Description

In the Linux kernel, the following vulnerability has been resolved: netlink: fix potential deadlock in netlink_set_err() syzbot reported a possible deadlock in netlink_set_err() [1] A similar issue was fixed in commit 1d482e666b8e ("netlink: disable IRQs for netlink_lock_table()") in netlink_lock_table() This patch adds IRQ safety to netlink_set_err() and __netlink_diag_dump() which were not covered by cited commit. [1] WARNING: possible irq lock inversion dependency detected 6.4.0-rc6-syzkaller-00240-g4e9f0ec38852 #0 Not tainted syz-executor.2/23011 just changed the state of lock: ffffffff8e1a7a58 (nl_table_lock){.+.?}-{2:2}, at: netlink_set_err+0x2e/0x3a0 net/netlink/af_netlink.c:1612 but this lock was taken by another, SOFTIRQ-safe lock in the past: (&local->queue_stop_reason_lock){..-.}-{2:2} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(nl_table_lock); local_irq_disable(); lock(&local->queue_stop_reason_lock); lock(nl_table_lock); <Interrupt> lock(&local->queue_stop_reason_lock); *** DEADLOCK ***

References 9

• git.kernel.org https://git.kernel.org/stable/c/1556ba034b95cfd4f75ea93c1a2679ae0444bba1
• git.kernel.org https://git.kernel.org/stable/c/4b9adb8d4a62ff7608d4a7d4eb42036a88f30980
• git.kernel.org https://git.kernel.org/stable/c/61ffe8b1ee084e5c82a4e4bbf9e7b68e0c06e464
• git.kernel.org https://git.kernel.org/stable/c/8d61f926d42045961e6b65191c09e3678d86a9cf
• git.kernel.org https://git.kernel.org/stable/c/8f6652ed2ad98fe6d13b903483d9257762ab2ec6
• git.kernel.org https://git.kernel.org/stable/c/a641240b7e071c5538dc0e7894ece833fce459dd
• git.kernel.org https://git.kernel.org/stable/c/c09e8e3f7fd432984bf5422302b093d2371dfc48
• git.kernel.org https://git.kernel.org/stable/c/cde7b90e0539a3b11da377e463dfd2288a162dbf
• git.kernel.org https://git.kernel.org/stable/c/eb8e27c8fa9397b4a7b181c48fa58157dbe9902e

Remediation