Messages in this thread | | | From | Qi Zheng <> | Subject | [PATCH v1 0/2] arm64: run softirqs on the per-CPU IRQ stack | Date | Fri, 8 Jul 2022 17:49:48 +0800 |
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Hi all,
Currently arm64 supports per-CPU IRQ stack, but softirqs are still handled in the task context.
Since any call to local_bh_enable() at any level in the task's call stack may trigger a softirq processing run, which could potentially cause a task stack overflow if the combined stack footprints exceed the stack's size. And we did encounter this situation in the real environment:
Call trace: dump_backtrace+0x0/0x1cc, show_stack+0x14/0x1c, dump_stack+0xc4/0xfc, panic+0x150/0x2c8, panic+0x0/0x2c8, handle_bad_stack+0x11c/0x130, __bad_stack+0x88/0x8c, vsnprintf+0x2c/0x524, vscnprintf+0x38/0x7c, scnprintf+0x6c/0x90, /* ... */ __do_softirq+0x1e0/0x370, do_softirq+0x40/0x50, __local_bh_enable_ip+0x8c/0x90, _raw_spin_unlock_bh+0x1c/0x24, /* ... */ process_one_work+0x1dc/0x3e4, worker_thread+0x260/0x360, kthread+0x118/0x128, ret_from_fork+0x10/0x18,
So let's run these softirqs on the IRQ stack as well.
This series is based on next-20220707.
Comments and suggestions are welcome.
Thanks, Qi
RFC: https://lore.kernel.org/lkml/20220707110511.52129-1-zhengqi.arch@bytedance.com/
Changelog in RFC -> v1: - fix conflicts with commit f2c5092190f2 ("arch/*: Disable softirq stacks on PREEMPT_RT.")
Qi Zheng (2): arm64: run softirqs on the per-CPU IRQ stack arm64: support HAVE_IRQ_EXIT_ON_IRQ_STACK
arch/arm64/Kconfig | 2 ++ arch/arm64/include/asm/exception.h | 4 +++- arch/arm64/kernel/entry-common.c | 30 ++++++++++++++++++++---------- arch/arm64/kernel/entry.S | 6 ++++-- arch/arm64/kernel/irq.c | 14 ++++++++++++++ 5 files changed, 43 insertions(+), 13 deletions(-)
-- 2.20.1
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