x86/mce: Make sure to grab mce_sysfs_mutex in set_bank()

JIRA: https://issues.redhat.com/browse/RHEL-37264
CVE: CVE-2024-35876

https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=61385231
Tested: Did sanity mce testing using intel-arrowlake-s-02 system.

commit 3ddf944
Author: Borislav Petkov (AMD) <bp@alien8.de>
Date:   Wed Mar 13 14:48:27 2024 +0100

    x86/mce: Make sure to grab mce_sysfs_mutex in set_bank()

    Modifying a MCA bank's MCA_CTL bits which control which error types to
    be reported is done over

      /sys/devices/system/machinecheck/
      ├── machinecheck0
      │   ├── bank0
      │   ├── bank1
      │   ├── bank10
      │   ├── bank11
      ...

    sysfs nodes by writing the new bit mask of events to enable.

    When the write is accepted, the kernel deletes all current timers and
    reinits all banks.

    Doing that in parallel can lead to initializing a timer which is already
    armed and in the timer wheel, i.e., in use already:

      ODEBUG: init active (active state 0) object: ffff888063a28000 object
      type: timer_list hint: mce_timer_fn+0x0/0x240 arch/x86/kernel/cpu/mce/core.c:2642
      WARNING: CPU: 0 PID: 8120 at lib/debugobjects.c:514
      debug_print_object+0x1a0/0x2a0 lib/debugobjects.c:514

    Fix that by grabbing the sysfs mutex as the rest of the MCA sysfs code
    does.

    Reported by: Yue Sun <samsun1006219@gmail.com>
    Reported by: xingwei lee <xrivendell7@gmail.com>
    Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
    Cc: <stable@kernel.org>
    Link: https://lore.kernel.org/r/CAEkJfYNiENwQY8yV1LYJ9LjJs%2Bx_-PqMv98gKig55=2vbzffRw@mail.gmail.com

Signed-off-by: Steve Best <sbest@redhat.com>

Author: sfbest

arch/x86/kernel/cpu/mce/core.c

@@ -2473,12 +2473,14 @@ static ssize_t set_bank(struct device *s, struct device_attribute *attr,
 		return -EINVAL;
 
 	b = &per_cpu(mce_banks_array, s->id)[bank];
-
 	if (!b->init)
 		return -ENODEV;
 
 	b->ctl = new;
+
+	mutex_lock(&mce_sysfs_mutex);
 	mce_restart();
+	mutex_unlock(&mce_sysfs_mutex);
 
 	return size;
 }