linux-cve-announce - CVE-2022-50491: coresight: cti: Fix hang in cti_disable

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Message-ID: <2025100417-CVE-2022-50491-7a8b@gregkh>
Date: Sat,  4 Oct 2025 17:51:16 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50491: coresight: cti: Fix hang in cti_disable_hw()

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

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

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

coresight: cti: Fix hang in cti_disable_hw()

cti_enable_hw() and cti_disable_hw() are called from an atomic context
so shouldn't use runtime PM because it can result in a sleep when
communicating with firmware.

Since commit 3c6656337852 ("Revert "firmware: arm_scmi: Add clock
management to the SCMI power domain""), this causes a hang on Juno when
running the Perf Coresight tests or running this command:

  perf record -e cs_etm//u -- ls

This was also missed until the revert commit because pm_runtime_put()
was called with the wrong device until commit 692c9a499b28 ("coresight:
cti: Correct the parameter for pm_runtime_put")

With lock and scheduler debugging enabled the following is output:

   coresight cti_sys0: cti_enable_hw -- dev:cti_sys0  parent: 20020000.cti
   BUG: sleeping function called from invalid context at drivers/base/power/runtime.c:1151
   in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 330, name: perf-exec
   preempt_count: 2, expected: 0
   RCU nest depth: 0, expected: 0
   INFO: lockdep is turned off.
   irq event stamp: 0
   hardirqs last  enabled at (0): [<0000000000000000>] 0x0
   hardirqs last disabled at (0): [<ffff80000822b394>] copy_process+0xa0c/0x1948
   softirqs last  enabled at (0): [<ffff80000822b394>] copy_process+0xa0c/0x1948
   softirqs last disabled at (0): [<0000000000000000>] 0x0
   CPU: 3 PID: 330 Comm: perf-exec Not tainted 6.0.0-00053-g042116d99298 #7
   Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Sep 13 2022
   Call trace:
    dump_backtrace+0x134/0x140
    show_stack+0x20/0x58
    dump_stack_lvl+0x8c/0xb8
    dump_stack+0x18/0x34
    __might_resched+0x180/0x228
    __might_sleep+0x50/0x88
    __pm_runtime_resume+0xac/0xb0
    cti_enable+0x44/0x120
    coresight_control_assoc_ectdev+0xc0/0x150
    coresight_enable_path+0xb4/0x288
    etm_event_start+0x138/0x170
    etm_event_add+0x48/0x70
    event_sched_in.isra.122+0xb4/0x280
    merge_sched_in+0x1fc/0x3d0
    visit_groups_merge.constprop.137+0x16c/0x4b0
    ctx_sched_in+0x114/0x1f0
    perf_event_sched_in+0x60/0x90
    ctx_resched+0x68/0xb0
    perf_event_exec+0x138/0x508
    begin_new_exec+0x52c/0xd40
    load_elf_binary+0x6b8/0x17d0
    bprm_execve+0x360/0x7f8
    do_execveat_common.isra.47+0x218/0x238
    __arm64_sys_execve+0x48/0x60
    invoke_syscall+0x4c/0x110
    el0_svc_common.constprop.4+0xfc/0x120
    do_el0_svc+0x34/0xc0
    el0_svc+0x40/0x98
    el0t_64_sync_handler+0x98/0xc0
    el0t_64_sync+0x170/0x174

Fix the issue by removing the runtime PM calls completely. They are not
needed here because it must have already been done when building the
path for a trace.

[ Fix build warnings ]

The Linux kernel CVE team has assigned CVE-2022-50491 to this issue.


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

	Issue introduced in 5.7 with commit 835d722ba10ac924adba1e8a46f2d80955222b4b and fixed in 5.10.154 with commit e33ce54cef5d429430e3b1ae5c8ee4f4103c4fdc
	Issue introduced in 5.7 with commit 835d722ba10ac924adba1e8a46f2d80955222b4b and fixed in 5.15.77 with commit 4c365a0c21aaf2b8fcc88de8dc298803288f61ac
	Issue introduced in 5.7 with commit 835d722ba10ac924adba1e8a46f2d80955222b4b and fixed in 6.0.7 with commit c51cfba50df8b9e16bfe0e6d4f2f252a4a10063d
	Issue introduced in 5.7 with commit 835d722ba10ac924adba1e8a46f2d80955222b4b and fixed in 6.1 with commit 6746eae4bbaddcc16b40efb33dab79210828b3ce

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-2022-50491
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/hwtracing/coresight/coresight-cti-core.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/e33ce54cef5d429430e3b1ae5c8ee4f4103c4fdc
	https://git.kernel.org/stable/c/4c365a0c21aaf2b8fcc88de8dc298803288f61ac
	https://git.kernel.org/stable/c/c51cfba50df8b9e16bfe0e6d4f2f252a4a10063d
	https://git.kernel.org/stable/c/6746eae4bbaddcc16b40efb33dab79210828b3ce