tick/nohz: Add BLOCK_SOFTIRQ to the hotplug safe mask

During CPU-hotplug stress testing combined with an I/O workload, the
following message is observed:

  "NOHZ tick-stop error: local softirq work is pending, handler #10!!!"

On CPU offline, ksoftirqd is parked at CPUHP_AP_SMPBOOT_THREADS while the
CPU still takes interrupts. A block completion raised after that point
stays pending, and if the dying CPU goes idle before teardown,
report_idle_softirq() sees it, keeps the tick alive and prints the error
above.

Such pending block completions on the outgoing CPU are drained later by
blk_softirq_cpu_dead() (CPUHP_BLOCK_SOFTIRQ_DEAD), so a pending
BLOCK_SOFTIRQ is harmless here. Add it to SOFTIRQ_HOTPLUG_SAFE_MASK like
the other teardown-covered vectors.

Signed-off-by: Wang Shuaiwei <wangshuaiwei1@xiaomi.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://patch.msgid.link/20260904064506.671203-1-wangshuaiwei1@xiaomi.com

0 files changed, 0 insertions, 0 deletions