linux-stable.git/arch/x86/kernel, branch linux-3.10.y Linux kernel stable tree x86/apic: fix build breakage caused by incomplete backport to 3.10 2017-11-02T22:39:31+00:00 Willy Tarreau w@1wt.eu 2017-11-02T22:22:31+00:00 68cbe93962196f08a1a52e81dc6d5bedaca09b06 Commit 928a277 ("x86/apic: Do not init irq remapping if ioapic is disabled") introduced in 3.10.105 introduced an implicit dependency of CONFIG_X86_LOCAL_APIC to CONFIG_X86_IO_APIC which was later solved as part of simplifications on the config dependencies in more recent kernels. This dependency results in build failure when CONFIG_X86_LOCAL_APIC is set without CONFIG_X86_IO_APIC (this setup requires CONFIG_SMP=n). The reason is that skip_ioapic_setup is declared in apic.c and that the backported code was picked from a context where the #ifdef surrounding the function used to cover this condition. Let's just add the appropriate #ifdef to fix the 3.10 backport. Thanks to Christoph Biedl for reporting and diagnosing this one. Reported-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de> Cc: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de> Cc: Jan Beulich <JBeulich@suse.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Willy Tarreau <w@1wt.eu> 
Commit 928a277 ("x86/apic: Do not init irq remapping if ioapic is
disabled") introduced in 3.10.105 introduced an implicit dependency of
CONFIG_X86_LOCAL_APIC to CONFIG_X86_IO_APIC which was later solved as
part of simplifications on the config dependencies in more recent kernels.
This dependency results in build failure when CONFIG_X86_LOCAL_APIC is
set without CONFIG_X86_IO_APIC (this setup requires CONFIG_SMP=n). The
reason is that skip_ioapic_setup is declared in apic.c and that the
backported code was picked from a context where the #ifdef surrounding
the function used to cover this condition.

Let's just add the appropriate #ifdef to fix the 3.10 backport.

Thanks to Christoph Biedl for reporting and diagnosing this one.

Reported-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Cc: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
kvm: async_pf: fix rcu_irq_enter() with irqs enabled 2017-11-02T06:16:25+00:00 Paolo Bonzini pbonzini@redhat.com 2017-04-26T14:56:26+00:00 ca58e3129147cd80996c9a7cde5faee28f9981ec commit bbaf0e2b1c1b4f88abd6ef49576f0efb1734eae5 upstream. native_safe_halt enables interrupts, and you just shouldn't call rcu_irq_enter() with interrupts enabled. Reorder the call with the following local_irq_disable() to respect the invariant. Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit bbaf0e2b1c1b4f88abd6ef49576f0efb1734eae5 upstream.

native_safe_halt enables interrupts, and you just shouldn't
call rcu_irq_enter() with interrupts enabled.  Reorder the
call with the following local_irq_disable() to respect the
invariant.

Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Willy Tarreau <w@1wt.eu>
mm: larger stack guard gap, between vmas 2017-06-21T13:42:43+00:00 Hugh Dickins hughd@google.com 2017-06-19T11:03:24+00:00 1ad9a25dd06fda9bdc27875e1cedb8277accb212 commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream. Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> [wt: backport to 4.11: adjust context] [wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide] [wt: backport to 4.4: adjust context ; drop ppc hugetlb_radix changes] [wt: backport to 3.18: adjust context ; no FOLL_POPULATE ; s390 uses generic arch_get_unmapped_area()] [wt: backport to 3.16: adjust context] [wt: backport to 3.10: adjust context ; code logic in PARISC's arch_get_unmapped_area() wasn't found ; code inserted into expand_upwards() and expand_downwards() runs under anon_vma lock; changes for gup.c:faultin_page go to memory.c:__get_user_pages(); included Hugh Dickins' fixes] Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream.

Stack guard page is a useful feature to reduce a risk of stack smashing
into a different mapping. We have been using a single page gap which
is sufficient to prevent having stack adjacent to a different mapping.
But this seems to be insufficient in the light of the stack usage in
userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
which is 256kB or stack strings with MAX_ARG_STRLEN.

This will become especially dangerous for suid binaries and the default
no limit for the stack size limit because those applications can be
tricked to consume a large portion of the stack and a single glibc call
could jump over the guard page. These attacks are not theoretical,
unfortunatelly.

Make those attacks less probable by increasing the stack guard gap
to 1MB (on systems with 4k pages; but make it depend on the page size
because systems with larger base pages might cap stack allocations in
the PAGE_SIZE units) which should cover larger alloca() and VLA stack
allocations. It is obviously not a full fix because the problem is
somehow inherent, but it should reduce attack space a lot.

One could argue that the gap size should be configurable from userspace,
but that can be done later when somebody finds that the new 1MB is wrong
for some special case applications.  For now, add a kernel command line
option (stack_guard_gap) to specify the stack gap size (in page units).

Implementation wise, first delete all the old code for stack guard page:
because although we could get away with accounting one extra page in a
stack vma, accounting a larger gap can break userspace - case in point,
a program run with "ulimit -S -v 20000" failed when the 1MB gap was
counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
and strict non-overcommit mode.

Instead of keeping gap inside the stack vma, maintain the stack guard
gap as a gap between vmas: using vm_start_gap() in place of vm_start
(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
places which need to respect the gap - mainly arch_get_unmapped_area(),
and and the vma tree's subtree_gap support for that.

Original-patch-by: Oleg Nesterov <oleg@redhat.com>
Original-patch-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
[wt: backport to 4.11: adjust context]
[wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide]
[wt: backport to 4.4: adjust context ; drop ppc hugetlb_radix changes]
[wt: backport to 3.18: adjust context ; no FOLL_POPULATE ;
     s390 uses generic arch_get_unmapped_area()]
[wt: backport to 3.16: adjust context]
[wt: backport to 3.10: adjust context ; code logic in PARISC's
     arch_get_unmapped_area() wasn't found ; code inserted into
     expand_upwards() and expand_downwards() runs under anon_vma lock;
     changes for gup.c:faultin_page go to memory.c:__get_user_pages();
     included Hugh Dickins' fixes]
Signed-off-by: Willy Tarreau <w@1wt.eu>
ftrace/x86: Fix triple fault with graph tracing and suspend-to-ram 2017-06-20T12:04:53+00:00 Josh Poimboeuf jpoimboe@redhat.com 2017-04-13T22:53:55+00:00 b3d2d8af5b4791f60a1ced720a251c7f89badff7 commit 34a477e5297cbaa6ecc6e17c042a866e1cbe80d6 upstream. On x86-32, with CONFIG_FIRMWARE and multiple CPUs, if you enable function graph tracing and then suspend to RAM, it will triple fault and reboot when it resumes. The first fault happens when booting a secondary CPU: startup_32_smp() load_ucode_ap() prepare_ftrace_return() ftrace_graph_is_dead() (accesses 'kill_ftrace_graph') The early head_32.S code calls into load_ucode_ap(), which has an an ftrace hook, so it calls prepare_ftrace_return(), which calls ftrace_graph_is_dead(), which tries to access the global 'kill_ftrace_graph' variable with a virtual address, causing a fault because the CPU is still in real mode. The fix is to add a check in prepare_ftrace_return() to make sure it's running in protected mode before continuing. The check makes sure the stack pointer is a virtual kernel address. It's a bit of a hack, but it's not very intrusive and it works well enough. For reference, here are a few other (more difficult) ways this could have potentially been fixed: - Move startup_32_smp()'s call to load_ucode_ap() down to *after* paging is enabled. (No idea what that would break.) - Track down load_ucode_ap()'s entire callee tree and mark all the functions 'notrace'. (Probably not realistic.) - Pause graph tracing in ftrace_suspend_notifier_call() or bringup_cpu() or __cpu_up(), and ensure that the pause facility can be queried from real mode. Reported-by: Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Tested-by: Paul Menzel <pmenzel@molgen.mpg.de> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net> Cc: linux-acpi@vger.kernel.org Cc: Borislav Petkov <bp@alien8.de> Cc: Len Brown <lenb@kernel.org> Link: http://lkml.kernel.org/r/5c1272269a580660703ed2eccf44308e790c7a98.1492123841.git.jpoimboe@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 34a477e5297cbaa6ecc6e17c042a866e1cbe80d6 upstream.

On x86-32, with CONFIG_FIRMWARE and multiple CPUs, if you enable function
graph tracing and then suspend to RAM, it will triple fault and reboot when
it resumes.

The first fault happens when booting a secondary CPU:

startup_32_smp()
  load_ucode_ap()
    prepare_ftrace_return()
      ftrace_graph_is_dead()
        (accesses 'kill_ftrace_graph')

The early head_32.S code calls into load_ucode_ap(), which has an an
ftrace hook, so it calls prepare_ftrace_return(), which calls
ftrace_graph_is_dead(), which tries to access the global
'kill_ftrace_graph' variable with a virtual address, causing a fault
because the CPU is still in real mode.

The fix is to add a check in prepare_ftrace_return() to make sure it's
running in protected mode before continuing.  The check makes sure the
stack pointer is a virtual kernel address.  It's a bit of a hack, but
it's not very intrusive and it works well enough.

For reference, here are a few other (more difficult) ways this could
have potentially been fixed:

- Move startup_32_smp()'s call to load_ucode_ap() down to *after* paging
  is enabled.  (No idea what that would break.)

- Track down load_ucode_ap()'s entire callee tree and mark all the
  functions 'notrace'.  (Probably not realistic.)

- Pause graph tracing in ftrace_suspend_notifier_call() or bringup_cpu()
  or __cpu_up(), and ensure that the pause facility can be queried from
  real mode.

Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net>
Cc: linux-acpi@vger.kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/5c1272269a580660703ed2eccf44308e790c7a98.1492123841.git.jpoimboe@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>
x86/mce/AMD: Give a name to MCA bank 3 when accessed with legacy MSRs 2017-06-20T12:04:49+00:00 Yazen Ghannam yazen.ghannam@amd.com 2017-03-30T11:17:14+00:00 2c6896abfa6e0396b96e08c6edcd3a29f02f655b commit 29f72ce3e4d18066ec75c79c857bee0618a3504b upstream. MCA bank 3 is reserved on systems pre-Fam17h, so it didn't have a name. However, MCA bank 3 is defined on Fam17h systems and can be accessed using legacy MSRs. Without a name we get a stack trace on Fam17h systems when trying to register sysfs files for bank 3 on kernels that don't recognize Scalable MCA. Call MCA bank 3 "decode_unit" since this is what it represents on Fam17h. This will allow kernels without SMCA support to see this bank on Fam17h+ and prevent the stack trace. This will not affect older systems since this bank is reserved on them, i.e. it'll be ignored. Tested on AMD Fam15h and Fam17h systems. WARNING: CPU: 26 PID: 1 at lib/kobject.c:210 kobject_add_internal kobject: (ffff88085bb256c0): attempted to be registered with empty name! ... Call Trace: kobject_add_internal kobject_add kobject_create_and_add threshold_create_device threshold_init_device Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/1490102285-3659-1-git-send-email-Yazen.Ghannam@amd.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 29f72ce3e4d18066ec75c79c857bee0618a3504b upstream.

MCA bank 3 is reserved on systems pre-Fam17h, so it didn't have a name.
However, MCA bank 3 is defined on Fam17h systems and can be accessed
using legacy MSRs. Without a name we get a stack trace on Fam17h systems
when trying to register sysfs files for bank 3 on kernels that don't
recognize Scalable MCA.

Call MCA bank 3 "decode_unit" since this is what it represents on
Fam17h. This will allow kernels without SMCA support to see this bank on
Fam17h+ and prevent the stack trace. This will not affect older systems
since this bank is reserved on them, i.e. it'll be ignored.

Tested on AMD Fam15h and Fam17h systems.

  WARNING: CPU: 26 PID: 1 at lib/kobject.c:210 kobject_add_internal
  kobject: (ffff88085bb256c0): attempted to be registered with empty name!
  ...
  Call Trace:
   kobject_add_internal
   kobject_add
   kobject_create_and_add
   threshold_create_device
   threshold_init_device

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1490102285-3659-1-git-send-email-Yazen.Ghannam@amd.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>
ftrace/x86: Set ftrace_stub to weak to prevent gcc from using short jumps to it 2017-06-20T12:03:25+00:00 Steven Rostedt rostedt@goodmis.org 2016-05-17T03:00:35+00:00 fa51c867f4d587ff6d9b75ee9e9cb9e107165e7a commit 8329e818f14926a6040df86b2668568bde342ebf upstream. Matt Fleming reported seeing crashes when enabling and disabling function profiling which uses function graph tracer. Later Namhyung Kim hit a similar issue and he found that the issue was due to the jmp to ftrace_stub in ftrace_graph_call was only two bytes, and when it was changed to jump to the tracing code, it overwrote the ftrace_stub that was after it. Masami Hiramatsu bisected this down to a binutils change: 8dcea93252a9ea7dff57e85220a719e2a5e8ab41 is the first bad commit commit 8dcea93252a9ea7dff57e85220a719e2a5e8ab41 Author: H.J. Lu <hjl.tools@gmail.com> Date: Fri May 15 03:17:31 2015 -0700 Add -mshared option to x86 ELF assembler This patch adds -mshared option to x86 ELF assembler. By default, assembler will optimize out non-PLT relocations against defined non-weak global branch targets with default visibility. The -mshared option tells the assembler to generate code which may go into a shared library where all non-weak global branch targets with default visibility can be preempted. The resulting code is slightly bigger. This option only affects the handling of branch instructions. Declaring ftrace_stub as a weak call prevents gas from using two byte jumps to it, which would be converted to a jump to the function graph code. Link: http://lkml.kernel.org/r/20160516230035.1dbae571@gandalf.local.home Reported-by: Matt Fleming <matt@codeblueprint.co.uk> Reported-by: Namhyung Kim <namhyung@kernel.org> Tested-by: Matt Fleming <matt@codeblueprint.co.uk> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 8329e818f14926a6040df86b2668568bde342ebf upstream.

Matt Fleming reported seeing crashes when enabling and disabling
function profiling which uses function graph tracer. Later Namhyung Kim
hit a similar issue and he found that the issue was due to the jmp to
ftrace_stub in ftrace_graph_call was only two bytes, and when it was
changed to jump to the tracing code, it overwrote the ftrace_stub that
was after it.

Masami Hiramatsu bisected this down to a binutils change:

8dcea93252a9ea7dff57e85220a719e2a5e8ab41 is the first bad commit
commit 8dcea93252a9ea7dff57e85220a719e2a5e8ab41
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri May 15 03:17:31 2015 -0700

    Add -mshared option to x86 ELF assembler

    This patch adds -mshared option to x86 ELF assembler.  By default,
    assembler will optimize out non-PLT relocations against defined non-weak
    global branch targets with default visibility.  The -mshared option tells
    the assembler to generate code which may go into a shared library
    where all non-weak global branch targets with default visibility can
    be preempted.  The resulting code is slightly bigger.  This option
    only affects the handling of branch instructions.

Declaring ftrace_stub as a weak call prevents gas from using two byte
jumps to it, which would be converted to a jump to the function graph
code.

Link: http://lkml.kernel.org/r/20160516230035.1dbae571@gandalf.local.home

Reported-by: Matt Fleming <matt@codeblueprint.co.uk>
Reported-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
x86/cpu: Fix bootup crashes by sanitizing the argument of the 'clearcpuid=' command-line option 2017-06-07T22:46:55+00:00 Lukasz Odzioba lukasz.odzioba@intel.com 2016-12-28T13:55:40+00:00 0954c87c16bab5579b8c111887aafb6a75a17c0b commit dd853fd216d1485ed3045ff772079cc8689a9a4a upstream. A negative number can be specified in the cmdline which will be used as setup_clear_cpu_cap() argument. With that we can clear/set some bit in memory predceeding boot_cpu_data/cpu_caps_cleared which may cause kernel to misbehave. This patch adds lower bound check to setup_disablecpuid(). Boris Petkov reproduced a crash: [ 1.234575] BUG: unable to handle kernel paging request at ffffffff858bd540 [ 1.236535] IP: memcpy_erms+0x6/0x10 Signed-off-by: Lukasz Odzioba <lukasz.odzioba@intel.com> Acked-by: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: andi.kleen@intel.com Cc: bp@alien8.de Cc: dave.hansen@linux.intel.com Cc: luto@kernel.org Cc: slaoub@gmail.com Fixes: ac72e7888a61 ("x86: add generic clearcpuid=... option") Link: http://lkml.kernel.org/r/1482933340-11857-1-git-send-email-lukasz.odzioba@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit dd853fd216d1485ed3045ff772079cc8689a9a4a upstream.

A negative number can be specified in the cmdline which will be used as
setup_clear_cpu_cap() argument. With that we can clear/set some bit in
memory predceeding boot_cpu_data/cpu_caps_cleared which may cause kernel
to misbehave. This patch adds lower bound check to setup_disablecpuid().

Boris Petkov reproduced a crash:

  [    1.234575] BUG: unable to handle kernel paging request at ffffffff858bd540
  [    1.236535] IP: memcpy_erms+0x6/0x10

Signed-off-by: Lukasz Odzioba <lukasz.odzioba@intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andi.kleen@intel.com
Cc: bp@alien8.de
Cc: dave.hansen@linux.intel.com
Cc: luto@kernel.org
Cc: slaoub@gmail.com
Fixes: ac72e7888a61 ("x86: add generic clearcpuid=... option")
Link: http://lkml.kernel.org/r/1482933340-11857-1-git-send-email-lukasz.odzioba@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
ftrace/x86_32: Set ftrace_stub to weak to prevent gcc from using short jumps to it 2017-06-07T22:46:50+00:00 Steven Rostedt (Red Hat) rostedt@goodmis.org 2016-12-08T17:48:26+00:00 882f8f11c325c3873f41fe187bbf904f401dca76 commit 847fa1a6d3d00f3bdf68ef5fa4a786f644a0dd67 upstream. With new binutils, gcc may get smart with its optimization and change a jmp from a 5 byte jump to a 2 byte one even though it was jumping to a global function. But that global function existed within a 2 byte radius, and gcc was able to optimize it. Unfortunately, that jump was also being modified when function graph tracing begins. Since ftrace expected that jump to be 5 bytes, but it was only two, it overwrote code after the jump, causing a crash. This was fixed for x86_64 with commit 8329e818f149, with the same subject as this commit, but nothing was done for x86_32. Fixes: d61f82d06672 ("ftrace: use dynamic patching for updating mcount calls") Reported-by: Colin Ian King <colin.king@canonical.com> Tested-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 847fa1a6d3d00f3bdf68ef5fa4a786f644a0dd67 upstream.

With new binutils, gcc may get smart with its optimization and change a jmp
from a 5 byte jump to a 2 byte one even though it was jumping to a global
function. But that global function existed within a 2 byte radius, and gcc
was able to optimize it. Unfortunately, that jump was also being modified
when function graph tracing begins. Since ftrace expected that jump to be 5
bytes, but it was only two, it overwrote code after the jump, causing a
crash.

This was fixed for x86_64 with commit 8329e818f149, with the same subject as
this commit, but nothing was done for x86_32.

Fixes: d61f82d06672 ("ftrace: use dynamic patching for updating mcount calls")
Reported-by: Colin Ian King <colin.king@canonical.com>
Tested-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
x86/paravirt: Do not trace _paravirt_ident_*() functions 2017-02-06T22:32:51+00:00 Steven Rostedt rostedt@goodmis.org 2016-05-25T17:47:26+00:00 6523fa8c3451f903ee7feddfff18cd6763f804da commit 15301a570754c7af60335d094dd2d1808b0641a5 upstream. Łukasz Daniluk reported that on a RHEL kernel that his machine would lock up after enabling function tracer. I asked him to bisect the functions within available_filter_functions, which he did and it came down to three: _paravirt_nop(), _paravirt_ident_32() and _paravirt_ident_64() It was found that this is only an issue when noreplace-paravirt is added to the kernel command line. This means that those functions are most likely called within critical sections of the funtion tracer, and must not be traced. In newer kenels _paravirt_nop() is defined within gcc asm(), and is no longer an issue. But both _paravirt_ident_{32,64}() causes the following splat when they are traced: mm/pgtable-generic.c:33: bad pmd ffff8800d2435150(0000000001d00054) mm/pgtable-generic.c:33: bad pmd ffff8800d3624190(0000000001d00070) mm/pgtable-generic.c:33: bad pmd ffff8800d36a5110(0000000001d00054) mm/pgtable-generic.c:33: bad pmd ffff880118eb1450(0000000001d00054) NMI watchdog: BUG: soft lockup - CPU#2 stuck for 22s! [systemd-journal:469] Modules linked in: e1000e CPU: 2 PID: 469 Comm: systemd-journal Not tainted 4.6.0-rc4-test+ #513 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012 task: ffff880118f740c0 ti: ffff8800d4aec000 task.ti: ffff8800d4aec000 RIP: 0010:[<ffffffff81134148>] [<ffffffff81134148>] queued_spin_lock_slowpath+0x118/0x1a0 RSP: 0018:ffff8800d4aefb90 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88011eb16d40 RDX: ffffffff82485760 RSI: 000000001f288820 RDI: ffffea0000008030 RBP: ffff8800d4aefb90 R08: 00000000000c0000 R09: 0000000000000000 R10: ffffffff821c8e0e R11: 0000000000000000 R12: ffff880000200fb8 R13: 00007f7a4e3f7000 R14: ffffea000303f600 R15: ffff8800d4b562e0 FS: 00007f7a4e3d7840(0000) GS:ffff88011eb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7a4e3f7000 CR3: 00000000d3e71000 CR4: 00000000001406e0 Call Trace: _raw_spin_lock+0x27/0x30 handle_pte_fault+0x13db/0x16b0 handle_mm_fault+0x312/0x670 __do_page_fault+0x1b1/0x4e0 do_page_fault+0x22/0x30 page_fault+0x28/0x30 __vfs_read+0x28/0xe0 vfs_read+0x86/0x130 SyS_read+0x46/0xa0 entry_SYSCALL_64_fastpath+0x1e/0xa8 Code: 12 48 c1 ea 0c 83 e8 01 83 e2 30 48 98 48 81 c2 40 6d 01 00 48 03 14 c5 80 6a 5d 82 48 89 0a 8b 41 08 85 c0 75 09 f3 90 8b 41 08 <85> c0 74 f7 4c 8b 09 4d 85 c9 74 08 41 0f 18 09 eb 02 f3 90 8b Reported-by: Łukasz Daniluk <lukasz.daniluk@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 15301a570754c7af60335d094dd2d1808b0641a5 upstream.

Łukasz Daniluk reported that on a RHEL kernel that his machine would lock up
after enabling function tracer. I asked him to bisect the functions within
available_filter_functions, which he did and it came down to three:

  _paravirt_nop(), _paravirt_ident_32() and _paravirt_ident_64()

It was found that this is only an issue when noreplace-paravirt is added
to the kernel command line.

This means that those functions are most likely called within critical
sections of the funtion tracer, and must not be traced.

In newer kenels _paravirt_nop() is defined within gcc asm(), and is no
longer an issue.  But both _paravirt_ident_{32,64}() causes the
following splat when they are traced:

 mm/pgtable-generic.c:33: bad pmd ffff8800d2435150(0000000001d00054)
 mm/pgtable-generic.c:33: bad pmd ffff8800d3624190(0000000001d00070)
 mm/pgtable-generic.c:33: bad pmd ffff8800d36a5110(0000000001d00054)
 mm/pgtable-generic.c:33: bad pmd ffff880118eb1450(0000000001d00054)
 NMI watchdog: BUG: soft lockup - CPU#2 stuck for 22s! [systemd-journal:469]
 Modules linked in: e1000e
 CPU: 2 PID: 469 Comm: systemd-journal Not tainted 4.6.0-rc4-test+ #513
 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012
 task: ffff880118f740c0 ti: ffff8800d4aec000 task.ti: ffff8800d4aec000
 RIP: 0010:[<ffffffff81134148>]  [<ffffffff81134148>] queued_spin_lock_slowpath+0x118/0x1a0
 RSP: 0018:ffff8800d4aefb90  EFLAGS: 00000246
 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88011eb16d40
 RDX: ffffffff82485760 RSI: 000000001f288820 RDI: ffffea0000008030
 RBP: ffff8800d4aefb90 R08: 00000000000c0000 R09: 0000000000000000
 R10: ffffffff821c8e0e R11: 0000000000000000 R12: ffff880000200fb8
 R13: 00007f7a4e3f7000 R14: ffffea000303f600 R15: ffff8800d4b562e0
 FS:  00007f7a4e3d7840(0000) GS:ffff88011eb00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007f7a4e3f7000 CR3: 00000000d3e71000 CR4: 00000000001406e0
 Call Trace:
   _raw_spin_lock+0x27/0x30
   handle_pte_fault+0x13db/0x16b0
   handle_mm_fault+0x312/0x670
   __do_page_fault+0x1b1/0x4e0
   do_page_fault+0x22/0x30
   page_fault+0x28/0x30
   __vfs_read+0x28/0xe0
   vfs_read+0x86/0x130
   SyS_read+0x46/0xa0
   entry_SYSCALL_64_fastpath+0x1e/0xa8
 Code: 12 48 c1 ea 0c 83 e8 01 83 e2 30 48 98 48 81 c2 40 6d 01 00 48 03 14 c5 80 6a 5d 82 48 89 0a 8b 41 08 85 c0 75 09 f3 90 8b 41 08 <85> c0 74 f7 4c 8b 09 4d 85 c9 74 08 41 0f 18 09 eb 02 f3 90 8b

Reported-by: Łukasz Daniluk <lukasz.daniluk@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
x86/apic: Do not init irq remapping if ioapic is disabled 2017-02-06T22:32:51+00:00 Wanpeng Li wanpeng.li@hotmail.com 2016-08-23T12:07:19+00:00 928a27752e51670cd282848e7cde8e2e1ac4ec19 commit 2e63ad4bd5dd583871e6602f9d398b9322d358d9 upstream. native_smp_prepare_cpus -> default_setup_apic_routing -> enable_IR_x2apic -> irq_remapping_prepare -> intel_prepare_irq_remapping -> intel_setup_irq_remapping So IR table is setup even if "noapic" boot parameter is added. As a result we crash later when the interrupt affinity is set due to a half initialized remapping infrastructure. Prevent remap initialization when IOAPIC is disabled. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Joerg Roedel <joro@8bytes.org> Link: http://lkml.kernel.org/r/1471954039-3942-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Willy Tarreau <w@1wt.eu> 
commit 2e63ad4bd5dd583871e6602f9d398b9322d358d9 upstream.

native_smp_prepare_cpus
  -> default_setup_apic_routing
    -> enable_IR_x2apic
      -> irq_remapping_prepare
        -> intel_prepare_irq_remapping
          -> intel_setup_irq_remapping

So IR table is setup even if "noapic" boot parameter is added. As a result we
crash later when the interrupt affinity is set due to a half initialized
remapping infrastructure.

Prevent remap initialization when IOAPIC is disabled.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Joerg Roedel <joro@8bytes.org>
Link: http://lkml.kernel.org/r/1471954039-3942-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>