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path: root/kernel/printk.c
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* Fix locking bug in "acquire_console_semaphore_for_printk()"Linus Torvalds2008-04-15
| | | | | | | | | | | | | | | | | | | When I cleaned up printk() and split up the printk locking logic in commit 266c2e0abeca649fa6667a1a427ad1da507c6375 ("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>
* Make printk() console semaphore accesses sensibleLinus Torvalds2008-03-24
| | | | | | | | 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: fix possible printk overrunTejun Heo2008-02-26
| | | | | | | | | | | | | | | | | | | | | 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 32a76006683f7b28ae3cc491da37716e002f198e 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>
* printk_ratelimit() functions should use CONFIG_PRINTKJoe Perches2008-02-08
| | | | | | | | 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 'time' option removalAdrian Bunk2008-02-08
| | | | | | | | | 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>
* Nuke duplicate include from printk.cJesper Juhl2008-02-08
| | | | | | | | 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>
* printk.c: use unsigned ints instead of longs for logbuf indexDenys Vlasenko2008-02-06
| | | | | | | | | | | | | | | | 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>
* debug: turn ignore_loglevel into an early paramIngo Molnar2008-01-31
| | | | | | | 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>
* x86: make early printk selectable on 64-bit as wellIngo Molnar2008-01-30
| | | | | | | | | | | | | Enable CONFIG_EMBEDDED to select CONFIG_EARLY_PRINTK on 64-bit as well. saves ~2K: text data bss dec hex filename 7290283 3672091 1907848 12870222 c4624e vmlinux.before 7288373 3671795 1907848 12868016 c459b0 vmlinux.after Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* printk: revert ktime_get() timestampsIngo Molnar2008-01-27
| | | | | | | | | | revert 19ef9309273d26cb005cb23e6a370353dca91099. 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: use ktime_get()Ingo Molnar2008-01-25
| | | | | | | | | | | | | 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>
* sched: remove printk_clock()Ingo Molnar2008-01-25
| | | | | | printk_clock() is obsolete - it has been replaced with cpu_clock(). Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix CONFIG_PRINT_TIME's reliance on sched_clock()Ingo Molnar2008-01-25
| | | | | | | | | | | | | 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>
* printk: make printk more robust by not allowing recursionIngo Molnar2008-01-25
| | | | | | | | | | | | | | | | | 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>
* [SERIAL]: Fix section mismatches in Sun serial console drivers.David S. Miller2007-12-29
| | | | | | | | | | | | | | | | | | | 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>
* serial: turn serial console suspend a boot rather than compile time optionAndres Salomon2007-10-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* printk: add interfaces for external access to the log bufferMike Frysinger2007-10-17
| | | | | | | | | | | | | | | | | 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>
* slow down printk during bootRandy Dunlap2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | 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>
* fix - ensure we don't use bootconsoles after init has been releasedRobin Getz2007-08-21
| | | | | | | | | 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>
* ensure we don't use bootconsoles after init has been releasedRobin Getz2007-08-21
| | | | | | | | | | | | | | | | | 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>
* serial: fix 8250 early console setupDaniel Ritz2007-08-03
| | | | | | | | | | 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 schedulerJiri Kosina2007-07-16
| | | | | | | | | | | | | | | | 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>
* add printk.time option, deprecate 'time'Randy Dunlap2007-07-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* serial: convert early_uart to earlycon for 8250Yinghai Lu2007-07-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* console: console handover to preferred consoleYinghai Lu2007-07-16
| | | | | | | | | | | | | | | | | | | | | 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>
* console: more buf for index parsingYinghai Lu2007-07-16
| | | | | | | | | | | | 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>
* header cleaning: don't include smp_lock.h when not usedRandy Dunlap2007-05-08
| | | | | | | | | | | | 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>
* Fixes and cleanups for earlyprintk aka boot consoleGerd Hoffmann2007-05-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* kernel/printk.c: comment fixPatrick Pletscher2007-02-17
| | | | | Signed-off-by: Patrick Pletscher <pat@pletscher.org> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] order of lockdep off/on in vprintk() should be changedMathieu Desnoyers2007-02-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* [PATCH] Extract and use wake_up_klogd()Kirill Korotaev2007-02-11
| | | | | | | | | | | | Remove hack with printing space to wake up klogd. Use explicit wake_up_klogd(). See earlier discussion http://groups.google.com/group/fa.linux.kernel/browse_frm/thread/75f496668409f58d/1a8f28983a51e1ff?lnk=st&q=wake_up_klogd+group%3Afa.linux.kernel&rnum=2#1a8f28983a51e1ff Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Numerous fixes to kernel-doc info in source files.Robert P. J. Day2007-02-11
| | | | | | | | | | | | | | | 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>
* [PATCH] make kernel/printk.c:ignore_loglevel_setup() staticAdrian Bunk2006-12-22
| | | | | | Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] add ignore_loglevel boot optionIngo Molnar2006-12-07
| | | | | | | | | | Sometimes the kernel prints something interesting while userspace bootup keeps messages turned off via loglevel. Enable the printing of /all/ kernel messages via the "ignore_loglevel" boot option. Off by default. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbolsAdrian Bunk2006-12-07
| | | | | | | | In time for 2.6.20, we can get rid of this junk. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] remove the syslog interface when printk is disabledMike Galbraith2006-12-07
| | | | | | | | | | | Attempts to read() from the non-existent dmesg buffer will return zero and userspace tends to get stuck in a busyloop. So just remove /dev/kmsg altogether if CONFIG_PRINTK=n. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Add printk_timed_ratelimit()Andrew Morton2006-11-03
| | | | | | | | | | | | | | | | | | printk_ratelimit() has global state which makes it not useful for callers which wish to perform ratelimiting at a particular frequency. Add a printk_timed_ratelimit() which utilises caller-provided state storage to permit more flexibility. This function can in fact be used for things other than printk ratelimiting and is perhaps poorly named. Cc: Ulrich Drepper <drepper@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] lockdep: fix printk recursion logicIngo Molnar2006-10-11
| | | | | | | | | | | | | | | | | | | | Bug reported and fixed by Tilman Schmidt <tilman@imap.cc>: if lockdep is enabled then log messages make it to /var/log/messages belatedly. The reason is a missed wakeup of klogd. Initially there was only a lockdep_internal() protection against lockdep recursion within vprintk() - it grew the 'outer' lockdep_off()/on() protection only later on. But that lockdep_off() made the release_console_sem() within vprintk() always happen under the lockdep_internal() condition, causing the bug. The right solution to remove the inner protection against recursion here - the outer one is enough. Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Tilman Schmidt <tilman@imap.cc> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] PM: make it possible to disable console suspendingRafael J. Wysocki2006-09-26
| | | | | | | | | | | | Change suspend_console() so that it waits for all consoles to flush the remaining messages and make it possible to switch the console suspending off with the help of a Kconfig option. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Stefan Seyfried <seife@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] vt: printk: Fix framebuffer console triggering might_sleep assertionAntonino A. Daplas2006-08-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reported by: Dave Jones Whilst printk'ing to both console and serial console, I got this... (2.6.18rc1) BUG: sleeping function called from invalid context at kernel/sched.c:4438 in_atomic():0, irqs_disabled():1 Call Trace: [<ffffffff80271db8>] show_trace+0xaa/0x23d [<ffffffff80271f60>] dump_stack+0x15/0x17 [<ffffffff8020b9f8>] __might_sleep+0xb2/0xb4 [<ffffffff8029232e>] __cond_resched+0x15/0x55 [<ffffffff80267eb8>] cond_resched+0x3b/0x42 [<ffffffff80268c64>] console_conditional_schedule+0x12/0x14 [<ffffffff80368159>] fbcon_redraw+0xf6/0x160 [<ffffffff80369c58>] fbcon_scroll+0x5d9/0xb52 [<ffffffff803a43c4>] scrup+0x6b/0xd6 [<ffffffff803a4453>] lf+0x24/0x44 [<ffffffff803a7ff8>] vt_console_print+0x166/0x23d [<ffffffff80295528>] __call_console_drivers+0x65/0x76 [<ffffffff80295597>] _call_console_drivers+0x5e/0x62 [<ffffffff80217e3f>] release_console_sem+0x14b/0x232 [<ffffffff8036acd6>] fb_flashcursor+0x279/0x2a6 [<ffffffff80251e3f>] run_workqueue+0xa8/0xfb [<ffffffff8024e5e0>] worker_thread+0xef/0x122 [<ffffffff8023660f>] kthread+0x100/0x136 [<ffffffff8026419e>] child_rip+0x8/0x12 This can occur when release_console_sem() is called but the log buffer still has contents that need to be flushed. The console drivers are called while the console_may_schedule flag is still true. The might_sleep() is triggered when fbcon calls console_conditional_schedule(). Fix by setting console_may_schedule to zero earlier, before the call to the console drivers. Signed-off-by: Antonino Daplas <adaplas@pol.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kernel/printk.c: EXPORT_SYMBOL_UNUSEDAdrian Bunk2006-07-10
| | | | | | | | This patch marks unused exports as EXPORT_SYMBOL_UNUSED. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] lockdep: do not recurse in printkIngo Molnar2006-07-03
| | | | | | | | | | Make printk()-ing from within the lock validation code safer by using the lockdep-recursion counter. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-30
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] printk time parameterJan Engelhardt2006-06-25
| | | | | | | | | | | | | | | Currently, enabling/disabling printk timestamps is only possible through reboot (bootparam) or recompile. I normally do not run with timestamps (since syslog handles that in a good manner), but for measuring small kernel delays (e.g. irq probing - see parport thread) I needed subsecond precision, but then again, just for some minutes rather than all kernel messages to come. The following patch adds a module_param() with which the timestamps can be en-/disabled in a live system through /sys/modules/printk/parameters/printk_time. Signed-off-by: Jan Engelhardt <jengelh@gmx.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Make printk work for really early debuggingMichael Ellerman2006-06-25
| | | | | | | | | | | | | | | | | | | | | | | | | Currently printk is no use for early debugging because it refuses to actually print anything to the console unless cpu_online(smp_processor_id()) is true. The stated explanation is that console drivers may require per-cpu resources, or otherwise barf, because the system is not yet setup correctly. Fair enough. However some console drivers might be quite happy running early during boot, in fact we have one, and so it'd be nice if printk understood that. So I added a flag (which I would have called CON_BOOT, but that's taken) called CON_ANYTIME, which indicates that a console is happy to be called anytime, even if the cpu is not yet online. Tested on a Power 5 machine, with both a CON_ANYTIME driver and a bogus console driver that BUG()s if called while offline. No problems AFAICT. Built for i386 UP & SMP. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Add support for suspending and resuming the whole console subsystemLinus Torvalds2006-06-19
| | | | | | | | Trying to suspend/resume with console messages flying all around is doomed to failure, when the devices that the messages are trying to go to are being shut down. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* BUG_ON() Conversion in kernel/printk.cEric Sesterhenn2006-03-31
| | | | | | | | this changes if() BUG(); constructs to BUG_ON() which is cleaner, contains unlikely() and can better optimized away. Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] console_setup() depends (wrongly?) on CONFIG_PRINTKJohn Z. Bohach2006-03-24
| | | | | | | | | | | | | | | | | It appears that console_setup() code only gets compiled into the kernel if CONFIG_PRINTK is enabled. One detrimental side-effect of this is that serial8250_console_setup() never gets invoked when CONFIG_PRINTK is not set, resulting in baud rate not being read/parsed from command line (i.e. console=ttyS0,115200n8 is ignored, at least the baud rate part...) Attached patch moves console_setup() code from inside #ifdef CONFIG_PRINTK to outside (in printk.c), removing dependence on said config. option. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* correct email address of Manfred SpraulChristian Kujau2006-01-14
| | | | | | | | | | | I tried to send the forcedeth maintainer an email, but it came back with: "The mail address manfreds@colorfullife.com is not read anymore. Please resent your mail to manfred@ instead of manfreds@." This patch fixes this. Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] printk return value: fix itGuillaume Chazarain2006-01-08
| | | | | | | | | | | | | | | | | | | | | | What's the true meaning of the printk return value? Should it include the priority prefix length of 3? and what about the timing information? In both cases it was broken: strace -e write echo 1 > /dev/kmsg => write(1, "1\n", 2) = 5 strace -e write echo "<1>1" > /dev/kmsg => write(1, "<1>1\n", 5) = 8 The returned length was "length of input string + 3", I made it "length of string output to the log buffer". Note that I couldn't find any printk caller in the kernel interested by its return value besides kmsg_write. Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr> Acked-By: Tim Bird <tim.bird@am.sony.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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