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* kmsg: export printk records to the /dev/kmsg interfaceKay Sievers2012-05-071-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Support for multiple concurrent readers of /dev/kmsg, with read(), seek(), poll() support. Output of message sequence numbers, to allow userspace log consumers to reliably reconnect and reconstruct their state at any given time. After open("/dev/kmsg"), read() always returns *all* buffered records. If only future messages should be read, SEEK_END can be used. In case records get overwritten while /dev/kmsg is held open, or records get faster overwritten than they are read, the next read() will return -EPIPE and the current reading position gets updated to the next available record. The passed sequence numbers allow the log consumer to calculate the amount of lost messages. [root@mop ~]# cat /dev/kmsg 5,0,0;Linux version 3.4.0-rc1+ (kay@mop) (gcc version 4.7.0 20120315 ... 6,159,423091;ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff]) 7,160,424069;pci_root PNP0A03:00: host bridge window [io 0x0000-0x0cf7] (ignored) SUBSYSTEM=acpi DEVICE=+acpi:PNP0A03:00 6,339,5140900;NET: Registered protocol family 10 30,340,5690716;udevd[80]: starting version 181 6,341,6081421;FDC 0 is a S82078B 6,345,6154686;microcode: CPU0 sig=0x623, pf=0x0, revision=0x0 7,346,6156968;sr 1:0:0:0: Attached scsi CD-ROM sr0 SUBSYSTEM=scsi DEVICE=+scsi:1:0:0:0 6,347,6289375;microcode: CPU1 sig=0x623, pf=0x0, revision=0x0 Cc: Karel Zak <kzak@redhat.com> Tested-by: William Douglas <william.douglas@intel.com> Signed-off-by: Kay Sievers <kay@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* printk: convert byte-buffer to variable-length record bufferKay Sievers2012-05-071-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Record-based stream instead of the traditional byte stream buffer. All records carry a 64 bit timestamp, the syslog facility and priority in the record header. - Records consume almost the same amount, sometimes less memory than the traditional byte stream buffer (if printk_time is enabled). The record header is 16 bytes long, plus some padding bytes at the end if needed. The byte-stream buffer needed 3 chars for the syslog prefix, 15 char for the timestamp and a newline. - Buffer management is based on message sequence numbers. When records need to be discarded, the reading heads move on to the next full record. Unlike the byte-stream buffer, no old logged lines get truncated or partly overwritten by new ones. Sequence numbers also allow consumers of the log stream to get notified if any message in the stream they are about to read gets discarded during the time of reading. - Better buffered IO support for KERN_CONT continuation lines, when printk() is called multiple times for a single line. The use of KERN_CONT is now mandatory to use continuation; a few places in the kernel need trivial fixes here. The buffering could possibly be extended to per-cpu variables to allow better thread-safety for multiple printk() invocations for a single line. - Full-featured syslog facility value support. Different facilities can tag their messages. All userspace-injected messages enforce a facility value > 0 now, to be able to reliably distinguish them from the kernel-generated messages. Independent subsystems like a baseband processor running its own firmware, or a kernel-related userspace process can use their own unique facility values. Multiple independent log streams can co-exist that way in the same buffer. All share the same global sequence number counter to ensure proper ordering (and interleaving) and to allow the consumers of the log to reliably correlate the events from different facilities. Tested-by: William Douglas <william.douglas@intel.com> Signed-off-by: Kay Sievers <kay@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'driver-core-3.3' of ↵Linus Torvalds2012-03-201-4/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core patches for 3.4-rc1 from Greg KH: "Here's the big driver core merge for 3.4-rc1. Lots of various things here, sysfs fixes/tweaks (with the nlink breakage reverted), dynamic debugging updates, w1 drivers, hyperv driver updates, and a variety of other bits and pieces, full information in the shortlog." * tag 'driver-core-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (78 commits) Tools: hv: Support enumeration from all the pools Tools: hv: Fully support the new KVP verbs in the user level daemon Drivers: hv: Support the newly introduced KVP messages in the driver Drivers: hv: Add new message types to enhance KVP regulator: Support driver probe deferral Revert "sysfs: Kill nlink counting." uevent: send events in correct order according to seqnum (v3) driver core: minor comment formatting cleanups driver core: move the deferred probe pointer into the private area drivercore: Add driver probe deferral mechanism DS2781 Maxim Stand-Alone Fuel Gauge battery and w1 slave drivers w1_bq27000: Only one thread can access the bq27000 at a time. w1_bq27000 - remove w1_bq27000_write w1_bq27000: remove unnecessary NULL test. sysfs: Fix memory leak in sysfs_sd_setsecdata(). intel_idle: Revert change of auto_demotion_disable_flags for Nehalem w1: Fix w1_bq27000 driver-core: documentation: fix up Greg's email address powernow-k6: Really enable auto-loading powernow-k7: Fix CPU family number ...
| * dynamic_debug: make dynamic-debug supersede DEBUG ccflagJim Cromie2012-01-241-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If CONFIG_DYNAMIC_DEBUG is defined, honor it over DEBUG, so that pr_debug()s are controllable, instead of always-on. When DEBUG is also defined, change _DPRINTK_FLAGS_DEFAULT to enable printing by default. Also adding _DPRINTK_FLAGS_INCL_MODNAME would be nice, but there are numerous cases of pr_debug(NAME ": ...), which would result in double printing of module-name. So defer this until things settle. Cc: David Miller <davem@davemloft.net> Cc: Joe Perches <joe@perches.com> Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | printk/sched: Introduce special printk_sched() for those awkward momentsPeter Zijlstra2012-03-121-0/+10
|/ | | | | | | | | | | | | | | | | There's a few awkward printk()s inside of scheduler guts that people prefer to keep but really are rather deadlock prone. Fudge around it by storing the text in a per-cpu buffer and poll it using the existing printk_tick() handler. This will drop output when its more frequent than once a tick, however only the affinity thing could possible go that fast and for that just one should suffice to notify the admin he's done something silly.. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-wua3lmkt3dg8nfts66o6brne@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* treewide: use __printf not __attribute__((format(printf,...)))Joe Perches2011-10-311-6/+6
| | | | | | | | | | | | | | | | | Standardize the style for compiler based printf format verification. Standardized the location of __printf too. Done via script and a little typing. $ grep -rPl --include=*.[ch] -w "__attribute__" * | \ grep -vP "^(tools|scripts|include/linux/compiler-gcc.h)" | \ xargs perl -n -i -e 'local $/; while (<>) { s/\b__attribute__\s*\(\s*\(\s*format\s*\(\s*printf\s*,\s*(.+)\s*,\s*(.+)\s*\)\s*\)\s*\)/__printf($1, $2)/g ; print; }' [akpm@linux-foundation.org: revert arch bits] Signed-off-by: Joe Perches <joe@perches.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* printk: allocate kernel log buffer earlierMike Travis2011-05-251-0/+7
| | | | | | | | | | | | | | | | | | | | On larger systems, because of the numerous ACPI, Bootmem and EFI messages, the static log buffer overflows before the larger one specified by the log_buf_len param is allocated. Minimize the overflow by allocating the new log buffer as soon as possible. On kernels without memblock, a later call to setup_log_buf from kernel/init.c is the fallback. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix CONFIG_PRINTK=n build] Signed-off-by: Mike Travis <travis@sgi.com> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* include/linux/printk.h: use tab not spaces for indentJoe Perches2011-01-131-7/+7
| | | | | | | | Signed-off-by: Joe Perches <joe@perches.com> Cc: Matt Mackall <mpm@selenic.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>
* include/linux/printk.h: organize printk_ratelimited macrosJoe Perches2011-01-131-13/+12
| | | | | | | | | | | | - Use no_printk for !CONFIG_PRINTK printk_ratelimited. - Whitespace cleanup. Signed-off-by: Joe Perches <joe@perches.com> Cc: Matt Mackall <mpm@selenic.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>
* include/linux/printk.h lib/hexdump.c: neatening and add CONFIG_PRINTK guardJoe Perches2011-01-131-14/+28
| | | | | | | | | | | | - Move prototypes and align arguments. - Add CONFIG_PRINTK guard for print_hex functions Signed-off-by: Joe Perches <joe@perches.com> Cc: Matt Mackall <mpm@selenic.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>
* include/linux/printk.h: add pr_<level>_once macrosJoe Perches2011-01-131-15/+44
| | | | | | | | | | | | - Move printk_once definitions and add an #ifdef CONFIG_PRINTK - Add pr_<level>_once so printks can use pr_fmt Signed-off-by: Joe Perches <joe@perches.com> Cc: Matt Mackall <mpm@selenic.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>
* include/linux/printk.h: use and neaten no_printkJoe Perches2011-01-131-32/+43
| | | | | | | | | | | | | | | | | | | | | | - Move no_printk above first CONFIG_PRINTK block so it can be used by printk_once. - Convert statement expression if (0) printk macros to no_printk. - Convert printk_once(x...) to more normally used (fmt, ...) fmt, ##__VA_ARGS__. - Standardize __attribute__ use. - Expand single line inline functions. - Remove space before pointer. Signed-off-by: Joe Perches <joe@perches.com> Cc: Matt Mackall <mpm@selenic.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>
* include/linux/printk.h: use space after #defineJoe Perches2011-01-131-9/+9
| | | | | | | | Signed-off-by: Joe Perches <joe@perches.com> Cc: Matt Mackall <mpm@selenic.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>
* include/linux/printk.h: move console functions and variables togetherJoe Perches2011-01-131-11/+11
| | | | | | | | | | | | | | | | | | | There are many uses of printk_once(KERN_<level>, so add pr_<level>_once macros to avoid printk_once(KERN_<level> pr_fmt(fmt). Add an #ifdef CONFIG_PRINTK for print_hex_dump and static inline void functions for the #else cases to reduce embedded code size. Neaten and organize the rest of the code. This patch: Move console functions and variables together. Signed-off-by: Joe Perches <joe@perches.com> Cc: Matt Mackall <mpm@selenic.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>
* kptr_restrict for hiding kernel pointers from unprivileged usersDan Rosenberg2011-01-131-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the %pK printk format specifier and the /proc/sys/kernel/kptr_restrict sysctl. The %pK format specifier is designed to hide exposed kernel pointers, specifically via /proc interfaces. Exposing these pointers provides an easy target for kernel write vulnerabilities, since they reveal the locations of writable structures containing easily triggerable function pointers. The behavior of %pK depends on the kptr_restrict sysctl. If kptr_restrict is set to 0, no deviation from the standard %p behavior occurs. If kptr_restrict is set to 1, the default, if the current user (intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG (currently in the LSM tree), kernel pointers using %pK are printed as 0's. If kptr_restrict is set to 2, kernel pointers using %pK are printed as 0's regardless of privileges. Replacing with 0's was chosen over the default "(null)", which cannot be parsed by userland %p, which expects "(nil)". [akpm@linux-foundation.org: check for IRQ context when !kptr_restrict, save an indent level, s/WARN/WARN_ONCE/] [akpm@linux-foundation.org: coding-style fixup] [randy.dunlap@oracle.com: fix kernel/sysctl.c warning] Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: James Morris <jmorris@namei.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Thomas Graf <tgraf@infradead.org> Cc: Eugene Teo <eugeneteo@kernel.org> Cc: Kees Cook <kees.cook@canonical.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David S. Miller <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Eric Paris <eparis@parisplace.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* include/linux/kernel.h: Move logging bits to include/linux/printk.hLinus Torvalds2010-11-151-0/+248
Move the logging bits from kernel.h into printk.h so that there is a bit more logical separation of the generic from the printk logging specific parts. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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