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* nohz: Fix printk_needs_cpu() return value on offline cpusHeiko Carstens2010-11-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes a hang observed with 2.6.32 kernels where timers got enqueued on offline cpus. printk_needs_cpu() may return 1 if called on offline cpus. When a cpu gets offlined it schedules the idle process which, before killing its own cpu, will call tick_nohz_stop_sched_tick(). That function in turn will call printk_needs_cpu() in order to check if the local tick can be disabled. On offline cpus this function should naturally return 0 since regardless if the tick gets disabled or not the cpu will be dead short after. That is besides the fact that __cpu_disable() should already have made sure that no interrupts on the offlined cpu will be delivered anyway. In this case it prevents tick_nohz_stop_sched_tick() to call select_nohz_load_balancer(). No idea if that really is a problem. However what made me debug this is that on 2.6.32 the function get_nohz_load_balancer() is used within __mod_timer() to select a cpu on which a timer gets enqueued. If printk_needs_cpu() returns 1 then the nohz_load_balancer cpu doesn't get updated when a cpu gets offlined. It may contain the cpu number of an offline cpu. In turn timers get enqueued on an offline cpu and not very surprisingly they never expire and cause system hangs. This has been observed 2.6.32 kernels. On current kernels __mod_timer() uses get_nohz_timer_target() which doesn't have that problem. However there might be other problems because of the too early exit tick_nohz_stop_sched_tick() in case a cpu goes offline. Easiest way to fix this is just to test if the current cpu is offline and call printk_tick() directly which clears the condition. Alternatively I tried a cpu hotplug notifier which would clear the condition, however between calling the notifier function and printk_needs_cpu() something could have called printk() again and the problem is back again. This seems to be the safest fix. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: stable@kernel.org LKML-Reference: <20101126120235.406766476@de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* printk: Fix wake_up_klogd() vs cpu hotplugHeiko Carstens2010-11-26
| | | | | | | | | | | | | | | | | | | | | wake_up_klogd() may get called from preemptible context but uses __raw_get_cpu_var() to write to a per cpu variable. If it gets preempted between getting the address and writing to it, the cpu in question could be offline if the process gets scheduled back and hence writes to the per cpu data of an offline cpu. This buggy behaviour was introduced with fa33507a "printk: robustify printk, fix #2" which was supposed to fix a "using smp_processor_id() in preemptible" warning. Let's use this_cpu_write() instead which disables preemption and makes sure that the outlined scenario cannot happen. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20101126124247.GC7023@osiris.boeblingen.de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* capabilities/syslog: open code cap_syslog logic to fix build failureEric Paris2010-11-15
| | | | | | | | | | | | | | | | The addition of CONFIG_SECURITY_DMESG_RESTRICT resulted in a build failure when CONFIG_PRINTK=n. This is because the capabilities code which used the new option was built even though the variable in question didn't exist. The patch here fixes this by moving the capabilities checks out of the LSM and into the caller. All (known) LSMs should have been calling the capabilities hook already so it actually makes the code organization better to eliminate the hook altogether. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Restrict unprivileged access to kernel syslogDan Rosenberg2010-11-12
| | | | | | | | | | | | | | | | | | | | | | The kernel syslog contains debugging information that is often useful during exploitation of other vulnerabilities, such as kernel heap addresses. Rather than futilely attempt to sanitize hundreds (or thousands) of printk statements and simultaneously cripple useful debugging functionality, it is far simpler to create an option that prevents unprivileged users from reading the syslog. This patch, loosely based on grsecurity's GRKERNSEC_DMESG, creates the dmesg_restrict sysctl. When set to "0", the default, no restrictions are enforced. When set to "1", only users with CAP_SYS_ADMIN can read the kernel syslog via dmesg(8) or other mechanisms. [akpm@linux-foundation.org: explain the config option in kernel.txt] Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Eugene Teo <eugeneteo@kernel.org> Acked-by: Kees Cook <kees.cook@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* printk: change type of 'boot_delay' to int *Namhyung Kim2010-10-26
| | | | | | | | | | | | | | | | | get_option() takes its 2nd arg as int * so passing boot_delay to it caused following warnings from sparse: kernel/printk.c:223:27: warning: incorrect type in argument 2 (different signedness) kernel/printk.c:223:27: expected int *pint kernel/printk.c:223:27: got unsigned int static [toplevel] *<noident> Since boot_delay can't grow more than 10,000 changing it to 'int *' will not produce any problem. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* printk: add lock context annotationNamhyung Kim2010-10-26
| | | | | | | | | | acquire_console_semaphore_for_printk() releases logbuf_lock but was missing proper annotation. Add it. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* printk: fixup declaration of kmsg_reasonsNamhyung Kim2010-10-26
| | | | | | | | | Move redundant 'const' after '*' to make pointer itself const Signed-off-by: Namhyung Kim <namhyung@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* printk: Make console_sem a semaphore not a pseudo mutexThomas Gleixner2010-10-12
| | | | | | | | | | | 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>
* gcc-4.6: printk: use stable variable to dump kmsg bufferAndi Kleen2010-08-09
| | | | | | | | | | | | | | | 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>
* printk: fix delayed messages from CPU hotplug eventsKevin Cernekee2010-08-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* printk,kdb: capture printk() when in kdb shellJason Wessel2010-05-20
| | | | | | | | | | | 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>
* kdb: core for kgdb back end (2 of 2)Jason Wessel2010-05-20
| | | | | | | | | | 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>
* printk: avoid warning when CONFIG_PRINTK is disabledGustavo F. Padovan2010-03-06
| | | | | | | | | 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>
* Merge branch 'next' into for-linusJames Morris2010-02-28
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| * syslog: use defined constants instead of raw numbersKees Cook2010-02-03
| | | | | | | | | | | | | | | | | | | | | | 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>
| * syslog: distinguish between /proc/kmsg and syscallsKees Cook2010-02-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | Merge git://git.infradead.org/~dwmw2/mtd-2.6.33Linus Torvalds2010-01-24
|\ \ | |/ |/| | | | | | | | | * 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
| * kmsg_dump: Dump on crash_kexec as wellKOSAKI Motohiro2009-12-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | printk: fix new kernel-doc warningsRandy Dunlap2009-12-17
|/ | | | | | | | | | | | | 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>
* Merge git://git.infradead.org/mtd-2.6Linus Torvalds2009-12-16
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 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
| * kmsg_dump: fix build for CONFIG_PRINTK=nRandy Dunlap2009-12-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * core: Add kernel message dumper to call on oopses and panicsSimon Kagstrom2009-11-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | Merge branch 'core-printk-for-linus' of ↵Linus Torvalds2009-12-05
|\ \ | |/ |/| | | | | | | | | | | | | | | 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
| * ratelimit: Make suppressed output messages more usefulChristian Borntraeger2009-10-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * printk: Remove ratelimit.h from kernel.hIngo Molnar2009-09-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | printk: add printk_delay to make messages readable for some scenariosDave Young2009-09-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | printk boot_delay: rename printk_delay_msec to loops_per_msecDave Young2009-09-23
|/ | | | | | | | | | | | 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>
* cleanup console_print()Anirban Sinha2009-09-14
| | | | | | | | | 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>
* printk: Fix "printk: Enable the use of more than one CON_BOOT (early console)"Sonic Zhang2009-08-08
| | | | | | | | | | | | | 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>
* printk: Restore previous console_loglevel when re-enabling loggingFrans Pop2009-07-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* printk: Ensure that "console enabled" messages are printed on the consoleRobin Getz2009-07-10
| | | | | | | | | | | | | | | | | | | | | | | | 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>
* printk: Enable the use of more than one CON_BOOT (early console)Robin Getz2009-07-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* printk: Add KERN_DEFAULT printk log-levelLinus Torvalds2009-06-16
| | | | | | | | | | | | | | | | | | | 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>
* printk: clean up handling of log-levels and newlinesLinus Torvalds2009-06-16
| | | | | | | | | | | | | | | | | 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>
* Merge branch 'printk-for-linus' of ↵Linus Torvalds2009-04-05
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
| * printk: correct the behavior of printk_timed_ratelimit()Guillaume Knispel2009-03-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | kexec: add dmesg log symbols to /proc/vmcoreinfo listsNeil Horman2009-04-02
|/ | | | | | | | | | | | | | | | | | | | | 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>
* PM: Fix suspend_console and resume_console to use only one semaphoreArve Hjønnevåg2009-02-21
| | | | | | | | | | | | | | | | | | | | | | | 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>
* [CVE-2009-0029] System call wrappers part 27Heiko Carstens2009-01-14
| | | | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* [CVE-2009-0029] Make sys_syslog a conditional system callHeiko Carstens2009-01-14
| | | | | | | | 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>
* trivial: printk: fix indentation of new_text_line declarationJiri Kosina2009-01-06
| | | | | | | | 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>
* printk: fix discarding message when recursion_bugHiroshi Shimamoto2008-12-19
| | | | | | | | | | | | 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>
* printk: remove unused code from kernel/printk.croel kluin2008-10-23
| | | | | | both log_buf_copy() and log_buf_len are unused. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'core-v28-for-linus' of ↵Linus Torvalds2008-10-16
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
| *-. Merge branches 'core/softlockup', 'core/softirq', 'core/resources', ↵Ingo Molnar2008-10-15
| |\ \ | | | | | | | | | | | | 'core/printk' and 'core/misc' into core-v28-for-linus
| | | * printk: robustify printk, update commentJiri Kosina2008-08-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| | | * printk: robustify printk, fix #2Peter Zijlstra2008-08-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 b845b517b5e3706a3729f6ea83b88ab85f0725b0 > 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>
| | | * printk: robustify printkPeter Zijlstra2008-08-11
| | |/ | | | | | | | | | | | | | | | | | | | | | 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>
* | | Add kerneldoc documentation for new printk format extensionsAndi Kleen2008-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | Remove Andrew Morton's old email accountsFrancois Cami2008-10-16
|/ / | | | | | | | | | | | | | | | | 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>
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