[PATCH -tip v8 0/4] kprobes related bugfix

[PATCH -tip v8 0/4] kprobes related bugfix

[Masami Hiramatsu]

Hi,

Here are the series of patches to fix kprobes not
to optimize on the functions in irqentry text ([4/4]).
To check the irqentry text always, [3/4] makes irqentry
text section unconditional.

This involves some other cleanups on h8300, xtensa,
because those sources declare section start/end symbol
as single characters, but generic sections.h declares
it as character arrays. So it leads build errors if
we apply [3/4].

Thank you,

---

Masami Hiramatsu (4):
      h8300: mark _stext and _etext as char-arrays, not single char
      xtensa: mark _stext and _end as char-arrays, not single char
      irq: Make irqentry text section unconditional
      [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code


 arch/arm/include/asm/traps.h      |    7 -------
 arch/arm64/include/asm/traps.h    |    7 -------
 arch/h8300/include/asm/traps.h    |    6 +++---
 arch/x86/entry/entry_64.S         |    9 ++-------
 arch/x86/kernel/kprobes/opt.c     |    9 ++++++---
 arch/x86/kernel/unwind_frame.c    |    2 --
 arch/xtensa/kernel/setup.c        |    6 +++---
 include/asm-generic/sections.h    |    4 ++++
 include/asm-generic/vmlinux.lds.h |    8 --------
 include/linux/interrupt.h         |   14 +-------------
 10 files changed, 19 insertions(+), 53 deletions(-)

--
Masami Hiramatsu

[PATCH -tip v8 1/4] h8300: mark _stext and _etext as char-arrays, not single char

[Masami Hiramatsu]

Mark _stext and _etext as character arrays instead of
single character, as same as include/asm-generic/sections.h
does.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 arch/h8300/include/asm/traps.h |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/h8300/include/asm/traps.h b/arch/h8300/include/asm/traps.h
index 15e701130b27..1c5a30ec2df8 100644
--- a/arch/h8300/include/asm/traps.h
+++ b/arch/h8300/include/asm/traps.h
@@ -33,9 +33,9 @@ extern unsigned long *_interrupt_redirect_table;
 #define TRAP2_VEC 10
 #define TRAP3_VEC 11
 
-extern char _start, _etext;
+extern char _start[], _etext[];
 #define check_kernel_text(addr) \
-	((addr >= (unsigned long)(&_start)) && \
-	 (addr <  (unsigned long)(&_etext)) && !(addr & 1))
+	((addr >= (unsigned long)(_start)) && \
+	 (addr <  (unsigned long)(_etext)) && !(addr & 1))
 
 #endif /* _H8300_TRAPS_H */

[PATCH -tip v8 2/4] xtensa: mark _stext and _end as char-arrays, not single char

[Masami Hiramatsu]

Mark _stext and _end as character arrays instead of single
character, as same as include/asm-generic/sections.h does.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 arch/xtensa/kernel/setup.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index 33bfa5270d95..08175df7a69e 100644
--- a/arch/xtensa/kernel/setup.c
+++ b/arch/xtensa/kernel/setup.c
@@ -273,8 +273,8 @@ void __init init_arch(bp_tag_t *bp_start)
  * Initialize system. Setup memory and reserve regions.
  */
 
-extern char _end;
-extern char _stext;
+extern char _end[];
+extern char _stext[];
 extern char _WindowVectors_text_start;
 extern char _WindowVectors_text_end;
 extern char _DebugInterruptVector_literal_start;
@@ -333,7 +333,7 @@ void __init setup_arch(char **cmdline_p)
 	}
 #endif
 
-	mem_reserve(__pa(&_stext), __pa(&_end));
+	mem_reserve(__pa(_stext), __pa(_end));
 
 #ifdef CONFIG_VECTORS_OFFSET
 	mem_reserve(__pa(&_WindowVectors_text_start),

[PATCH -tip v8 3/4] irq: Make irqentry text section unconditional

[Masami Hiramatsu]

Generate irqentry and softirqentry text sections without
any configs. This will add above extra sections, but
no performace impact.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Suggested-by: Ingo Molnar <mingo@kernel.org>
---
 arch/arm/include/asm/traps.h      |    7 -------
 arch/arm64/include/asm/traps.h    |    7 -------
 arch/x86/entry/entry_64.S         |    9 ++-------
 arch/x86/kernel/unwind_frame.c    |    2 --
 include/asm-generic/sections.h    |    4 ++++
 include/asm-generic/vmlinux.lds.h |    8 --------
 include/linux/interrupt.h         |   14 +-------------
 7 files changed, 7 insertions(+), 44 deletions(-)

diff --git a/arch/arm/include/asm/traps.h b/arch/arm/include/asm/traps.h
index f555bb3664dc..683d9230984a 100644
--- a/arch/arm/include/asm/traps.h
+++ b/arch/arm/include/asm/traps.h
@@ -18,7 +18,6 @@ struct undef_hook {
 void register_undef_hook(struct undef_hook *hook);
 void unregister_undef_hook(struct undef_hook *hook);
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static inline int __in_irqentry_text(unsigned long ptr)
 {
 	extern char __irqentry_text_start[];
@@ -27,12 +26,6 @@ static inline int __in_irqentry_text(unsigned long ptr)
 	return ptr >= (unsigned long)&__irqentry_text_start &&
 	       ptr < (unsigned long)&__irqentry_text_end;
 }
-#else
-static inline int __in_irqentry_text(unsigned long ptr)
-{
-	return 0;
-}
-#endif
 
 static inline int in_exception_text(unsigned long ptr)
 {
diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h
index 02e9035b0685..47a9066f7c86 100644
--- a/arch/arm64/include/asm/traps.h
+++ b/arch/arm64/include/asm/traps.h
@@ -37,18 +37,11 @@ void unregister_undef_hook(struct undef_hook *hook);
 
 void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr);
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static inline int __in_irqentry_text(unsigned long ptr)
 {
 	return ptr >= (unsigned long)&__irqentry_text_start &&
 	       ptr < (unsigned long)&__irqentry_text_end;
 }
-#else
-static inline int __in_irqentry_text(unsigned long ptr)
-{
-	return 0;
-}
-#endif
 
 static inline int in_exception_text(unsigned long ptr)
 {
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index aa58155187c5..5e41396efbbf 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -766,13 +766,8 @@ apicinterrupt3 \num trace(\sym) smp_trace(\sym)
 #endif
 
 /* Make sure APIC interrupt handlers end up in the irqentry section: */
-#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
-# define PUSH_SECTION_IRQENTRY	.pushsection .irqentry.text, "ax"
-# define POP_SECTION_IRQENTRY	.popsection
-#else
-# define PUSH_SECTION_IRQENTRY
-# define POP_SECTION_IRQENTRY
-#endif
+#define PUSH_SECTION_IRQENTRY	.pushsection .irqentry.text, "ax"
+#define POP_SECTION_IRQENTRY	.popsection
 
 .macro apicinterrupt num sym do_sym
 PUSH_SECTION_IRQENTRY
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index 7574ef5f16ec..d145a0b1f529 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -84,10 +84,8 @@ static bool in_entry_code(unsigned long ip)
 	if (addr >= __entry_text_start && addr < __entry_text_end)
 		return true;
 
-#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
 	if (addr >= __irqentry_text_start && addr < __irqentry_text_end)
 		return true;
-#endif
 
 	return false;
 }
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index 532372c6cf15..e5da44eddd2f 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -27,6 +27,8 @@
  *	__kprobes_text_start, __kprobes_text_end
  *	__entry_text_start, __entry_text_end
  *	__ctors_start, __ctors_end
+ *	__irqentry_text_start, __irqentry_text_end
+ *	__softirqentry_text_start, __softirqentry_text_end
  */
 extern char _text[], _stext[], _etext[];
 extern char _data[], _sdata[], _edata[];
@@ -39,6 +41,8 @@ extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[];
 extern char __kprobes_text_start[], __kprobes_text_end[];
 extern char __entry_text_start[], __entry_text_end[];
 extern char __start_rodata[], __end_rodata[];
+extern char __irqentry_text_start[], __irqentry_text_end[];
+extern char __softirqentry_text_start[], __softirqentry_text_end[];
 
 /* Start and end of .ctors section - used for constructor calls. */
 extern char __ctors_start[], __ctors_end[];
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index fffc9bdae025..438b014c192f 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -483,25 +483,17 @@
 		*(.entry.text)						\
 		VMLINUX_SYMBOL(__entry_text_end) = .;
 
-#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
 #define IRQENTRY_TEXT							\
 		ALIGN_FUNCTION();					\
 		VMLINUX_SYMBOL(__irqentry_text_start) = .;		\
 		*(.irqentry.text)					\
 		VMLINUX_SYMBOL(__irqentry_text_end) = .;
-#else
-#define IRQENTRY_TEXT
-#endif
 
-#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
 #define SOFTIRQENTRY_TEXT						\
 		ALIGN_FUNCTION();					\
 		VMLINUX_SYMBOL(__softirqentry_text_start) = .;		\
 		*(.softirqentry.text)					\
 		VMLINUX_SYMBOL(__softirqentry_text_end) = .;
-#else
-#define SOFTIRQENTRY_TEXT
-#endif
 
 /* Section used for early init (in .S files) */
 #define HEAD_TEXT  *(.head.text)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index a2fddddb0d60..59ba11661b6e 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -18,6 +18,7 @@
 #include <linux/atomic.h>
 #include <asm/ptrace.h>
 #include <asm/irq.h>
+#include <asm/sections.h>
 
 /*
  * These correspond to the IORESOURCE_IRQ_* defines in
@@ -726,7 +727,6 @@ extern int early_irq_init(void);
 extern int arch_probe_nr_irqs(void);
 extern int arch_early_irq_init(void);
 
-#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
 /*
  * We want to know which function is an entrypoint of a hardirq or a softirq.
  */
@@ -734,16 +734,4 @@ extern int arch_early_irq_init(void);
 #define __softirq_entry  \
 	__attribute__((__section__(".softirqentry.text")))
 
-/* Limits of hardirq entrypoints */
-extern char __irqentry_text_start[];
-extern char __irqentry_text_end[];
-/* Limits of softirq entrypoints */
-extern char __softirqentry_text_start[];
-extern char __softirqentry_text_end[];
-
-#else
-#define __irq_entry
-#define __softirq_entry
-#endif
-
 #endif

Re: [PATCH -tip v8 3/4] irq: Make irqentry text section unconditional

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2355 bytes --]

Hi Masami,

[auto build test ERROR on tip/x86/core]
[also build test ERROR on v4.13-rc3 next-20170802]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Masami-Hiramatsu/kprobes-related-bugfix/20170731-031202
config: cris-artpec_3_defconfig (attached as .config)
compiler: cris-linux-gcc (GCC) 6.2.0
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=cris 

All errors (new ones prefixed by >>):

>> arch/cris/arch-v32/mach-a3/arbiter.c:230:13: error: conflicting types for '_stext'
    extern char _stext, _etext;
                ^~~~~~
   In file included from ./arch/cris/include/generated/asm/sections.h:1:0,
                    from include/linux/interrupt.h:21,
                    from arch/cris/arch-v32/mach-a3/arbiter.c:44:
   include/asm-generic/sections.h:33:22: note: previous declaration of '_stext' was here
    extern char _text[], _stext[], _etext[];
                         ^~~~~~
>> arch/cris/arch-v32/mach-a3/arbiter.c:230:21: error: conflicting types for '_etext'
    extern char _stext, _etext;
                        ^~~~~~
   In file included from ./arch/cris/include/generated/asm/sections.h:1:0,
                    from include/linux/interrupt.h:21,
                    from arch/cris/arch-v32/mach-a3/arbiter.c:44:
   include/asm-generic/sections.h:33:32: note: previous declaration of '_etext' was here
    extern char _text[], _stext[], _etext[];
                                   ^~~~~~

vim +/_stext +230 arch/cris/arch-v32/mach-a3/arbiter.c

035e111f Jesper Nilsson 2007-11-29  229  
035e111f Jesper Nilsson 2007-11-29 @230  extern char _stext, _etext;
035e111f Jesper Nilsson 2007-11-29  231  

:::::: The code at line 230 was first introduced by commit
:::::: 035e111f9a9b29843bc899f03d56f19d94bebb53 CRIS v32: Add new machine dependent files for Etrax-FS and Artpec-3.

:::::: TO: Jesper Nilsson <jespern@stork.se.axis.com>
:::::: CC: Jesper Nilsson <jesper.nilsson@axis.com>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 9199 bytes --]

Re: [PATCH -tip v8 3/4] irq: Make irqentry text section unconditional

[Masami Hiramatsu]

On Thu, 3 Aug 2017 01:35:11 +0800
kbuild test robot <lkp@intel.com> wrote:

> Hi Masami,
> 
> [auto build test ERROR on tip/x86/core]
> [also build test ERROR on v4.13-rc3 next-20170802]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> 
> url:    https://github.com/0day-ci/linux/commits/Masami-Hiramatsu/kprobes-related-bugfix/20170731-031202
> config: cris-artpec_3_defconfig (attached as .config)
> compiler: cris-linux-gcc (GCC) 6.2.0
> reproduce:
>         wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # save the attached .config to linux build tree
>         make.cross ARCH=cris 
> 
> All errors (new ones prefixed by >>):
> 
> >> arch/cris/arch-v32/mach-a3/arbiter.c:230:13: error: conflicting types for '_stext'
>     extern char _stext, _etext;
>                 ^~~~~~
>    In file included from ./arch/cris/include/generated/asm/sections.h:1:0,
>                     from include/linux/interrupt.h:21,
>                     from arch/cris/arch-v32/mach-a3/arbiter.c:44:
>    include/asm-generic/sections.h:33:22: note: previous declaration of '_stext' was here
>     extern char _text[], _stext[], _etext[];
>                          ^~~~~~
> >> arch/cris/arch-v32/mach-a3/arbiter.c:230:21: error: conflicting types for '_etext'
>     extern char _stext, _etext;
>                         ^~~~~~
>    In file included from ./arch/cris/include/generated/asm/sections.h:1:0,
>                     from include/linux/interrupt.h:21,
>                     from arch/cris/arch-v32/mach-a3/arbiter.c:44:
>    include/asm-generic/sections.h:33:32: note: previous declaration of '_etext' was here
>     extern char _text[], _stext[], _etext[];
>                                    ^~~~~~

OK, I'll add a fix for cris.

Thanks,

> 
> vim +/_stext +230 arch/cris/arch-v32/mach-a3/arbiter.c
> 
> 035e111f Jesper Nilsson 2007-11-29  229  
> 035e111f Jesper Nilsson 2007-11-29 @230  extern char _stext, _etext;
> 035e111f Jesper Nilsson 2007-11-29  231  
> 
> :::::: The code at line 230 was first introduced by commit
> :::::: 035e111f9a9b29843bc899f03d56f19d94bebb53 CRIS v32: Add new machine dependent files for Etrax-FS and Artpec-3.
> 
> :::::: TO: Jesper Nilsson <jespern@stork.se.axis.com>
> :::::: CC: Jesper Nilsson <jesper.nilsson@axis.com>
> 
> ---
> 0-DAY kernel test infrastructure                Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation


-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: [PATCH -tip v8 3/4] irq: Make irqentry text section unconditional

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2354 bytes --]

Hi Masami,

[auto build test ERROR on tip/x86/core]
[also build test ERROR on v4.13-rc3 next-20170802]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Masami-Hiramatsu/kprobes-related-bugfix/20170731-031202
config: cris-etraxfs_defconfig (attached as .config)
compiler: cris-linux-gcc (GCC) 6.2.0
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=cris 

All errors (new ones prefixed by >>):

>> arch/cris/arch-v32/mach-fs/arbiter.c:161:13: error: conflicting types for '_stext'
    extern char _stext, _etext;
                ^~~~~~
   In file included from ./arch/cris/include/generated/asm/sections.h:1:0,
                    from include/linux/interrupt.h:21,
                    from arch/cris/arch-v32/mach-fs/arbiter.c:17:
   include/asm-generic/sections.h:33:22: note: previous declaration of '_stext' was here
    extern char _text[], _stext[], _etext[];
                         ^~~~~~
>> arch/cris/arch-v32/mach-fs/arbiter.c:161:21: error: conflicting types for '_etext'
    extern char _stext, _etext;
                        ^~~~~~
   In file included from ./arch/cris/include/generated/asm/sections.h:1:0,
                    from include/linux/interrupt.h:21,
                    from arch/cris/arch-v32/mach-fs/arbiter.c:17:
   include/asm-generic/sections.h:33:32: note: previous declaration of '_etext' was here
    extern char _text[], _stext[], _etext[];
                                   ^~~~~~

vim +/_stext +161 arch/cris/arch-v32/mach-fs/arbiter.c

035e111f Jesper Nilsson 2007-11-29  160  
035e111f Jesper Nilsson 2007-11-29 @161  extern char _stext, _etext;
035e111f Jesper Nilsson 2007-11-29  162  

:::::: The code at line 161 was first introduced by commit
:::::: 035e111f9a9b29843bc899f03d56f19d94bebb53 CRIS v32: Add new machine dependent files for Etrax-FS and Artpec-3.

:::::: TO: Jesper Nilsson <jespern@stork.se.axis.com>
:::::: CC: Jesper Nilsson <jesper.nilsson@axis.com>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 9137 bytes --]

[PATCH -tip v8 4/4] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code

[Masami 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
kernel panic.
However, if the kprobe is not optimized, it kicks int3
exception and set segment registers correctly.

This checks probe-address and if it is in irq-entry code,
it prohibits optimizing such kprobes. This means we can
continuously probing such interrupt handlers by kprobes
but it is not optimized anymore.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reported-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Tested-by: Francis Deslauriers <francis.deslauriers@efficios.com>
---
 arch/x86/kernel/kprobes/opt.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index 69ea0bc1cfa3..4f98aad38237 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -39,6 +39,7 @@
 #include <asm/insn.h>
 #include <asm/debugreg.h>
 #include <asm/set_memory.h>
+#include <asm/sections.h>
 
 #include "common.h"
 
@@ -251,10 +252,12 @@ static int can_optimize(unsigned long paddr)
 
 	/*
 	 * Do not optimize in the entry code due to the unstable
-	 * stack handling.
+	 * stack handling and registers setup.
 	 */
-	if ((paddr >= (unsigned long)__entry_text_start) &&
-	    (paddr <  (unsigned long)__entry_text_end))
+	if (((paddr >= (unsigned long)__entry_text_start) &&
+	     (paddr <  (unsigned long)__entry_text_end)) ||
+	    ((paddr >= (unsigned long)__irqentry_text_start) &&
+	     (paddr <  (unsigned long)__irqentry_text_end)))
 		return 0;
 
 	/* Check there is enough space for a relative jump. */