| Message ID | 20220708094950.41944-1-zhengqi.arch@bytedance.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | arm64: run softirqs on the per-CPU IRQ stack | expand |
On 2022/7/8 17:49, Qi Zheng wrote: > 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(-) > Hi all, Any other suggestions and comments for this patch set? If not, can this patch set be merged into some trees for testing? :) Thanks, Qi
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(-)