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2012-10-06lib/plist.c: make plist test announcements KERN_DEBUGBorislav Petkov
They show up in dmesg [ 4.041094] start plist test [ 4.045804] end plist test without a lot of meaning so hide them behind debug loglevel. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06lib/vsprintf.c: improve standard conformance of sscanf()Jan Beulich
Xen's pciback points out a couple of deficiencies with vsscanf()'s standard conformance: - Trailing character matching cannot be checked by the caller: With a format string of "(%x:%x.%x) %n" absence of the closing parenthesis cannot be checked, as input of "(00:00.0)" doesn't cause the %n to be evaluated (because of the code not skipping white space before the trailing %n). - The parameter corresponding to a trailing %n could get filled even if there was a matching error: With a format string of "(%x:%x.%x)%n", input of "(00:00.0]" would still fill the respective variable pointed to (and hence again make the mismatch non-detectable by the caller). This patch aims at fixing those, but leaves other non-conforming aspects of it untouched, among them these possibly relevant ones: - improper handling of the assignment suppression character '*' (blindly discarding all succeeding non-white space from the format and input strings), - not honoring conversion specifiers for %n, - not recognizing the C99 conversion specifier 't' (recognized by vsprintf()). Signed-off-by: Jan Beulich <jbeulich@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06lib/spinlock_debug: avoid livelock in do_raw_spin_lock()Vikram Mulukutla
The logic in do_raw_spin_lock() attempts to acquire a spinlock by invoking arch_spin_trylock() in a loop with a delay between each attempt. Now consider the following situation in a 2 CPU system: 1. CPU-0 continually acquires and releases a spinlock in a tight loop; it stays in this loop until some condition X is satisfied. X can only be satisfied by another CPU. 2. CPU-1 tries to acquire the same spinlock, in an attempt to satisfy the aforementioned condition X. However, it never sees the unlocked value of the lock because the debug spinlock code uses trylock instead of just lock; it checks at all the wrong moments - whenever CPU-0 has locked the lock. Now in the absence of debug spinlocks, the architecture specific spinlock code can correctly allow CPU-1 to wait in a "queue" (e.g., ticket spinlocks), ensuring that it acquires the lock at some point. However, with the debug spinlock code, livelock can easily occur due to the use of try_lock, which obviously cannot put the CPU in that "queue". This queueing mechanism is implemented in both x86 and ARM spinlock code. Note that the situation mentioned above is not hypothetical. A real problem was encountered where CPU-0 was running hrtimer_cancel with interrupts disabled, and CPU-1 was attempting to run the hrtimer that CPU-0 was trying to cancel. Address this by actually attempting arch_spin_lock once it is suspected that there is a spinlock lockup. If we're in a situation that is described above, the arch_spin_lock should succeed; otherwise other timeout mechanisms (e.g., watchdog) should alert the system of a lockup. Therefore, if there is a genuine system problem and the spinlock can't be acquired, the end result (irrespective of this change being present) is the same. If there is a livelock caused by the debug code, this change will allow the lock to be acquired, depending on the implementation of the lower level arch specific spinlock code. [akpm@linux-foundation.org: tweak comment] Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06genalloc: make it possible to use a custom allocation algorithmBenjamin Gaignard
Premit use of another algorithm than the default first-fit one. For example a custom algorithm could be used to manage alignment requirements. As I can't predict all the possible requirements/needs for all allocation uses cases, I add a "free" field 'void *data' to pass any needed information to the allocation function. For example 'data' could be used to handle a structure where you store the alignment, the expected memory bank, the requester device, or any information that could influence the allocation algorithm. An usage example may look like this: struct my_pool_constraints { int align; int bank; ... }; unsigned long my_custom_algo(unsigned long *map, unsigned long size, unsigned long start, unsigned int nr, void *data) { struct my_pool_constraints *constraints = data; ... deal with allocation contraints ... return the index in bitmap where perform the allocation } void create_my_pool() { struct my_pool_constraints c; struct gen_pool *pool = gen_pool_create(...); gen_pool_add(pool, ...); gen_pool_set_algo(pool, my_custom_algo, &c); } Add of best-fit algorithm function: most of the time best-fit is slower then first-fit but memory fragmentation is lower. The random buffer allocation/free tests don't show any arithmetic relation between the allocation time and fragmentation but the best-fit algorithm is sometime able to perform the allocation when the first-fit can't. This new algorithm help to remove static allocations on ESRAM, a small but fast on-chip RAM of few KB, used for high-performance uses cases like DMA linked lists, graphic accelerators, encoders/decoders. On the Ux500 (in the ARM tree) we have define 5 ESRAM banks of 128 KB each and use of static allocations becomes unmaintainable: cd arch/arm/mach-ux500 && grep -r ESRAM . ./include/mach/db8500-regs.h:/* Base address and bank offsets for ESRAM */ ./include/mach/db8500-regs.h:#define U8500_ESRAM_BASE 0x40000000 ./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK_SIZE 0x00020000 ./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK0 U8500_ESRAM_BASE ./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK1 (U8500_ESRAM_BASE + U8500_ESRAM_BANK_SIZE) ./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK2 (U8500_ESRAM_BANK1 + U8500_ESRAM_BANK_SIZE) ./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK3 (U8500_ESRAM_BANK2 + U8500_ESRAM_BANK_SIZE) ./include/mach/db8500-regs.h:#define U8500_ESRAM_BANK4 (U8500_ESRAM_BANK3 + U8500_ESRAM_BANK_SIZE) ./include/mach/db8500-regs.h:#define U8500_ESRAM_DMA_LCPA_OFFSET 0x10000 ./include/mach/db8500-regs.h:#define U8500_DMA_LCPA_BASE (U8500_ESRAM_BANK0 + U8500_ESRAM_DMA_LCPA_OFFSET) ./include/mach/db8500-regs.h:#define U8500_DMA_LCLA_BASE U8500_ESRAM_BANK4 I want to use genalloc to do dynamic allocations but I need to be able to fine tune the allocation algorithm. I my case best-fit algorithm give better results than first-fit, but it will not be true for every use case. Signed-off-by: Benjamin Gaignard <benjamin.gaignard@stericsson.com> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06lib/gcd.c: prevent possible div by 0Davidlohr Bueso
Account for all properties when a and/or b are 0: gcd(0, 0) = 0 gcd(a, 0) = a gcd(0, b) = b Fixes no known problems in current kernels. Signed-off-by: Davidlohr Bueso <dave@gnu.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06lib/Kconfig.debug: adjust hard-lockup related Kconfig optionsJan Beulich
The main option should not appear in the resulting .config when the dependencies aren't met (i.e. use "depends on" rather than directly setting the default from the combined dependency values). The sub-options should depend on the main option rather than a more generic higher level one. Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06lib/parser.c: avoid overflow in match_number()Alex Elder
The result of converting an integer value to another signed integer type that's unable to represent the original value is implementation defined. (See notes in section 6.3.1.3 of the C standard.) In match_number(), the result of simple_strtol() (which returns type long) is assigned to a value of type int. Instead, handle the result of simple_strtol() in a well-defined way, and return -ERANGE if the result won't fit in the int variable used to hold the parsed result. No current callers pay attention to the particular error value returned, so this additional return code shouldn't do any harm. [akpm@linux-foundation.org: coding-style tweaks] Signed-off-by: Alex Elder <elder@inktank.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06idr: rename MAX_LEVEL to MAX_IDR_LEVELFengguang Wu
To avoid name conflicts: drivers/video/riva/fbdev.c:281:9: sparse: preprocessor token MAX_LEVEL redefined While at it, also make the other names more consistent and add parentheses. [akpm@linux-foundation.org: repair fallout] [sfr@canb.auug.org.au: IB/mlx4: fix for MAX_ID_MASK to MAX_IDR_MASK name change] Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at> Cc: walter harms <wharms@bfs.de> Cc: Glauber Costa <glommer@parallels.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Roland Dreier <roland@purestorage.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06lib/vsprintf: update documentation to cover all of %p[Mm][FR]Andy Shevchenko
Acked-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06lib: vsprintf: fix broken commentsGeorge Spelvin
Numbering the 8 potential digits 2 though 9 never did make a lot of sense. Signed-off-by: George Spelvin <linux@horizon.com> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06lib: vsprintf: optimize put_dec_trunc8()George Spelvin
If you're going to have a conditional branch after each 32x32->64-bit multiply, might as well shrink the code and make it a loop. This also avoids using the long multiply for small integers. (This leaves the comments in a confusing state, but that's a separate patch to make review easier.) Signed-off-by: George Spelvin <linux@horizon.com> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Rabin Vincent <rabin@rab.in> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06lib: vsprintf: optimize division by 10000George Spelvin
The same multiply-by-inverse technique can be used to convert division by 10000 to a 32x32->64-bit multiply. Signed-off-by: George Spelvin <linux@horizon.com> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06lib: vsprintf: optimize division by 10 for small integersGeorge Spelvin
Shrink the reciprocal approximations used in put_dec_full4() based on the comments in put_dec_full9(). Signed-off-by: George Spelvin <linux@horizon.com> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-06sections: fix const sections for crc32 tableJoe Mario
Fix the const sections for the code generated by crc32 table. There's no ro version of the cacheline aligned section, so we cannot put in const data without a conflict Just don't make the crc tables const for now. [ak@linux.intel.com: some fixes and new description] [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Joe Mario <jmario@redhat.com> 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>
2012-10-02Merge tag 'stable/for-linus-3.7-x86-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen Pull Xen update from Konrad Rzeszutek Wilk: "Features: - When hotplugging PCI devices in a PV guest we can allocate Xen-SWIOTLB later. - Cleanup Xen SWIOTLB. - Support pages out grants from HVM domains in the backends. - Support wild cards in xen-pciback.hide=(BDF) arguments. - Update grant status updates with upstream hypervisor. - Boot PV guests with more than 128GB. - Cleanup Xen MMU code/add comments. - Obtain XENVERS using a preferred method. - Lay out generic changes to support Xen ARM. - Allow privcmd ioctl for HVM (used to do only PV). - Do v2 of mmap_batch for privcmd ioctls. - If hypervisor saves the LED keyboard light - we will now instruct the kernel about its state. Fixes: - More fixes to Xen PCI backend for various calls/FLR/etc. - With more than 4GB in a 64-bit PV guest disable native SWIOTLB. - Fix up smatch warnings. - Fix up various return values in privmcmd and mm." * tag 'stable/for-linus-3.7-x86-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: (48 commits) xen/pciback: Restore the PCI config space after an FLR. xen-pciback: properly clean up after calling pcistub_device_find() xen/vga: add the xen EFI video mode support xen/x86: retrieve keyboard shift status flags from hypervisor. xen/gndev: Xen backend support for paged out grant targets V4. xen-pciback: support wild cards in slot specifications xen/swiotlb: Fix compile warnings when using plain integer instead of NULL pointer. xen/swiotlb: Remove functions not needed anymore. xen/pcifront: Use Xen-SWIOTLB when initting if required. xen/swiotlb: For early initialization, return zero on success. xen/swiotlb: Use the swiotlb_late_init_with_tbl to init Xen-SWIOTLB late when PV PCI is used. xen/swiotlb: Move the error strings to its own function. xen/swiotlb: Move the nr_tbl determination in its own function. xen/arm: compile and run xenbus xen: resynchronise grant table status codes with upstream xen/privcmd: return -EFAULT on error xen/privcmd: Fix mmap batch ioctl error status copy back. xen/privcmd: add PRIVCMD_MMAPBATCH_V2 ioctl xen/mm: return more precise error from xen_remap_domain_range() xen/mmu: If the revector fails, don't attempt to revector anything else. ...
2012-10-02Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds
Pull networking changes from David Miller: 1) GRE now works over ipv6, from Dmitry Kozlov. 2) Make SCTP more network namespace aware, from Eric Biederman. 3) TEAM driver now works with non-ethernet devices, from Jiri Pirko. 4) Make openvswitch network namespace aware, from Pravin B Shelar. 5) IPV6 NAT implementation, from Patrick McHardy. 6) Server side support for TCP Fast Open, from Jerry Chu and others. 7) Packet BPF filter supports MOD and XOR, from Eric Dumazet and Daniel Borkmann. 8) Increate the loopback default MTU to 64K, from Eric Dumazet. 9) Use a per-task rather than per-socket page fragment allocator for outgoing networking traffic. This benefits processes that have very many mostly idle sockets, which is quite common. From Eric Dumazet. 10) Use up to 32K for page fragment allocations, with fallbacks to smaller sizes when higher order page allocations fail. Benefits are a) less segments for driver to process b) less calls to page allocator c) less waste of space. From Eric Dumazet. 11) Allow GRO to be used on GRE tunnels, from Eric Dumazet. 12) VXLAN device driver, one way to handle VLAN issues such as the limitation of 4096 VLAN IDs yet still have some level of isolation. From Stephen Hemminger. 13) As usual there is a large boatload of driver changes, with the scale perhaps tilted towards the wireless side this time around. Fix up various fairly trivial conflicts, mostly caused by the user namespace changes. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1012 commits) hyperv: Add buffer for extended info after the RNDIS response message. hyperv: Report actual status in receive completion packet hyperv: Remove extra allocated space for recv_pkt_list elements hyperv: Fix page buffer handling in rndis_filter_send_request() hyperv: Fix the missing return value in rndis_filter_set_packet_filter() hyperv: Fix the max_xfer_size in RNDIS initialization vxlan: put UDP socket in correct namespace vxlan: Depend on CONFIG_INET sfc: Fix the reported priorities of different filter types sfc: Remove EFX_FILTER_FLAG_RX_OVERRIDE_IP sfc: Fix loopback self-test with separate_tx_channels=1 sfc: Fix MCDI structure field lookup sfc: Add parentheses around use of bitfield macro arguments sfc: Fix null function pointer in efx_sriov_channel_type vxlan: virtual extensible lan igmp: export symbol ip_mc_leave_group netlink: add attributes to fdb interface tg3: unconditionally select HWMON support when tg3 is enabled. Revert "net: ti cpsw ethernet: allow reading phy interface mode from DT" gre: fix sparse warning ...
2012-10-02dma-debug: Remove local BUS_NOTIFY_UNBOUND_DRIVER defineShuah Khan
Remove local BUS_NOTIFY_UNBOUND_DRIVER define. This is not used since BUS_NOTIFY_UNBOUND_DRIVER is defined in include/linux/device.h Signed-off-by: Shuah Khan <shuah.khan@hp.com> Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
2012-10-01Merge tag 'usb-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usbLinus Torvalds
Pull USB changes from Greg Kroah-Hartman: "Here is the big USB pull request for 3.7-rc1 There are lots of gadget driver changes (including copying a bunch of files into the drivers/staging/ccg/ directory so that the other gadget drivers can be fixed up properly without breaking that driver), and we remove the old obsolete ub.c driver from the tree. There are also the usual XHCI set of updates, and other various driver changes and updates. We also are trying hard to remove the old dbg() macro, but the final bits of that removal will be coming in through the networking tree before we can delete it for good. All of these patches have been in the linux-next tree. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>" Fix up several annoying - but fairly mindless - conflicts due to the termios structure having moved into the tty device, and often clashing with dbg -> dev_dbg conversion. * tag 'usb-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (339 commits) USB: ezusb: move ezusb.c from drivers/usb/serial to drivers/usb/misc USB: uas: fix gcc warning USB: uas: fix locking USB: Fix race condition when removing host controllers USB: uas: add locking USB: uas: fix abort USB: uas: remove aborted field, replace with status bit. USB: uas: fix task management USB: uas: keep track of command urbs xhci: Intel Panther Point BEI quirk. powerpc/usb: remove checking PHY_CLK_VALID for UTMI PHY USB: ftdi_sio: add TIAO USB Multi-Protocol Adapter (TUMPA) support Revert "usb : Add sysfs files to control port power." USB: serial: remove vizzini driver usb: host: xhci: Fix Null pointer dereferencing with 71c731a for non-x86 systems Increase XHCI suspend timeout to 16ms USB: ohci-at91: fix null pointer in ohci_hcd_at91_overcurrent_irq USB: sierra_ms: don't keep unused variable fsl/usb: Add support for USB controller version 2.4 USB: qcaux: add Pantech vendor class match ...
2012-10-01Merge tag 'driver-core-3.6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core merge from Greg Kroah-Hartman: "Here is the big driver core update for 3.7-rc1. A number of firmware_class.c updates (as you saw a month or so ago), and some hyper-v updates and some printk fixes as well. All patches that are outside of the drivers/base area have been acked by the respective maintainers, and have all been in the linux-next tree for a while. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>" * tag 'driver-core-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (95 commits) memory: tegra{20,30}-mc: Fix reading incorrect register in mc_readl() device.h: Add missing inline to #ifndef CONFIG_PRINTK dev_vprintk_emit memory: emif: Add ifdef CONFIG_DEBUG_FS guard for emif_debugfs_[init|exit] Documentation: Fixes some translation error in Documentation/zh_CN/gpio.txt Documentation: Remove 3 byte redundant code at the head of the Documentation/zh_CN/arm/booting Documentation: Chinese translation of Documentation/video4linux/omap3isp.txt device and dynamic_debug: Use dev_vprintk_emit and dev_printk_emit dev: Add dev_vprintk_emit and dev_printk_emit netdev_printk/netif_printk: Remove a superfluous logging colon netdev_printk/dynamic_netdev_dbg: Directly call printk_emit dev_dbg/dynamic_debug: Update to use printk_emit, optimize stack driver-core: Shut up dev_dbg_reatelimited() without DEBUG tools/hv: Parse /etc/os-release tools/hv: Check for read/write errors tools/hv: Fix exit() error code tools/hv: Fix file handle leak Tools: hv: Implement the KVP verb - KVP_OP_GET_IP_INFO Tools: hv: Rename the function kvp_get_ip_address() Tools: hv: Implement the KVP verb - KVP_OP_SET_IP_INFO Tools: hv: Add an example script to configure an interface ...
2012-10-01Merge tag 'arm64-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64 Pull arm64 support from Catalin Marinas: "Linux support for the 64-bit ARM architecture (AArch64) Features currently supported: - 39-bit address space for user and kernel (each) - 4KB and 64KB page configurations - Compat (32-bit) user applications (ARMv7, EABI only) - Flattened Device Tree (mandated for all AArch64 platforms) - ARM generic timers" * tag 'arm64-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64: (35 commits) arm64: ptrace: remove obsolete ptrace request numbers from user headers arm64: Do not set the SMP/nAMP processor bit arm64: MAINTAINERS update arm64: Build infrastructure arm64: Miscellaneous header files arm64: Generic timers support arm64: Loadable modules arm64: Miscellaneous library functions arm64: Performance counters support arm64: Add support for /proc/sys/debug/exception-trace arm64: Debugging support arm64: Floating point and SIMD arm64: 32-bit (compat) applications support arm64: User access library functions arm64: Signal handling support arm64: VDSO support arm64: System calls handling arm64: ELF definitions arm64: SMP support arm64: DMA mapping API ...
2012-10-01Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU changes from Ingo Molnar: 0. 'idle RCU': Adds RCU APIs that allow non-idle tasks to enter RCU idle mode and provides x86 code to make use of them, allowing RCU to treat user-mode execution as an extended quiescent state when the new RCU_USER_QS kernel configuration parameter is specified. (Work is in progress to port this to a few other architectures, but is not part of this series.) 1. A fix for a latent bug that has been in RCU ever since the addition of CPU stall warnings. This bug results in false-positive stall warnings, but thus far only on embedded systems with severely cut-down userspace configurations. 2. Further reductions in latency spikes for huge systems, along with additional boot-time adaptation to the actual hardware. This is a large change, as it moves RCU grace-period initialization and cleanup, along with quiescent-state forcing, from softirq to a kthread. However, it appears to be in quite good shape (famous last words). 3. Updates to documentation and rcutorture, the latter category including keeping statistics on CPU-hotplug latencies and fixing some initialization-time races. 4. CPU-hotplug fixes and improvements. 5. Idle-loop fixes that were omitted on an earlier submission. 6. Miscellaneous fixes and improvements In certain RCU configurations new kernel threads will show up (rcu_bh, rcu_sched), showing RCU processing overhead. * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits) rcu: Apply micro-optimization and int/bool fixes to RCU's idle handling rcu: Userspace RCU extended QS selftest x86: Exit RCU extended QS on notify resume x86: Use the new schedule_user API on userspace preemption rcu: Exit RCU extended QS on user preemption rcu: Exit RCU extended QS on kernel preemption after irq/exception x86: Exception hooks for userspace RCU extended QS x86: Unspaghettize do_general_protection() x86: Syscall hooks for userspace RCU extended QS rcu: Switch task's syscall hooks on context switch rcu: Ignore userspace extended quiescent state by default rcu: Allow rcu_user_enter()/exit() to nest rcu: Settle config for userspace extended quiescent state rcu: Make RCU_FAST_NO_HZ handle adaptive ticks rcu: New rcu_user_enter_after_irq() and rcu_user_exit_after_irq() APIs rcu: New rcu_user_enter() and rcu_user_exit() APIs ia64: Add missing RCU idle APIs on idle loop xtensa: Add missing RCU idle APIs on idle loop score: Add missing RCU idle APIs on idle loop parisc: Add missing RCU idle APIs on idle loop ...
2012-09-28Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: drivers/net/team/team.c drivers/net/usb/qmi_wwan.c net/batman-adv/bat_iv_ogm.c net/ipv4/fib_frontend.c net/ipv4/route.c net/l2tp/l2tp_netlink.c The team, fib_frontend, route, and l2tp_netlink conflicts were simply overlapping changes. qmi_wwan and bat_iv_ogm were of the "use HEAD" variety. With help from Antonio Quartulli. Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-28scatterlist: refactor the sg_nentsMaxim Levitsky
Replace 'while' with 'for' as suggested by Tejun Heo Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-09-27scatterlist: add sg_nentsMaxim Levitsky
Useful helper to know the number of entries in scatterlist. Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com> Cc: Alex Dubov <oakad@yahoo.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-09-25Merge remote-tracking branch 'tip/core/rcu' into next.2012.09.25bPaul E. McKenney
Resolved conflict in kernel/sched/core.c using Peter Zijlstra's approach from https://lkml.org/lkml/2012/9/5/585.
2012-09-25lib/flex_proportions.c: fix corruption of denominator in flexible proportionsJan Kara
When racing with CPU hotplug, percpu_counter_sum() can return negative values for the number of observed events. This confuses fprop_new_period(), which uses unsigned type and as a result number of events is set to big *positive* number. From that moment on, things go pear shaped and can result e.g. in division by zero as denominator is later truncated to 32-bits. This bug causes a divide-by-zero oops in bdi_dirty_limit() in Borislav's 3.6.0-rc6 based kernel. Fix the issue by using a signed type in fprop_new_period(). That makes us bail out from the function without doing anything (mistakenly) thinking there are no events to age. That makes aging somewhat inaccurate but getting accurate data would be rather hard. Signed-off-by: Jan Kara <jack@suse.cz> Reported-by: Borislav Petkov <bp@amd64.org> Reported-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-09-23rcu: Add PROVE_RCU_DELAY to provoke difficult racesPaul E. McKenney
There have been some recent bugs that were triggered only when preemptible RCU's __rcu_read_unlock() was preempted just after setting ->rcu_read_lock_nesting to INT_MIN, which is a low-probability event. Therefore, reproducing those bugs (to say nothing of gaining confidence in alleged fixes) was quite difficult. This commit therefore creates a new debug-only RCU kernel config option that forces a short delay in __rcu_read_unlock() to increase the probability of those sorts of bugs occurring. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-09-22Merge branch 'stable/late-swiotlb.v3.3' into stable/for-linus-3.7Konrad Rzeszutek Wilk
* stable/late-swiotlb.v3.3: xen/swiotlb: Fix compile warnings when using plain integer instead of NULL pointer. xen/swiotlb: Remove functions not needed anymore. xen/pcifront: Use Xen-SWIOTLB when initting if required. xen/swiotlb: For early initialization, return zero on success. xen/swiotlb: Use the swiotlb_late_init_with_tbl to init Xen-SWIOTLB late when PV PCI is used. xen/swiotlb: Move the error strings to its own function. xen/swiotlb: Move the nr_tbl determination in its own function. swiotlb: add the late swiotlb initialization function with iotlb memory xen/swiotlb: With more than 4GB on 64-bit, disable the native SWIOTLB. xen/swiotlb: Simplify the logic. Conflicts: arch/x86/xen/pci-swiotlb-xen.c Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-09-17device and dynamic_debug: Use dev_vprintk_emit and dev_printk_emitJoe Perches
Convert direct calls of vprintk_emit and printk_emit to the dev_ equivalents. Make create_syslog_header static. Signed-off-by: Joe Perches <joe@perches.com> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Jim Cromie <jim.cromie@gmail.com> Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-17netdev_printk/netif_printk: Remove a superfluous logging colonJoe Perches
netdev_printk originally called dev_printk with %pV. This style emitted the complete dev_printk header with a colon followed by the netdev_name prefix followed by a colon. Now that netdev_printk does not call dev_printk, the extra colon is superfluous. Remove it. Example: old: sky2 0000:02:00.0: eth0: Link is up at 100 Mbps, full duplex, flow control both new: sky2 0000:02:00.0 eth0: Link is up at 100 Mbps, full duplex, flow control both Signed-off-by: Joe Perches <joe@perches.com> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Jim Cromie <jim.cromie@gmail.com> Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-17netdev_printk/dynamic_netdev_dbg: Directly call printk_emitJoe Perches
A lot of stack is used in recursive printks with %pV. Using multiple levels of %pV (a logging function with %pV that calls another logging function with %pV) can consume more stack than necessary. Avoid excessive stack use by not calling dev_printk from netdev_printk and dynamic_netdev_dbg. Duplicate the logic and form of dev_printk instead. Make __netdev_printk static. Remove EXPORT_SYMBOL(__netdev_printk) Whitespace and brace style neatening. Signed-off-by: Joe Perches <joe@perches.com> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Jim Cromie <jim.cromie@gmail.com> Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-17dev_dbg/dynamic_debug: Update to use printk_emit, optimize stackJoe Perches
commit c4e00daaa9 ("driver-core: extend dev_printk() to pass structured data") changed __dev_printk and broke dynamic-debug's ability to control the dynamic prefix of dev_dbg(dev,..). commit af7f2158fd ("drivers-core: make structured logging play nice with dynamic-debug") made a minimal correction. The current dynamic debug code uses up to 3 recursion levels via %pV. This can consume quite a bit of stack. Directly call printk_emit to reduce the recursion depth. These changes include: dev_dbg: o Create and use function create_syslog_header to format the syslog header for printk_emit uses. o Call create_syslog_header and neaten __dev_printk o Make __dev_printk static not global o Remove include header declaration of __dev_printk o Remove now unused EXPORT_SYMBOL() of __dev_printk o Whitespace neatening dynamic_dev_dbg: o Remove KERN_DEBUG from dynamic_emit_prefix o Call create_syslog_header and printk_emit o Whitespace neatening Signed-off-by: Joe Perches <joe@perches.com> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Jim Cromie <jim.cromie@gmail.com> Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-17arm64: Build infrastructureCatalin Marinas
This patch adds Makefile and Kconfig files required for building an AArch64 kernel. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Olof Johansson <olof@lixom.net> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
2012-09-16Merge 3.6-rc6 into usb-nextGreg Kroah-Hartman
This resolves the merge problems with: drivers/usb/dwc3/gadget.c drivers/usb/musb/tusb6010.c that had been seen in linux-next. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-15Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: net/netfilter/nfnetlink_log.c net/netfilter/xt_LOG.c Rather easy conflict resolution, the 'net' tree had bug fixes to make sure we checked if a socket is a time-wait one or not and elide the logging code if so. Whereas on the 'net-next' side we are calculating the UID and GID from the creds using different interfaces due to the user namespace changes from Eric Biederman. Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-13digsig: add hash size comparision on signature verificationDmitry Kasatkin
When pkcs_1_v1_5_decode_emsa() returns without error and hash sizes do not match, hash comparision is not done and digsig_verify_rsa() returns no error. This is a bug and this patch fixes it. The bug was introduced in v3.3 by commit b35e286a640f ("lib/digsig: pkcs_1_v1_5_decode_emsa cleanup"). Cc: stable@vger.kernel.org Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-09-10usb/core: use bin2bcd() for bcdDevice in RHSebastian Andrzej Siewior
The kernel's version number is used as decimal in the bcdDevice field of the RH descriptor. For kernel version v3.12 we would see 3.0c in lsusb. I am not sure how important it is to stick with bcd values since this is this way since we started git history and nobody complained (however back then we reported only 2.6). Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-08netlink: hide struct module parameter in netlink_kernel_createPablo Neira Ayuso
This patch defines netlink_kernel_create as a wrapper function of __netlink_kernel_create to hide the struct module *me parameter (which seems to be THIS_MODULE in all existing netlink subsystems). Suggested by David S. Miller. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-08netlink: kill netlink_set_nonrootPablo Neira Ayuso
Replace netlink_set_nonroot by one new field `flags' in struct netlink_kernel_cfg that is passed to netlink_kernel_create. This patch also renames NL_NONROOT_* to NL_CFG_F_NONROOT_* since now the flags field in nl_table is generic (so we can add more flags if needed in the future). Also adjust all callers in the net-next tree to use these flags instead of netlink_set_nonroot. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-30netlink: add minlen validation for the new signed typesJulian Anastasov
Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-21swiotlb: add the late swiotlb initialization function with iotlb memoryKonrad Rzeszutek Wilk
This enables the caller to initialize swiotlb with its own iotlb memory late in the bootup. See git commit eb605a5754d050a25a9f00d718fb173f24c486ef "swiotlb: add swiotlb_tbl_map_single library function" which will explain the full details of what it can be used for. CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> [v1: Fold in smatch warning] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-08-01Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull second vfs pile from Al Viro: "The stuff in there: fsfreeze deadlock fixes by Jan (essentially, the deadlock reproduced by xfstests 068), symlink and hardlink restriction patches, plus assorted cleanups and fixes. Note that another fsfreeze deadlock (emergency thaw one) is *not* dealt with - the series by Fernando conflicts a lot with Jan's, breaks userland ABI (FIFREEZE semantics gets changed) and trades the deadlock for massive vfsmount leak; this is going to be handled next cycle. There probably will be another pull request, but that stuff won't be in it." Fix up trivial conflicts due to unrelated changes next to each other in drivers/{staging/gdm72xx/usb_boot.c, usb/gadget/storage_common.c} * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits) delousing target_core_file a bit Documentation: Correct s_umount state for freeze_fs/unfreeze_fs fs: Remove old freezing mechanism ext2: Implement freezing btrfs: Convert to new freezing mechanism nilfs2: Convert to new freezing mechanism ntfs: Convert to new freezing mechanism fuse: Convert to new freezing mechanism gfs2: Convert to new freezing mechanism ocfs2: Convert to new freezing mechanism xfs: Convert to new freezing code ext4: Convert to new freezing mechanism fs: Protect write paths by sb_start_write - sb_end_write fs: Skip atime update on frozen filesystem fs: Add freezing handling to mnt_want_write() / mnt_drop_write() fs: Improve filesystem freezing handling switch the protection of percpu_counter list to spinlock nfsd: Push mnt_want_write() outside of i_mutex btrfs: Push mnt_want_write() outside of i_mutex fat: Push mnt_want_write() outside of i_mutex ...
2012-07-31switch the protection of percpu_counter list to spinlockAl Viro
... making percpu_counter_destroy() non-blocking Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-30Merge tag 'writeback-proportions' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux Pull writeback updates from Wu Fengguang: "Use time based periods to age the writeback proportions, which can adapt equally well to fast/slow devices." Fix up trivial conflict in comment in fs/sync.c * tag 'writeback-proportions' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux: writeback: Fix some comment errors block: Convert BDI proportion calculations to flexible proportions lib: Fix possible deadlock in flexible proportion code lib: Proportions with flexible period
2012-07-30Merge branch 'akpm' (Andrew's patch-bomb)Linus Torvalds
Merge Andrew's first set of patches: "Non-MM patches: - lots of misc bits - tree-wide have_clk() cleanups - quite a lot of printk tweaks. I draw your attention to "printk: convert the format for KERN_<LEVEL> to a 2 byte pattern" which looks a bit scary. But afaict it's solid. - backlight updates - lib/ feature work (notably the addition and use of memweight()) - checkpatch updates - rtc updates - nilfs updates - fatfs updates (partial, still waiting for acks) - kdump, proc, fork, IPC, sysctl, taskstats, pps, etc - new fault-injection feature work" * Merge emailed patches from Andrew Morton <akpm@linux-foundation.org>: (128 commits) drivers/misc/lkdtm.c: fix missing allocation failure check lib/scatterlist: do not re-write gfp_flags in __sg_alloc_table() fault-injection: add tool to run command with failslab or fail_page_alloc fault-injection: add selftests for cpu and memory hotplug powerpc: pSeries reconfig notifier error injection module memory: memory notifier error injection module PM: PM notifier error injection module cpu: rewrite cpu-notifier-error-inject module fault-injection: notifier error injection c/r: fcntl: add F_GETOWNER_UIDS option resource: make sure requested range is included in the root range include/linux/aio.h: cpp->C conversions fs: cachefiles: add support for large files in filesystem caching pps: return PTR_ERR on error in device_create taskstats: check nla_reserve() return sysctl: suppress kmemleak messages ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION ipc: compat: use signed size_t types for msgsnd and msgrcv ipc: allow compat IPC version field parsing if !ARCH_WANT_OLD_COMPAT_IPC ipc: add COMPAT_SHMLBA support ...
2012-07-30lib/scatterlist: do not re-write gfp_flags in __sg_alloc_table()Mandeep Singh Baines
We are seeing a lot of sg_alloc_table allocation failures using the new drm prime infrastructure. We isolated the cause to code in __sg_alloc_table that was re-writing the gfp_flags. There is a comment in the code that suggest that there is an assumption about the allocation coming from a memory pool. This was likely true when sg lists were primarily used for disk I/O. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Cong Wang <amwang@redhat.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Rob Clark <rob.clark@linaro.org> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Inki Dae <inki.dae@samsung.com> Cc: Dave Airlie <airlied@redhat.com> Cc: Sonny Rao <sonnyrao@chromium.org> Cc: Olof Johansson <olofj@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30powerpc: pSeries reconfig notifier error injection moduleAkinobu Mita
This provides the ability to inject artifical errors to pSeries reconfig notifier chain callbacks. It is controlled through debugfs interface under /sys/kernel/debug/notifier-error-inject/pSeries-reconfig If the notifier call chain should be failed with some events notified, write the error code to "actions/<notifier event>/error". Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Dave Jones <davej@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30memory: memory notifier error injection moduleAkinobu Mita
This provides the ability to inject artifical errors to memory hotplug notifier chain callbacks. It is controlled through debugfs interface under /sys/kernel/debug/notifier-error-inject/memory If the notifier call chain should be failed with some events notified, write the error code to "actions/<notifier event>/error". Example: Inject memory hotplug offline error (-12 == -ENOMEM) # cd /sys/kernel/debug/notifier-error-inject/memory # echo -12 > actions/MEM_GOING_OFFLINE/error # echo offline > /sys/devices/system/memory/memoryXXX/state bash: echo: write error: Cannot allocate memory Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Dave Jones <davej@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30PM: PM notifier error injection moduleAkinobu Mita
This provides the ability to inject artifical errors to PM notifier chain callbacks. It is controlled through debugfs interface under /sys/kernel/debug/notifier-error-inject/pm Each of the files in "error" directory represents an event which can be failed and contains the error code. If the notifier call chain should be failed with some events notified, write the error code to the files. If the notifier call chain should be failed with some events notified, write the error code to "actions/<notifier event>/error". Example: Inject PM suspend error (-12 = -ENOMEM) # cd /sys/kernel/debug/notifier-error-inject/pm # echo -12 > actions/PM_SUSPEND_PREPARE/error # echo mem > /sys/power/state bash: echo: write error: Cannot allocate memory Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Dave Jones <davej@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30cpu: rewrite cpu-notifier-error-inject moduleAkinobu Mita
Rewrite existing cpu-notifier-error-inject module to use debugfs based new framework. This change removes cpu_up_prepare_error and cpu_down_prepare_error module parameters which were used to specify error code to be injected. We could keep these module parameters for backward compatibility by module_param_cb but it seems overkill for this module. This provides the ability to inject artifical errors to CPU notifier chain callbacks. It is controlled through debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu If the notifier call chain should be failed with some events notified, write the error code to "actions/<notifier event>/error". Example1: inject CPU offline error (-1 == -EPERM) # cd /sys/kernel/debug/notifier-error-inject/cpu # echo -1 > actions/CPU_DOWN_PREPARE/error # echo 0 > /sys/devices/system/cpu/cpu1/online bash: echo: write error: Operation not permitted Example2: inject CPU online error (-2 == -ENOENT) # cd /sys/kernel/debug/notifier-error-inject/cpu # echo -2 > actions/CPU_UP_PREPARE/error # echo 1 > /sys/devices/system/cpu/cpu1/online bash: echo: write error: No such file or directory Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Dave Jones <davej@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>