Since commit 04c6862c055f ("kmsg_dump: add kmsg_dump() calls to the
reboot, halt, poweroff and emergency_restart paths"), kmsg_dump() gets
run on normal paths including poweroff and reboot.
This is less than ideal given pstore implementations that can only
represent single backtraces, since a reboot may overwrite a stored oops
before it's been picked up by userspace. In addition, some pstore
backends may have low performance and provide a significant delay in
reboot as a result.
This patch adds a printk.always_kmsg_dump kernel parameter (which can also
be changed from userspace). Without it, the code will only be run on
failure paths rather than on normal paths. The option can be enabled in
environments where there's a desire to attempt to audit whether or not a
reboot was cleanly requested or not.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Marco Stornelli <marco.stornelli@gmail.com>
Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This includes initial support for the recently published ACPI 5.0 spec. In particular, support for the "hardware-reduced" bit that eliminates the dependency on legacy hardware. APEI has patches resulting from testing on real hardware. Plus other random fixes. * 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux: (52 commits) acpi/apei/einj: Add extensions to EINJ from rev 5.0 of acpi spec intel_idle: Split up and provide per CPU initialization func ACPI processor: Remove unneeded variable passed by acpi_processor_hotadd_init V2 ACPI processor: Remove unneeded cpuidle_unregister_driver call intel idle: Make idle driver more robust intel_idle: Fix a cast to pointer from integer of different size warning in intel_idle ACPI: kernel-parameters.txt : Add intel_idle.max_cstate intel_idle: remove redundant local_irq_disable() call ACPI processor: Fix error path, also remove sysdev link ACPI: processor: fix acpi_get_cpuid for UP processor intel_idle: fix API misuse ACPI APEI: Convert atomicio routines ACPI: Export interfaces for ioremapping/iounmapping ACPI registers ACPI: Fix possible alignment issues with GAS 'address' references ACPI, ia64: Use SRAT table rev to use 8bit or 16/32bit PXM fields (ia64) ACPI, x86: Use SRAT table rev to use 8bit or 32bit PXM fields (x86/x86-64) ACPI: Store SRAT table revision ACPI, APEI, Resolve false conflict between ACPI NVS and APEI ACPI, Record ACPI NVS regions ACPI, APEI, EINJ, Refine the fix of resource conflict ...
Add missing intel_idle.max_cstate in kernel-parameters.txt Signed-off-by Masanari Iida <standby24x7@gmail.com> Signed-off-by: Len Brown <len.brown@intel.com>
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits) perf tools: Fix compile error on x86_64 Ubuntu perf report: Fix --stdio output alignment when --showcpuutilization used perf annotate: Get rid of field_sep check perf annotate: Fix usage string perf kmem: Fix a memory leak perf kmem: Add missing closedir() calls perf top: Add error message for EMFILE perf test: Change type of '-v' option to INCR perf script: Add missing closedir() calls tracing: Fix compile error when static ftrace is enabled recordmcount: Fix handling of elf64 big-endian objects. perf tools: Add const.h to MANIFEST to make perf-tar-src-pkg work again perf tools: Add support for guest/host-only profiling perf kvm: Do guest-only counting by default perf top: Don't update total_period on process_sample perf hists: Stop using 'self' for struct hist_entry perf hists: Rename total_session to total_period x86: Add counter when debug stack is used with interrupts enabled x86: Allow NMIs to hit breakpoints in i386 x86: Keep current stack in NMI breakpoints ...
* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, reboot: Fix typo in nmi reboot path x86, NMI: Add to_cpumask() to silence compile warning x86, NMI: NMI selftest depends on the local apic x86: Add stack top margin for stack overflow checking x86, NMI: NMI-selftest should handle the UP case properly x86: Fix the 32-bit stackoverflow-debug build x86, NMI: Add knob to disable using NMI IPIs to stop cpus x86, NMI: Add NMI IPI selftest x86, reboot: Use NMI instead of REBOOT_VECTOR to stop cpus x86: Clean up the range of stack overflow checking x86: Panic on detection of stack overflow x86: Check stack overflow in detail
* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux: slub: disallow changing cpu_partial from userspace for debug caches slub: add missed accounting slub: Extract get_freelist from __slab_alloc slub: Switch per cpu partial page support off for debugging slub: fix a possible memleak in __slab_alloc() slub: fix slub_max_order Documentation slub: add missed accounting slab: add taint flag outputting to debug paths. slub: add taint flag outputting to debug paths slab: introduce slab_max_order kernel parameter slab: rename slab_break_gfp_order to slab_max_order
Andrew elucidates: - First installmeant of MM. We have a HUGE number of MM patches this time. It's crazy. - MAINTAINERS updates - backlight updates - leds - checkpatch updates - misc ELF stuff - rtc updates - reiserfs - procfs - some misc other bits * akpm: (124 commits) user namespace: make signal.c respect user namespaces workqueue: make alloc_workqueue() take printf fmt and args for name procfs: add hidepid= and gid= mount options procfs: parse mount options procfs: introduce the /proc/<pid>/map_files/ directory procfs: make proc_get_link to use dentry instead of inode signal: add block_sigmask() for adding sigmask to current->blocked sparc: make SA_NOMASK a synonym of SA_NODEFER reiserfs: don't lock root inode searching reiserfs: don't lock journal_init() reiserfs: delay reiserfs lock until journal initialization reiserfs: delete comments referring to the BKL drivers/rtc/interface.c: fix alarm rollover when day or month is out-of-range drivers/rtc/rtc-twl.c: add DT support for RTC inside twl4030/twl6030 drivers/rtc/: remove redundant spi driver bus initialization drivers/rtc/rtc-jz4740.c: make jz4740_rtc_driver static drivers/rtc/rtc-mc13xxx.c: make mc13xxx_rtc_idtable static rtc: convert drivers/rtc/* to use module_platform_driver() drivers/rtc/rtc-wm831x.c: convert to devm_kzalloc() drivers/rtc/rtc-wm831x.c: remove unused period IRQ handler ...
With CONFIG_DEBUG_PAGEALLOC configured, the CPU will generate an exception on access (read,write) to an unallocated page, which permits us to catch code which corrupts memory. However the kernel is trying to maximise memory usage, hence there are usually few free pages in the system and buggy code usually corrupts some crucial data. This patch changes the buddy allocator to keep more free/protected pages and to interlace free/protected and allocated pages to increase the probability of catching corruption. When the kernel is compiled with CONFIG_DEBUG_PAGEALLOC, debug_guardpage_minorder defines the minimum order used by the page allocator to grant a request. The requested size will be returned with the remaining pages used as guard pages. The default value of debug_guardpage_minorder is zero: no change from current behaviour. [akpm@linux-foundation.org: tweak documentation, s/flg/flag/] Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'nfs-for-3.3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: NFSv4: Change the default setting of the nfs4_disable_idmapping parameter NFSv4: Save the owner/group name string when doing open NFS: Remove pNFS bloat from the generic write path pnfs-obj: Must return layout on IO error pnfs-obj: pNFS errors are communicated on iodata->pnfs_error NFS: Cache state owners after files are closed NFS: Clean up nfs4_find_state_owners_locked() NFSv4: include bitmap in nfsv4 get acl data nfs: fix a minor do_div portability issue NFSv4.1: cleanup comment and debug printk NFSv4.1: change nfs4_free_slot parameters for dynamic slots NFSv4.1: cleanup init and reset of session slot tables NFSv4.1: fix backchannel slotid off-by-one bug nfs: fix regression in handling of context= option in NFSv4 NFS - fix recent breakage to NFS error handling. NFS: Retry mounting NFSROOT SUNRPC: Clean up the RPCSEC_GSS service ticket requests