CVE-2025-21733: 
Linux Kernel vulnerability analysis and mitigation

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

tracing/osnoise: Fix resetting of tracepoints

If a timerlat tracer is started with the osnoise option OSNOISE_WORKLOAD disabled, but then that option is enabled and timerlat is removed, the tracepoints that were enabled on timerlat registration do not get disabled. If the option is disabled again and timelat is started, then it triggers a warning in the tracepoint code due to registering the tracepoint again without ever disabling it.

Do not use the same user space defined options to know to disable the tracepoints when timerlat is removed. Instead, set a global flag when it is enabled and use that flag to know to disable the events.

~# echo NOOSNOISEWORKLOAD > /sys/kernel/tracing/osnoise/options ~# echo timerlat > /sys/kernel/tracing/currenttracer ~# echo OSNOISEWORKLOAD > /sys/kernel/tracing/osnoise/options ~# echo nop > /sys/kernel/tracing/currenttracer ~# echo NOOSNOISEWORKLOAD > /sys/kernel/tracing/osnoise/options ~# echo timerlat > /sys/kernel/tracing/currenttracer

Triggers:

------------[ cut here ]------------ WARNING: CPU: 6 PID: 1337 at kernel/tracepoint.c:294 tracepointaddfunc+0x3b6/0x3f0 Modules linked in: CPU: 6 UID: 0 PID: 1337 Comm: rtla Not tainted 6.13.0-rc4-test-00018-ga867c441128e-dirty #73 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:tracepointaddfunc+0x3b6/0x3f0 Code: 48 8b 53 28 48 8b 73 20 4c 89 04 24 e8 23 59 11 00 4c 8b 04 24 e9 36 fe ff ff 0f 0b b8 ea ff ff ff 45 84 e4 0f 84 68 fe ff ff <0f> 0b e9 61 fe ff ff 48 8b 7b 18 48 85 ff 0f 84 4f ff ff ff 49 8b RSP: 0018:ffffb9b003a87ca0 EFLAGS: 00010202 RAX: 00000000ffffffef RBX: ffffffff92f30860 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff9bf59e91ccd0 RDI: ffffffff913b6410 RBP: 000000000000000a R08: 00000000000005c7 R09: 0000000000000002 R10: ffffb9b003a87ce0 R11: 0000000000000002 R12: 0000000000000001 R13: ffffb9b003a87ce0 R14: ffffffffffffffef R15: 0000000000000008 FS: 00007fce81209240(0000) GS:ffff9bf6fdd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055e99b728000 CR3: 00000001277c0002 CR4: 0000000000172ef0 Call Trace: ? warn.cold+0xb7/0x14d ? tracepointaddfunc+0x3b6/0x3f0 ? reportbug+0xea/0x170 ? handlebug+0x58/0x90 ? excinvalidop+0x17/0x70 ? asmexcinvalid_op+0x1a/0x20 ? pfxtraceschedmigratecallback+0x10/0x10 ? tracepointaddfunc+0x3b6/0x3f0 ? pfxtraceschedmigratecallback+0x10/0x10 ? pfxtraceschedmigratecallback+0x10/0x10 tracepointproberegister+0x78/0xb0 ? _pfxtraceschedmigratecallback+0x10/0x10 osnoiseworkloadstart+0x2b5/0x370 timerlattracerinit+0x76/0x1b0 tracingsettracer+0x244/0x400 tracingsettracewrite+0xa0/0xe0 vfswrite+0xfc/0x570 ? dosysopenat2+0x9c/0xe0 ksyswrite+0x72/0xf0 dosyscall64+0x79/0x1c0 entrySYSCALL64afterhwframe+0x76/0x7e