Subject: + printk-report-dropping-of-messages-from-logbuf.patch added to -mm tree
To: will.deacon@xxxxxxx,jack@xxxxxxx,kay@xxxxxxxx,peterz@xxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Fri, 02 May 2014 14:22:21 -0700
The patch titled
Subject: printk: report dropping of messages from logbuf
has been added to the -mm tree. Its filename is
printk-report-dropping-of-messages-from-logbuf.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/printk-report-dropping-of-messages-from-logbuf.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/printk-report-dropping-of-messages-from-logbuf.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Will Deacon <will.deacon@xxxxxxx>
Subject: printk: report dropping of messages from logbuf
If the log ring buffer becomes full, we silently overwrite old messages
with new data. console_unlock will detect this case and fast-forward the
console_* pointers to skip over the corrupted data, but nothing will be
reported to the user.
This patch hijacks the first valid log message after detecting that we
dropped messages and prefixes it with a note detailing how many messages
were dropped. For long (~1000 char) messages, this will result in some
truncation of the real message, but given that we're dropping things
anyway, that doesn't seem to be the end of the world.
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Kay Sievers <kay@xxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/printk/printk.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff -puN kernel/printk/printk.c~printk-report-dropping-of-messages-from-logbuf kernel/printk/printk.c
--- a/kernel/printk/printk.c~printk-report-dropping-of-messages-from-logbuf
+++ a/kernel/printk/printk.c
@@ -2160,10 +2160,15 @@ again_noirq:
}
if (console_seq < log_first_seq) {
+ len = sprintf(text, "** %u printk messages dropped ** ",
+ (unsigned)(log_first_seq - console_seq));
+
/* messages are gone, move to first one */
console_seq = log_first_seq;
console_idx = log_first_idx;
console_prev = 0;
+ } else {
+ len = 0;
}
skip:
if (console_seq == log_next_seq)
@@ -2188,8 +2193,8 @@ skip:
}
level = msg->level;
- len = msg_print_text(msg, console_prev, false,
- text, sizeof(text));
+ len += msg_print_text(msg, console_prev, false,
+ text + len, sizeof(text) - len);
console_idx = log_next(console_idx);
console_seq++;
console_prev = msg->flags;
_
Patches currently in -mm which might be from will.deacon@xxxxxxx are
origin.patch
printk-print-initial-logbuf-contents-before-re-enabling-interrupts.patch
printk-report-dropping-of-messages-from-logbuf.patch
documentation-devicetree-bindings-add-documentation-for-the-apm-x-gene-soc-rtc-dts-binding.patch
drivers-rtc-add-apm-x-gene-soc-rtc-driver.patch
arm64-add-apm-x-gene-soc-rtc-dts-entry.patch
linux-next.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
