Messages in this thread | | | Date | Thu, 7 Jun 2018 23:03:19 +0900 | From | Sergey Senozhatsky <> | Subject | Re: possible deadlock in console_unlock |
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On (06/07/18 20:40), Tetsuo Handa wrote: > >> diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c > >> index c996b6859c5e..71958ef6a831 100644 > >> --- a/drivers/tty/tty_buffer.c > >> +++ b/drivers/tty/tty_buffer.c > >> @@ -167,7 +167,8 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size) > >> have queued and recycle that ? */ > >> if (atomic_read(&port->buf.mem_used) > port->buf.mem_limit) > >> return NULL; > >> - p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); > >> + p = kmalloc(sizeof(struct tty_buffer) + 2 * size, > >> + GFP_ATOMIC | __GFP_NOWARN); > >> if (p == NULL) > >> return NULL; > >> > >> --- > > > > This looks like the most simple solution for this particular problem. > > I am just afraid that there are many other locations like this. > > > I haven't tried the reproducer with that change. But isn't __GFP_NOWARN > ignored by fail_dump() (and thus printk() from fault injection still occurs)?
Thanks for the info. Need to check it [I didn't know that GFP_NOWARN meant GFP_WARN_ME_SOMETIMES]. If this is the case then we have just one option left - printk_safe contexts for TTY/UART locks.
-ss
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