It needs to be investigated whether it can be replaced by a real
mutex, but that needs more thought.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
LKML-Reference: <20100907125057.179587334@linutronix.de>
kmsg_dump takes care to sample the global variables
inside a spinlock, but then goes on to use the same
variables outside the spinlock region too.
Use the correct variable. This will make the race
window smaller.
Found by gcc 4.6's new warnings.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a secondary CPU is being brought up, it is not uncommon for
printk() to be invoked when cpu_online(smp_processor_id()) == 0. The
case that I witnessed personally was on MIPS:
http://lkml.org/lkml/2010/5/30/4
If (can_use_console() == 0), printk() will spool its output to log_buf
and it will be visible in "dmesg", but that output will NOT be echoed to
the console until somebody calls release_console_sem() from a CPU that
is online. Therefore, the boot time messages from the new CPU can get
stuck in "limbo" for a long time, and might suddenly appear on the
screen when a completely unrelated event (e.g. "eth0: link is down")
occurs.
This patch modifies the console code so that any pending messages are
automatically flushed out to the console whenever a CPU hotplug
operation completes successfully or aborts.
The issue was seen on 2.6.34.
Original patch by Kevin Cernekee with cleanups by akpm and additional fixes
by Santosh Shilimkar. This patch superseeds
https://patchwork.linux-mips.org/patch/1357/.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
To: <mingo@elte.hu>
To: <akpm@linux-foundation.org>
To: <simon.kagstrom@netinsight.net>
To: <David.Woodhouse@intel.com>
To: <lethal@linux-sh.org>
Cc: <linux-kernel@vger.kernel.org>
Cc: <linux-mips@linux-mips.org>
Reviewed-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/1534/
LKML-Reference: <ede63b5a20af951c755736f035d1e787772d7c28@localhost>
LKML-Reference: <EAF47CD23C76F840A9E7FCE10091EFAB02C5DB6D1F@dbde02.ent.ti.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Certain calls from the kdb shell will call out to printk(), and any of
these calls should get vectored back to the kdb_printf() so that the
kdb pager and processing can be used, as well as to properly channel
I/O to the polled I/O devices.
CC: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
This patch contains the hooks and instrumentation into kernel which
live outside the kernel/debug directory, which the kdb core
will call to run commands like lsmod, dmesg, bt etc...
CC: linux-arch@vger.kernel.org
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Martin Hicks <mort@sgi.com>
kernel/printk.c:72: warning: `saved_console_loglevel' defined but not used
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Right now the syslog "type" action are just raw numbers which makes
the source difficult to follow. This patch replaces the raw numbers
with defined constants for some level of sanity.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
This allows the LSM to distinguish between syslog functions originating
from /proc/kmsg access and direct syscalls. By default, the commoncaps
will now no longer require CAP_SYS_ADMIN to read an opened /proc/kmsg
file descriptor. For example the kernel syslog reader can now drop
privileges after opening /proc/kmsg, instead of staying privileged with
CAP_SYS_ADMIN. MAC systems that implement security_syslog have unchanged
behavior.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
* git://git.infradead.org/~dwmw2/mtd-2.6.33:
mtd: tests: fix read, speed and stress tests on NOR flash
mtd: Really add ARM pismo support
kmsg_dump: Dump on crash_kexec as well
crash_kexec gets called before kmsg_dump(KMSG_DUMP_OOPS) if
panic_on_oops is set, so the kernel log buffer is not stored
for this case.
This patch adds a KMSG_DUMP_KEXEC dump type which gets called
when crash_kexec() is invoked. To avoid getting double dumps,
the old KMSG_DUMP_PANIC is moved below crash_kexec(). The
mtdoops driver is modified to handle KMSG_DUMP_KEXEC in the
same way as a panic.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Fix kernel-doc warnings in printk.c:
Warning(kernel/printk.c:1422): No description found for parameter 'dumper'
Warning(kernel/printk.c:1422): Excess function parameter 'dump' description in 'kmsg_dump_register'
Warning(kernel/printk.c:1451): No description found for parameter 'dumper'
Warning(kernel/printk.c:1451): Excess function parameter 'dump' description in 'kmsg_dump_unregister'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.infradead.org/mtd-2.6: (90 commits)
jffs2: Fix long-standing bug with symlink garbage collection.
mtd: OneNAND: Fix test of unsigned in onenand_otp_walk()
mtd: cfi_cmdset_0002, fix lock imbalance
Revert "mtd: move mxcnd_remove to .exit.text"
mtd: m25p80: add support for Macronix MX25L4005A
kmsg_dump: fix build for CONFIG_PRINTK=n
mtd: nandsim: add support for 4KiB pages
mtd: mtdoops: refactor as a kmsg_dumper
mtd: mtdoops: make record size configurable
mtd: mtdoops: limit the maximum mtd partition size
mtd: mtdoops: keep track of used/unused pages in an array
mtd: mtdoops: several minor cleanups
core: Add kernel message dumper to call on oopses and panics
mtd: add ARM pismo support
mtd: pxa3xx_nand: Fix PIO data transfer
mtd: nand: fix multi-chip suspend problem
mtd: add support for switching old SST chips into QRY mode
mtd: fix M29W800D dev_id and uaddr
mtd: don't use PF_MEMALLOC
mtd: Add bad block table overrides to Davinci NAND driver
...
Fixed up conflicts (mostly trivial) in
drivers/mtd/devices/m25p80.c
drivers/mtd/maps/pcmciamtd.c
drivers/mtd/nand/pxa3xx_nand.c
kernel/printk.c
* 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
ratelimit: Make suppressed output messages more useful
printk: Remove ratelimit.h from kernel.h
ratelimit: Fix/allow use in atomic contexts
ratelimit: Use per ratelimit context locking
kmsg_dump() fails to build when CONFIG_PRINTK=n; provide stubs
for the kmsg_dump*() functions when CONFIG_PRINTK=n.
kernel/printk.c: In function 'kmsg_dump':
kernel/printk.c:1501: error: 'log_buf_len' undeclared (first use in this function)
kernel/printk.c:1502: error: 'logged_chars' undeclared (first use in this function)
kernel/printk.c:1506: error: 'log_buf' undeclared (first use in this function)
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
The core functionality is implemented as per Linus suggestion from
http://lists.infradead.org/pipermail/linux-mtd/2009-October/027620.html
(with the kmsg_dump implementation by Linus). A struct kmsg_dumper has
been added which contains a callback to dump the kernel log buffers on
crashes. The kmsg_dump function gets called from oops_exit() and panic()
and invokes this callbacks with the crash reason.
[dwmw2: Fix log_end handling]
Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Reviewed-by: Anders Grafstrom <anders.grafstrom@netinsight.net>
Reviewed-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Today I got:
[39648.224782] Registered led device: iwl-phy0::TX
[40676.545099] __ratelimit: 246 callbacks suppressed
[40676.545103] abcdef[23675]: segfault at 0 ...
as you can see the ratelimit message contains a function prefix.
Since this is always __ratelimit, this wont help much.
This patch changes __ratelimit and printk_ratelimit to print the
function name that calls ratelimit.
This will pinpoint the responsible function, as long as not several
different places call ratelimit with the same ratelimit state at
the same time. In that case we catch only one random function that
calls ratelimit after the wait period.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dave Young <hidave.darkstar@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <200910231458.11832.borntraeger@de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When syslog is not possible, at the same time there's no serial/net
console available, it will be hard to read the printk messages. For
example oops/panic/warning messages in shutdown phase.
Add a printk delay feature, we can make each printk message delay some
milliseconds.
Setting the delay by proc/sysctl interface: /proc/sys/kernel/printk_delay
The value range from 0 - 10000, default value is 0
[akpm@linux-foundation.org: fix a few things]
Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename `printk_delay_msec' to `loops_per_msec', because the patch "printk:
add printk_delay to make messages readable for some scenarios" wishes to
more appropriately use the `printk_delay_msec' identifier.
[akpm@linux-foundation.org: add a comment]
Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Decouple kernel.h from ratelimit.h: the global declaration of
printk's ratelimit_state is not needed, and it leads to messy
circular dependencies due to ratelimit.h's (new) adding of a
spinlock_types.h include.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David S. Miller <davem@davemloft.net>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
console_print() is an old legacy interface mostly unused in the entire
kernel tree. It's best to clean up its existing use and let developers
use their own implementation of it as they feel fit.
Signed-off-by: Anirban Sinha <asinha@zeugmasystems.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Don't return when we find the first bootconsole - it can leave
other bootconsoles still installed, and they can be used and
cause problems later (if they are in the init section, and
eventually released), and cause problems. Make sure we remove
all of them.
Signed-off-by: Sonic Zhang <Sonic.Zhang@analog.com>
Signed-off-by: Robin Getz <rgetz@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When logging to console is disabled from userspace using klogctl()
and later re-enabled, console_loglevel gets set to the default
log level instead to the previous value.
This means that if the kernel was booted with 'quiet', the boot is
suddenly no longer quiet after logging to console gets re-enabled.
Save the current console_loglevel when logging is disabled and
restore to that value. If the log level is set to a specific value
while disabled, this is interpreted as an implicit re-enabling of
the logging.
The problem that prompted this patch is described in:
http://lkml.org/lkml/2009/6/28/234
There are two variations possible on the patch below:
1) If klogctl(7) is called while logging is not disabled, then set level
to default (partially preserving current functionality):
case 7: /* Enable logging to console */
- console_loglevel = default_console_loglevel;
+ if (saved_console_loglevel == -1)
+ console_loglevel = default_console_loglevel;
+ else {
+ console_loglevel = saved_console_loglevel;
+ saved_console_loglevel = -1;
+ }
2) If klogctl(8) is called while logging is disabled, then don't enable
logging, but remember the requested value for when logging does get
enabled again:
case 8: /* Set level of messages printed to console */
[...]
- console_loglevel = len;
+ if (saved_console_loglevel == -1)
+ console_loglevel = len;
+ else
+ saved_console_loglevel = len;
Yet another option would be to ignore the request.
Signed-off-by: Frans Pop <elendil@planet.nl>
Cc: cryptsetup@packages.debian.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <200907061331.49930.elendil@planet.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Today, when a console is registered without CON_PRINTBUFFER,
end users never see the announcement of it being added, and
never know if they missed something, if the console is really
at the start or not, and just leads to general confusion.
This re-orders existing code, to make sure the console is
added, before the "console [%s%d] enabled" is printed out -
ensuring that this message is _always_ seen.
This has the desired/intended side effect of making sure that
"console enabled:" messages are printed on the bootconsole, and
the real console. This does cause the same line is printed
twice if the bootconsole and real console are the same device,
but if they are on different devices, the message is printed to
both consoles.
Signed-off-by : Robin Getz <rgetz@blackfin.uclinux.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>
Cc: "Linus Torvalds" <torvalds@linux-foundation.org>
LKML-Reference: <200907091308.37370.rgetz@blackfin.uclinux.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Today, register_console() assumes the following usage:
- The first console to register with a flag set to CON_BOOT
is the one and only bootconsole.
- If another register_console() is called with an additional
CON_BOOT, it is silently rejected.
- As soon as a console without the CON_BOOT set calls
registers the bootconsole is automatically unregistered.
- Once there is a "real" console - register_console() will
silently reject any consoles with it's CON_BOOT flag set.
In many systems (alpha, blackfin, microblaze, mips, powerpc,
sh, & x86), there are early_printk implementations, which use
the CON_BOOT which come out serial ports, vga, usb, & memory
buffers.
In many embedded systems, it would be nice to have two
bootconsoles - in case the primary fails, you always have
access to a backup memory buffer - but this requires at least
two CON_BOOT consoles...
This patch enables that functionality.
With the change applied, on boot you get (if you try to
re-enable a boot console after the "real" console has been
registered):
root:/> dmesg | grep console
bootconsole [early_shadow0] enabled
bootconsole [early_BFuart0] enabled
Kernel command line: root=/dev/mtdblock0 rw earlyprintk=serial,uart0,57600 console=ttyBF0,57600 nmi_debug=regs
console handover:boot [early_BFuart0] boot [early_shadow0] -> real [ttyBF0]
Too late to register bootconsole early_shadow0
or:
root:/> dmesg | grep console
Kernel command line: root=/dev/mtdblock0 rw console=ttyBF0,57600
console [ttyBF0] enabled
Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Cc: "Linus Torvalds" <torvalds@linux-foundation.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>
Cc: "Mike Frysinger" <vapier.adi@gmail.com>
Cc: "Paul Mundt" <lethal@linux-sh.org>
LKML-Reference: <200907012108.38030.rgetz@blackfin.uclinux.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This adds a KERN_DEFAULT loglevel marker, for when you cannot decide
which loglevel you want, and just want to keep an existing printk
with the default loglevel.
The difference between having KERN_DEFAULT and having no log-level
marker at all is two-fold:
- having the log-level marker will now force a new-line if the
previous printout had not added one (perhaps because it forgot,
but perhaps because it expected a continuation)
- having a log-level marker is required if you are printing out a
message that otherwise itself could perhaps otherwise be mistaken
for a log-level.
Signed-of-by: Linus Torvalds <torvalds@linux-foundation.org>
It used to be that we would only look at the log-level in a printk()
after explicit newlines, which can cause annoying problems when the
previous printk() did not end with a '\n'. In that case, the log-level
marker would be just printed out in the middle of the line, and be
seen as just noise rather than change the logging level.
This changes things to always look at the log-level in the first
bytes of the printout. If a log level marker is found, it is always
used as the log-level. Additionally, if no newline existed, one is
added (unless the log-level is the explicit KERN_CONT marker, to
explicitly show that it's a continuation of a previous line).
Acked-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
printk: correct the behavior of printk_timed_ratelimit()
vsprintf: unify the format decoding layer for its 3 users, cleanup
fix regression from "vsprintf: unify the format decoding layer for its 3 users"
vsprintf: fix bug in negative value printing
vsprintf: unify the format decoding layer for its 3 users
vsprintf: add binary printf
printk: introduce printk_once()
Fix trivial conflicts (printk_once vs log_buf_kexec_setup() added near
each other) in include/linux/kernel.h.
It would be nice to be able to extract the dmesg log from a vmcore file
without needing to keep the debug symbols for the running kernel handy all
the time. We have a facility to do this in /proc/vmcore. This patch adds
the log_buf and log_end symbols to the vmcoreinfo area so that tools (like
makedumpfile) can easily extract the dmesg logs from a vmcore image.
[akpm@linux-foundation.org: several fixes and cleanups]
[akpm@linux-foundation.org: fix unused log_buf_kexec_setup()]
[akpm@linux-foundation.org: build fix]
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Cc: Simon Horman <horms@verge.net.au>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: fix jiffies-comparison sign-wrap behavior
The behavior provided by printk_timed_ratelimit() is, in some
situations, probably not what a caller would reasonably expect:
bool printk_timed_ratelimit(unsigned long *caller_jiffies,
unsigned int interval_msecs)
{
if (*caller_jiffies == 0 || time_after(jiffies, *caller_jiffies)) {
*caller_jiffies = jiffies + msecs_to_jiffies(interval_msecs);
return true;
}
return false;
}
On a 32 bit computer, if printk_timed_ratelimit() is initially called at
time jiffies == Ja, *caller_jiffies is set to
Ja + msecs_to_jiffies(interval_msecs): let's say Ja + 42 for this
example.
If this caller then doesn't call printk_timed_ratelimit() until
jiffies == Ja + (1 << 31) + 42 (which can happen as soon as ~ 25 days
later on a 1000 HZ system), printk_timed_ratelimit() will then always
return false to this caller until jiffies loops completely (1 << 31 more
ticks).
Ths change makes it only return false if jiffies is in the small
time window starting at the previous call when true was returned and
ending interval_msecs later. Note that if jiffies loops completely
between two calls to printk_timed_ratelimit(), it will obviously still
wrongly return false, but this is something with a low probability.
If something completely reliable is needed I guess jiffies_64 must be
used (which this change does not do).
Signed-off-by: Guillaume Knispel <gknispel@proformatique.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20090317161842.0059096b@xilun.lan.proformatique.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This fixes a race where a thread acquires the console while the
console is suspended, and the console is resumed before this
thread releases it. In this case, the secondary console
semaphore would be left locked, and the primary semaphore would
be released twice. This in turn would cause the console switch
on suspend or resume to hang forever.
Note that suspend_console does not actually lock the console
for clients that use acquire_console_sem, it only locks it for
clients that use try_acquire_console_sem. If we change
suspend_console to fully lock the console, then the kernel
may deadlock on suspend. One client of try_acquire_console_sem
is acquire_console_semaphore_for_printk, which uses it to
prevent printk from using the console while it is suspended.
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the -ENOSYS implementation for !CONFIG_PRINTK and use
the cond_syscall infrastructure instead.
Acked-by: Kyle McMartin <kyle@redhat.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Remove bogus indentation of new_text_line declaration introduced in
commit ac60ad741.
Acked-by: Nick Andrew <nick@nick-andrew.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Impact: fix truncated recursion bug message printout
When recursion_bug is true, kernel discards original message because printk_buf
contains recursion_bug_msg with NULL terminator. The sizeof(recursion_bug_msg)
makes this, use strlen() to get correct length without NULL terminator.
Reported-by: Toshikazu Nakayama <nakayama.ts@ncos.nec.co.jp>
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add documentation in kerneldoc for new printk format extensions
This patch documents the new %pS/%pF options in printk in kernel doc.
Hope I didn't miss any other extension.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
People can use the real name an an index into MAINTAINERS to find the
current email address.
Signed-off-by: Francois Cami <francois.cami@free.fr>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is pure tty code so put it in the tty layer where it can be with the
locking relevant material it uses
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the comment describing the possibility of printk() deadlocking on
runqueue lock.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Avoid deadlocks against rq->lock and xtime_lock by deferring the klogd
wakeup by polling from the timer tick.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The comment assumed the burst to be one and the ratelimit used to be named
printk_ratelimit_jiffies.
Signed-off-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>
Cc: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All ratelimit user use same jiffies and burst params, so some messages
(callbacks) will be lost.
For example:
a call printk_ratelimit(5 * HZ, 1)
b call printk_ratelimit(5 * HZ, 1) before the 5*HZ timeout of a, then b will
will be supressed.
- rewrite __ratelimit, and use a ratelimit_state as parameter. Thanks for
hints from andrew.
- Add WARN_ON_RATELIMIT, update rcupreempt.h
- remove __printk_ratelimit
- use __ratelimit in net_ratelimit
Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tell the user about the no_console_suspend option, so that we don't have to
tell each bug reporter personally.
[akpm@linux-foundation.org: clarify the text a little]
Signed-off-by: Pavel Machek <pavel@suse.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'core/printk' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, generic: mark early_printk as asmlinkage
printk: export console_drivers
printk: remember the message level for multi-line output
printk: refactor processing of line severity tokens
printk: don't prefer unsuited consoles on registration
printk: clean up recursion check related static variables
namespacecheck: more kernel/printk.c fixes
namespacecheck: fix kernel printk.c
It's not explicitly marked as asmlinkage, but invoked from x86_32
startup code with parameters on stack.
No other architectures define early_printk and none of them are affected
by this change, since defines asmlinkage as empty token.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Without console= arguments on the kernel command line, the first
console to register becomes enabled and the preferred console (the one
behind /dev/console). This is normally tty (assuming
CONFIG_VT_CONSOLE is enabled, which it commonly is).
This is okay as long tty is a useful console. But unless we have the
PV framebuffer, and it is enabled for this domain, tty0 in domU is
merely a dummy. In that case, we want the preferred console to be the
Xen console hvc0, and we want it without having to fiddle with the
kernel command line. Commit b8c2d3dfbc
did that for us.
Since we now have the PV framebuffer, we want to enable and prefer tty
again, but only when PVFB is enabled. But even then we still want to
enable the Xen console as well.
Problem: when tty registers, we can't yet know whether the PVFB is
enabled. By the time we can know (xenstore is up), the console setup
game is over.
Solution: enable console tty by default, but keep hvc as the preferred
console. Change the preferred console to tty when PVFB probes
successfully, unless we've been given console kernel parameters.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
printk(KERN_ALERT "Danger Will Robinson!\nAlien Approaching!\n");
At present this will result in one message at ALERT level and one
at the current default message loglevel (e.g. WARNING). This is
non-intuitive.
Modify vprintk() to remember the message loglevel each time it
is specified and use it for subsequent lines of output which do
not specify one, within the same call to printk.
Signed-off-by: Nick Andrew <nick@nick-andrew.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Restructure the logic of vprintk() so the processing of the leading
3 characters of each input line is in one place, regardless whether
printk_time is enabled. This makes the code smaller and easier to
understand.
size reduction in kernel/printk.o:
text data bss dec hex filename
6157 397 1049804 1056358 101e66 printk.o.before
6117 397 1049804 1056318 101e3e printk.o.after
and some style uncleanlinesses removed as well as a side-effect:
Before:
total: 19 errors, 22 warnings, 1340 lines checked
After:
total: 17 errors, 22 warnings, 1333 lines checked
Signed-off-by: Nick Andrew <nick@nick-andrew.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
console election: If some console happens to be registered first which does
not provide a tty binding (!console->device), it prevents that more suited
consoles which are registered later on can enter the candidate pool for
console_device(). This is observable with KGDB's console which may already
be registered (and exploited!) during early debugger connections, that is
before any regular console registration.
This patch fixes the issue by postponing the final, automated
preferred_console selection until someone with a non-NULL device handler
comes around.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Make printk_recursion_bug_msg static and drop printk prefix from recursion
variables.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Fix update_console_cmdline() not to to read beyond the terminating zero of its
name argument.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds a minimalistic braille screen reader support. This is meant to
be used by blind people e.g. on boot failures or when / cannot be mounted
etc and thus the userland screen readers can not work.
[akpm@linux-foundation.org: fix exports]
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Jiri Kosina <jikos@jikos.cz>
Cc: Dmitry Torokhov <dtor@mail.ru>
Acked-by: Alan Cox <alan@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Operations are now a shared const function block as with most other Linux
objects
- Introduce wrappers for some optional functions to get consistent behaviour
- Wrap put_char which used to be patched by the tty layer
- Document which functions are needed/optional
- Make put_char report success/fail
- Cache the driver->ops pointer in the tty as tty->ops
- Remove various surplus lock calls we no longer need
- Remove proc_write method as noted by Alexey Dobriyan
- Introduce some missing sanity checks where certain driver/ldisc
combinations would oops as they didn't check needed methods were present
[akpm@linux-foundation.org: fix fs/compat_ioctl.c build]
[akpm@linux-foundation.org: fix isicom]
[akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build]
[akpm@linux-foundation.org: fix kgdb]
Signed-off-by: Alan Cox <alan@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Due to the rcupreempt.h WARN_ON trigged, I got 2G syslog file. For some
serious complaining of kernel, we need repeat the warnings, so here I isolate
the ratelimit part of printk.c to a standalone file.
Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When I cleaned up printk() and split up the printk locking logic in
commit 266c2e0abe ("Make printk() console
semaphore accesses sensible") I had incorrectly moved the call to
have_callable_console() outside of the console semaphore.
That was buggy. The console semaphore protects the console_drivers list
that is used by have_callable_console().
Thanks go to Bongani Hlope who saw this as a hang on shutdown and reboot
and bisected the bug to the right commit, and tested this patch. See
http://lkml.org/lkml/2008/4/11/315
Bisected-and-tested-by: Bongani Hlope <bonganilinux@mweb.co.za>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The printk() logic on when/how to get the console semaphore was
unreadable, this splits the code up into a few helper functions and
makes it easier to follow what is going on.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
printk recursion detection prepends message to printk_buf and offsets
printk_buf when actual message is printed but it forgets to trim buffer
length accordingly. This can result in overrun in extreme cases. Fix it.
[ mingo@elte.hu:
bug was introduced by me via:
commit 32a7600668
Author: Ingo Molnar <mingo@elte.hu>
Date: Fri Jan 25 21:07:58 2008 +0100
printk: make printk more robust by not allowing recursion
]
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Makes an embedded image a bit smaller.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The scheduled removal of the 'time' option.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the duplicate inclusion of linux/jiffies.h from kernel/printk.c
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Stop using unsigned _longs_ for printk buffer indexes. Log buffer is way
smaller than 2 gigabytes and unsigned ints will work too . Indeed, they do
work nicely on all 32-bit platforms where longs and ints are the same.
With this patch, we have following size savings on amd64:
text data bss dec hex filename
5997 313 17736 24046 5dee 2.6.23.1.t64/kernel/printk.o
5858 313 17700 23871 5d3f 2.6.23.1.printk.t64/kernel/printk.o
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
i was debugging early crashes and wondered where all the printks
went. The reason: ignore_loglevel_setup() was not called yet ...
Signed-off-by: Ingo Molnar <mingo@elte.hu>
revert 19ef930927.
Kevin Winchester reported a lockup during X startup an bisected
it to this commit.
Reported-by: Kevin Winchester <kjwinchester@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
printk timestamps: use ktime_get().
Some platforms have a functioning clocksource function only after
they are done with early bootup, so delay this until out of
SYSTEM_BOOTING state.
it's also inherently safe now, as any bugs in this area will be
caught by the printk recursion checks.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Stefano Brivio reported weird printk timestamp behavior during
CPU frequency changes:
http://bugzilla.kernel.org/show_bug.cgi?id=9475
fix CONFIG_PRINT_TIME's reliance on sched_clock() and use cpu_clock()
instead.
Reported-and-bisected-by: Stefano Brivio <stefano.brivio@polimi.it>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
make printk more robust by allowing recursion only if there's a crash
going on. Also add recursion detection.
I've tested it with an artificially injected printk recursion - instead
of a lockup or spontaneous reboot or other crash, the output was a well
controlled:
[ 41.057335] SysRq : <2>BUG: recent printk recursion!
[ 41.057335] loglevel0-8 reBoot Crashdump show-all-locks(D) tErm Full kIll saK showMem Nice powerOff showPc show-all-timers(Q) unRaw Sync showTasks Unmount shoW-blocked-tasks
also do all this printk-debug logic with irqs disabled.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Nick Piggin <npiggin@suse.de>
We're exporting an __init function, oops :-)
The core issue here is that add_preferred_console() is marked
as __init, this makes it impossible to invoke this thing from
a driver probe routine which is what the Sparc serial drivers
need to do.
There is no harm in dropping the __init marker. This code will
actually work properly when invoked from a modular driver,
except that init will probably not pick up the console change
without some other support code.
Then we can drop the __init from sunserial_console_match()
and we're no longer exporting an __init function to modules.
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, there's a CONFIG_DISABLE_CONSOLE_SUSPEND that allows one to stop
the serial console from being suspended when the rest of the machine goes
to sleep. This is incredibly useful for debugging power management-related
things; however, having it as a compile-time option has proved to be
incredibly inconvenient for us (OLPC). There are plenty of times that we
want serial console to not suspend, but for the most part we'd like serial
console to be suspended.
This drops CONFIG_DISABLE_CONSOLE_SUSPEND, and replaces it with a kernel
boot parameter (no_console_suspend). By default, the serial console will
be suspended along with the rest of the system; by passing
'no_console_suspend' to the kernel during boot, serial console will remain
alive during suspend.
For now, this is pretty serial console specific; further fixes could be
applied to make this work for things like netconsole.
Signed-off-by: Andres Salomon <dilinger@debian.org>
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@suspend2.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add two new functions for reading the kernel log buffer. The intention is for
them to be used by recovery/dump/debug code so the kernel log can be easily
retrieved/parsed in a crash scenario, but they are generic enough for other
people to dream up other fun uses.
[akpm@linux-foundation.org: buncha fixes]
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Cc: Robin Getz <rgetz@blackfin.uclinux.org>
Cc: Greg Ungerer <gerg@snapgear.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Optionally add a boot delay after each kernel printk() call, crudely
measured in milliseconds, with a maximum delay of 10 seconds per printk.
Enable CONFIG_BOOT_PRINTK_DELAY=y and then add (e.g.):
"lpj=loops_per_jiffy boot_delay=100"
to the kernel command line.
It has been useful in cases like "during boot, my machine just reboots or the
screen goes black" by slowing down printk, (and adding initcall_debug), we can
usually see the last thing that happened before the lights went out which is
usually a valuable clue.
[akpm@linux-foundation.org: not all architectures implement CONFIG_HZ]
[akpm@linux-foundation.org: fix lots of stuff]
[bunk@stusta.de: kernel/printk.c: make 2 variables static]
[heiko.carstens@de.ibm.com: fix slow down printk on boot compile error]
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Gerd Hoffmann pointed out that my patch from yesterday can lead
to a null pointer dereference if the kernel is booted with no
console, and no earlyprintk defined. This fixes that issue.
Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a followup to the cleanups for earlyprintk patch from Gerd Hoffmann
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=69331af79cf29e26d1231152a172a1a10c2df511
This ensures that a bootconsole is unregistered if it is not replaced.
The current implementation spews garbage out the bootconsole in this case,
since the bootconsole structure is normally in the init section, and is
freed, but still used.
Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
the early setup function serial8250_console_early_setup() can be called
from non __init code (eg. hotpluggable serial ports like serial_cs) so
remove the __init from the call chain to avoid crashes.
Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch>
Cc: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kernel/printk.c: document possible deadlock against scheduler
The printk's comment states that it can be called from every context,
which might lead to false illusion that it could be called from everywhere
without any restrictions.
This is however not true - a call to printk() could deadlock if called from
scheduler code (namely from schedule(), wake_up(), etc) on runqueue lock
when it tries to wake up klogd. Document this.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow printk_time to be enabled or disabled at boot time. Previously it
could be enabled only, but not disabled.
Change printk_time from an int to a bool since that's what it is. Make its
logical (exposed) name just be "time" (was "printk_time").
Note: Changes kernel boot option syntax from "time" to "printk.time=value".
Since printk_time is declared as a module_param, it can also be
changed at run-time by modifying
/sys/module/printk/parameters/time
to a value of 1/Y/y to enabled it or 0/N/n to disable it.
Since printk_time is declared as a module_param, its value can also
be set at boot-time by using
linux printk.time=<bool>
If the "time" boot option is used, print a message that it is deprecated
and will be removed.
Note its planned removal in feature-removal-schedule.txt.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Beacuse SERIAL_PORT_DFNS is removed from include/asm-i386/serial.h and
include/asm-x86_64/serial.h. the serial8250_ports need to be probed late in
serial initializing stage. the console_init=>serial8250_console_init=>
register_console=>serial8250_console_setup will return -ENDEV, and console
ttyS0 can not be enabled at that time. need to wait till uart_add_one_port in
drivers/serial/serial_core.c to call register_console to get console ttyS0.
that is too late.
Make early_uart to use early_param, so uart console can be used earlier. Make
it to be bootconsole with CON_BOOT flag, so can use console handover feature.
and it will switch to corresponding normal serial console automatically.
new command line will be:
console=uart8250,io,0x3f8,9600n8
console=uart8250,mmio,0xff5e0000,115200n8
or
earlycon=uart8250,io,0x3f8,9600n8
earlycon=uart8250,mmio,0xff5e0000,115200n8
it will print in very early stage:
Early serial console at I/O port 0x3f8 (options '9600n8')
console [uart0] enabled
later for console it will print:
console handover: boot [uart0] -> real [ttyS0]
Signed-off-by: <yinghai.lu@sun.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
for earlyprintk=ttyS0,9600 console=tty0 console=ttyS0,9600n8
the handover will happen from earlyser0 to tty0. but what we want is to
hand over to ttyS0.
Later with serial-convert-early_uart-to-earlycon-for-8250.patch,
console=tty0 console=uart8250,io,0x3f8,9600n8
will handover to ttyS0 instead of tty0.
Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change name to buf according to the usage as name + index
Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.
Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The console subsystem already has an idea of a boot console, using the
CON_BOOT flag. The implementation has some flaws though. The major
problem is that presence of a boot console makes register_console() ignore
any other console devices (unless explicitly specified on the kernel
command line).
This patch fixes the console selection code to *not* consider a boot
console a full-featured one, so the first non-boot console registering will
become the default console instead. This way the unregister call for the
boot console in the register_console() function actually triggers and the
handover from the boot console to the real console device works smoothly.
Added a printk for the handover, so you know which console device the
output goes to when the boot console stops printing messages.
The disable_early_printk() call is obsolete with that patch, explicitly
disabling the early console isn't needed any more as it works automagically
with that patch.
I've walked through the tree, dropped all disable_early_printk() instances
found below arch/ and tagged the consoles with CON_BOOT if needed. The
code is tested on x86, sh (thanks to Paul) and mips (thanks to Ralf).
Changes to last version: Rediffed against -rc3, adapted to mips cleanups by
Ralf, fixed "udbg-immortal" cmd line arg on powerpc.
Signed-off-by: Gerd Hoffmann <kraxel@exsuse.de>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The order of locking between lockdep_off/on() and local_irq_save/restore() in
vprintk() should be changed.
* In kernel/printk.c :
vprintk() does :
preempt_disable()
local_irq_save()
lockdep_off()
spin_lock(&logbuf_lock)
spin_unlock(&logbuf_lock)
if(!down_trylock(&console_sem))
up(&console_sem)
lockdep_on()
local_irq_restore()
preempt_enable()
The goals here is to make sure we do not call printk() recursively from
kernel/lockdep.c:__lock_acquire() (called from spin_* and down/up) nor from
kernel/lockdep.c:trace_hardirqs_on/off() (called from local_irq_restore/save).
It can then potentially call printk() through mark_held_locks/mark_lock.
It correctly protects against the spin_lock call and the up/down call, but it
does not protect against local_irq_restore. It could cause infinite recursive
printk/trace_hardirqs_on() calls when printk() is called from the
mark_lock() error handing path.
We should change the locking so it becomes correct :
preempt_disable()
lockdep_off()
local_irq_save()
spin_lock(&logbuf_lock)
spin_unlock(&logbuf_lock)
if(!down_trylock(&console_sem))
up(&console_sem)
local_irq_restore()
lockdep_on()
preempt_enable()
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A variety of (mostly) innocuous fixes to the embedded kernel-doc content in
source files, including:
* make multi-line initial descriptions single line
* denote some function names, constants and structs as such
* change erroneous opening '/*' to '/**' in a few places
* reword some text for clarity
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
