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2014-12-10kernel: add panic_on_warnPrarit Bhargava1-0/+7
There have been several times where I have had to rebuild a kernel to cause a panic when hitting a WARN() in the code in order to get a crash dump from a system. Sometimes this is easy to do, other times (such as in the case of a remote admin) it is not trivial to send new images to the user. A much easier method would be a switch to change the WARN() over to a panic. This makes debugging easier in that I can now test the actual image the WARN() was seen on and I do not have to engage in remote debugging. This patch adds a panic_on_warn kernel parameter and /proc/sys/kernel/panic_on_warn calls panic() in the warn_slowpath_common() path. The function will still print out the location of the warning. An example of the panic_on_warn output: The first line below is from the WARN_ON() to output the WARN_ON()'s location. After that the panic() output is displayed. WARNING: CPU: 30 PID: 11698 at /home/prarit/dummy_module/dummy-module.c:25 init_dummy+0x1f/0x30 [dummy_module]() Kernel panic - not syncing: panic_on_warn set ... CPU: 30 PID: 11698 Comm: insmod Tainted: G W OE 3.17.0+ #57 Hardware name: Intel Corporation S2600CP/S2600CP, BIOS RMLSDP.86I.00.29.D696.1311111329 11/11/2013 0000000000000000 000000008e3f87df ffff88080f093c38 ffffffff81665190 0000000000000000 ffffffff818aea3d ffff88080f093cb8 ffffffff8165e2ec ffffffff00000008 ffff88080f093cc8 ffff88080f093c68 000000008e3f87df Call Trace: [<ffffffff81665190>] dump_stack+0x46/0x58 [<ffffffff8165e2ec>] panic+0xd0/0x204 [<ffffffffa038e05f>] ? init_dummy+0x1f/0x30 [dummy_module] [<ffffffff81076b90>] warn_slowpath_common+0xd0/0xd0 [<ffffffffa038e040>] ? dummy_greetings+0x40/0x40 [dummy_module] [<ffffffff81076c8a>] warn_slowpath_null+0x1a/0x20 [<ffffffffa038e05f>] init_dummy+0x1f/0x30 [dummy_module] [<ffffffff81002144>] do_one_initcall+0xd4/0x210 [<ffffffff811b52c2>] ? __vunmap+0xc2/0x110 [<ffffffff810f8889>] load_module+0x16a9/0x1b30 [<ffffffff810f3d30>] ? store_uevent+0x70/0x70 [<ffffffff810f49b9>] ? copy_module_from_fd.isra.44+0x129/0x180 [<ffffffff810f8ec6>] SyS_finit_module+0xa6/0xd0 [<ffffffff8166cf29>] system_call_fastpath+0x12/0x17 Successfully tested by me. hpa said: There is another very valid use for this: many operators would rather a machine shuts down than being potentially compromised either functionally or security-wise. Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Acked-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Fabian Frederick <fabf@skynet.be> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-29Documentation/kdump/kdump.txt: add ARM descriptionHuKeping1-3/+33
Add arm specific parts to kdump kernel documentation. Signed-off-by: Hu Keping <hukeping@huawei.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: Haren Myneni <hbabu@us.ibm.com> Cc: Rob Landley <rob@landley.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-04Merge branch 'for-linus' of ↵Linus Torvalds1-8/+0
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial Pull trivial tree updates from Jiri Kosina: "The usual stuff from trivial tree" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (34 commits) treewide: relase -> release Documentation/cgroups/memory.txt: fix stat file documentation sysctl/net.txt: delete reference to obsolete 2.4.x kernel spinlock_api_smp.h: fix preprocessor comments treewide: Fix typo in printk doc: device tree: clarify stuff in usage-model.txt. open firmware: "/aliasas" -> "/aliases" md: bcache: Fixed a typo with the word 'arithmetic' irq/generic-chip: fix a few kernel-doc entries frv: Convert use of typedef ctl_table to struct ctl_table sgi: xpc: Convert use of typedef ctl_table to struct ctl_table doc: clk: Fix incorrect wording Documentation/arm/IXP4xx fix a typo Documentation/networking/ieee802154 fix a typo Documentation/DocBook/media/v4l fix a typo Documentation/video4linux/si476x.txt fix a typo Documentation/virtual/kvm/api.txt fix a typo Documentation/early-userspace/README fix a typo Documentation/video4linux/soc-camera.txt fix a typo lguest: fix CONFIG_PAE -> CONFIG_x86_PAE in comment ...
2013-07-03Documentation/kdump/kdump.txt: remove /dev/oldmem descriptionZhang Yanfei1-25/+6
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Hansen <dave@sr71.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Fleming <matt.fleming@intel.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-28Documentation/kdump: Remove TODO in this documentZhang Yanfei1-8/+0
We have already had the relocatable kernel, so just remove the TODO in the kdump document. Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by: Rob Landley <rob@landley.net> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2013-04-02Add size restriction to the kdump documentationXishi Qiu1-0/+1
In efi_init() memory aligns in IA64_GRANULE_SIZE(16M). If set "crashkernel=1024M-:600M" and use sparse memory model, when crash kernel booting it changes [128M-728M] to [128M-720M]. But initrd memory is in [709M-727M], and virt_addr_valid() *can not* check the invalid pages when freeing initrd memory, because there are some pages missed at the end of the section, and this causes error. ... Unpacking initramfs... Freeing initrd memory: 19648kB freed BUG: Bad page state in process swapper pfn:02d00 page:e0000000102dd800 flags:(null) count:0 mapcount:1 mapping:(null) index:0 Call Trace: [<a000000100018dc0>] show_stack+0x80/0xa0 sp=e000000021e8fbd0 bsp=e000000021e81360 [<a00000010090fcc0>] dump_stack+0x30/0x50 sp=e000000021e8fda0 bsp=e000000021e81348 [<a0000001001a3180>] bad_page+0x280/0x380 sp=e000000021e8fda0 bsp=e000000021e81308 [<a0000001001a8740>] free_hot_cold_page+0x3a0/0x5c0 sp=e000000021e8fda0 bsp=e000000021e812a0 [<a0000001001a8a50>] free_hot_page+0x30/0x60 sp=e000000021e8fda0 bsp=e000000021e81280 [<a0000001001a8b30>] __free_pages+0xb0/0xe0 sp=e000000021e8fda0 bsp=e000000021e81258 [<a0000001001a8c00>] free_pages+0xa0/0xc0 sp=e000000021e8fda0 bsp=e000000021e81230 [<a000000100bb40c0>] free_initrd_mem+0x230/0x290 sp=e000000021e8fda0 bsp=e000000021e811d8 [<a000000100ba6620>] populate_rootfs+0x1c0/0x280 sp=e000000021e8fdb0 bsp=e000000021e811a0 [<a00000010000ac30>] do_one_initcall+0x3b0/0x3e0 sp=e000000021e8fdb0 bsp=e000000021e81158 [<a000000100ba0a90>] kernel_init+0x3f0/0x4b0 sp=e000000021e8fdb0 bsp=e000000021e81108 [<a000000100016890>] kernel_thread_helper+0xd0/0x100 sp=e000000021e8fe30 bsp=e000000021e810e0 [<a00000010000a4c0>] start_kernel_thread+0x20/0x40 sp=e000000021e8fe30 bsp=e000000021e810e0 ... In "http://marc.info/?l=linux-arch&m=136147092429314&w=2" Tony said: "Perhaps in Documentation/kdump/kdump.txt (which the crashkernel entry in kernel-parameters.txt points at). The ia64 section of kdump.txt notes that the start address will be rounded up to a GRANULE boundary, but doesn't talk about restrictions on the size." This patch add size restriction to the documentation of kdump. Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
2012-07-18kexec: update URL of kexec homepageOlaf Hering1-1/+1
The referenced html file does not exist anymore. Replace the URL with the current project homepage. Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-12-27[S390] Add s390x description to Documentation/kdump/kdump.txtMichael Holzheu1-3/+32
Add s390x specific parts to kdump kernel documentation. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-11-25kdump: update kexec-tools URL and Vivek's emailSimon Horman1-6/+9
Signed-off-by: Simon Horman <horms@verge.net.au> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-06-12trivial: Miscellaneous documentation typo fixesMatt LaPlante1-2/+2
Fix various typos in documentation txts. Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2008-10-22powerpc: Support for relocatable kdump kernelMohan Kumar M1-3/+11
This adds relocatable kernel support for kdump. With this one can use the same regular kernel to capture the kdump. A signature (0xfeed1234) is passed in r6 from panic code to the next kernel through kexec_sequence and purgatory code. The signature is used to differentiate between kdump kernel and non-kdump kernels. The purgatory code compares the signature and sets the __kdump_flag in head_64.S. During the boot up, kernel code checks __kdump_flag and if it is set, the kernel will behave as relocatable kdump kernel. This kernel will boot at the address where it was loaded by kexec-tools ie. at the address reserved through crashkernel boot parameter. CONFIG_CRASH_DUMP depends on CONFIG_RELOCATABLE option to build kdump kernel as relocatable. So the same kernel can be used as production and kdump kernel. This patch incorporates the changes suggested by Paul Mackerras to avoid GOT use and to avoid two copies of the code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Mohan Kumar M <mohan@in.ibm.com> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2008-07-28kdump: update kdump documentation as kexec-tools-resting has been renamed ↵Simon Horman1-10/+10
kexec-tools Signed-off-by: Simon Horman <horms@verge.net.au> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-08x86: fix documentation bug about relocatabilityBernhard Walle1-1/+1
This patch fixes a small bug in documentation: x86_64 also has now the ability to build a relocatable kernel. Signed-off-by: Bernhard Walle <bwalle@suse.de> Cc: vgoyal@redhat.com Cc: kexec@lists.infradead.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-01kexec: make extended crashkernel= syntax less confusingMichael Ellerman1-1/+4
The extended crashkernel syntax is a little confusing in the way it handles ranges. eg: crashkernel=512M-2G:64M,2G-:128M Means if the machine has between 512M and 2G of memory the crash region should be 64M, and if the machine has 2G of memory the region should be 64M. Only if the machine has more than 2G memory will 128M be allocated. Although that semantic is correct, it is somewhat baffling. Instead I propose that the end of the range means the first address past the end of the range, ie: 512M up to but not including 2G. [bwalle@suse.de: clarify inclusive/exclusive in crashkernel commandline in documentation] Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Bernhard Walle <bwalle@suse.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Simon Horman <horms@verge.net.au> Signed-off-by: Bernhard Walle <bwalle@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19Add documentation for extended crashkernel syntaxBernhard Walle1-0/+26
This adds the documentation for the extended crashkernel syntax into Documentation/kdump/kdump.txt. Signed-off-by: Bernhard Walle <bwalle@suse.de> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Vivek Goyal <vgoyal@in.ibm.com> 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>
2007-10-17kdump: documentation cleanupsPavel Machek1-9/+3
This cleans up kdump documentation a bit. Plus I do not think we want to mention Linux trademark in _every_ file in documentation.... 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>
2007-10-17Add reset_devices to the recommended parametersBernhard Walle1-2/+2
This patch adds the "reset_devices" option (that's used only by one device driver for now) to the recommended list of command line parameters for kdump. Meaning (Documentation/kernel-parameters.txt): reset_devices [KNL] Force drivers to reset the underlying device during initialization. Signed-off-by: Bernhard Walle <bwalle@suse.de> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Cc: Vivek Goyal <vgoyal@in.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Haren Myneni <hbabu@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17Express new ELF32 mechanisms in documentationBernhard Walle1-5/+7
This patch reflects the http://git.kernel.org/?p=linux/kernel/git/horms/kexec-tools-testing.git;a=commit;h=b9c3648e690ad0dad12389659673206213a09760 change in kexec-tools-testing also now in the kernel documentation. Signed-off-by: Bernhard Walle <bwalle@suse.de> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Cc: Vivek Goyal <vgoyal@in.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Haren Myneni <hbabu@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17Express relocatability of kernel on x86_64 in documentationBernhard Walle1-29/+6
This patch adapts the Documentation/kdump/kdump.txt file to express the fact that the x86_64 kernel is now also relocatable. This makes i386 and x86_64 now behave the same, simplifying the documentation. Signed-off-by: Bernhard Walle <bwalle@suse.de> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Cc: Vivek Goyal <vgoyal@in.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Haren Myneni <hbabu@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-20[PATCH] PPC64 Kdump documentation updateSimon Horman1-11/+13
Patch from Mohan Kumar M to add the ppc64 portions of the kdump documentation. http://thread.gmane.org/gmane.linux.kernel/481689/focus=3375 Cc: Mohan Kumar M <mohan@in.ibm.com> Cc: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Simon Horman <horms@verge.net.au> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] kexec: fix references to init in documentation for kexecHorms1-4/+4
I've noticed that the boot options are not correct for in the documentation for kdump. The "init" keyword is not necessary, and causes a kernel panic when booting with an initrd on Fedora 5. [horms@verge.net.au: put original comment with the latest version of the patch] Signed-off-by: Judith Lebzeelter <judith@osdl.org> Acked-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Simon Horman <horms@verge.net.au> 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>
2007-01-23[PATCH] Kdump documentation update: ia64 portionHorms1-7/+29
this patch fills in the portions for ia64 kexec. Signed-off-by: Simon Horman <horms@verge.net.au> Cc: "Zou, Nanhai" <nanhai.zou@intel.com> Cc: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-01-23[PATCH] Kdump documentation update: kexec-tools updateHorms1-4/+9
Mohan Kumar suggested making kexec-tools-testing.tar.gz a link to the latest version. I have done this and this patch updates the documentation accordingly. Signed-off-by: Simon Horman <horms@verge.net.au> Cc: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-01-11[PATCH] Kdump documentation updateVivek Goyal1-72/+152
o Kdump documentation update. - Update details for using relocatable kernel. - Start using kexec-tools-testing release as it is latest and old kexec-tools can't load relocatable bzImage file. - Also add kdump on ia64 specific details. Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Cc: Horms <horms@verge.net.au> Cc: Mohan Kumar M <mohan@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-03Documentation: remove duplicated wordsPaolo Ornati1-1/+1
Remove many duplicated words under Documentation/ and do other small cleanups. Examples: "and and" --> "and" "in in" --> "in" "the the" --> "the" "the the" --> "to the" ... Signed-off-by: Paolo Ornati <ornati@fastwebnet.it> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-26fix paniced->panicked typosLee Revell1-1/+1
In a testament to the utter simplicity and logic of the English language ;-), I found a single correct use - in kernel/panic.c - and 10-15 incorrect ones. Signed-Off-By: Lee Revell <rlrevell@joe-job.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-25[PATCH] Updated kdump documentationDavid Wilder1-125/+295
Cc: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-11[PATCH] kdump: add dmesg gdbmacro into documentAkinobu Mita1-0/+22
Add gdb macro which print the kernel ring buffer into kdump docs Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10[PATCH] Kdump documentation updateManeesh Soni1-70/+79
Update the kdump documentation to reflect the changes due to recent kernel config option changes for kexec and kdump. Signed-off-by: Maneesh Soni <maneesh@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-13[PATCH] More documentation, minor cleanup in kdump.txtVivek Goyal1-3/+8
Added clarification on the root device format to be used for second kernel, as well as specifying initrd if drivers are built as modules. Signed-off-by: Kishore Sampathkumar <kishore.sampathkumar@hp.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09[PATCH] Kdump: Documentation UpdateVivek Goyal1-8/+8
There are minor changes in command line options in kexec-tools for kdump. This patch updates the documentation to reflect those changes. Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25[PATCH] kdump documentation update to introduce use of irqpollVivek Goyal1-11/+17
o Specify "irqpoll" command line option which loading second kernel. This helps in reducing driver initialization failures in second kernel due to shared interrupts. o Enabled LAPIC/IOAPIC support for UP kernels in second kernel. This reduces the chances of devices sharing the irq and hence reduces the chances of driver initialization failures in second kernel. o Build a UP capture kernel and disabled SMP support. Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25[PATCH] kdump: Documentation for KdumpVivek Goyal2-0/+314
This patch contains the documentation for the kexec based crash dump tool. Quick kdump-howto ================================================================ 1) Download and build kexec-tools. 2) Download and build the latest kexec/kdump (-mm) kernel patchset. Two kernels need to be built in order to get this feature working. A) First kernel: a) Enable "kexec system call" feature: CONFIG_KEXEC=y b) Physical load address (use default): CONFIG_PHYSICAL_START=0x100000 c) Enable "sysfs file system support": CONFIG_SYSFS=y d) Boot into first kernel with the command line parameter "crashkernel=Y@X": For example: "crashkernel=64M@16M". B) Second kernel: a) Enable "kernel crash dumps" feature: CONFIG_CRASH_DUMP=y b) Physical load addreess, use same load address as X in "crashkernel" kernel parameter in d) above, e.g., 16 MB or 0x1000000. CONFIG_PHYSICAL_START=0x1000000 c) Enable "/proc/vmcore support" (Optional, in Pseudo filesystems). CONFIG_PROC_VMCORE=y 3) Boot into the first kernel. 4) Load the second kernel to be booted using: kexec -p <second-kernel> --crash-dump --args-linux --append="root=<root-dev> maxcpus=1 init 1" 5) System reboots into the second kernel when a panic occurs. A module can be written to force the panic, for testing purposes. 6) See Documentation/kdump.txt for how to read the first kernel's memory image and how to analyze it. Signed-off-by: Hariprasad Nellitheertha <hari@in.ibm.com> Signed-off-by: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: randy_dunlap <rdunlap@xenotime.net> Signed-off-by: Maneesh Soni <maneesh@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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