netlink: fix potential deadlock in netlink_set_err()

Summary

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 ***

Timeline

1. Oct 22, 2025, 1:23 PM UTCCVE published
2. May 23, 2026, 3:30 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 4.14.237 · fixed in 4.14.322; From 4.19.195 · fixed in 4.19.291; From 5.4.126 · fixed in 5.4.251; From 5.10.44 · fixed in 5.10.188; From 4.4.273 · fixed in 4.5; From 4.9.273 · fixed in 4.10; From 5.12.11 · fixed in 5.13

• Linux Linux

  5.13

References 9