CVE-2023-52839

In the Linux kernel, the following vulnerability has been resolved:
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 3fec323339a4
(“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.