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  1. Aug 27, 2010
  3. Aug 23, 2010
  5. Aug 21, 2010
  7. Aug 20, 2010
  9. Aug 19, 2010
    • Borislav Petkov's avatar
      x86, hotplug: Serialize CPU hotplug to avoid bringup concurrency issues · d7c53c9e
      Borislav Petkov authored 
      

When testing cpu hotplug code on 32-bit we kept hitting the "CPU%d:
Stuck ??" message due to multiple cores concurrently accessing the
cpu_callin_mask, among others.

Since these codepaths are not protected from concurrent access due to
the fact that there's no sane reason for making an already complex
code unnecessarily more complex - we hit the issue only when insanely
switching cores off- and online - serialize hotplugging cores on the
sysfs level and be done with it.

[ v2.1: fix !HOTPLUG_CPU build ]

Cc: <stable@kernel.org>
Signed-off-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <20100819181029.GC17171@aftab>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
      d7c53c9e
    • KUMANO Syuhei's avatar
      kprobes/x86: Fix the return address of multiple kretprobes · 737480a0
      KUMANO Syuhei authored 
      

Fix the return address of subsequent kretprobes when multiple
kretprobes are set on the same function.

For example:

 # cd /sys/kernel/debug/tracing
 # echo "r:event1 sys_symlink" > kprobe_events
 # echo "r:event2 sys_symlink" >> kprobe_events
 # echo 1 > events/kprobes/enable
 # ln -s /tmp/foo /tmp/bar

(without this patch)

 # cat trace
              ln-897   [000] 20404.133727: event1: (kretprobe_trampoline+0x0/0x4c <- sys_symlink)
              ln-897   [000] 20404.133747: event2: (system_call_fastpath+0x16/0x1b <- sys_symlink)

(with this patch)

 # cat trace
              ln-740   [000] 13799.491076: event1: (system_call_fastpath+0x16/0x1b <- sys_symlink)
              ln-740   [000] 13799.491096: event2: (system_call_fastpath+0x16/0x1b <- sys_symlink)

Signed-off-by: default avatarKUMANO Syuhei <kumano.prog@gmail.com>
Reviewed-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
LKML-Reference: <1281853084.3254.11.camel@camp10-laptop>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      737480a0
  11. Aug 18, 2010
    • H. Peter Anvin's avatar
      x86-32: Fix dummy trampoline-related inline stubs · 8848a910
      H. Peter Anvin authored 
      

Fix dummy inline stubs for trampoline-related functions when no
trampolines exist (until we get rid of the no-trampoline case
entirely.)

Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <4C6C294D.3030404@zytor.com>
      8848a910
    • Tony Luck's avatar
      [IA64] Fix build error: conflicting types for ‘sys_execve’ · 145e5aa2
      Tony Luck authored 
      

arch/ia64/kernel/process.c:636: error: conflicting types for ‘sys_execve’

commit d7627467
Make do_execve() take a const filename pointer

Missed the declaration of sys_execve in the ia64 asm/unistd.h (perhaps
because there is no reason for it to be there ... it might be a left over
from the COMPAT code?). Just delete the conflicting version.

Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
      145e5aa2
    • Joerg Roedel's avatar
      x86-32: Separate 1:1 pagetables from swapper_pg_dir · fd89a137
      Joerg Roedel authored 
      

This patch fixes machine crashes which occur when heavily exercising the
CPU hotplug codepaths on a 32-bit kernel. These crashes are caused by
AMD Erratum 383 and result in a fatal machine check exception. Here's
the scenario:

1. On 32-bit, the swapper_pg_dir page table is used as the initial page
table for booting a secondary CPU.

2. To make this work, swapper_pg_dir needs a direct mapping of physical
memory in it (the low mappings). By adding those low, large page (2M)
mappings (PAE kernel), we create the necessary conditions for Erratum
383 to occur.

3. Other CPUs which do not participate in the off- and onlining game may
use swapper_pg_dir while the low mappings are present (when leave_mm is
called). For all steps below, the CPU referred to is a CPU that is using
swapper_pg_dir, and not the CPU which is being onlined.

4. The presence of the low mappings in swapper_pg_dir can result
in TLB entries for addresses below __PAGE_OFFSET to be established
speculatively. These TLB entries are marked global and large.

5. When the CPU with such TLB entry switches to another page table, this
TLB entry remains because it is global.

6. The process then generates an access to an address covered by the
above TLB entry but there is a permission mismatch - the TLB entry
covers a large global page not accessible to userspace.

7. Due to this permission mismatch a new 4kb, user TLB entry gets
established. Further, Erratum 383 provides for a small window of time
where both TLB entries are present. This results in an uncorrectable
machine check exception signalling a TLB multimatch which panics the
machine.

There are two ways to fix this issue:

        1. Always do a global TLB flush when a new cr3 is loaded and the
        old page table was swapper_pg_dir. I consider this a hack hard
        to understand and with performance implications

        2. Do not use swapper_pg_dir to boot secondary CPUs like 64-bit
        does.

This patch implements solution 2. It introduces a trampoline_pg_dir
which has the same layout as swapper_pg_dir with low_mappings. This page
table is used as the initial page table of the booting CPU. Later in the
bringup process, it switches to swapper_pg_dir and does a global TLB
flush. This fixes the crashes in our test cases.

-v2: switch to swapper_pg_dir right after entering start_secondary() so
that we are able to access percpu data which might not be mapped in the
trampoline page table.

Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
LKML-Reference: <20100816123833.GB28147@aftab>
Signed-off-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
      fd89a137
    • Hans Rosenfeld's avatar
      x86, cpu: Fix regression in AMD errata checking code · 07a7795c
      Hans Rosenfeld authored 
      

A bug in the family-model-stepping matching code caused the presence of
errata to go undetected when OSVW was not used. This causes hangs on
some K8 systems because the E400 workaround is not enabled.

Signed-off-by: default avatarHans Rosenfeld <hans.rosenfeld@amd.com>
LKML-Reference: <1282141190-930137-1-git-send-email-hans.rosenfeld@amd.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
      07a7795c
    • Zhang, Yanmin's avatar
      perf, x86: Fix Intel-nhm PMU programming errata workaround · 351af072
      Zhang, Yanmin authored 
      

Fix the Errata AAK100/AAP53/BD53 workaround, the officialy documented
workaround we implemented in:

 11164cd4: perf, x86: Add Nehelem PMU programming errata workaround

doesn't actually work fully and causes a stuck PMU state
under load and non-functioning perf profiling.

A functional workaround was found by trial & error.

Affects all Nehalem-class Intel PMUs.

Signed-off-by: default avatarZhang Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1281073148.2125.63.camel@ymzhang.sh.intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <stable@kernel.org> # .35.x
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      351af072
    • Kulikov Vasiliy's avatar
      m68knommu: formatting of pointers in printk() · c7484cf4
      Kulikov Vasiliy authored 
      

arch/m68knommu/kernel/process.c: formatting of pointers in printk()

Use %p instead of %08x in printk().

Signed-off-by: default avatarKulikov Vasiliy <segooon@gmail.com>
Signed-off-by: default avatarGreg Ungerer <gerg@uclinux.org>
      c7484cf4
    • Jate Sujjavanich's avatar
      m68knommu: arch/m68k/include/asm/ide.h fix for nommu · dc6ae5e4
      Jate Sujjavanich authored 
      

The arch/m68k/include/asm/ide.h produces errors when the IDE driver is compiled for my 523x uClinux system under kernel. The header makes some redefines of operators not defined in the arch/m68k/include/asm/io_no.h header. There are no separate mmio and iospace defines.

Signed-off-by: default avatarJate Sujjavanich <jsujjavanich@syntech-fuelmaster.com>
Acked-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarGreg Ungerer <gerg@uclinux.org>
      dc6ae5e4
    • David Howells's avatar
      Make do_execve() take a const filename pointer · d7627467
      David Howells authored 
      

Make do_execve() take a const filename pointer so that kernel_execve() compiles
correctly on ARM:

arch/arm/kernel/sys_arm.c:88: warning: passing argument 1 of 'do_execve' discards qualifiers from pointer target type

This also requires the argv and envp arguments to be consted twice, once for
the pointer array and once for the strings the array points to.  This is
because do_execve() passes a pointer to the filename (now const) to
copy_strings_kernel().  A simpler alternative would be to cast the filename
pointer in do_execve() when it's passed to copy_strings_kernel().

do_execve() may not change any of the strings it is passed as part of the argv
or envp lists as they are some of them in .rodata, so marking these strings as
const should be fine.

Further kernel_execve() and sys_execve() need to be changed to match.

This has been test built on x86_64, frv, arm and mips.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Tested-by: default avatarRalf Baechle <ralf@linux-mips.org>
Acked-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d7627467
    • David S. Miller's avatar
      sparc64: Fix atomic64_t routine return values. · 86fa04b8
      David S. Miller authored 
      

Should return 'long' instead of 'int'.

Thanks to Dimitris Michailidis and Tony Luck.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      86fa04b8
    • David S. Miller's avatar
      sparc64: Fix rwsem constant bug leading to hangs. · ef201beb
      David S. Miller authored 
      

As noticed by Linus, it is critical that some of the
rwsem constants be signed.  Yet, hex constants are
unsigned unless explicitly casted or negated.

The most critical one is RWSEM_WAITING_BIAS.

This bug was exacerbated by commit
424acaae ("rwsem: wake queued readers
when writer blocks on active read lock")

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ef201beb
  13. Aug 17, 2010
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  19. Aug 14, 2010