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Alexandre Ghiti 61e3d993c8
drivers: perf: Do not broadcast to other cpus when starting a counter
This command:

$ perf record -e cycles:k -e instructions:k -c 10000 -m 64M dd if=/dev/zero of=/dev/null count=1000

gives rise to this kernel warning:

[  444.364395] WARNING: CPU: 0 PID: 104 at kernel/smp.c:775 smp_call_function_many_cond+0x42c/0x436
[  444.364515] Modules linked in:
[  444.364657] CPU: 0 PID: 104 Comm: perf-exec Not tainted 6.6.0-rc6-00051-g391df82e8ec3-dirty #73
[  444.364771] Hardware name: riscv-virtio,qemu (DT)
[  444.364868] epc : smp_call_function_many_cond+0x42c/0x436
[  444.364917]  ra : on_each_cpu_cond_mask+0x20/0x32
[  444.364948] epc : ffffffff8009f9e0 ra : ffffffff8009fa5a sp : ff20000000003800
[  444.364966]  gp : ffffffff81500aa0 tp : ff60000002b83000 t0 : ff200000000038c0
[  444.364982]  t1 : ffffffff815021f0 t2 : 000000000000001f s0 : ff200000000038b0
[  444.364998]  s1 : ff60000002c54d98 a0 : ff60000002a73940 a1 : 0000000000000000
[  444.365013]  a2 : 0000000000000000 a3 : 0000000000000003 a4 : 0000000000000100
[  444.365029]  a5 : 0000000000010100 a6 : 0000000000f00000 a7 : 0000000000000000
[  444.365044]  s2 : 0000000000000000 s3 : ffffffffffffffff s4 : ff60000002c54d98
[  444.365060]  s5 : ffffffff81539610 s6 : ffffffff80c20c48 s7 : 0000000000000000
[  444.365075]  s8 : 0000000000000000 s9 : 0000000000000001 s10: 0000000000000001
[  444.365090]  s11: ffffffff80099394 t3 : 0000000000000003 t4 : 00000000eac0c6e6
[  444.365104]  t5 : 0000000400000000 t6 : ff60000002e010d0
[  444.365120] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003
[  444.365226] [<ffffffff8009f9e0>] smp_call_function_many_cond+0x42c/0x436
[  444.365295] [<ffffffff8009fa5a>] on_each_cpu_cond_mask+0x20/0x32
[  444.365311] [<ffffffff806e90dc>] pmu_sbi_ctr_start+0x7a/0xaa
[  444.365327] [<ffffffff806e880c>] riscv_pmu_start+0x48/0x66
[  444.365339] [<ffffffff8012111a>] perf_adjust_freq_unthr_context+0x196/0x1ac
[  444.365356] [<ffffffff801237aa>] perf_event_task_tick+0x78/0x8c
[  444.365368] [<ffffffff8003faf4>] scheduler_tick+0xe6/0x25e
[  444.365383] [<ffffffff8008a042>] update_process_times+0x80/0x96
[  444.365398] [<ffffffff800991ec>] tick_sched_handle+0x26/0x52
[  444.365410] [<ffffffff800993e4>] tick_sched_timer+0x50/0x98
[  444.365422] [<ffffffff8008a6aa>] __hrtimer_run_queues+0x126/0x18a
[  444.365433] [<ffffffff8008b350>] hrtimer_interrupt+0xce/0x1da
[  444.365444] [<ffffffff806cdc60>] riscv_timer_interrupt+0x30/0x3a
[  444.365457] [<ffffffff8006afa6>] handle_percpu_devid_irq+0x80/0x114
[  444.365470] [<ffffffff80065b82>] generic_handle_domain_irq+0x1c/0x2a
[  444.365483] [<ffffffff8045faec>] riscv_intc_irq+0x2e/0x46
[  444.365497] [<ffffffff808a9c62>] handle_riscv_irq+0x4a/0x74
[  444.365521] [<ffffffff808aa760>] do_irq+0x7c/0x7e
[  444.365796] ---[ end trace 0000000000000000 ]---

That's because the fix in commit 3fec323339 ("drivers: perf: Fix panic
in riscv SBI mmap support") was wrong since there is no need to broadcast
to other cpus when starting a counter, that's only needed in mmap when
the counters could have already been started on other cpus, so simply
remove this broadcast.

Fixes: 3fec323339 ("drivers: perf: Fix panic in riscv SBI mmap support")
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Tested-by: Clément Léger <cleger@rivosinc.com>
Tested-by: Yu Chien Peter Lin <peterlin@andestech.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> #On
Link: https://lore.kernel.org/r/20231026084010.11888-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-11-09 06:43:42 -08:00
arch riscv: Fix ftrace syscall handling which are now prefixed with __riscv_ 2023-10-12 11:35:48 -07:00
block block: fix pin count management when merging same-page segments 2023-09-06 07:32:27 -06:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto This update includes the following changes: 2023-08-29 11:23:29 -07:00
Documentation drm ci for 6.6-rc1 2023-09-10 11:55:26 -07:00
drivers drivers: perf: Do not broadcast to other cpus when starting a counter 2023-11-09 06:43:42 -08:00
fs six smb3 client fixes, one fix for nls Kconfig, one minor spnego registry update 2023-09-09 19:56:23 -07:00
include six smb3 client fixes, one fix for nls Kconfig, one minor spnego registry update 2023-09-09 19:56:23 -07:00
init workqueue: Changes for v6.6 2023-09-01 16:06:32 -07:00
io_uring Revert "io_uring: fix IO hang in io_wq_put_and_exit from do_exit()" 2023-09-07 09:41:49 -06:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel RISC-V Patches for the 6.6 Merge Window, Part 2 (try 2) 2023-09-09 14:25:11 -07:00
lib iov_iter: Kunit tests for page extraction 2023-09-09 15:11:49 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm LoongArch changes for v6.6 2023-09-08 12:16:52 -07:00
net Including fixes from netfilter and bpf. 2023-09-07 18:33:07 -07:00
rust Documentation work keeps chugging along; stuff for 6.6 includes: 2023-08-30 20:05:42 -07:00
samples VFIO updates for v6.6-rc1 2023-08-30 20:36:01 -07:00
scripts Fix preemption delays in the SGX code, remove unnecessarily UAPI-exported code, 2023-09-10 10:39:31 -07:00
security Landlock updates for v6.6-rc1 2023-09-08 12:06:51 -07:00
sound sound fixes for 6.6-rc1 2023-09-08 13:07:50 -07:00
tools riscv: kselftests: Fix mm build by removing testcases subdirectory 2023-09-20 02:29:26 -07:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap for-linus-2023083101 2023-09-01 12:31:44 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS drm ci for 6.6-rc1 2023-09-10 11:55:26 -07:00
Makefile Linux 6.6-rc1 2023-09-10 16:28:41 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.