linux-stable.git/init/main.c, branch linux-2.6.32.y Linux kernel stable tree x86, espfix: Make espfix64 a Kconfig option, fix UML 2014-12-13T14:16:09+00:00 H. Peter Anvin hpa@zytor.com 2014-05-04T17:00:49+00:00 6e4bcdb55bf0a18b3dbbd6b3bc4d4526133fcd0c commit 197725de65477bc8509b41388157c1a2283542bb upstream. Make espfix64 a hidden Kconfig option. This fixes the x86-64 UML build which had broken due to the non-existence of init_espfix_bsp() in UML: since UML uses its own Kconfig, this option does not appear in the UML build. This also makes it possible to make support for 16-bit segments a configuration option, for the people who want to minimize the size of the kernel. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Richard Weinberger <richard@nod.at> Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> (cherry picked from 3.2 commit da22646d97b7322c757f3a7a21805a3475fed231) Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 197725de65477bc8509b41388157c1a2283542bb upstream.

Make espfix64 a hidden Kconfig option.  This fixes the x86-64 UML
build which had broken due to the non-existence of init_espfix_bsp()
in UML: since UML uses its own Kconfig, this option does not appear in
the UML build.

This also makes it possible to make support for 16-bit segments a
configuration option, for the people who want to minimize the size of
the kernel.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Richard Weinberger <richard@nod.at>
Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
(cherry picked from 3.2 commit da22646d97b7322c757f3a7a21805a3475fed231)
Signed-off-by: Willy Tarreau <w@1wt.eu>
x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack 2014-12-13T14:16:08+00:00 H. Peter Anvin hpa@linux.intel.com 2014-04-29T23:46:09+00:00 36102caaf7d9000fb04592163ffc623d834cc540 commit 3891a04aafd668686239349ea58f3314ea2af86b upstream. The IRET instruction, when returning to a 16-bit segment, only restores the bottom 16 bits of the user space stack pointer. This causes some 16-bit software to break, but it also leaks kernel state to user space. We have a software workaround for that ("espfix") for the 32-bit kernel, but it relies on a nonzero stack segment base which is not available in 64-bit mode. In checkin: b3b42ac2cbae x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels we "solved" this by forbidding 16-bit segments on 64-bit kernels, with the logic that 16-bit support is crippled on 64-bit kernels anyway (no V86 support), but it turns out that people are doing stuff like running old Win16 binaries under Wine and expect it to work. This works around this by creating percpu "ministacks", each of which is mapped 2^16 times 64K apart. When we detect that the return SS is on the LDT, we copy the IRET frame to the ministack and use the relevant alias to return to userspace. The ministacks are mapped readonly, so if IRET faults we promote #GP to #DF which is an IST vector and thus has its own stack; we then do the fixup in the #DF handler. (Making #GP an IST exception would make the msr_safe functions unsafe in NMI/MC context, and quite possibly have other effects.) Special thanks to: - Andy Lutomirski, for the suggestion of using very small stack slots and copy (as opposed to map) the IRET frame there, and for the suggestion to mark them readonly and let the fault promote to #DF. - Konrad Wilk for paravirt fixup and testing. - Borislav Petkov for testing help and useful comments. Reported-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Andrew Lutomriski <amluto@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Dirk Hohndel <dirk@hohndel.org> Cc: Arjan van de Ven <arjan.van.de.ven@intel.com> Cc: comex <comexk@gmail.com> Cc: Alexander van Heukelum <heukelum@fastmail.fm> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> (cherry picked from 3.2 commit e7836514086d53e0ffaee18d67d85d9477ecdb12) [wt: backport notes for 2.6.32 differences : - use DECLARE_PER_CPU instead of DECLARE_PER_CPU_READ_MOSTLY - replace this_cpu_read(foo) with per_cpu(foo, smp_processor_id()) - replace this_cpu_write(foo,bar) with per_cpu(foo,smp_processor_id())=bar /wt] Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 3891a04aafd668686239349ea58f3314ea2af86b upstream.

The IRET instruction, when returning to a 16-bit segment, only
restores the bottom 16 bits of the user space stack pointer.  This
causes some 16-bit software to break, but it also leaks kernel state
to user space.  We have a software workaround for that ("espfix") for
the 32-bit kernel, but it relies on a nonzero stack segment base which
is not available in 64-bit mode.

In checkin:

    b3b42ac2cbae x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels

we "solved" this by forbidding 16-bit segments on 64-bit kernels, with
the logic that 16-bit support is crippled on 64-bit kernels anyway (no
V86 support), but it turns out that people are doing stuff like
running old Win16 binaries under Wine and expect it to work.

This works around this by creating percpu "ministacks", each of which
is mapped 2^16 times 64K apart.  When we detect that the return SS is
on the LDT, we copy the IRET frame to the ministack and use the
relevant alias to return to userspace.  The ministacks are mapped
readonly, so if IRET faults we promote #GP to #DF which is an IST
vector and thus has its own stack; we then do the fixup in the #DF
handler.

(Making #GP an IST exception would make the msr_safe functions unsafe
in NMI/MC context, and quite possibly have other effects.)

Special thanks to:

- Andy Lutomirski, for the suggestion of using very small stack slots
  and copy (as opposed to map) the IRET frame there, and for the
  suggestion to mark them readonly and let the fault promote to #DF.
- Konrad Wilk for paravirt fixup and testing.
- Borislav Petkov for testing help and useful comments.

Reported-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andrew Lutomriski <amluto@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dirk Hohndel <dirk@hohndel.org>
Cc: Arjan van de Ven <arjan.van.de.ven@intel.com>
Cc: comex <comexk@gmail.com>
Cc: Alexander van Heukelum <heukelum@fastmail.fm>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
(cherry picked from 3.2 commit e7836514086d53e0ffaee18d67d85d9477ecdb12)
[wt: backport notes for 2.6.32 differences :
     - use DECLARE_PER_CPU instead of DECLARE_PER_CPU_READ_MOSTLY
     - replace this_cpu_read(foo) with per_cpu(foo, smp_processor_id())
     - replace this_cpu_write(foo,bar) with per_cpu(foo,smp_processor_id())=bar
/wt]
Signed-off-by: Willy Tarreau <w@1wt.eu>
init, sched: Fix race between init and kthreadd 2011-05-09T22:55:36+00:00 Peter Zijlstra peterz@infradead.org 2010-06-28T14:51:01+00:00 572a42d1f4c4dcf686eb7b25741e99e789f8d213 commit b433c3d4549ae74935b585115f076c6fb7bc48fe upstream. Ilya reported that on a very slow machine he could reliably reproduce a race between forking init and kthreadd. We first fork init so that it obtains pid-1, however since the scheduler is already fully running at this point it can preempt and run the init thread before we spawn and set kthreadd_task. The init thread can then attempt spawning kthreads without kthreadd being present which results in an OOPS. Reported-by: Ilya Loginov <isloginov@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <1277736661.3561.110.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
commit b433c3d4549ae74935b585115f076c6fb7bc48fe upstream.

Ilya reported that on a very slow machine he could reliably
reproduce a race between forking init and kthreadd. We first
fork init so that it  obtains pid-1, however since the scheduler
is already fully running at this point it can preempt and run
the init thread before we spawn and set kthreadd_task.

The init thread can then attempt spawning kthreads without
kthreadd being present which results in an OOPS.

Reported-by: Ilya Loginov <isloginov@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <1277736661.3561.110.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
cpuset: fix the problem that cpuset_mem_spread_node() returns an offline node 2010-04-01T22:58:46+00:00 Miao Xie miaox@cn.fujitsu.com 2010-03-23T20:35:34+00:00 893b328f07c17aa84f562fc5566eb524bd76188e commit 5ab116c9349ef52d6fbd2e2917a53f13194b048e upstream. cpuset_mem_spread_node() returns an offline node, and causes an oops. This patch fixes it by initializing task->mems_allowed to node_states[N_HIGH_MEMORY], and updating task->mems_allowed when doing memory hotplug. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Acked-by: David Rientjes <rientjes@google.com> Reported-by: Nick Piggin <npiggin@suse.de> Tested-by: Nick Piggin <npiggin@suse.de> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
commit 5ab116c9349ef52d6fbd2e2917a53f13194b048e upstream.

cpuset_mem_spread_node() returns an offline node, and causes an oops.

This patch fixes it by initializing task->mems_allowed to
node_states[N_HIGH_MEMORY], and updating task->mems_allowed when doing
memory hotplug.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Reported-by: Nick Piggin <npiggin@suse.de>
Tested-by: Nick Piggin <npiggin@suse.de>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
sched: Mark boot-cpu active before smp_init() 2010-04-01T22:58:15+00:00 Peter Zijlstra a.p.zijlstra@chello.nl 2009-12-16T17:04:31+00:00 8c2b12e12010928b6c5dd06447eccb99b0629515 commit 933b0618d8b2a59c7a0742e43836544e02f1e9bd upstream. A UP machine has 1 active cpu, not having the boot-cpu in the active map when starting the scheduler confuses things. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091216170517.423469527@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
commit 933b0618d8b2a59c7a0742e43836544e02f1e9bd upstream.

A UP machine has 1 active cpu, not having the boot-cpu in the
active map when starting the scheduler confuses things.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091216170517.423469527@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
param: don't complain about unused module parameters. 2009-12-02T23:40:07+00:00 Rusty Russell rusty@rustcorp.com.au 2009-12-01T04:26:44+00:00 f066a4f6df68f03b565dfe867dde54dfeb26576e Jon confirms that recent modprobe will look in /proc/cmdline, so these cmdline options can still be used. See http://bugzilla.kernel.org/show_bug.cgi?id=14164 Reported-by: Adam Williamson <awilliam@redhat.com> Cc: stable@kernel.org Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Jon confirms that recent modprobe will look in /proc/cmdline, so these
cmdline options can still be used.

See http://bugzilla.kernel.org/show_bug.cgi?id=14164

Reported-by: Adam Williamson <awilliam@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-10-08T19:16:35+00:00 Linus Torvalds torvalds@linux-foundation.org 2009-10-08T19:16:35+00:00 f579bbcd9bb8b688df03191b92c56ab8af4d6322 * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: futex: fix requeue_pi key imbalance futex: Fix typo in FUTEX_WAIT/WAKE_BITSET_PRIVATE definitions rcu: Place root rcu_node structure in separate lockdep class rcu: Make hot-unplugged CPU relinquish its own RCU callbacks rcu: Move rcu_barrier() to rcutree futex: Move exit_pi_state() call to release_mm() futex: Nullify robust lists after cleanup futex: Fix locking imbalance panic: Fix panic message visibility by calling bust_spinlocks(0) before dying rcu: Replace the rcu_barrier enum with pointer to call_rcu*() function rcu: Clean up code based on review feedback from Josh Triplett, part 4 rcu: Clean up code based on review feedback from Josh Triplett, part 3 rcu: Fix rcu_lock_map build failure on CONFIG_PROVE_LOCKING=y rcu: Clean up code to address Ingo's checkpatch feedback rcu: Clean up code based on review feedback from Josh Triplett, part 2 rcu: Clean up code based on review feedback from Josh Triplett 
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  futex: fix requeue_pi key imbalance
  futex: Fix typo in FUTEX_WAIT/WAKE_BITSET_PRIVATE definitions
  rcu: Place root rcu_node structure in separate lockdep class
  rcu: Make hot-unplugged CPU relinquish its own RCU callbacks
  rcu: Move rcu_barrier() to rcutree
  futex: Move exit_pi_state() call to release_mm()
  futex: Nullify robust lists after cleanup
  futex: Fix locking imbalance
  panic: Fix panic message visibility by calling bust_spinlocks(0) before dying
  rcu: Replace the rcu_barrier enum with pointer to call_rcu*() function
  rcu: Clean up code based on review feedback from Josh Triplett, part 4
  rcu: Clean up code based on review feedback from Josh Triplett, part 3
  rcu: Fix rcu_lock_map build failure on CONFIG_PROVE_LOCKING=y
  rcu: Clean up code to address Ingo's checkpatch feedback
  rcu: Clean up code based on review feedback from Josh Triplett, part 2
  rcu: Clean up code based on review feedback from Josh Triplett
Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus 2009-09-24T01:14:11+00:00 Linus Torvalds torvalds@linux-foundation.org 2009-09-24T01:14:11+00:00 94a8d5caba74211ec76dac80fc6e2d5c391530df * git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (39 commits) cpumask: Move deprecated functions to end of header. cpumask: remove unused deprecated functions, avoid accusations of insanity cpumask: use new-style cpumask ops in mm/quicklist. cpumask: use mm_cpumask() wrapper: x86 cpumask: use mm_cpumask() wrapper: um cpumask: use mm_cpumask() wrapper: mips cpumask: use mm_cpumask() wrapper: mn10300 cpumask: use mm_cpumask() wrapper: m32r cpumask: use mm_cpumask() wrapper: arm cpumask: Use accessors for cpu_*_mask: um cpumask: Use accessors for cpu_*_mask: powerpc cpumask: Use accessors for cpu_*_mask: mips cpumask: Use accessors for cpu_*_mask: m32r cpumask: remove arch_send_call_function_ipi cpumask: arch_send_call_function_ipi_mask: s390 cpumask: arch_send_call_function_ipi_mask: powerpc cpumask: arch_send_call_function_ipi_mask: mips cpumask: arch_send_call_function_ipi_mask: m32r cpumask: arch_send_call_function_ipi_mask: alpha cpumask: remove obsolete topology_core_siblings and topology_thread_siblings: ia64 ... 
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (39 commits)
  cpumask: Move deprecated functions to end of header.
  cpumask: remove unused deprecated functions, avoid accusations of insanity
  cpumask: use new-style cpumask ops in mm/quicklist.
  cpumask: use mm_cpumask() wrapper: x86
  cpumask: use mm_cpumask() wrapper: um
  cpumask: use mm_cpumask() wrapper: mips
  cpumask: use mm_cpumask() wrapper: mn10300
  cpumask: use mm_cpumask() wrapper: m32r
  cpumask: use mm_cpumask() wrapper: arm
  cpumask: Use accessors for cpu_*_mask: um
  cpumask: Use accessors for cpu_*_mask: powerpc
  cpumask: Use accessors for cpu_*_mask: mips
  cpumask: Use accessors for cpu_*_mask: m32r
  cpumask: remove arch_send_call_function_ipi
  cpumask: arch_send_call_function_ipi_mask: s390
  cpumask: arch_send_call_function_ipi_mask: powerpc
  cpumask: arch_send_call_function_ipi_mask: mips
  cpumask: arch_send_call_function_ipi_mask: m32r
  cpumask: arch_send_call_function_ipi_mask: alpha
  cpumask: remove obsolete topology_core_siblings and topology_thread_siblings: ia64
  ...
headers: utsname.h redux 2009-09-24T01:13:10+00:00 Alexey Dobriyan adobriyan@gmail.com 2009-09-24T00:22:25+00:00 2bcd57ab61e7cabed626226a3771617981c11ce1 * remove asm/atomic.h inclusion from linux/utsname.h -- not needed after kref conversion * remove linux/utsname.h inclusion from files which do not need it NOTE: it looks like fs/binfmt_elf.c do not need utsname.h, however due to some personality stuff it _is_ needed -- cowardly leave ELF-related headers and files alone. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
* remove asm/atomic.h inclusion from linux/utsname.h --
   not needed after kref conversion
 * remove linux/utsname.h inclusion from files which do not need it

NOTE: it looks like fs/binfmt_elf.c do not need utsname.h, however
due to some personality stuff it _is_ needed -- cowardly leave ELF-related
headers and files alone.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
cpumask: remove unused cpu_mask_all 2009-09-24T00:04:36+00:00 Rusty Russell rusty@rustcorp.com.au 2009-09-24T15:34:36+00:00 72d78d05cbaa69f2a32f5f9d65a4551ba0da571f It's only defined for NR_CPUS > BITS_PER_LONG; cpu_all_mask is always defined (and const). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> 
It's only defined for NR_CPUS > BITS_PER_LONG; cpu_all_mask is always
defined (and const).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>