kernel/linux.git/init, branch v3.16.50

cpu: Defer smpboot kthread unparking until CPU known to scheduler

2016-03-30T11:02:54+00:00

commit 00df35f991914db6b8bde8cf09808e19a9cffc3d upstream. Currently, smpboot_unpark_threads() is invoked before the incoming CPU has been added to the scheduler's runqueue structures. This might potentially cause the unparked kthread to run on the wrong CPU, since the correct CPU isn't fully set up yet. That causes a sporadic, hard to debug boot crash triggering on some systems, reported by Borislav Petkov, and bisected down to: 2a442c9c6453 ("x86: Use common outgoing-CPU-notification code") This patch places smpboot_unpark_threads() in a CPU hotplug notifier with priority set so that these kthreads are unparked just after the CPU has been added to the runqueues. Reported-and-tested-by: Borislav Petkov Signed-off-by: Paul E. McKenney Cc: Andrew Morton Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar Cc: Owen Hofmann Signed-off-by: Luis Henriques

ACPI / init: Switch over platform to the ACPI mode later

2015-07-15T09:01:26+00:00

commit b064a8fa77dfead647564c46ac8fc5b13bd1ab73 upstream. Commit 73f7d1ca3263 "ACPI / init: Run acpi_early_init() before timekeeping_init()" moved the ACPI subsystem initialization, including the ACPI mode enabling, to an earlier point in the initialization sequence, to allow the timekeeping subsystem use ACPI early. Unfortunately, that resulted in boot regressions on some systems and the early ACPI initialization was moved toward its original position in the kernel initialization code by commit c4e1acbb35e4 "ACPI / init: Invoke early ACPI initialization later". However, that turns out to be insufficient, as boot is still broken on the Tyan S8812 mainboard. To fix that issue, split the ACPI early initialization code into two pieces so the majority of it still located in acpi_early_init() and the part switching over the platform into the ACPI mode goes into a new function, acpi_subsystem_init(), executed at the original early ACPI initialization spot. That fixes the Tyan S8812 boot problem, but still allows ACPI tables to be loaded earlier which is useful to the EFI code in efi_enter_virtual_mode(). Link: https://bugzilla.kernel.org/show_bug.cgi?id=97141 Fixes: 73f7d1ca3263 "ACPI / init: Run acpi_early_init() before timekeeping_init()" Reported-and-tested-by: Marius Tolzmann Signed-off-by: Rafael J. Wysocki Acked-by: Toshi Kani Reviewed-by: Hanjun Guo Reviewed-by: Lee, Chun-Yi Signed-off-by: Luis Henriques

param: fix crash on bad kernel arguments

2014-11-27T11:21:42+00:00

commit 3438cf549d2f3ee8e52c82acc8e2a9710ac21a5b upstream. Currently if the user passes an invalid value on the kernel command line then the kernel will crash during argument parsing. On most systems this is very hard to debug because the console hasn't been initialized yet. This is a regression due to commit 51e158c12aca ("param: hand arguments after -- straight to init") which, in response to the systemd debug controversy, made it possible to explicitly pass arguments to init. To achieve this parse_args() was extended from simply returning an error code to returning a pointer. Regretably the new init args logic does not perform a proper validity check on the pointer resulting in a crash. This patch fixes the validity check. Should the check fail then no arguments will be passed to init. This is reasonable and matches how the kernel treats its own arguments (i.e. no error recovery). Signed-off-by: Daniel Thompson Signed-off-by: Rusty Russell Signed-off-by: Luis Henriques

init/Kconfig: Hide printk log config if CONFIG_PRINTK=n

2014-11-05T13:55:02+00:00

commit 361e9dfbaae84b0b246ed18d1ab7c82a1a41b53e upstream. The buffers sized by CONFIG_LOG_BUF_SHIFT and CONFIG_LOG_CPU_MAX_BUF_SHIFT do not exist if CONFIG_PRINTK=n, so don't ask about their size at all. Signed-off-by: Josh Triplett Acked-by: Randy Dunlap [ kamal: backport to 3.13-stable: only LOG_BUF_SHIFT ] Signed-off-by: Kamal Mostafa Signed-off-by: Luis Henriques

init/Kconfig: Fix HAVE_FUTEX_CMPXCHG to not break up the EXPERT menu

2014-10-09T19:23:48+00:00

commit 62b4d2041117f35ab2409c9f5c4b8d3dc8e59d0f upstream. commit 03b8c7b623c80af264c4c8d6111e5c6289933666 ("futex: Allow architectures to skip futex_atomic_cmpxchg_inatomic() test") added the HAVE_FUTEX_CMPXCHG symbol right below FUTEX. This placed it right in the middle of the options for the EXPERT menu. However, HAVE_FUTEX_CMPXCHG does not depend on EXPERT or FUTEX, so Kconfig stops placing items in the EXPERT menu, and displays the remaining several EXPERT items (starting with EPOLL) directly in the General Setup menu. Since both users of HAVE_FUTEX_CMPXCHG only select it "if FUTEX", make HAVE_FUTEX_CMPXCHG itself depend on FUTEX. With this change, the subsequent items display as part of the EXPERT menu again; the EMBEDDED menu now appears as the next top-level item in the General Setup menu, which makes General Setup much shorter and more usable. Signed-off-by: Josh Triplett Acked-by: Randy Dunlap Signed-off-by: Greg Kroah-Hartman

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2014-06-11T23:09:14+00:00

Pull module updates from Rusty Russell: "Most of this is cleaning up various driver sysfs permissions so we can re-add the perm check (we unified the module param and sysfs checks, but the module ones were stronger so we weakened them temporarily). Param parsing gets documented, and also "--" now forces args to be handed to init (and ignored by the kernel). Module NX/RO protections get tightened: we now set them before calling parse_args()" * tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: module: set nx before marking module MODULE_STATE_COMING. samples/kobject/: avoid world-writable sysfs files. drivers/hid/hid-picolcd_fb: avoid world-writable sysfs files. drivers/staging/speakup/: avoid world-writable sysfs files. drivers/regulator/virtual: avoid world-writable sysfs files. drivers/scsi/pm8001/pm8001_ctl.c: avoid world-writable sysfs files. drivers/hid/hid-lg4ff.c: avoid world-writable sysfs files. drivers/video/fbdev/sm501fb.c: avoid world-writable sysfs files. drivers/mtd/devices/docg3.c: avoid world-writable sysfs files. speakup: fix incorrect perms on speakup_acntsa.c cpumask.h: silence warning with -Wsign-compare Documentation: Update kernel-parameters.tx param: hand arguments after -- straight to init modpost: Fix resource leak in read_dump()

Merge branch 'x86/espfix' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next

2014-06-05T14:46:15+00:00

Pull x86-64 espfix changes from Peter Anvin: "This is the espfix64 code, which fixes the IRET information leak as well as the associated functionality problem. With this code applied, 16-bit stack segments finally work as intended even on a 64-bit kernel. Consequently, this patchset also removes the runtime option that we added as an interim measure. To help the people working on Linux kernels for very small systems, this patchset also makes these compile-time configurable features" * 'x86/espfix' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Revert "x86-64, modify_ldt: Make support for 16-bit segments a runtime option" x86, espfix: Make it possible to disable 16-bit support x86, espfix: Make espfix64 a Kconfig option, fix UML x86, espfix: Fix broken header guard x86, espfix: Move espfix definitions into a separate header file x86-32, espfix: Remove filter for espfix32 due to race x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack

init/main.c: remove an ifdef

2014-06-04T23:54:21+00:00

Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kthreads: kill CLONE_KERNEL, change kernel_thread(kernel_init) to avoid CLONE_SIGHAND

2014-06-04T23:54:21+00:00

1. Remove CLONE_KERNEL, it has no users and it is dangerous. The (old) comment says "List of flags we want to share for kernel threads" but this is not true, we do not want to share ->sighand by default. This flag can only be used if the caller is sure that both parent/child will never play with signals (say, allow_signal/etc). 2. Change rest_init() to clone kernel_init() without CLONE_SIGHAND. In this case CLONE_SIGHAND does not really hurt, and it looks like optimization because copy_sighand() can avoid kmem_cache_alloc(). But in fact this only adds the minor pessimization. kernel_init() is going to exec the init process, and de_thread() will need to unshare ->sighand and do kmem_cache_alloc(sighand_cachep) anyway, but it needs to do more work and take tasklist_lock and siglock. Signed-off-by: Oleg Nesterov Acked-by: Peter Zijlstra Acked-by: Steven Rostedt Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Mathieu Desnoyers Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

init/main.c: add initcall_blacklist kernel parameter

2014-06-04T23:54:21+00:00

When a module is built into the kernel the module_init() function becomes an initcall. Sometimes debugging through dynamic debug can help, however, debugging built in kernel modules is typically done by changing the .config, recompiling, and booting the new kernel in an effort to determine exactly which module caused a problem. This patchset can be useful stand-alone or combined with initcall_debug. There are cases where some initcalls can hang the machine before the console can be flushed, which can make initcall_debug output inaccurate. Having the ability to skip initcalls can help further debugging of these scenarios. Usage: initcall_blacklist= ex) added "initcall_blacklist=sgi_uv_sysfs_init" as a kernel parameter and the log contains: blacklisting initcall sgi_uv_sysfs_init ... ... initcall sgi_uv_sysfs_init blacklisted ex) added "initcall_blacklist=foo_bar,sgi_uv_sysfs_init" as a kernel parameter and the log contains: blacklisting initcall foo_bar blacklisting initcall sgi_uv_sysfs_init ... ... initcall sgi_uv_sysfs_init blacklisted [akpm@linux-foundation.org: tweak printk text] Signed-off-by: Prarit Bhargava Cc: Richard Weinberger Cc: Andi Kleen Cc: Josh Boyer Cc: Rob Landley Cc: Steven Rostedt Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Frederic Weisbecker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds