Hi Jisheng, 在 2021/4/2 21:32, Jisheng Zhang 写道: > On Thu, 1 Apr 2021 16:49:47 +0800 > "liaochang (A)" <liaocha...@huawei.com> wrote: > >> Hi Jisheng, > > Hi, > >> >> 在 2021/3/31 22:22, Jisheng Zhang 写道: >>> On Tue, 30 Mar 2021 18:33:16 +0900 >>> Masami Hiramatsu <mhira...@kernel.org> wrote: >>> >>>> Hi Jisheng, >>> >>> Hi Masami, >>> >>>> >>>> On Tue, 30 Mar 2021 02:16:24 +0800 >>>> Jisheng Zhang <jszha...@mail.ustc.edu.cn> wrote: >>>> >>>>> From: Jisheng Zhang <jszh...@kernel.org> >>>>> >>>>> Current riscv's kprobe handlers are run with both preemption and >>>>> interrupt enabled, this violates kprobe requirements. Fix this issue >>>>> by keeping interrupts disabled for BREAKPOINT exception. >>>> >>>> Not only while the breakpoint exception but also until the end of >>>> the single step (maybe you are using __BUG_INSN_32 ??) need to be >>>> disable interrupts. Can this do that? >>>> >>> >>> interrupt is disabled during "single step" by kprobes_save_local_irqflag() >>> and kprobes_restore_local_irqflag(). The code flow looks like: >>> >>> do_trap_break() // for bp >>> kprobe_breakpoint_handler() >>> setup_singlestep() >>> kprobes_restore_local_irqflag() >>> >>> do_trap_break() // for ss >>> kprobe_single_step_handler() >>> kprobes_restore_local_irqflag() >> >> Recently, kernel hit BUG_ON() on QEMU after I install a probe at "sys_read" >> via kprobe, > > TIPS: Each line should not exceed 80 chars > >> accoriding to my debugging and analysis it looks like caused by the "irq >> disable" operation for single-stepping. >> >> I present a detailed description about this problem in the mail with title >> "[PATCH] riscv/kprobe: fix kernel panic when invoking sys_read traced by >> kprobe". >> Looking forward to some feedback,Thanks. >> > > I will comment that patch.
Thanks for your reminder. > > thanks > > . >
