Message-ID: <2025100424-CVE-2023-53583-b831@gregkh>
Date: Sat,  4 Oct 2025 17:51:37 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53583: perf: RISC-V: Remove PERF_HES_STOPPED flag checking in riscv_pmu_start()

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

perf: RISC-V: Remove PERF_HES_STOPPED flag checking in riscv_pmu_start()

Since commit 096b52fd2bb4 ("perf: RISC-V: throttle perf events") the
perf_sample_event_took() function was added to report time spent in
overflow interrupts. If the interrupt takes too long, the perf framework
will lower the sysctl_perf_event_sample_rate and max_samples_per_tick.
When hwc->interrupts is larger than max_samples_per_tick, the
hwc->interrupts will be set to MAX_INTERRUPTS, and events will be
throttled within the __perf_event_account_interrupt() function.

However, the RISC-V PMU driver doesn't call riscv_pmu_stop() to update the
PERF_HES_STOPPED flag after perf_event_overflow() in pmu_sbi_ovf_handler()
function to avoid throttling. When the perf framework unthrottled the event
in the timer interrupt handler, it triggers riscv_pmu_start() function
and causes a WARN_ON_ONCE() warning, as shown below:

 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 240 at drivers/perf/riscv_pmu.c:184 riscv_pmu_start+0x7c/0x8e
 Modules linked in:
 CPU: 0 PID: 240 Comm: ls Not tainted 6.4-rc4-g19d0788e9ef2 #1
 Hardware name: SiFive (DT)
 epc : riscv_pmu_start+0x7c/0x8e
  ra : riscv_pmu_start+0x28/0x8e
 epc : ffffffff80aef864 ra : ffffffff80aef810 sp : ffff8f80004db6f0
  gp : ffffffff81c83750 tp : ffffaf80069f9bc0 t0 : ffff8f80004db6c0
  t1 : 0000000000000000 t2 : 000000000000001f s0 : ffff8f80004db720
  s1 : ffffaf8008ca1068 a0 : 0000ffffffffffff a1 : 0000000000000000
  a2 : 0000000000000001 a3 : 0000000000000870 a4 : 0000000000000000
  a5 : 0000000000000000 a6 : 0000000000000840 a7 : 0000000000000030
  s2 : 0000000000000000 s3 : ffffaf8005165800 s4 : ffffaf800424da00
  s5 : ffffffffffffffff s6 : ffffffff81cc7590 s7 : 0000000000000000
  s8 : 0000000000000006 s9 : 0000000000000001 s10: ffffaf807efbc340
  s11: ffffaf807efbbf00 t3 : ffffaf8006a16028 t4 : 00000000dbfbb796
  t5 : 0000000700000000 t6 : ffffaf8005269870
 status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003
 [<ffffffff80aef864>] riscv_pmu_start+0x7c/0x8e
 [<ffffffff80185b56>] perf_adjust_freq_unthr_context+0x15e/0x174
 [<ffffffff80188642>] perf_event_task_tick+0x88/0x9c
 [<ffffffff800626a8>] scheduler_tick+0xfe/0x27c
 [<ffffffff800b5640>] update_process_times+0x9a/0xba
 [<ffffffff800c5bd4>] tick_sched_handle+0x32/0x66
 [<ffffffff800c5e0c>] tick_sched_timer+0x64/0xb0
 [<ffffffff800b5e50>] __hrtimer_run_queues+0x156/0x2f4
 [<ffffffff800b6bdc>] hrtimer_interrupt+0xe2/0x1fe
 [<ffffffff80acc9e8>] riscv_timer_interrupt+0x38/0x42
 [<ffffffff80090a16>] handle_percpu_devid_irq+0x90/0x1d2
 [<ffffffff8008a9f4>] generic_handle_domain_irq+0x28/0x36

After referring other PMU drivers like Arm, Loongarch, Csky, and Mips,
they don't call *_pmu_stop() to update with PERF_HES_STOPPED flag
after perf_event_overflow() function nor do they add PERF_HES_STOPPED
flag checking in *_pmu_start() which don't cause this warning.

Thus, it's recommended to remove this unnecessary check in
riscv_pmu_start() function to prevent this warning.

The Linux kernel CVE team has assigned CVE-2023-53583 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.1 with commit 096b52fd2bb4996fd68d22b3b7ad21a1296db9d3 and fixed in 6.1.40 with commit aeb62beaf9cbd0a72e7f97c9af6d3e7f76ce2946
	Issue introduced in 6.1 with commit 096b52fd2bb4996fd68d22b3b7ad21a1296db9d3 and fixed in 6.4.5 with commit 8270d539a943d00cf6a094da0073e2b5972b641d
	Issue introduced in 6.1 with commit 096b52fd2bb4996fd68d22b3b7ad21a1296db9d3 and fixed in 6.5 with commit 66843b14fb71825fdd73ab12f6594f2243b402be

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2023-53583
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/perf/riscv_pmu.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/aeb62beaf9cbd0a72e7f97c9af6d3e7f76ce2946
	https://git.kernel.org/stable/c/8270d539a943d00cf6a094da0073e2b5972b641d
	https://git.kernel.org/stable/c/66843b14fb71825fdd73ab12f6594f2243b402be

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