Commit Graph

127 Commits

Author SHA1 Message Date
Andi Kleen 8c4af38e9b gcc-4.6: printk: use stable variable to dump kmsg buffer
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>
2010-08-09 20:45:06 -07:00
Kevin Cernekee 034260d677 printk: fix delayed messages from CPU hotplug events
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>
2010-08-05 13:25:59 +01:00
Jason Wessel d37d39ae3b printk,kdb: capture printk() when in kdb shell
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>
2010-05-20 21:04:27 -05:00
Jason Wessel 67fc4e0cb9 kdb: core for kgdb back end (2 of 2)
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>
2010-05-20 21:04:21 -05:00
Gustavo F. Padovan cea83886dd printk: avoid warning when CONFIG_PRINTK is disabled
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>
2010-03-06 11:26:33 -08:00
James Morris b4ccebdd37 Merge branch 'next' into for-linus 2010-03-01 09:36:31 +11:00
Kees Cook d78ca3cd73 syslog: use defined constants instead of raw numbers
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>
2010-02-04 14:20:41 +11:00
Kees Cook 002345925e syslog: distinguish between /proc/kmsg and syscalls
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>
2010-02-04 14:20:12 +11:00
Linus Torvalds b8be634e01 Merge git://git.infradead.org/~dwmw2/mtd-2.6.33
* 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
2010-01-24 10:31:34 -08:00
KOSAKI Motohiro 0f4bd46ec2 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>
2009-12-31 19:45:04 +00:00
Randy Dunlap 6485536bcf printk: fix new kernel-doc warnings
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>
2009-12-17 15:45:32 -08:00
Linus Torvalds 60d9aa758c Merge git://git.infradead.org/mtd-2.6
* 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
2009-12-16 10:23:43 -08:00
Linus Torvalds d0b093a8b5 Merge branch 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* '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
2009-12-05 09:50:22 -08:00
Randy Dunlap 595dd3d8bf kmsg_dump: fix build for CONFIG_PRINTK=n
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>
2009-12-02 08:44:33 +00:00
Simon Kagstrom 456b565cc5 core: Add kernel message dumper to call on oopses and panics
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>
2009-11-30 12:01:49 +00:00
Christian Borntraeger 5c82871335 ratelimit: Make suppressed output messages more useful
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>
2009-10-23 17:26:37 +02:00
Dave Young af91322ef3 printk: add printk_delay to make messages readable for some scenarios
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>
2009-09-23 07:39:28 -07:00
Dave Young 3a3b6ed223 printk boot_delay: rename printk_delay_msec to loops_per_msec
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>
2009-09-23 07:39:28 -07:00
Ingo Molnar 3fff4c42bd printk: Remove ratelimit.h from kernel.h
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>
2009-09-22 16:18:09 +02:00
Anirban Sinha 353f6dd2de cleanup console_print()
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>
2009-09-14 17:41:42 -07:00
Sonic Zhang 42c2c8c854 printk: Fix "printk: Enable the use of more than one CON_BOOT (early console)"
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>
2009-08-08 18:27:37 +02:00
Frans Pop 1aaad49e85 printk: Restore previous console_loglevel when re-enabling logging
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>
2009-07-10 16:02:23 +02:00
Robin Getz 8259cf4342 printk: Ensure that "console enabled" messages are printed on the console
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>
2009-07-10 12:24:47 +02:00
Robin Getz 4d09161196 printk: Enable the use of more than one CON_BOOT (early console)
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>
2009-07-03 10:10:43 +02:00
Linus Torvalds e28d713704 printk: Add KERN_DEFAULT printk log-level
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>
2009-06-16 11:02:28 -07:00
Linus Torvalds 5fd29d6ccb printk: clean up handling of log-levels and newlines
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>
2009-06-16 10:57:02 -07:00
Linus Torvalds e4c393fd55 Merge branch 'printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* '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.
2009-04-05 10:23:25 -07:00
Neil Horman 04d491ab2a kexec: add dmesg log symbols to /proc/vmcoreinfo lists
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>
2009-04-02 19:05:04 -07:00
Guillaume Knispel f2d28a2ebc printk: correct the behavior of printk_timed_ratelimit()
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>
2009-03-17 16:25:28 +01:00
Arve Hjønnevåg 403f307576 PM: Fix suspend_console and resume_console to use only one semaphore
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>
2009-02-21 14:17:18 -08:00
Heiko Carstens 1e7bfb2134 [CVE-2009-0029] System call wrappers part 27
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2009-01-14 14:15:29 +01:00
Heiko Carstens f627a741d2 [CVE-2009-0029] Make sys_syslog a conditional system call
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>
2009-01-14 14:15:16 +01:00
Jiri Kosina edb123e16c trivial: printk: fix indentation of new_text_line declaration
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>
2009-01-06 11:28:06 +01:00
Hiroshi Shimamoto 26cc271db7 printk: fix discarding message when recursion_bug
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>
2008-12-19 22:52:47 +01:00
roel kluin acff181d35 printk: remove unused code from kernel/printk.c
both log_buf_copy() and log_buf_len are unused.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-23 21:54:29 +02:00
Linus Torvalds e533b22705 Merge branch 'core-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  do_generic_file_read: s/EINTR/EIO/ if lock_page_killable() fails
  softirq, warning fix: correct a format to avoid a warning
  softirqs, debug: preemption check
  x86, pci-hotplug, calgary / rio: fix EBDA ioremap()
  IO resources, x86: ioremap sanity check to catch mapping requests exceeding, fix
  IO resources, x86: ioremap sanity check to catch mapping requests exceeding the BAR sizes
  softlockup: Documentation/sysctl/kernel.txt: fix softlockup_thresh description
  dmi scan: warn about too early calls to dmi_check_system()
  generic: redefine resource_size_t as phys_addr_t
  generic: make PFN_PHYS explicitly return phys_addr_t
  generic: add phys_addr_t for holding physical addresses
  softirq: allocate less vectors
  IO resources: fix/remove printk
  printk: robustify printk, update comment
  printk: robustify printk, fix #2
  printk: robustify printk, fix
  printk: robustify printk

Fixed up conflicts in:
	arch/powerpc/include/asm/types.h
	arch/powerpc/platforms/Kconfig.cputype
manually.
2008-10-16 15:17:40 -07:00
Andi Kleen 20036fdcaf Add kerneldoc documentation for new printk format extensions
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>
2008-10-16 11:21:32 -07:00
Francois Cami e1f8e87449 Remove Andrew Morton's old email accounts
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>
2008-10-16 11:21:32 -07:00
Ingo Molnar 6b2ada8210 Merge branches 'core/softlockup', 'core/softirq', 'core/resources', 'core/printk' and 'core/misc' into core-v28-for-linus 2008-10-15 12:48:44 +02:00
Alan Cox 95f9bfc6b7 tty: Move tty_write_message out of kernel/printk
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>
2008-10-13 09:51:41 -07:00
Jiri Kosina 1fa63a817d printk: robustify printk, update comment
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>
2008-08-20 15:39:59 +02:00
Peter Zijlstra fa33507a22 printk: robustify printk, fix #2
Dmitry Adamushko reported:

> [*] btw., with DEBUG being enabled, pr_debug() generates [1] when
> debug_smp_processor_id() is used (CONFIG_DEBUG_PREEMPT).
>
> the problem seems to be caused by the following commit:
> commit b845b517b5
> Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Date:   Fri Aug 8 21:47:09 2008 +0200
>
>     printk: robustify printk
>
>
> wake_up_klogd() -> __get_cpu_var() -> smp_processor_id()
>
> and that's being called from release_console_sem() which is, in turn,
> said to be "may be called from any context" [2]
>
> and in this case, it seems to be called from some non-preemptible
> context (although, it can't be printk()...
> although, I haven't looked carefully yet).
>
> Provided [2], __get_cpu_var() is perhaps not the right solution there.
>
>
> [1]
>
> [ 7697.942005] BUG: using smp_processor_id() in preemptible [00000000] code: syslogd/3542
> [ 7697.942005] caller is wake_up_klogd+0x1b/0x50
> [ 7697.942005] Pid: 3542, comm: syslogd Not tainted 2.6.27-rc3-tip-git #2
> [ 7697.942005] Call Trace:
> [ 7697.942005]  [<ffffffff8036b398>] debug_smp_processor_id+0xe8/0xf0
> [ 7697.942005]  [<ffffffff80239d3b>] wake_up_klogd+0x1b/0x50
> [ 7697.942005]  [<ffffffff8023a047>] release_console_sem+0x1e7/0x200
> [ 7697.942005]  [<ffffffff803c0f17>] do_con_write+0xb7/0x1f30
> [ 7697.942005]  [<ffffffff8020d920>] ? show_trace+0x10/0x20
> [ 7697.942005]  [<ffffffff8020dc42>] ? dump_stack+0x72/0x80
> [ 7697.942005]  [<ffffffff8036392d>] ? __ratelimit+0xbd/0xe0
> [ 7697.942005]  [<ffffffff8036b398>] ? debug_smp_processor_id+0xe8/0xf0
> [ 7697.942005]  [<ffffffff80239d3b>] ? wake_up_klogd+0x1b/0x50
> [ 7697.942005]  [<ffffffff8023a047>] ? release_console_sem+0x1e7/0x200
> [ 7697.942005]  [<ffffffff803c2de9>] con_write+0x19/0x30
> [ 7697.942005]  [<ffffffff803b37b6>] write_chan+0x276/0x3c0
> [ 7697.942005]  [<ffffffff80232b20>] ? default_wake_function+0x0/0x10
> [ 7697.942005]  [<ffffffff804cb872>] ? _spin_lock_irqsave+0x22/0x50
> [ 7697.942005]  [<ffffffff803b1334>] tty_write+0x194/0x260
> [ 7697.942005]  [<ffffffff803b3540>] ? write_chan+0x0/0x3c0
> [ 7697.942005]  [<ffffffff803b14a4>] redirected_tty_write+0xa4/0xb0
> [ 7697.942005]  [<ffffffff803b1400>] ? redirected_tty_write+0x0/0xb0
> [ 7697.942005]  [<ffffffff802a88c2>] do_loop_readv_writev+0x52/0x80
> [ 7697.942005]  [<ffffffff802a939d>] do_readv_writev+0x1bd/0x1d0
> [ 7697.942005]  [<ffffffff802a93e9>] vfs_writev+0x39/0x60
> [ 7697.942005]  [<ffffffff802a9870>] sys_writev+0x50/0x90
> [ 7697.942005]  [<ffffffff8020bb3b>] system_call_fastpath+0x16/0x1b

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reported-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-20 12:22:37 +02:00
Peter Zijlstra b845b517b5 printk: robustify printk
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>
2008-08-11 13:46:53 +02:00
Uwe Kleine-König 641de9d8f5 printk: fix comment for printk ratelimiting
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>
2008-07-30 09:41:45 -07:00
Dave Young 717115e1a5 printk ratelimiting rewrite
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>
2008-07-25 10:53:29 -07:00
Pavel Machek 0d63081d41 swsusp: provide users with a hint about the no_console_suspend option
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>
2008-07-24 10:47:22 -07:00
Linus Torvalds 4bb0057f99 Merge branch 'core/printk' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* '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
2008-07-14 15:27:43 -07:00
Ingo Molnar 5806b81ac1 Merge branch 'auto-ftrace-next' into tracing/for-linus
Conflicts:

	arch/x86/kernel/entry_32.S
	arch/x86/kernel/process_32.c
	arch/x86/kernel/process_64.c
	arch/x86/lib/Makefile
	include/asm-x86/irqflags.h
	kernel/Makefile
	kernel/sched.c

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-14 16:11:52 +02:00
Ingo Molnar ae94b8075a Merge branch 'linus' into x86/core
Conflicts:

	arch/x86/mm/ioremap.c

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-12 07:29:02 +02:00
Ingo Molnar bac0c9103b Merge branch 'tracing/ftrace' into auto-ftrace-next 2008-07-10 11:43:00 +02:00