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2019-06-09x86/kprobes: Set instruction page as executableNadav Amit
[ Upstream commit 7298e24f904224fa79eb8fd7e0fbd78950ccf2db ] Set the page as executable after allocation. This patch is a preparatory patch for a following patch that makes module allocated pages non-executable. While at it, do some small cleanup of what appears to be unnecessary masking. Signed-off-by: Nadav Amit <namit@vmware.com> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <akpm@linux-foundation.org> Cc: <ard.biesheuvel@linaro.org> Cc: <deneen.t.dock@intel.com> Cc: <kernel-hardening@lists.openwall.com> Cc: <kristen@linux.intel.com> Cc: <linux_dti@icloud.com> Cc: <will.deacon@arm.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190426001143.4983-11-namit@vmware.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-05-16x86/kprobes: Avoid kretprobe recursion bugMasami Hiramatsu
[ Upstream commit b191fa96ea6dc00d331dcc28c1f7db5e075693a0 ] Avoid kretprobe recursion loop bg by setting a dummy kprobes to current_kprobe per-CPU variable. This bug has been introduced with the asm-coded trampoline code, since previously it used another kprobe for hooking the function return placeholder (which only has a nop) and trampoline handler was called from that kprobe. This revives the old lost kprobe again. With this fix, we don't see deadlock anymore. And you can see that all inner-called kretprobe are skipped. event_1 235 0 event_2 19375 19612 The 1st column is recorded count and the 2nd is missed count. Above shows (event_1 rec) + (event_2 rec) ~= (event_2 missed) (some difference are here because the counter is racy) Reported-by: Andrea Righi <righi.andrea@gmail.com> Tested-by: Andrea Righi <righi.andrea@gmail.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Fixes: c9becf58d935 ("[PATCH] kretprobe: kretprobe-booster") Link: http://lkml.kernel.org/r/155094064889.6137.972160690963039.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
2019-04-27x86/kprobes: Verify stack frame on kretprobeMasami Hiramatsu
commit 3ff9c075cc767b3060bdac12da72fc94dd7da1b8 upstream. Verify the stack frame pointer on kretprobe trampoline handler, If the stack frame pointer does not match, it skips the wrong entry and tries to find correct one. This can happen if user puts the kretprobe on the function which can be used in the path of ftrace user-function call. Such functions should not be probed, so this adds a warning message that reports which function should be blacklisted. Tested-by: Andrea Righi <righi.andrea@gmail.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/155094059185.6137.15527904013362842072.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-23x86/kprobes: Prohibit probing on optprobe template codeMasami Hiramatsu
commit 0192e6535ebe9af68614198ced4fd6d37b778ebf upstream. Prohibit probing on optprobe template code, since it is not a code but a template instruction sequence. If we modify this template, copied template must be broken. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andrea Righi <righi.andrea@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Fixes: 9326638cbee2 ("kprobes, x86: Use NOKPROBE_SYMBOL() instead of __kprobes annotation") Link: http://lkml.kernel.org/r/154998787911.31052.15274376330136234452.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-13kprobes/x86: Fix instruction patching corruption when copying more than one ↵Masami Hiramatsu
RIP-relative instruction commit 43a1b0cb4cd6dbfd3cd9c10da663368394d299d8 upstream. After copy_optimized_instructions() copies several instructions to the working buffer it tries to fix up the real RIP address, but it adjusts the RIP-relative instruction with an incorrect RIP address for the 2nd and subsequent instructions due to a bug in the logic. This will break the kernel pretty badly (with likely outcomes such as a kernel freeze, a crash, or worse) because probed instructions can refer to the wrong data. For example putting kprobes on cpumask_next() typically hits this bug. cpumask_next() is normally like below if CONFIG_CPUMASK_OFFSTACK=y (in this case nr_cpumask_bits is an alias of nr_cpu_ids): <cpumask_next>: 48 89 f0 mov %rsi,%rax 8b 35 7b fb e2 00 mov 0xe2fb7b(%rip),%esi # ffffffff82db9e64 <nr_cpu_ids> 55 push %rbp ... If we put a kprobe on it and it gets jump-optimized, it gets patched by the kprobes code like this: <cpumask_next>: e9 95 7d 07 1e jmpq 0xffffffffa000207a 7b fb jnp 0xffffffff81f8a2e2 <cpumask_next+2> e2 00 loop 0xffffffff81f8a2e9 <cpumask_next+9> 55 push %rbp This shows that the first two MOV instructions were copied to a trampoline buffer at 0xffffffffa000207a. Here is the disassembled result of the trampoline, skipping the optprobe template instructions: # Dump of assembly code from 0xffffffffa000207a to 0xffffffffa00020ea: 54 push %rsp ... 48 83 c4 08 add $0x8,%rsp 9d popfq 48 89 f0 mov %rsi,%rax 8b 35 82 7d db e2 mov -0x1d24827e(%rip),%esi # 0xffffffff82db9e67 <nr_cpu_ids+3> This dump shows that the second MOV accesses *(nr_cpu_ids+3) instead of the original *nr_cpu_ids. This leads to a kernel freeze because cpumask_next() always returns 0 and for_each_cpu() never ends. Fix this by adding 'len' correctly to the real RIP address while copying. [ mingo: Improved the changelog. ] Reported-by: Michael Rodin <michael@rodin.online> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org # v4.15+ Fixes: 63fef14fc98a ("kprobes/x86: Make insn buffer always ROX and use text_poke()") Link: http://lkml.kernel.org/r/153504457253.22602.1314289671019919596.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-13kprobes/x86: Use preempt_enable() in optimized_callback()Masami Hiramatsu
commit 2e62024c265aa69315ed02835623740030435380 upstream. The following commit: a19b2e3d7839 ("kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobes”) removed local_irq_save/restore() from optimized_callback(), the handler might be interrupted by the rescheduling interrupt and might be rescheduled - so we must not use the preempt_enable_no_resched() macro. Use preempt_enable() instead, to not lose preemption events. [ mingo: Improved the changelog. ] Reported-by: Nadav Amit <namit@vmware.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@vger.kernel.org> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dwmw@amazon.co.uk Fixes: a19b2e3d7839 ("kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobes”) Link: http://lkml.kernel.org/r/154002887331.7627.10194920925792947001.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-21kprobes/x86: Fix %p uses in error messagesMasami Hiramatsu
Remove all %p uses in error messages in kprobes/x86. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: David Howells <dhowells@redhat.com> Cc: David S . Miller <davem@davemloft.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Jon Medhurst <tixy@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Richter <tmricht@linux.ibm.com> Cc: Tobin C . Harding <me@tobin.cc> Cc: Will Deacon <will.deacon@arm.com> Cc: acme@kernel.org Cc: akpm@linux-foundation.org Cc: brueckner@linux.vnet.ibm.com Cc: linux-arch@vger.kernel.org Cc: rostedt@goodmis.org Cc: schwidefsky@de.ibm.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/lkml/152491902310.9916.13355297638917767319.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21kprobes/x86: Do not disable preempt on int3 pathMasami Hiramatsu
Since int3 and debug exception(for singlestep) are run with IRQ disabled and while running single stepping we drop IF from regs->flags, that path must not be preemptible. So we can remove the preempt disable/enable calls from that path. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Link: https://lore.kernel.org/lkml/152942497779.15209.2879580696589868291.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21bpf/error-inject/kprobes: Clear current_kprobe and enable preempt in kprobeMasami Hiramatsu
Clear current_kprobe and enable preemption in kprobe even if pre_handler returns !0. This simplifies function override using kprobes. Jprobe used to require to keep the preemption disabled and keep current_kprobe until it returned to original function entry. For this reason kprobe_int3_handler() and similar arch dependent kprobe handers checks pre_handler result and exit without enabling preemption if the result is !0. After removing the jprobe, Kprobes does not need to keep preempt disabled even if user handler returns !0 anymore. But since the function override handler in error-inject and bpf is also returns !0 if it overrides a function, to balancing the preempt count, it enables preemption and reset current kprobe by itself. That is a bad design that is very buggy. This fixes such unbalanced preempt-count and current_kprobes setting in kprobes, bpf and error-inject. Note: for powerpc and x86, this removes all preempt_disable from kprobe_ftrace_handler because ftrace callbacks are called under preempt disabled. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: James Hogan <jhogan@kernel.org> Cc: Josef Bacik <jbacik@fb.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: linux-arch@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-ia64@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-s390@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: linuxppc-dev@lists.ozlabs.org Cc: sparclinux@vger.kernel.org Link: https://lore.kernel.org/lkml/152942494574.15209.12323837825873032258.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21kprobes/x86: Don't call the ->break_handler() in x86 kprobesMasami Hiramatsu
Don't call the ->break_handler() and remove break_handler related code from x86 since that was only used by jprobe which got removed. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arch@vger.kernel.org Link: https://lore.kernel.org/lkml/152942465549.15209.15889693025972771135.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21kprobes/x86: Remove jprobe implementationMasami Hiramatsu
Remove arch dependent setjump/longjump functions and unused fields in kprobe_ctlblk for jprobes from arch/x86. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arch@vger.kernel.org Link: https://lore.kernel.org/lkml/152942433578.15209.14034551799624757792.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-05-13kprobes/x86: Prohibit probing on exception masking instructionsMasami Hiramatsu
Since MOV SS and POP SS instructions will delay the exceptions until the next instruction is executed, single-stepping on it by kprobes must be prohibited. However, kprobes usually executes those instructions directly on trampoline buffer (a.k.a. kprobe-booster), except for the kprobes which has post_handler. Thus if kprobe user probes MOV SS with post_handler, it will do single-stepping on the MOV SS. This means it is safe that if it is used via ftrace or perf/bpf since those don't use the post_handler. Anyway, since the stack switching is a rare case, it is safer just rejecting kprobes on such instructions. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Cc: Francis Deslauriers <francis.deslauriers@efficios.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Yonghong Song <yhs@fb.com> Cc: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "David S . Miller" <davem@davemloft.net> Link: https://lkml.kernel.org/r/152587069574.17316.3311695234863248641.stgit@devbox
2018-03-09x86/kprobes: Fix kernel crash when probing .entry_trampoline codeFrancis Deslauriers
Disable the kprobe probing of the entry trampoline: .entry_trampoline is a code area that is used to ensure page table isolation between userspace and kernelspace. At the beginning of the execution of the trampoline, we load the kernel's CR3 register. This has the effect of enabling the translation of the kernel virtual addresses to physical addresses. Before this happens most kernel addresses can not be translated because the running process' CR3 is still used. If a kprobe is placed on the trampoline code before that change of the CR3 register happens the kernel crashes because int3 handling pages are not accessible. To fix this, add the .entry_trampoline section to the kprobe blacklist to prohibit the probing of code before all the kernel pages are accessible. Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: mathieu.desnoyers@efficios.com Cc: mhiramat@kernel.org Link: http://lkml.kernel.org/r/1520565492-4637-2-git-send-email-francis.deslauriers@efficios.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-21Merge branch 'x86-pti-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 pti fixes from Thomas Gleixner: "A small set of fixes for the meltdown/spectre mitigations: - Make kprobes aware of retpolines to prevent probes in the retpoline thunks. - Make the machine check exception speculation protected. MCE used to issue an indirect call directly from the ASM entry code. Convert that to a direct call into a C-function and issue the indirect call from there so the compiler can add the retpoline protection, - Make the vmexit_fill_RSB() assembly less stupid - Fix a typo in the PTI documentation" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/retpoline: Optimize inline assembler for vmexit_fill_RSB x86/pti: Document fix wrong index kprobes/x86: Disable optimizing on the function jumps to indirect thunk kprobes/x86: Blacklist indirect thunk functions for kprobes retpoline: Introduce start/end markers of indirect thunk x86/mce: Make machine check speculation protected
2018-01-19kprobes/x86: Disable optimizing on the function jumps to indirect thunkMasami Hiramatsu
Since indirect jump instructions will be replaced by jump to __x86_indirect_thunk_*, those jmp instruction must be treated as an indirect jump. Since optprobe prohibits to optimize probes in the function which uses an indirect jump, it also needs to find out the function which jump to __x86_indirect_thunk_* and disable optimization. Add a check that the jump target address is between the __indirect_thunk_start/end when optimizing kprobe. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: David Woodhouse <dwmw@amazon.co.uk> Cc: Andi Kleen <ak@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/151629212062.10241.6991266100233002273.stgit@devbox
2017-11-07Merge branch 'linus' into perf/core, to fix conflictsIngo Molnar
Conflicts: tools/perf/arch/arm/annotate/instructions.c tools/perf/arch/arm64/annotate/instructions.c tools/perf/arch/powerpc/annotate/instructions.c tools/perf/arch/s390/annotate/instructions.c tools/perf/arch/x86/tests/intel-cqm.c tools/perf/ui/tui/progress.c tools/perf/util/zlib.c Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-20Merge branch 'perf/urgent' into perf/core, to pick up fixesIngo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-03kprobes/x86: Remove IRQ disabling from jprobe handlersMasami Hiramatsu
Jprobes actually don't need to disable IRQs while calling handlers, because of how we specify the kernel interface in Documentation/kprobes.txt: ----- Probe handlers are run with preemption disabled. Depending on the architecture and optimization state, handlers may also run with interrupts disabled (e.g., kretprobe handlers and optimized kprobe handlers run without interrupt disabled on x86/x86-64). ----- So let's remove IRQ disabling from jprobes too. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexei Starovoitov <ast@fb.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150701508194.32266.14458959863314097305.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-03kprobes/x86: Set up frame pointer in kprobe trampolineJosh Poimboeuf
Richard Weinberger saw an unwinder warning when running bcc's opensnoop: WARNING: kernel stack frame pointer at ffff99ef4076bea0 in opensnoop:2008 has bad value 0000000000000008 unwind stack type:0 next_sp: (null) mask:0x2 graph_idx:0 ... ffff99ef4076be88: ffff99ef4076bea0 (0xffff99ef4076bea0) ffff99ef4076be90: ffffffffac442721 (optimized_callback +0x81/0x90) ... A lockdep stack trace was initiated from inside a kprobe handler, when the unwinder noticed a bad frame pointer on the stack. The bad frame pointer is related to the fact that the kprobe optprobe trampoline doesn't save the frame pointer before calling into optimized_callback(). Reported-and-tested-by: Richard Weinberger <richard@sigma-star.at> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S . Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/7aef2f8ecd75c2f505ef9b80490412262cf4a44c.1507038547.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-28kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobesMasami Hiramatsu
Kkprobes don't need to disable IRQs if they are called from the ftrace/jump trampoline code, because Documentation/kprobes.txt says: ----- Probe handlers are run with preemption disabled. Depending on the architecture and optimization state, handlers may also run with interrupts disabled (e.g., kretprobe handlers and optimized kprobe handlers run without interrupt disabled on x86/x86-64). ----- So let's remove IRQ disabling from those handlers. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexei Starovoitov <ast@fb.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150581534039.32348.11331736206004264553.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-28kprobes/x86: Disable preemption in ftrace-based jprobesMasami Hiramatsu
Disable preemption in ftrace-based jprobe handlers as described in Documentation/kprobes.txt: "Probe handlers are run with preemption disabled." This will fix jprobes behavior when CONFIG_PREEMPT=y. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexei Starovoitov <ast@fb.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150581530024.32348.9863783558598926771.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-28kprobes/x86: Disable preemption in optprobeMasami Hiramatsu
Disable preemption in optprobe handler as described in Documentation/kprobes.txt, which says: "Probe handlers are run with preemption disabled." Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexei Starovoitov <ast@fb.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150581525942.32348.6359217983269060829.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-28kprobes/x86: Move the get_kprobe_ctlblk() into irq-disabled blockMasami Hiramatsu
Since get_kprobe_ctlblk() accesses per-cpu variables which calls smp_processor_id(), it must be called under preempt-disabled or irq-disabled. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexei Starovoitov <ast@fb.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150581517952.32348.2655896843219158446.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-28kprobes/x86: Remove addressof() operatorsMasami Hiramatsu
The following commit: 54a7d50b9205 ("x86: mark kprobe templates as character arrays, not single characters") changed optprobe_template_* to arrays, so we can remove the addressof() operators from those symbols. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S . Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150304469798.17009.15886717935027472863.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-28kprobes/x86: Make insn buffer always ROX and use text_poke()Masami Hiramatsu
Make insn buffer always ROX and use text_poke() to write the copied instructions instead of set_memory_*(). This makes instruction buffer stronger against other kernel subsystems because there is no window time to modify the buffer. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S . Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150304463032.17009.14195368040691676813.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-10kprobes/x86: Do not jump-optimize kprobes on irq entry codeMasami Hiramatsu
Since the kernel segment registers are not prepared at the entry of irq-entry code, if a kprobe on such code is jump-optimized, accessing per-CPU variables may cause a kernel panic. However, if the kprobe is not optimized, it triggers an int3 exception and sets segment registers correctly. With this patch we check the probe-address and if it is in the irq-entry code, it prohibits optimizing such kprobes. This means we can continue probing such interrupt handlers by kprobes but it is not optimized anymore. Reported-by: Francis Deslauriers <francis.deslauriers@efficios.com> Tested-by: Francis Deslauriers <francis.deslauriers@efficios.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Chris Zankel <chris@zankel.net> Cc: David S . Miller <davem@davemloft.net> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: linux-arch@vger.kernel.org Cc: linux-cris-kernel@axis.com Cc: mathieu.desnoyers@efficios.com Link: http://lkml.kernel.org/r/150172795654.27216.9824039077047777477.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-24kprobes/x86: Release insn_slot in failure pathMasami Hiramatsu
The following commit: 003002e04ed3 ("kprobes: Fix arch_prepare_kprobe to handle copy insn failures") returns an error if the copying of the instruction, but does not release the allocated insn_slot. Clean up correctly. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S . Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 003002e04ed3 ("kprobes: Fix arch_prepare_kprobe to handle copy insn failures") Link: http://lkml.kernel.org/r/150064834183.6172.11694375818447664416.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-06-30objtool, x86: Add several functions and files to the objtool whitelistJosh Poimboeuf
In preparation for an objtool rewrite which will have broader checks, whitelist functions and files which cause problems because they do unusual things with the stack. These whitelists serve as a TODO list for which functions and files don't yet have undwarf unwinder coverage. Eventually most of the whitelists can be removed in favor of manual CFI hint annotations or objtool improvements. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/7f934a5d707a574bda33ea282e9478e627fb1829.1498659915.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-26kprobes/x86: Fix to set RWX bits correctly before releasing trampolineMasami Hiramatsu
Fix kprobes to set(recover) RWX bits correctly on trampoline buffer before releasing it. Releasing readonly page to module_memfree() crash the kernel. Without this fix, if kprobes user register a bunch of kprobes in function body (since kprobes on function entry usually use ftrace) and unregister it, kernel hits a BUG and crash. Link: http://lkml.kernel.org/r/149570868652.3518.14120169373590420503.stgit@devbox Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Fixes: d0381c81c2f7 ("kprobes/x86: Set kprobes pages read-only") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-05-08treewide: decouple cacheflush.h and set_memory.hLaura Abbott
Now that all call sites, completely decouple cacheflush.h and set_memory.h [sfr@canb.auug.org.au: kprobes/x86: merge fix for set_memory.h decoupling] Link: http://lkml.kernel.org/r/20170418180903.10300fd3@canb.auug.org.au Link: http://lkml.kernel.org/r/1488920133-27229-17-git-send-email-labbott@redhat.com Signed-off-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-12kprobes/x86: Consolidate insn decoder users for copying codeMasami Hiramatsu
Consolidate x86 instruction decoder users on the path of copying original code for kprobes. Kprobes decodes the same instruction a maximum of 3 times when preparing the instruction buffer: - The first time for getting the length of the instruction, - the 2nd for adjusting displacement, - and the 3rd for checking whether the instruction is boostable or not. For each time, the actual decoding target address is slightly different (1st is original address or recovered instruction buffer, 2nd and 3rd are pointing to the copied buffer), but all have the same instruction. Thus, this patch also changes the target address to the copied buffer at first and reuses the decoded "insn" for displacement adjusting and checking boostability. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David S . Miller <davem@davemloft.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ye Xiaolong <xiaolong.ye@intel.com> Link: http://lkml.kernel.org/r/149076389643.22469.13151892839998777373.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-12kprobes/x86: Use probe_kernel_read() instead of memcpy()Masami Hiramatsu
Use probe_kernel_read() for avoiding unexpected faults while copying kernel text in __recover_probed_insn(), __recover_optprobed_insn() and __copy_instruction(). Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David S . Miller <davem@davemloft.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ye Xiaolong <xiaolong.ye@intel.com> Link: http://lkml.kernel.org/r/149076382624.22469.10091613887942958518.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-12kprobes/x86: Set kprobes pages read-onlyMasami Hiramatsu
Set the pages which is used for kprobes' singlestep buffer and optprobe's trampoline instruction buffer to readonly. This can prevent unexpected (or unintended) instruction modification. This also passes rodata_test as below. Without this patch, rodata_test shows a warning: WARNING: CPU: 0 PID: 1 at arch/x86/mm/dump_pagetables.c:235 note_page+0x7a9/0xa20 x86/mm: Found insecure W+X mapping at address ffffffffa0000000/0xffffffffa0000000 With this fix, no W+X pages are found: x86/mm: Checked W+X mappings: passed, no W+X pages found. rodata_test: all tests were successful Reported-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David S . Miller <davem@davemloft.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ye Xiaolong <xiaolong.ye@intel.com> Link: http://lkml.kernel.org/r/149076375592.22469.14174394514338612247.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-12kprobes/x86: Make boostable flag booleanMasami Hiramatsu
Make arch_specific_insn.boostable to boolean, since it has only 2 states, boostable or not. So it is better to use boolean from the viewpoint of code readability. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David S . Miller <davem@davemloft.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ye Xiaolong <xiaolong.ye@intel.com> Link: http://lkml.kernel.org/r/149076368566.22469.6322906866458231844.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-12kprobes/x86: Do not modify singlestep buffer while resumingMasami Hiramatsu
Do not modify singlestep execution buffer (kprobe.ainsn.insn) while resuming from single-stepping, instead, modifies the buffer to add a jump back instruction at preparing buffer. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David S . Miller <davem@davemloft.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ye Xiaolong <xiaolong.ye@intel.com> Link: http://lkml.kernel.org/r/149076361560.22469.1610155860343077495.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-12kprobes/x86: Use instruction decoder for boosterMasami Hiramatsu
Use x86 instruction decoder for checking whether the probed instruction is able to boost or not, instead of hand-written code. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David S . Miller <davem@davemloft.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ye Xiaolong <xiaolong.ye@intel.com> Link: http://lkml.kernel.org/r/149076354563.22469.13379472209338986858.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-12kprobes/x86: Fix the description of __copy_instruction()Masami Hiramatsu
Fix the description comment of __copy_instruction() function since it has already been changed to return the length of the copied instruction. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David S . Miller <davem@davemloft.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ye Xiaolong <xiaolong.ye@intel.com> Link: http://lkml.kernel.org/r/149076347582.22469.3775133607244923462.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-12kprobes/x86: Fix kprobe-booster not to boost far call instructionsMasami Hiramatsu
Fix the kprobe-booster not to boost far call instruction, because a call may store the address in the single-step execution buffer to the stack, which should be modified after single stepping. Currently, this instruction will be filtered as not boostable in resume_execution(), so this is not a critical issue. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David S . Miller <davem@davemloft.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ye Xiaolong <xiaolong.ye@intel.com> Link: http://lkml.kernel.org/r/149076340615.22469.14066273186134229909.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-07Merge tag 'perf-core-for-mingo-4.11-20170306' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo: New features: - Allow sorting by symbol_size in 'perf report' and 'perf top' (Charles Baylis) E.g.: # perf report -s symbol_size,symbol Samples: 9K of event 'cycles:k', Event count (approx.): 2870461623 Overhead Symbol size Symbol 14.55% 326 [k] flush_tlb_mm_range 7.20% 1045 [k] filemap_map_pages 5.82% 124 [k] vma_interval_tree_insert 5.18% 2430 [k] unmap_page_range 2.57% 571 [k] vma_interval_tree_remove 1.94% 494 [k] page_add_file_rmap 1.82% 740 [k] page_remove_rmap 1.66% 1017 [k] release_pages 1.57% 1636 [k] update_blocked_averages 1.57% 76 [k] unlock_page - Add support for -p/--pid, -a/--all-cpus and -C/--cpu in 'perf ftrace' (Namhyung Kim) Change in behaviour: - Make system wide (-a) the default option if no target was specified and one of following conditions is met: - No workload specified (current behaviour) - A workload is specified but all requested events are system wide ones, like uncore ones. (Jiri Olsa) Fixes: - Add missing initialization to the instruction decoder used in the intel PT/BTS code, which was causing lots of failures in 'perf test', looking for a value when there was none (Adrian Hunter) Infrastructure changes: - Add arch code needed to adopt the kernel's refcount_t to aid in catching bugs when using atomic_t as a reference counter, basically cmpxchg related functions (Arnaldo Carvalho de Melo) - Convert the code using atomic_t as reference counts to refcount_t (Elena Rashetova) - Add feature test for sched_getcpu() to more easily check for its presence in the many libc implementations and accross different versions of such C libraries (Arnaldo Carvalho de Melo) - Issue a HW watchdog disable hint in 'perf stat' for when some of the requested events can't get counted because a PMU counter is taken by that watchdog (Borislav Petkov). - Add mapping for Intel's KnightsMill PMU events (Karol Wachowski) Documentation changes: - Clarify the term 'convergence' in: perf bench numa numa-mem -h --show_convergence (Jiri Olsa) Kernel code changes: - Ensure probe location is at function entry in kretprobes (Naveen N. Rao) - Allow return probes with offsets and absolute addresses (Naveen N. Rao) Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar
<linux/sched/debug.h> We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/debug.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-01kprobes/x86: Fix kernel panic when certain exception-handling addresses are ↵Masami Hiramatsu
probed Fix to the exception table entry check by using probed address instead of the address of copied instruction. This bug may cause unexpected kernel panic if user probe an address where an exception can happen which should be fixup by __ex_table (e.g. copy_from_user.) Unless user puts a kprobe on such address, this doesn't cause any problem. This bug has been introduced years ago, by commit: 464846888d9a ("x86/kprobes: Fix a bug which can modify kernel code permanently"). Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 464846888d9a ("x86/kprobes: Fix a bug which can modify kernel code permanently") Link: http://lkml.kernel.org/r/148829899399.28855.12581062400757221722.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-06kprobes/x86: Use hlist_for_each_entry() instead of hlist_for_each_entry_safe()Masami Hiramatsu
Use hlist_for_each_entry() in the first loop in the kretprobe trampoline_handler() function, because it doesn't change the hlist. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/148637493309.19245.12546866092052500584.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-24Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds
This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-16kprobes: Unpoison stack in jprobe_return() for KASANDmitry Vyukov
I observed false KSAN positives in the sctp code, when sctp uses jprobe_return() in jsctp_sf_eat_sack(). The stray 0xf4 in shadow memory are stack redzones: [ ] ================================================================== [ ] BUG: KASAN: stack-out-of-bounds in memcmp+0xe9/0x150 at addr ffff88005e48f480 [ ] Read of size 1 by task syz-executor/18535 [ ] page:ffffea00017923c0 count:0 mapcount:0 mapping: (null) index:0x0 [ ] flags: 0x1fffc0000000000() [ ] page dumped because: kasan: bad access detected [ ] CPU: 1 PID: 18535 Comm: syz-executor Not tainted 4.8.0+ #28 [ ] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ ] ffff88005e48f2d0 ffffffff82d2b849 ffffffff0bc91e90 fffffbfff10971e8 [ ] ffffed000bc91e90 ffffed000bc91e90 0000000000000001 0000000000000000 [ ] ffff88005e48f480 ffff88005e48f350 ffffffff817d3169 ffff88005e48f370 [ ] Call Trace: [ ] [<ffffffff82d2b849>] dump_stack+0x12e/0x185 [ ] [<ffffffff817d3169>] kasan_report+0x489/0x4b0 [ ] [<ffffffff817d31a9>] __asan_report_load1_noabort+0x19/0x20 [ ] [<ffffffff82d49529>] memcmp+0xe9/0x150 [ ] [<ffffffff82df7486>] depot_save_stack+0x176/0x5c0 [ ] [<ffffffff817d2031>] save_stack+0xb1/0xd0 [ ] [<ffffffff817d27f2>] kasan_slab_free+0x72/0xc0 [ ] [<ffffffff817d05b8>] kfree+0xc8/0x2a0 [ ] [<ffffffff85b03f19>] skb_free_head+0x79/0xb0 [ ] [<ffffffff85b0900a>] skb_release_data+0x37a/0x420 [ ] [<ffffffff85b090ff>] skb_release_all+0x4f/0x60 [ ] [<ffffffff85b11348>] consume_skb+0x138/0x370 [ ] [<ffffffff8676ad7b>] sctp_chunk_put+0xcb/0x180 [ ] [<ffffffff8676ae88>] sctp_chunk_free+0x58/0x70 [ ] [<ffffffff8677fa5f>] sctp_inq_pop+0x68f/0xef0 [ ] [<ffffffff8675ee36>] sctp_assoc_bh_rcv+0xd6/0x4b0 [ ] [<ffffffff8677f2c1>] sctp_inq_push+0x131/0x190 [ ] [<ffffffff867bad69>] sctp_backlog_rcv+0xe9/0xa20 [ ... ] [ ] Memory state around the buggy address: [ ] ffff88005e48f380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ ] ffff88005e48f400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ ] >ffff88005e48f480: f4 f4 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ ] ^ [ ] ffff88005e48f500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ ] ffff88005e48f580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ ] ================================================================== KASAN stack instrumentation poisons stack redzones on function entry and unpoisons them on function exit. If a function exits abnormally (e.g. with a longjmp like jprobe_return()), stack redzones are left poisoned. Later this leads to random KASAN false reports. Unpoison stack redzones in the frames we are going to jump over before doing actual longjmp in jprobe_return(). Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Alexander Potapenko <glider@google.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: kasan-dev@googlegroups.com Cc: surovegin@google.com Cc: rostedt@goodmis.org Link: http://lkml.kernel.org/r/1476454043-101898-1-git-send-email-dvyukov@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-10-16kprobes: Avoid false KASAN reports during stack copyDmitry Vyukov
Kprobes save and restore raw stack chunks with memcpy(). With KASAN these chunks can contain poisoned stack redzones, as the result memcpy() interceptor produces false stack out-of-bounds reports. Use __memcpy() instead of memcpy() for stack copying. __memcpy() is not instrumented by KASAN and does not lead to the false reports. Currently there is a spew of KASAN reports during boot if CONFIG_KPROBES_SANITY_TEST is enabled: [ ] Kprobe smoke test: started [ ] ================================================================== [ ] BUG: KASAN: stack-out-of-bounds in setjmp_pre_handler+0x17c/0x280 at addr ffff88085259fba8 [ ] Read of size 64 by task swapper/0/1 [ ] page:ffffea00214967c0 count:0 mapcount:0 mapping: (null) index:0x0 [ ] flags: 0x2fffff80000000() [ ] page dumped because: kasan: bad access detected [...] Reported-by: CAI Qian <caiqian@redhat.com> Tested-by: CAI Qian <caiqian@redhat.com> Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David S. Miller <davem@davemloft.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kasan-dev@googlegroups.com [ Improved various details. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-20x86: Migrate exception table users off module.h and onto extable.hPaul Gortmaker
These files were only including module.h for exception table related functions. We've now separated that content out into its own file "extable.h" so now move over to that and avoid all the extra header content in module.h that we don't really need to compile these files. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Acked-by: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/20160919210418.30243-1-paul.gortmaker@windriver.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-06-14kprobes/x86: Clear TF bit in fault on single-steppingMasami Hiramatsu
Fix kprobe_fault_handler() to clear the TF (trap flag) bit of the flags register in the case of a fault fixup on single-stepping. If we put a kprobe on the instruction which caused a page fault (e.g. actual mov instructions in copy_user_*), that fault happens on the single-stepping buffer. In this case, kprobes resets running instance so that the CPU can retry execution on the original ip address. However, current code forgets to reset the TF bit. Since this fault happens with TF bit set for enabling single-stepping, when it retries, it causes a debug exception and kprobes can not handle it because it already reset itself. On the most of x86-64 platform, it can be easily reproduced by using kprobe tracer. E.g. # cd /sys/kernel/debug/tracing # echo p copy_user_enhanced_fast_string+5 > kprobe_events # echo 1 > events/kprobes/enable And you'll see a kernel panic on do_debug(), since the debug trap is not handled by kprobes. To fix this problem, we just need to clear the TF bit when resetting running kprobe. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: systemtap@sourceware.org Cc: stable@vger.kernel.org # All the way back to ancient kernels Link: http://lkml.kernel.org/r/20160611140648.25885.37482.stgit@devbox [ Updated the comments. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-29x86/asm: Stop depending on ptrace.h in alternative.hAndy Lutomirski
alternative.h pulls in ptrace.h, which means that alternatives can't be used in anything referenced from ptrace.h, which is a mess. Break the dependency by pulling text patching helpers into their own header. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/99b93b13f2c9eb671f5c98bba4c2cbdc061293a2.1461698311.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-29x86/kprobes: Mark kretprobe_trampoline() stack frame as non-standardJosh Poimboeuf
objtool reports the following warning for kretprobe_trampoline(): arch/x86/kernel/kprobes/core.o: warning: objtool: kretprobe_trampoline()+0x20: call without frame pointer save/setup kretprobes are a special case where the stack is intentionally wrong. The return address isn't known at the beginning of the trampoline, so the stack frame can't be set up properly before it calls trampoline_handler(). Because kretprobe handlers don't sleep, the frame pointer doesn't *have* to be accurate in the trampoline. So it's ok to tell objtool to ignore it. This results in no actual changes to the generated code. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris J Arges <chris.j.arges@canonical.com> Cc: David S. Miller <davem@davemloft.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Michal Marek <mmarek@suse.cz> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Pedro Alves <palves@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/7eaf37de52456ff822ffc86b928edb5d48a40ef1.1456719558.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>