crash when reading from /sys/kernel/tracing/rv/enabled_monitors

[Edoardo Canepa]

As reported in https://lore.kernel.org/linux-trace-kernel/20250923002004.GA2836051@ax162/, commit "rv: Fix wrong type cast in enabled_monitors_next()" introduces a crash when accessing the sys node in Questing.

Crash has been fixed in upstream commit 103541e6a5854b08a25e4caa61e990af1009a52e:
"rv: Fully convert enabled_monitors to use list_head as iterator"

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux/6.17.0-8.8 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-questing-linux' to 'verification-done-questing-linux'. If the problem still exists, change the tag 'verification-needed-questing-linux' to 'verification-failed-questing-linux'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-aws-6.17/6.17.0-1005.5~24.04.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-aws-6.17' to 'verification-done-noble-linux-aws-6.17'. If the problem still exists, change the tag 'verification-needed-noble-linux-aws-6.17' to 'verification-failed-noble-linux-aws-6.17'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Manuel Diewald (diewald)]

Crash with latest available kernel linux/6.17.0-7.7 when accessing /sys/kernel/tracing/rv/enabled_monitors:

$ sudo cat /sys/kernel/tracing/rv/enabled_monitors
[ 1295.472802] UBSAN: invalid-load in /build/linux-8YMEfB/linux-6.17.0/kernel/trace/rv/rv.c:503:10
[ 1295.477607] load of value 247 is not a valid value for type '_Bool'
[ 1295.492854] BUG: unable to handle page fault for address: 0000000a800001f7
[ 1295.493756] #PF: supervisor read access in kernel mode
[ 1295.494099] #PF: error_code(0x0000) - not-present page
[ 1295.494604] PGD 0 P4D 0
[ 1295.496689] Oops: Oops: 0000 [#1] SMP NOPTI
[ 1295.497106] CPU: 2 UID: 0 PID: 1506 Comm: cat Not tainted 6.17.0-7-generic #7-Ubuntu PREEMPT(voluntary)
[ 1295.497834] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
[ 1295.498404] RIP: 0010:monitors_show+0x16/0x60
[ 1295.499320] Code: 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 55 48 8b 46 10 48 8b 4e c0 48 89 e5 48 85 c0 74 1f <48> 8b 10 48 c7 c6 79 3e be 91 e8 5b cc 26 00 31 c0 5d 31 d2 31 c9
[ 1295.500537] RSP: 0018:ffffcb0d4058fa78 EFLAGS: 00000202
[ 1295.500969] RAX: 0000000a800001f7 RBX: 0000000000000000 RCX: 0000000000000000
[ 1295.501405] RDX: 0000000000000000 RSI: ffffffff9261eb78 RDI: ffff8a8b4b30cf00
[ 1295.501800] RBP: ffffcb0d4058fa78 R08: 0000000000000000 R09: 0000000000000000
[ 1295.502143] R10: 0000000000000000 R11: 0000000000000000 R12: ffffcb0d4058fb20
[ 1295.502540] R13: ffff8a8b4554d100 R14: ffff8a8b4b30cf00 R15: ffffffff9261eb78
[ 1295.503282] FS: 00007023dd92ebc0(0000) GS:ffff8a8ce4d7f000(0000) knlGS:0000000000000000
[ 1295.503814] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1295.504198] CR2: 0000000a800001f7 CR3: 000000010ebf2000 CR4: 00000000000006f0
[ 1295.504778] Call Trace:
[ 1295.505236] <TASK>
[ 1295.505454] seq_read_iter+0x130/0x490
[ 1295.505752] seq_read+0x11b/0x160
[ 1295.505933] vfs_read+0xbf/0x3a0
[ 1295.506161] ksys_read+0x71/0xf0
[ 1295.506384] __x64_sys_read+0x19/0x30
[ 1295.506627] x64_sys_call+0x1e95/0x2330
[ 1295.506879] do_syscall_64+0x81/0xc90
[ 1295.507171] ? __memcg_slab_free_hook+0x115/0x190
[ 1295.507460] ? kmem_cache_free+0x4b4/0x4f0
[ 1295.507717] ? refill_obj_stock+0x149/0x270
[ 1295.508014] ? refill_obj_stock+0x149/0x270
[ 1295.508280] ? __memcg_slab_free_hook+0x115/0x190
[ 1295.508581] ? dentry_free+0x35/0x90
[ 1295.508909] ? kmem_cache_free+0x4b4/0x4f0
[ 1295.509201] ? __fput+0x1a2/0x2d0
[ 1295.509537] ? __fput+0x1a2/0x2d0
[ 1295.509791] ? fput_close_sync+0x40/0xc0
[ 1295.510038] ? __x64_sys_close+0x3e/0x90
[ 1295.510248] ? arch_exit_to_user_mode_prepare.isra.0+0xd/0xe0
[ 1295.510636] ? do_syscall_64+0xb9/0xc90
[ 1295.510851] ? exc_page_fault+0x90/0x1b0
[ 1295.511124] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 1295.515590] RIP: 0033:0x7023dd6a0186
[ 1295.517613] Code: 47 ba 04 00 00 00 48 8b 05 87 3c 19 00 64 89 10 48 c7 c2 ff ff ff ff c9 48 89 d0 c3 0f 1f 84 00 00 00 00 00 48 8b 45 10 0f 05 <48> 89 c2 48 3d 00 f0 ff ff 77 0f c9 48 89 d0 c3 66 2e 0f 1f 84 00
[ 1295.521139] RSP: 002b:00007ffc8c2fc3e0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
[ 1295.522786] RAX: ffffffffffffffda RBX: 00007ffc8c30c550 RCX...

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 6.17.0-8.8

---------------
linux (6.17.0-8.8) questing; urgency=medium

  * questing/linux: 6.17.0-8.8 -proposed tracker (LP: #2131554)

  * crash when reading from /sys/kernel/tracing/rv/enabled_monitors
    (LP: #2131136)
    - rv: Fully convert enabled_monitors to use list_head as iterator

  * i40e driver is triggering VF resets on every link state change
    (LP: #2130552)
    - i40e: avoid redundant VF link state updates

  * kernel crash on bootup for some arm64 machines (LP: #2129770)
    - KVM: arm64: Guard PMSCR_EL1 initialization with SPE presence check

  * CVE-2025-40018
    - ipvs: Defer ip_vs_ftp unregister during netns cleanup

 -- Manuel Diewald <email address hidden> Fri, 14 Nov 2025 17:53:03 +0100

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-realtime-6.17/6.17.0-1004.5~24.04.2 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-realtime-6.17' to 'verification-done-noble-linux-realtime-6.17'. If the problem still exists, change the tag 'verification-needed-noble-linux-realtime-6.17' to 'verification-failed-noble-linux-realtime-6.17'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 6.17.0-8.8

---------------
linux (6.17.0-8.8) questing; urgency=medium

  * questing/linux: 6.17.0-8.8 -proposed tracker (LP: #2131554)

  * crash when reading from /sys/kernel/tracing/rv/enabled_monitors
    (LP: #2131136)
    - rv: Fully convert enabled_monitors to use list_head as iterator

  * i40e driver is triggering VF resets on every link state change
    (LP: #2130552)
    - i40e: avoid redundant VF link state updates

  * kernel crash on bootup for some arm64 machines (LP: #2129770)
    - KVM: arm64: Guard PMSCR_EL1 initialization with SPE presence check

  * CVE-2025-40018
    - ipvs: Defer ip_vs_ftp unregister during netns cleanup

 -- Manuel Diewald <email address hidden> Fri, 14 Nov 2025 17:53:03 +0100

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-nvidia-6.17/6.17.0-1006.6 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-nvidia-6.17' to 'verification-done-noble-linux-nvidia-6.17'. If the problem still exists, change the tag 'verification-needed-noble-linux-nvidia-6.17' to 'verification-failed-noble-linux-nvidia-6.17'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-intel/6.17.0-1006.6 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-questing-linux-intel' to 'verification-done-questing-linux-intel'. If the problem still exists, change the tag 'verification-needed-questing-linux-intel' to 'verification-failed-questing-linux-intel'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-hwe-6.17/6.17.0-14.14~24.04.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-hwe-6.17' to 'verification-done-noble-linux-hwe-6.17'. If the problem still exists, change the tag 'verification-needed-noble-linux-hwe-6.17' to 'verification-failed-noble-linux-hwe-6.17'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-azure-6.17/6.17.0-1008.8~24.04.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-azure-6.17' to 'verification-done-noble-linux-azure-6.17'. If the problem still exists, change the tag 'verification-needed-noble-linux-azure-6.17' to 'verification-failed-noble-linux-azure-6.17'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-azure-fde-6.17/6.17.0-1005.5~24.04.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-azure-fde-6.17' to 'verification-done-noble-linux-azure-fde-6.17'. If the problem still exists, change the tag 'verification-needed-noble-linux-azure-fde-6.17' to 'verification-failed-noble-linux-azure-fde-6.17'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-gcp-6.17/6.17.0-1007.7~24.04.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-gcp-6.17' to 'verification-done-noble-linux-gcp-6.17'. If the problem still exists, change the tag 'verification-needed-noble-linux-gcp-6.17' to 'verification-failed-noble-linux-gcp-6.17'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Stefan Bader (smb)]

# uname -a
Linux testn1 6.17.0-14-generic #14~24.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Jan 15 15:52:10 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
# ls -la /sys/kernel/tracing/rv/enabled_monitors
-rw-r----- 1 root root 0 Feb 3 13:51 /sys/kernel/tracing/rv/enabled_monitors
# cat /sys/kernel/tracing/rv/enabled_monitors
# journalctl -b0|grep BUG
<nothing printed>

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-oracle-6.17/6.17.0-1007.7~24.04.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-oracle-6.17' to 'verification-done-noble-linux-oracle-6.17'. If the problem still exists, change the tag 'verification-needed-noble-linux-oracle-6.17' to 'verification-failed-noble-linux-oracle-6.17'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!