000020fac0 [26215.051957] Oops: Kernel access of bad area, sig: 11 [#1] [...] [26215.052049] Call Trace: [26215.052050] [c000000061da6d30] [c00000000020fc10] perf_callchain_user_64+0x2d0/0x490 (unreliable) [26215.052054] [c000000061da6dc0] [c00000000020f92c] perf_callchain_user+0x1c/0x30 [26215.052057] [c000000061da6de0] [c0000000005ab2a0] get_perf_callchain+0x100/0x360 [26215.052063] [c000000061da6e70] [c000000000573bc8] bpf_get_stackid+0x88/0xf0 [26215.052067] [c000000061da6ea0] [c008000000042258] bpf_prog_16d4ab9ab662f669_do_perf_event+0xf8/0x274 [...] In addition, move storing the top-level stack entry to generic perf_callchain_user to make sure the top-evel entry is always captured, even if current->mm is NULL. Fixes: 20002ded4d93 ("perf_counter: powerpc: Add callchain support") Signed-off-by: Viktor Malik Tested-by: Qiao Zhao Tested-by: Venkat Rao Bagalkote Reviewed-by: Saket Kumar Bhaskar [Maddy: fixed message to avoid checkpatch format style error] Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260309144045.169427-1-vmalik@redhat.com

Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses

2026-02-22T16:26:33+00:00

Conversion performed via this Coccinelle script: // SPDX-License-Identifier: GPL-2.0-only // Options: --include-headers-for-types --all-includes --include-headers --keep-comments virtual patch @gfp depends on patch && !(file in "tools") && !(file in "samples")@ identifier ALLOC = {kmalloc_obj,kmalloc_objs,kmalloc_flex, kzalloc_obj,kzalloc_objs,kzalloc_flex, kvmalloc_obj,kvmalloc_objs,kvmalloc_flex, kvzalloc_obj,kvzalloc_objs,kvzalloc_flex}; @@ ALLOC(... - , GFP_KERNEL ) $ make coccicheck MODE=patch COCCI=gfp.cocci Build and boot tested x86_64 with Fedora 42's GCC and Clang: Linux version 6.19.0+ (user@host) (gcc (GCC) 15.2.1 20260123 (Red Hat 15.2.1-7), GNU ld version 2.44-12.fc42) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Linux version 6.19.0+ (user@host) (clang version 20.1.8 (Fedora 20.1.8-4.fc42), LLD 20.1.8) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Signed-off-by: Kees Cook Signed-off-by: Linus Torvalds

Convert more 'alloc_obj' cases to default GFP_KERNEL arguments

2026-02-22T04:03:00+00:00

This converts some of the visually simpler cases that have been split over multiple lines. I only did the ones that are easy to verify the resulting diff by having just that final GFP_KERNEL argument on the next line. Somebody should probably do a proper coccinelle script for this, but for me the trivial script actually resulted in an assertion failure in the middle of the script. I probably had made it a bit _too_ trivial. So after fighting that far a while I decided to just do some of the syntactically simpler cases with variations of the previous 'sed' scripts. The more syntactically complex multi-line cases would mostly really want whitespace cleanup anyway. Signed-off-by: Linus Torvalds

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

powerpc/perf/vpa-dtl: Handle the writing of perf record when aux wake up is needed

2025-09-22T09:18:57+00:00

Handle the case when the aux buffer is going to be full and data needs to be written to the data file. perf_aux_output_begin() function checks if there is enough space depending on the values of aux_wakeup and aux_watermark which is part of "struct perf_buffer". Inorder to maintain where to write to aux buffer, add two fields to "struct vpa_pmu_buf". Field "threshold" to indicate total possible DTL entries that can be contained in aux buffer and field "full" to indicate anytime when buffer is full. In perf_aux_output_end, there is check to see if wake up is needed based on aux head value. In vpa_dtl_capture_aux(), check if there is enough space to contain the DTL data. If not, save the data for available memory and set full to true. Set head of private aux to zero when buffer is full so that next data will be copied to beginning of the buffer. The address used for copying to aux is "aux_copy_buf + buf->head". So once buffer is full, set head to zero, so that next time it will be written from start of the buffer. Signed-off-by: Athira Rajeev Tested-by: Tejas Manhas Tested-by: Venkat Rao Bagalkote Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20250915102947.26681-7-atrajeev@linux.ibm.com

powerpc/perf/vpa-dtl: Add support to capture DTL data in aux buffer

2025-09-22T09:18:57+00:00

vpa dtl pmu has one hrtimer added per vpa-dtl pmu thread. When the hrtimer expires, in the timer handler, code is added to save the DTL data to perf event record via vpa_dtl_capture_aux() function. The DTL (Dispatch Trace Log) contains information about dispatch/preempt, enqueue time etc. We directly copy the DTL buffer data as part of auxiliary buffer. Data will be written to disk only when the allocated buffer is full. By this approach, all the DTL data will be present as-is in the perf.data. The data will be post-processed in perf tools side when doing perf report/perf script and this will avoid time taken to create samples in the kernel space. To corelate each DTL entry with other events across CPU's, we need to map timebase from "struct dtl_entry" which phyp provides with boot timebase. This also needs timebase frequency. Define "struct boottb_freq" to save these details. Added changes to capture the Dispatch Trace Log details to AUX buffer in vpa_dtl_dump_sample_data(). Boot timebase and frequency needs to be saved only at once, added field to indicate this as part of "vpa_pmu_buf" structure. perf_aux_output_begin: This function is called before writing to AUX area. This returns the pointer to aux area private structure, ie "struct vpa_pmu_buf". The function obtains the output handle (used in perf_aux_output_end). when capture completes in vpa_dtl_capture_aux(), call perf_aux_output_end() to commit the recorded data. perf_aux_output_end() is called to move the aux->head of "struct perf_buffer" to indicate size of data in aux buffer. aux_tail will be moved in perf tools side when writing the data from aux buffer to perf.data file in disk. It is responsiblity of PMU driver to make sure data is copied between perf_aux_output_begin and perf_aux_output_end. Signed-off-by: Athira Rajeev Tested-by: Tejas Manhas Tested-by: Venkat Rao Bagalkote Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20250915102947.26681-6-atrajeev@linux.ibm.com

powerpc/perf/vpa-dtl: Add support to setup and free aux buffer for capturing DTL data

2025-09-22T09:18:57+00:00

vpa dtl pmu has one hrtimer added per vpa-dtl pmu thread. When the hrtimer expires, in the timer handler, code is added to save the DTL data to perf event record. DTL (Dispatch Trace Log) contains information about dispatch/preempt, enqueue time etc. We directly copy the DTL buffer data as part of auxiliary buffer and it will be postprocessed later. To enable the support for aux buffer, add the PMU callbacks for setup_aux and free_aux. In setup_aux, set up pmu-private data structures for an AUX area. rb_alloc_aux uses "alloc_pages_node" and returns pointer to each page address. Map these pages to contiguous space using vmap and use that as base address. The aux private data structure ie, "struct vpa_pmu_buf" mainly saves: 1. buf->base: aux buffer base address 2. buf->head: offset from base address where data will be written to. 3. buf->size: Size of allocated memory free_aux will free pmu-private AUX data structures. Signed-off-by: Athira Rajeev Tested-by: Tejas Manhas Tested-by: Venkat Rao Bagalkote Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20250915102947.26681-5-atrajeev@linux.ibm.com

powerpc/vpa_dtl: Add interface to expose vpa dtl counters via perf

2025-09-22T09:18:57+00:00

The pseries Shared Processor Logical Partition(SPLPAR) machines can retrieve a log of dispatch and preempt events from the hypervisor using data from Disptach Trace Log(DTL) buffer. With this information, user can retrieve when and why each dispatch & preempt has occurred. Added an interface to expose the Virtual Processor Area(VPA) DTL counters via perf. The following events are available and exposed in sysfs: vpa_dtl/dtl_cede/ - Trace voluntary (OS initiated) virtual processor waits vpa_dtl/dtl_preempt/ - Trace time slice preempts vpa_dtl/dtl_fault/ - Trace virtual partition memory page faults. vpa_dtl/dtl_all/ - Trace all (dtl_cede/dtl_preempt/dtl_fault) Added interface defines supported event list, config fields for the event attributes and their corresponding bit values which are exported via sysfs. User could use the standard perf tool to access perf events exposed via vpa-dtl pmu. The VPA DTL PMU counters do not interrupt on overflow or generate any PMI interrupts. Therefore, the kernel needs to poll the counters, added hrtimer code to do that. The timer interval can be provided by user via sample_period field in nano seconds. There is one hrtimer added per vpa-dtl pmu thread. To ensure there are no other conflicting dtl users (example: debugfs dtl or /proc/powerpc/vcpudispatch_stats), interface added code to use "down_write_trylock" call to take the dtl_access_lock. The dtl_access_lock is defined in dtl.h file. Also added global reference count variable called "dtl_global_refc", to ensure dtl data can be captured per-cpu. Code also added global lock called "dtl_global_lock" to avoid race condition. Signed-off-by: Kajol Jain Tested-by: Tejas Manhas Tested-by: Venkat Rao Bagalkote Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20250915102947.26681-3-atrajeev@linux.ibm.com

Merge tag 'powerpc-6.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2025-07-30T03:28:38+00:00

Pull powerpc updates from Madhavan Srinivasan: - CONFIG_HZ changes to move the base_slice from 10ms to 1ms - Patchset to move some of the mutex handling to lock guard - Expose secvars relevant to the key management mode - Misc cleanups and fixes Thanks to Ankit Chauhan, Christophe Leroy, Donet Tom, Gautam Menghani, Haren Myneni, Johan Korsnes, Madadi Vineeth Reddy, Paul Mackerras, Shrikanth Hegde, Srish Srinivasan, Thomas Fourier, Thomas Huth, Thomas Weißschuh, Souradeep, Amit Machhiwal, R Nageswara Sastry, Venkat Rao Bagalkote, Andrew Donnellan, Greg Kroah-Hartman, Mimi Zohar, Mukesh Kumar Chaurasiya, Nayna Jain, Ritesh Harjani (IBM), Sourabh Jain, Srikar Dronamraju, Stefan Berger, Tyrel Datwyler, and Kowshik Jois. * tag 'powerpc-6.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (23 commits) arch/powerpc: Remove .interp section in vmlinux powerpc: Drop GPL boilerplate text with obsolete FSF address powerpc: Don't use %pK through printk arch: powerpc: defconfig: Drop obsolete CONFIG_NET_CLS_TCINDEX misc: ocxl: Replace scnprintf() with sysfs_emit() in sysfs show functions integrity/platform_certs: Allow loading of keys in the static key management mode powerpc/secvar: Expose secvars relevant to the key management mode powerpc/pseries: Correct secvar format representation for static key management (powerpc/512) Fix possible `dma_unmap_single()` on uninitialized pointer powerpc: floppy: Add missing checks after DMA map book3s64/radix : Optimize vmemmap start alignment book3s64/radix : Handle error conditions properly in radix_vmemmap_populate powerpc/pseries/dlpar: Search DRC index from ibm,drc-indexes for IO add KVM: PPC: Book3S HV: Add H_VIRT mapping for tracing exits powerpc: sysdev: use lock guard for mutex powerpc: powernv: ocxl: use lock guard for mutex powerpc: book3s: vas: use lock guard for mutex powerpc: fadump: use lock guard for mutex powerpc: rtas: use lock guard for mutex powerpc: eeh: use lock guard for mutex ...