kernel/init, branch linux-2.6.39.y

Fix CPU spinlock lockups on secondary CPU bringup

2011-07-09T06:15:35Z

commit 1b19ca9f0bdab7d5035821e1ec8f39df9a6e3ee0 upstream. Secondary CPU bringup typically calls calibrate_delay() during its initialization. However, calibrate_delay() modifies a global variable (loops_per_jiffy) used for udelay() and __delay(). A side effect of 71c696b1 ("calibrate: extract fall-back calculation into own helper") introduced in the 2.6.39 merge window means that we end up with a substantial period where loops_per_jiffy is zero. This causes the spinlock debugging code to malfunction: u64 loops = loops_per_jiffy * HZ; for (;;) { for (i = 0; i < loops; i++) { if (arch_spin_trylock(&lock->raw_lock)) return; __delay(1); } ... } by never calling arch_spin_trylock() - resulting in the CPU locking up in an infinite loop inside __spin_lock_debug(). Work around this by only writing to loops_per_jiffy only once we have completed all the calibration decisions. Tested-by: Santosh Shilimkar Signed-off-by: Russell King -- Better solutions (such as omitting the calibration for secondary CPUs, or arranging for calibrate_delay() to return the LPJ value and leave it to the caller to decide where to store it) are a possibility, but would be much more invasive into each architecture. I think this is the best solution for -rc and stable, but it should be revisited for the next merge window. Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

kmemleak: Initialise kmemleak after debug_objects_mem_init()

2011-06-03T00:31:24Z

commit 9b090f2da85bd0df5e1a1ecfe4120b7b50358f48 upstream. Kmemleak frees objects via RCU and when CONFIG_DEBUG_OBJECTS_RCU_HEAD is enabled, the RCU callback triggers a call to free_object() in lib/debugobjects.c. Since kmemleak is initialised before debug objects initialisation, it may result in a kernel panic during booting. This patch moves the kmemleak_init() call after debug_objects_mem_init(). Reported-by: Marcin Slusarz Tested-by: Tejun Heo Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman

slub: Revert "[PARISC] slub: fix panic with DISCONTIGMEM"

2011-05-11T00:37:34Z

This reverts commit 4a5fa3590f09, which did not allow SLUB to be used on architectures that use DISCONTIGMEM without compiling NUMA support without CONFIG_BROKEN also set. The slub panic that it was intended to prevent is addressed by d9b41e0b54fd ("[PARISC] set memory ranges in N_NORMAL_MEMORY when onlined") on parisc so there is no further slub issues with such a configuration. The reverts allows SLUB now to be used on such architectures since there haven't been any reports of additional errors. Cc: James Bottomley Signed-off-by: David Rientjes Signed-off-by: Linus Torvalds

Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/parisc-2.6

2011-04-27T22:20:33Z

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/parisc-2.6: [PARISC] slub: fix panic with DISCONTIGMEM [PARISC] set memory ranges in N_NORMAL_MEMORY when onlined

init/Kconfig: fix EXPERT menu list

2011-04-27T03:48:37Z

The EXPERT menu list was recently broken by the insertion of a kconfig symbol (EMBEDDED) at the beginning of the EXPERT list of kconfig items. Broken by: commit 6a108a14fa356ef607be308b68337939e56ea94e Author: David Rientjes Date: Thu Jan 20 14:44:16 2011 -0800 kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT Restore the EXPERT menu list -- don't inject a symbol (EMBEDDED) that does not depend on EXPERT into the list. Signed-off-by: Randy Dunlap Cc: David Rientjes Cc: Peter Foley Signed-off-by: Linus Torvalds

[PARISC] slub: fix panic with DISCONTIGMEM

2011-04-22T20:42:46Z

Slub makes assumptions about page_to_nid() which are violated by DISCONTIGMEM and !NUMA. This violation results in a panic because page_to_nid() can be non-zero for pages in the discontiguous ranges and this leads to a null return by get_node(). The assertion by the maintainer is that DISCONTIGMEM should only be allowed when NUMA is also defined. However, at least six architectures: alpha, ia64, m32r, m68k, mips, parisc violate this. The panic is a regression against slab, so just mark slub broken in the problem configuration to prevent users reporting these panics. Cc: stable@kernel.org Acked-by: David Rientjes Acked-by: Pekka Enberg Signed-off-by: James Bottomley

Fix common misspellings

2011-03-31T14:26:23Z

Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi

userns: add a user_namespace as creator/owner of uts_namespace

2011-03-24T02:46:59Z

The expected course of development for user namespaces targeted capabilities is laid out at https://wiki.ubuntu.com/UserNamespace. Goals: - Make it safe for an unprivileged user to unshare namespaces. They will be privileged with respect to the new namespace, but this should only include resources which the unprivileged user already owns. - Provide separate limits and accounting for userids in different namespaces. Status: Currently (as of 2.6.38) you can clone with the CLONE_NEWUSER flag to get a new user namespace if you have the CAP_SYS_ADMIN, CAP_SETUID, and CAP_SETGID capabilities. What this gets you is a whole new set of userids, meaning that user 500 will have a different 'struct user' in your namespace than in other namespaces. So any accounting information stored in struct user will be unique to your namespace. However, throughout the kernel there are checks which - simply check for a capability. Since root in a child namespace has all capabilities, this means that a child namespace is not constrained. - simply compare uid1 == uid2. Since these are the integer uids, uid 500 in namespace 1 will be said to be equal to uid 500 in namespace 2. As a result, the lxc implementation at lxc.sf.net does not use user namespaces. This is actually helpful because it leaves us free to develop user namespaces in such a way that, for some time, user namespaces may be unuseful. Bugs aside, this patchset is supposed to not at all affect systems which are not actively using user namespaces, and only restrict what tasks in child user namespace can do. They begin to limit privilege to a user namespace, so that root in a container cannot kill or ptrace tasks in the parent user namespace, and can only get world access rights to files. Since all files currently belong to the initila user namespace, that means that child user namespaces can only get world access rights to *all* files. While this temporarily makes user namespaces bad for system containers, it starts to get useful for some sandboxing. I've run the 'runltplite.sh' with and without this patchset and found no difference. This patch: copy_process() handles CLONE_NEWUSER before the rest of the namespaces. So in the case of clone(CLONE_NEWUSER|CLONE_NEWUTS) the new uts namespace will have the new user namespace as its owner. That is what we want, since we want root in that new userns to be able to have privilege over it. Changelog: Feb 15: don't set uts_ns->user_ns if we didn't create a new uts_ns. Feb 23: Move extern init_user_ns declaration from init/version.c to utsname.h. Signed-off-by: Serge E. Hallyn Acked-by: "Eric W. Biederman" Acked-by: Daniel Lezcano Acked-by: David Howells Cc: James Morris Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pid: remove the child_reaper special case in init/main.c

2011-03-24T02:46:57Z

This patchset is a cleanup and a preparation to unshare the pid namespace. These prerequisites prepare for Eric's patchset to give a file descriptor to a namespace and join an existing namespace. This patch: It turns out that the existing assignment in copy_process of the child_reaper can handle the initial assignment of child_reaper we just need to generalize the test in kernel/fork.c Signed-off-by: Eric W. Biederman Signed-off-by: Daniel Lezcano Cc: Oleg Nesterov Cc: Alexey Dobriyan Acked-by: Serge E. Hallyn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

init: return proper error code in do_mounts_rd()

2011-03-23T00:44:15Z

In do_mounts_rd() if memory cannot be allocated, return -ENOMEM. Signed-off-by: Davidlohr Bueso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds