lkml.org 
[lkml]   [2020]   [Jan]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH] sched/core: fix illegal RCU from offline CPUs
    From
    Date
    On 2020/01/13 15:30, Qian Cai wrote:
    >>> - mmdrop(mm);
    >>> + smp_call_function_single(cpumask_first(cpu_online_mask),
    >>> + (void (*)(void *))mmdrop, mm, 0);
    >>
    >> mmdrop() might sleep, but
    >
    > If that is the case, and then the commit e78a7614f387 (“idle: Prevent
    > late-arriving interrupts from disrupting offline”) is incorrect because it
    > will disable local irq before calling mmdrop() which will trigger
    > the might_sleep() warning. Can you prove it?

    Is commit 7283094ec3db318e ("kernel, oom: fix potential pgd_lock deadlock from
    __mmdrop") about only softirq? Is it guaranteed that smp_call_function_single()
    does not hit such race? Then just my overcareful...

    \
     
     \ /
      Last update: 2020-01-13 09:21    [W:6.540 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site