linux-kernel - [PATCH v3 0/3] blk-mq: Don't complete in IRQ, use llist

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20210123201027.3262800-1-bigeasy@linutronix.de>
Date:   Sat, 23 Jan 2021 21:10:24 +0100
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Jens Axboe <axboe@...nel.dk>, Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>
Subject: [PATCH v3 0/3] blk-mq: Don't complete in IRQ, use llist_head

Patch 2+3 were applied and then dropped by Jens due to a NOHZ+softirq
related warning [0]. Turns out a successful wakeup via
set_nr_if_polling() will not process any softirqs and the CPU may go
back to idle. This is addressed by patch #1.

smpcfd_dying_cpu() will also invoke SMP-functions calls via
flush_smp_call_function_queue() but the block layer shouldn't queue
anything because the CPU isn't online anymore.
The two caller of flush_smp_call_function_from_idle() look fine with
opening interrupts from within do_softirq().

[0] https://lkml.kernel.org/r/1ee4b31b-350e-a9f5-4349-cfb34b89829a@kernel.dk

Sebastian