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

s390/dasd: fix Oops in dasd_alias_get_start_dev due to missing pavgroup

Fix Oops in dasd_alias_get_start_dev() function caused by the pavgroup
pointer being NULL.

The pavgroup pointer is checked on the entrance of the function but
without the lcu->lock being held. Therefore there is a race window
between dasd_alias_get_start_dev() and _lcu_update() which sets
pavgroup to NULL with the lcu->lock held.

Fix by checking the pavgroup pointer with lcu->lock held.

References

• https://nvd.nist.gov/vuln/detail/CVE-2022-48636
• https://git.kernel.org/stable/c/2e473351400e3dd66f0b71eddcef82ee45a584c1
• https://git.kernel.org/stable/c/49f401a98b318761ca2e15d4c7869a20043fbed4
• https://git.kernel.org/stable/c/650a2e79d176db753654d3dde88e53a2033036ac
• https://git.kernel.org/stable/c/aaba5ff2742043705bc4c02fd0b2b246e2e16da1
• https://git.kernel.org/stable/c/d3a67c21b18f33c79382084af556557c442f12a6
• https://git.kernel.org/stable/c/d86b4267834e6d4af62e3073e48166e349ab1b70
• https://git.kernel.org/stable/c/db7ba07108a48c0f95b74fabbfd5d63e924f992d
• https://git.kernel.org/stable/c/f5fcc9d6d71d9ff7fdbdd4b89074e6e24fffc20b