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2015-09-08mm, oom: do not panic for oom kills triggered from sysrqDavid Rientjes
Sysrq+f is used to kill a process either for debug or when the VM is otherwise unresponsive. It is not intended to trigger a panic when no process may be killed. Avoid panicking the system for sysrq+f when no processes are killed. Signed-off-by: David Rientjes <rientjes@google.com> Suggested-by: Michal Hocko <mhocko@suse.cz> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-03Documentation/sysrq.txt: Mention MIPS TLB dump (x)James Hogan
Commit d1e9a4f54735 ("MIPS: Add SysRq operation to dump TLBs on all CPUs") added the 'x' sysrq key for dumping MIPS TLB entries, but didn't document it in Documentation/sysrq.txt. Add mention of the MIPS use of the 'x' SysRq key. Reported-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: James Hogan <james.hogan@imgtec.com> Acked-by: Jonathan Corbet <corbet@lwn.net> Cc: Maciej W. Rozycki <macro@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: linux-doc@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/10720/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-10-16sysrq: Allow magic SysRq key functions to be disabled through KconfigBen Hutchings
Turn the initial value of sysctl kernel.sysrq (SYSRQ_DEFAULT_ENABLE) into a Kconfig variable. Original version by Bastian Blank <waldi@debian.org>. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-10-16sysrq: Document hexadecimal values for kernel.sysrq bitmaskBen Hutchings
It makes more sense to enter a bitmask in hexadecimal rather than decimal. Sadly we can't make it read back as hexadecimal. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-04-30Documentation/sysrq: fix inconstistent help message of sysrq keyzhangwei(Jovi)
Currently help message of /proc/sysrq-trigger highlight its upper-case characters, like below: SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) ... this would confuse user trigger sysrq by upper-case character, which is inconsistent with the real lower-case character registed key. This inconsistent help message will also lead more confused when 26 upper-case letters put into use in future. This patch fix sysrq documentation. Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-16sparc64: Add global PMU register dumping via sysrq.David S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-03-30Documentation: sysrq: Crutcher Dunnavant is unavailableRandy Dunlap
Reported-by: Křištof Želechovski <giecrilj@stegny.2a.pl> Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26documentation: update sysrq.txt magic sysrq keysRandy Dunlap
Update Documentation/sysrq.txt magic sysrq keys: - 'g' is for kgdb (not arch-specific); - add 2 new uses for 'v', remove the Voyager info; - add 'y' info (SPARC-64 specific); Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: "James E.J. Bottomley" <James.Bottomley@suse.de> Cc: David Airlie <airlied@linux.ie> Acked-by: Alexander Shishkin <virtuoso@slind.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-19Input: Documentation/sysrq.txt - update KEY_SYSRQ infoPaul Fox
While setting up sysrq operation on the XO laptop (which lacks a SysRq key), i realized that the documentation was quite out of date. Change documentation of SysRq to reflect current KEY_SYSRQ value. Signed-off-by: Paul Fox <pgf@laptop.org> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2009-07-29sysrq, kdump: make sysrq-c consistentHidetoshi Seto
commit d6580a9f15238b87e618310c862231ae3f352d2d ("kexec: sysrq: simplify sysrq-c handler") changed the behavior of sysrq-c to unconditional dereference of NULL pointer. So in cases with CONFIG_KEXEC, where crash_kexec() was directly called from sysrq-c before, now it can be said that a step of "real oops" was inserted before starting kdump. However, in contrast to oops via SysRq-c from keyboard which results in panic due to in_interrupt(), oops via "echo c > /proc/sysrq-trigger" will not become panic unless panic_on_oops=1. It means that even if dump is properly configured to be taken on panic, the sysrq-c from proc interface might not start crashdump while the sysrq-c from keyboard can start crashdump. This confuses traditional users of kdump, i.e. people who expect sysrq-c to do common behavior in both of the keyboard and proc interface. This patch brings the keyboard and proc interface behavior of sysrq-c in line, by forcing panic_on_oops=1 before oops in sysrq-c handler. And some updates in documentation are included, to clarify that there is no longer dependency with CONFIG_KEXEC, and that now the system can just crash by sysrq-c if no dump mechanism is configured. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: Brayan Arraes <brayan@yack.com.br> Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02Merge branch 'tracing/core-v2' into tracing-for-linusIngo Molnar
Conflicts: include/linux/slub_def.h lib/Kconfig.debug mm/slob.c mm/slub.c
2009-04-01filesystem freeze: allow SysRq emergency thaw to thaw frozen filesystemsEric Sandeen
Now that the filesystem freeze operation has been elevated to the VFS, and is just an ioctl away, some sort of safety net for unintentionally frozen root filesystems may be in order. The timeout thaw originally proposed did not get merged, but perhaps something like this would be useful in emergencies. For example, freeze /path/to/mountpoint may freeze your root filesystem if you forgot that you had that unmounted. I chose 'j' as the last remaining character other than 'h' which is sort of reserved for help (because help is generated on any unknown character). I've tested this on a non-root fs with multiple (nested) freezers, as well as on a system rendered unresponsive due to a frozen root fs. [randy.dunlap@oracle.com: emergency thaw only if CONFIG_BLOCK enabled] Signed-off-by: Eric Sandeen <sandeen@redhat.com> Cc: Takashi Sato <t-sato@yk.jp.nec.com> 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>
2009-01-18Merge branch 'tracing/ftrace'; commit 'v2.6.29-rc2' into tracing/coreIngo Molnar
2009-01-15sysrq documentation: document why the command header only is shownAndy Whitcroft
Document the interactions between loglevel and the sysrq output. Also document how to work round it should output be required on the console. Signed-off-by: Andy Whitcroft <apw@canonical.com> Cc: Martin Mares <mj@ucw.cz> 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>
2009-01-15sysrq documentation: remove the redundant updated dateAndy Whitcroft
git is maintaining the last update time much more accuratly than the internal update time. Remove it. Signed-off-by: Andy Whitcroft <apw@canonical.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>
2008-12-26sysrq: fix ftrace help msg & doc.Randy Dunlap
Impact: update documentation and help messages We have a conventional method of explicitly stating the sysrq action key in a sysrq help message, so change dump-ftrace-buffer to use that method and add it to Documentation/sysrq.txt. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-20Merge branch 'v28-timers-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'v28-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (36 commits) fix documentation of sysrq-q really Fix documentation of sysrq-q timer_list: add base address to clock base timer_list: print cpu number of clockevents device timer_list: print real timer address NOHZ: restart tick device from irq_enter() NOHZ: split tick_nohz_restart_sched_tick() NOHZ: unify the nohz function calls in irq_enter() timers: fix itimer/many thread hang, fix timers: fix itimer/many thread hang, v3 ntp: improve adjtimex frequency rounding timekeeping: fix rounding problem during clock update ntp: let update_persistent_clock() sleep hrtimer: reorder struct hrtimer to save 8 bytes on 64bit builds posix-timers: lock_timer: make it readable posix-timers: lock_timer: kill the bogus ->it_id check posix-timers: kill ->it_sigev_signo and ->it_sigev_value posix-timers: sys_timer_create: cleanup the error handling posix-timers: move the initialization of timer->sigq from send to create path posix-timers: sys_timer_create: simplify and s/tasklist/rcu/ ... Fix trivial conflicts due to sysrq-q description clahes in Documentation/sysrq.txt and drivers/char/sysrq.c
2008-10-20Fix documentation of sysrq-qAndi Kleen
I fell into the trap recently that it only dumps hrtimers instead of all timers. Fix the documentation. Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20fix documentation of sysrq-q reallyThomas Gleixner
SysRq-Q also dumps information about the clockevent devices. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-10-20Fix documentation of sysrq-qAndi Kleen
I fell into the trap recently that it only dumps hrtimers instead of all timers. Fix the documentation. Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: torvalds@linux-foundation.org Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-29sysrq: add show-backtrace-on-all-cpus functionRik van Riel
SysRQ-P is not always useful on SMP systems, since it usually ends up showing the backtrace of a CPU that is doing just fine, instead of the backtrace of the CPU that is having problems. This patch adds SysRQ show-all-cpus(L), which shows the backtrace of every active CPU in the system. It skips idle CPUs because some SMP systems are just too large and we already know what the backtrace of the idle task looks like. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Rik van Riel <riel@redhat.com> Randy Dunlap <randy.dunlap@oracle.com> Cc: <lwoodman@redhat.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>
2007-10-07sysrq docs: document sequence that actually worksPavel Machek
Document sequence of keypresses that actually works. Yes, this changed year-or-so ago. Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-11Documentation: sysrq, description of 'h' slightly inaccurateJesper Juhl
In Documentation/sysrq.txt, the description of 'h' says that any key not listed *above* will generate help. That's obviously not true since all the keys listed below 'h' will do what they are described to do, not display help. So change the text so that it says that any key not listed in the table will generate help, which is what really happens. 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>
2007-05-07doc: Update sysrq doc for sh kgdb trigger.Paul Mundt
sh uses the same sysrq trigger as ppc, update the documentation to reflect that. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-03-22[PATCH] Documentation/sysrq.txt: added short description for 'Q' (timerlist)Johannes Weiner
I added the 'Q' to list. A short description in the `Ok, so what can I use them for'-section, on when or why to use it would be nice! Signed-off-by: Johannes Weiner <hannes-kernel@saeurebad.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11[PATCH] sysrq: alphabetize command keys docRandy Dunlap
Alphabetize the sysrq command keys list. 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>
2007-02-01[PATCH] sysrq: showBlockedTasks is sysrq-WRandy Dunlap
Change SysRq showBlockedTasks from sysrq-X to sysrq-W and show that in the Help message. It was previously done via X, but X is already used for Xmon on ppc & powerpc platforms and this collision needs to be avoided. All callers of register_sysrq_key() are now marked in the sysrq op/key table. I didn't mark 'h' as Help because Help is just printed for any unknown key, such as '?'. Added some omitted sysrq key entries in the sysrq.txt file. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-06-25[PATCH] Correct sa'K' description in sysrq.txtJesper Juhl
sysrq SAK is described as being something you should mistake for SAK from c2 compliant systems - whoops. What's meant is that it should *not* be mistaken as such. Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-03update for Documentation/sysrq.txtAdam D. Moss
This patch for 2.4.x updates the dead email address for 'Mydraal' and since he no longer wishes to field questions concerning SysRq or this document removes the statement stating otherwise. Signed-off-by: Adrian Bunk <bunk@stusta.de>
2005-09-10[PATCH] merge some from Rusty's trivial patchesAdrian Bunk
This patch contains the most trivial from Rusty's trivial patches: - spelling fixes - remove duplicate includes Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25[PATCH] kdump: sysrq trigger mechanism for kexec based crashdumpsHariprasad Nellitheertha
Add a sysrq-trigger mechanism for kexec based crashdumps. Alt-Sysrq-c triggers a kexec based crashdump. Signed-off-by: Hariprasad Nellitheertha <hari@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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