CVE-2024-46788

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

tracing/osnoise: Use a cpumask to know what threads are kthreads

The start_kthread() and stop_thread() code was not always called with the

interface_lock held. This means that the kthread variable could be

unexpectedly changed causing the kthread_stop() to be called on it when it

should not have been, leading to:

while true; do

rtla timerlat top -u -q & PID=$!;

sleep 5;

kill -INT $PID;

sleep 0.001;

kill -TERM $PID;

wait $PID;

done

Causing the following OOPS:

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN PTI

KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]

CPU: 5 UID: 0 PID: 885 Comm: timerlatu/5 Not tainted 6.11.0-rc4-test-00002-gbc754cc76d1b-dirty #125 a533010b71dab205ad2f507188ce8c82203b0254

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014

RIP: 0010:hrtimer_active+0x58/0x300

Code: 48 c1 ee 03 41 54 48 01 d1 48 01 d6 55 53 48 83 ec 20 80 39 00 0f 85 30 02 00 00 49 8b 6f 30 4c 8d 75 10 4c 89 f0 48 c1 e8 03 <0f> b6 3c 10 4c 89 f0 83 e0 07 83 c0 03 40 38 f8 7c 09 40 84 ff 0f

RSP: 0018:ffff88811d97f940 EFLAGS: 00010202

RAX: 0000000000000002 RBX: ffff88823c6b5b28 RCX: ffffed10478d6b6b

RDX: dffffc0000000000 RSI: ffffed10478d6b6c RDI: ffff88823c6b5b28

RBP: 0000000000000000 R08: ffff88823c6b5b58 R09: ffff88823c6b5b60

R10: ffff88811d97f957 R11: 0000000000000010 R12: 00000000000a801d

R13: ffff88810d8b35d8 R14: 0000000000000010 R15: ffff88823c6b5b28

FS: 0000000000000000(0000) GS:ffff88823c680000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000561858ad7258 CR3: 000000007729e001 CR4: 0000000000170ef0

Call Trace:

<TASK>

? die_addr+0x40/0xa0

? exc_general_protection+0x154/0x230

? asm_exc_general_protection+0x26/0x30

? hrtimer_active+0x58/0x300

? __pfx_mutex_lock+0x10/0x10

? __pfx_locks_remove_file+0x10/0x10

hrtimer_cancel+0x15/0x40

timerlat_fd_release+0x8e/0x1f0

? security_file_release+0x43/0x80

__fput+0x372/0xb10

task_work_run+0x11e/0x1f0

? _raw_spin_lock+0x85/0xe0

? __pfx_task_work_run+0x10/0x10

? poison_slab_object+0x109/0x170

? do_exit+0x7a0/0x24b0

do_exit+0x7bd/0x24b0

? __pfx_migrate_enable+0x10/0x10

? __pfx_do_exit+0x10/0x10

? __pfx_read_tsc+0x10/0x10

? ktime_get+0x64/0x140

? _raw_spin_lock_irq+0x86/0xe0

do_group_exit+0xb0/0x220

get_signal+0x17ba/0x1b50

? vfs_read+0x179/0xa40

? timerlat_fd_read+0x30b/0x9d0

? __pfx_get_signal+0x10/0x10

? __pfx_timerlat_fd_read+0x10/0x10

arch_do_signal_or_restart+0x8c/0x570

? __pfx_arch_do_signal_or_restart+0x10/0x10

? vfs_read+0x179/0xa40

? ksys_read+0xfe/0x1d0

? __pfx_ksys_read+0x10/0x10

syscall_exit_to_user_mode+0xbc/0x130

do_syscall_64+0x74/0x110

? __pfx___rseq_handle_notify_resume+0x10/0x10

? __pfx_ksys_read+0x10/0x10

? fpregs_restore_userregs+0xdb/0x1e0

? fpregs_restore_userregs+0xdb/0x1e0

? syscall_exit_to_user_mode+0x116/0x130

? do_syscall_64+0x74/0x110

? do_syscall_64+0x74/0x110

? do_syscall_64+0x74/0x110

entry_SYSCALL_64_after_hwframe+0x71/0x79

RIP: 0033:0x7ff0070eca9c

Code: Unable to access opcode bytes at 0x7ff0070eca72.

RSP: 002b:00007ff006dff8c0 EFLAGS: 00000246 ORIG_RAX: 0000000000000000

RAX: 0000000000000000 RBX: 0000000000000005 RCX: 00007ff0070eca9c

RDX: 0000000000000400 RSI: 00007ff006dff9a0 RDI: 0000000000000003

RBP: 00007ff006dffde0 R08: 0000000000000000 R09: 00007ff000000ba0

R10: 00007ff007004b08 R11: 0000000000000246 R12: 0000000000000003

R13: 00007ff006dff9a0 R14: 0000000000000007 R15: 0000000000000008

</TASK>

Modules linked in: snd_hda_intel snd_intel_dspcfg snd_intel_sdw_acpi snd_hda_codec snd_hwdep snd_hda_core

---[ end trace 0000000000000000 ]---

This is because it would mistakenly call kthread_stop() on a user space

thread making it "exit" before it actually exits.

Since kthread

---truncated---