Messages in this thread | | | From | John Ogness <> | Subject | Re: [PATCH v2 4/4] printk: Drop console_sem during panic | Date | Thu, 27 Jan 2022 10:28:53 +0106 |
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On 2022-01-26, Stephen Brennan <stephen.s.brennan@oracle.com> wrote: > --- a/kernel/printk/printk.c > +++ b/kernel/printk/printk.c > @@ -2759,7 +2782,7 @@ void console_unlock(void) > * flush, no worries. > */ > retry = prb_read_valid(prb, next_seq, NULL); > - if (retry && console_trylock()) > + if (retry && !abandon_console_lock_in_panic() && console_trylock())
As Sergey suggested [0], I would like to see the call to abandon_console_lock_in_panic() move inside console_trylock(). This will help to avoid the race between NMI CPU halt and the internal sema.lock spinlock.
John Ogness
[0] https://lore.kernel.org/all/YfJFjHdg%2FkhNXiRd@google.com
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