On 03/02/2017 04:11 PM, Aleksey Makarov wrote: > If a console was specified by ACPI SPCR table _and_ command line > parameters like "console=ttyAMA0" _and_ "earlycon" were specified, > then log messages appear twice. > > The root cause is that the code traverses the list of specified > consoles (the `console_cmdline` array) and stops at the first match. > But it may happen that the same console is referred by the elements > of this array twice: > > pl011,mmio,0x87e024000000,115200 -- from SPCR > ttyAMA0 -- from command line > > but in this case `preferred_console` points to the second entry and > the flag CON_CONSDEV is not set, so bootconsole is not deregistered. > > To fix that, match the console against the `console_cmdline` entry > pointed by `preferred_console` instead of the first match. > > Signed-off-by: Aleksey Makarov <[email protected]> > --- > kernel/printk/printk.c | 49 ++++++++++++++++++++++++++++++++++--------------- > 1 file changed, 34 insertions(+), 15 deletions(-) > > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c > index ed2a9b31f214..ad35011f8374 100644 > --- a/kernel/printk/printk.c > +++ b/kernel/printk/printk.c > @@ -2380,6 +2380,24 @@ static int __init keep_bootcon_setup(char *str) > > early_param("keep_bootcon", keep_bootcon_setup); > > +static int match_console(struct console *newcon, struct console_cmdline *c) > +{ > + if (!newcon->match || > + newcon->match(newcon, c->name, c->index, c->options) != 0) { > + /* default matching */ > + BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name)); > + if (strcmp(c->name, newcon->name) != 0) > + return -ENODEV; > + if (newcon->index >= 0 && > + newcon->index != c->index) > + return -ENODEV; > + if (newcon->index < 0) > + newcon->index = c->index; > + } > + > + return 0; > +} > + > /* > * The console driver calls this routine during kernel initialization > * to register the console printing procedure with printk() and to > @@ -2460,17 +2478,9 @@ void register_console(struct console *newcon) > for (i = 0, c = console_cmdline; > i < MAX_CMDLINECONSOLES && c->name[0]; > i++, c++) { > - if (!newcon->match || > - newcon->match(newcon, c->name, c->index, c->options) != 0) { > - /* default matching */ > - BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name)); > - if (strcmp(c->name, newcon->name) != 0) > - continue; > - if (newcon->index >= 0 && > - newcon->index != c->index) > - continue; > - if (newcon->index < 0) > - newcon->index = c->index; > + if (match_console(newcon, c)) { > + continue; > + } else {
My bad. The first version of this patch was closer to the original logic, despite this patch looks simpler. The problem is that newcon->setup() is called twice, firstly from newcon->match(), then explicitly. And it could be called third time later in another call to newcon->match(). The correct sequence is 1) try to match against preferred_console, 2) if that fails check other entries of console_cmdline. That would require some work so I will send a correction tomorrow. All the best Aleksey Makarov
