Am 15.11.2012 17:05, schrieb Kay Sievers:
> This with all your patches applied:
> [ 1.032804] input: ImExPS/2 Generic Explorer Mouse as
> /devices/platform/i8042/serio1/input/input2
> [ 1.063915] List of all partitions:
> [ 1.065521] 0800 117220824 sda driver: sd
> [ 1.067444] 0801 1048576 sda1
> 1fcbc57f-4bfc-4c2b-91a3-9c84fbcd9af1 0802 30720000 sda2
> 084917b7-8be2-4e86-838d-f771a9902e08 0803 15360000 sda3
> 180053b6-6697-4f4c-b331-4925773197ff 0804 54730752 sda4
> b67dfc6e-d06f-4b11-bd52-96c09163aca9 0805 15360000 sda5
> 6d0d537c-3107-4057-a57b-5379a0cd8e31No filesystem could mount root, tried:
> btrfs
> [ 1.077120] Kernel panic - not syncing: VFS: Unable to mount root fs on
> unknown-block(8,1)
>
>
> Something seems broken in the patches regarding the console or newline logic.
(Just to mention it: I did do quite some testing, but this case must have
escaped me.)
Hmm... the code in question does only continuation prints, without any PREFIX.
Especially, it issues a single
printk("\n");
at the end of each line (and does not start the next line with a KERN_ prefix).
This newline gets lost on the console.
This is due to patch 3, which reclaims a fully printed cont buffer
immediately. It does only a length check, without considering the LOG_NEWLINE
flag. So we never come around to print it. (And then, patch 9 has a similar
check -- which, btw, is necessary already in patch 7 I think...)
Please, try the patch below on top of everything. If this works, I'll prepare
a -v2 where everything is sorted into the correct patches.
(Though that makes patch 3 less efficient as we add newlines very late in two
places via cont_flush(). OTOH, the newlines are not strictly needed, I think.)
(And another note: the longer I look at all the code, the more I want to try
the alternative mentioned in patch 6, might be easier to read overall.)
Regards
Jan
diff --git a/kernel/printk.c b/kernel/printk.c
index d27da0a..51da981 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1434,7 +1434,8 @@ static void cont_flush(enum log_flags flags)
* If no fragment of this line ever reached the console or everything
* has been printed, free the buffer. Otherwise keep it available.
*/
- if (!cont.cons || cont.cons == cont.msg.text_len)
+ if (!cont.cons || (cont.cons == cont.msg.text_len &&
+ !(cont.msg.flags & LOG_NEWLINE)))
cont.msg.text_len = 0;
else
cont.flushed = log_next_seq - 1;
@@ -1475,14 +1476,17 @@ static bool cont_add(int facility, int level, enum
log_flags flags,
static size_t cont_print_text(char *text, size_t size)
{
- size_t textlen;
+ size_t textlen = 0;
enum log_flags flags = cont.msg.flags;
u64 seq = cont.flushed ? cont.flushed : log_next_seq;
if (cont.msg.text_len == cont.cons) {
- if (cont.flushed)
- cont.msg.text_len = 0;
- return 0;
+ /* Not even a newline to print? */
+ if (!(cont.msg.flags & LOG_NEWLINE))
+ goto out;
+ /* Newline already printed due to other messages? */
+ if (console_printed_seq != 0)
+ goto out;
}
/* Avoid a break, when we continuously print the cont buffer */
@@ -1505,6 +1509,7 @@ static size_t cont_print_text(char *text, size_t size)
console_prev = cont.msg.flags;
console_printed_seq = cont.flushed;
+out:
if (cont.flushed)
cont.msg.text_len = 0;
--
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