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); lock(&local->queue_stop_reason_lock);
*** DEADLOCK ***