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* [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access
@ 2019-05-15  5:37 Masami Hiramatsu
  2019-05-15  5:38 ` [PATCH -tip v9 1/6] x86/uaccess: Allow access_ok() in irq context if pagefault_disabled Masami Hiramatsu
                   ` (6 more replies)
  0 siblings, 7 replies; 13+ messages in thread
From: Masami Hiramatsu @ 2019-05-15  5:37 UTC (permalink / raw)
  To: Steven Rostedt, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra
  Cc: mhiramat, linux-kernel, Andy Lutomirski, Ingo Molnar,
	Andrew Morton, Changbin Du, Jann Horn, Kees Cook,
	Andy Lutomirski, Alexei Starovoitov, Nadav Amit, Joel Fernandes,
	yhs

Hi,

Here is the v9 series of probe-event to support user-space access.
Previous version is here.

https://lkml.kernel.org/r/155741476971.28419.15837024173365724167.stgit@devnote2

In this version, I fixed more typos/style issues.

Changes in v9:
 [3/6]
      - Fix other style & coding issues (Thanks Ingo!)
      - Update fetch_store_string() for style consistency.
 [4/6]
      - Remove an unneeded line break.
      - Move || and && in if-condition at the end of line.

In summary, strncpy_from_user() should work as below

 - strncpy_from_user() can access user memory with set_fs(USER_DS)
   in task context

 - strncpy_from_user() can access kernel memory with set_fs(KERNEL_DS)
   in task context (e.g. devtmpfsd and init)

 - strncpy_from_user() can access user/kernel memory (depends on DS)
   in IRQ context if pagefault is disabled. (both verified)

Note that this changes the warning behavior when
CONFIG_DEBUG_ATOMIC_SLEEP=y, it still warns when
__copy_from_user_inatomic() is called in IRQ context, but don't
warn if pagefault is disabled because it will not sleep in
atomic.

====
Kprobe event user-space memory access features:

For user-space access extension, this series adds 2 features,
"ustring" type and user-space dereference syntax. "ustring" is
used for recording a null-terminated string in user-space from
kprobe events.

"ustring" type is easy, it is able to use instead of "string"
type, so if you want to record a user-space string via
"__user char *", you can use ustring type instead of string.
For example,

echo 'p do_sys_open path=+0($arg2):ustring' >> kprobe_events

will record the path string from user-space.

The user-space dereference syntax is also simple. Thi just
adds 'u' prefix before an offset value.

   +|-u<OFFSET>(<FETCHARG>)

e.g. +u8(%ax), +u0(+0(%si))

This is more generic. If you want to refer the variable in user-
space from its address or access a field in data structure in
user-space, you need to use this.

For example, if you probe do_sched_setscheduler(pid, policy,
param) and record param->sched_priority, you can add new
probe as below;
    
   p do_sched_setscheduler priority=+u0($arg3)

Actually, with this feature, "ustring" type is not absolutely
necessary, because these are same meanings.

  +0($arg2):ustring == +u0($arg2):string

Note that kprobe event provides these methods, but it doesn't
change it from kernel to user automatically because we do not
know whether the given address is in userspace or kernel on
some arch.


Thank you,

---

Masami Hiramatsu (6):
      x86/uaccess: Allow access_ok() in irq context if pagefault_disabled
      uaccess: Add non-pagefault user-space read functions
      tracing/probe: Add ustring type for user-space string
      tracing/probe: Support user-space dereference
      selftests/ftrace: Add user-memory access syntax testcase
      perf-probe: Add user memory access attribute support


 Documentation/trace/kprobetrace.rst                |   28 ++++-
 Documentation/trace/uprobetracer.rst               |   10 +-
 arch/x86/include/asm/uaccess.h                     |    4 -
 include/linux/uaccess.h                            |   19 +++
 kernel/trace/trace.c                               |    7 +
 kernel/trace/trace_kprobe.c                        |   48 +++++++-
 kernel/trace/trace_probe.c                         |   37 +++++-
 kernel/trace/trace_probe.h                         |    3 
 kernel/trace/trace_probe_tmpl.h                    |   36 +++++-
 kernel/trace/trace_uprobe.c                        |   19 +++
 mm/maccess.c                                       |  122 +++++++++++++++++++-
 tools/perf/Documentation/perf-probe.txt            |    3 
 tools/perf/util/probe-event.c                      |   11 ++
 tools/perf/util/probe-event.h                      |    2 
 tools/perf/util/probe-file.c                       |    7 +
 tools/perf/util/probe-file.h                       |    1 
 tools/perf/util/probe-finder.c                     |   19 ++-
 .../ftrace/test.d/kprobe/kprobe_args_user.tc       |   32 +++++
 18 files changed, 364 insertions(+), 44 deletions(-)
 create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc

--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH -tip v9 1/6] x86/uaccess: Allow access_ok() in irq context if pagefault_disabled
  2019-05-15  5:37 [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Masami Hiramatsu
@ 2019-05-15  5:38 ` Masami Hiramatsu
  2019-05-15  5:38 ` [PATCH -tip v9 2/6] uaccess: Add non-pagefault user-space read functions Masami Hiramatsu
                   ` (5 subsequent siblings)
  6 siblings, 0 replies; 13+ messages in thread
From: Masami Hiramatsu @ 2019-05-15  5:38 UTC (permalink / raw)
  To: Steven Rostedt, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra
  Cc: mhiramat, linux-kernel, Andy Lutomirski, Ingo Molnar,
	Andrew Morton, Changbin Du, Jann Horn, Kees Cook,
	Andy Lutomirski, Alexei Starovoitov, Nadav Amit, Joel Fernandes,
	yhs

WARN_ON_IN_IRQ() assumes that the access_ok() and following
user memory access can sleep. But this assumption is not
always correct; when the pagefault is disabled, following
memory access will just returns -EFAULT and never sleep.

Add pagefault_disabled() check in WARN_ON_ONCE() so that
it can ignore the case we call it with disabling pagefault.
For this purpose, this modified pagefault_disabled() as
an inline function.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 arch/x86/include/asm/uaccess.h |    4 +++-
 include/linux/uaccess.h        |    5 ++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index c82abd6e4ca3..9c4435307ff8 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -66,7 +66,9 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un
 })
 
 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
-# define WARN_ON_IN_IRQ()	WARN_ON_ONCE(!in_task())
+static inline bool pagefault_disabled(void);
+# define WARN_ON_IN_IRQ()	\
+	WARN_ON_ONCE(!in_task() && !pagefault_disabled())
 #else
 # define WARN_ON_IN_IRQ()
 #endif
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 2b70130af585..5a43ef7db492 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -203,7 +203,10 @@ static inline void pagefault_enable(void)
 /*
  * Is the pagefault handler disabled? If so, user access methods will not sleep.
  */
-#define pagefault_disabled() (current->pagefault_disabled != 0)
+static inline bool pagefault_disabled(void)
+{
+	return current->pagefault_disabled != 0;
+}
 
 /*
  * The pagefault handler is in general disabled by pagefault_disable() or


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH -tip v9 2/6] uaccess: Add non-pagefault user-space read functions
  2019-05-15  5:37 [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Masami Hiramatsu
  2019-05-15  5:38 ` [PATCH -tip v9 1/6] x86/uaccess: Allow access_ok() in irq context if pagefault_disabled Masami Hiramatsu
@ 2019-05-15  5:38 ` Masami Hiramatsu
  2019-05-15  5:38 ` [PATCH -tip v9 3/6] tracing/probe: Add ustring type for user-space string Masami Hiramatsu
                   ` (4 subsequent siblings)
  6 siblings, 0 replies; 13+ messages in thread
From: Masami Hiramatsu @ 2019-05-15  5:38 UTC (permalink / raw)
  To: Steven Rostedt, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra
  Cc: mhiramat, linux-kernel, Andy Lutomirski, Ingo Molnar,
	Andrew Morton, Changbin Du, Jann Horn, Kees Cook,
	Andy Lutomirski, Alexei Starovoitov, Nadav Amit, Joel Fernandes,
	yhs

Add probe_user_read(), strncpy_from_unsafe_user() and
strnlen_unsafe_user() which allows caller to access user-space
in IRQ context.

Current probe_kernel_read() and strncpy_from_unsafe() are
not available for user-space memory, because it sets
KERNEL_DS while accessing data. On some arch, user address
space and kernel address space can be co-exist, but others
can not. In that case, setting KERNEL_DS means given
address is treated as a kernel address space.
Also strnlen_user() is only available from user context since
it can sleep if pagefault is enabled.

To access user-space memory without pagefault, we need
these new functions which sets USER_DS while accessing
the data.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
  Changes in v8:
   - Fix style issues and typos according to Ingo's comment (Thanks!)
  Changes in v6:
   - Remove user_access_ok()
  Changes in v5:
   - Simplify probe_user_read() (Thanks, Peter!)
   - Add strnlen_unsafe_user()
  Changes in v3:
   - Use user_access_ok() for probe_user_read().
  Changes in v2:
   - Simplify strncpy_from_unsafe_user() using strncpy_from_user()
     according to Linus's suggestion.
   - Simplify probe_user_read() not using intermediate function.
---
 include/linux/uaccess.h |   14 +++++
 mm/maccess.c            |  122 +++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 130 insertions(+), 6 deletions(-)

diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 5a43ef7db492..9c435c3f2105 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -242,6 +242,17 @@ static inline unsigned long __copy_from_user_inatomic_nocache(void *to,
 extern long probe_kernel_read(void *dst, const void *src, size_t size);
 extern long __probe_kernel_read(void *dst, const void *src, size_t size);
 
+/*
+ * probe_user_read(): safely attempt to read from a location in user space
+ * @dst: pointer to the buffer that shall take the data
+ * @src: address to read from
+ * @size: size of the data chunk
+ *
+ * Safely read from address @src to the buffer at @dst.  If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+extern long probe_user_read(void *dst, const void __user *src, size_t size);
+
 /*
  * probe_kernel_write(): safely attempt to write to a location
  * @dst: address to write to
@@ -255,6 +266,9 @@ extern long notrace probe_kernel_write(void *dst, const void *src, size_t size);
 extern long notrace __probe_kernel_write(void *dst, const void *src, size_t size);
 
 extern long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count);
+extern long strncpy_from_unsafe_user(char *dst, const void __user *unsafe_addr,
+				     long count);
+extern long strnlen_unsafe_user(const void __user *unsafe_addr, long count);
 
 /**
  * probe_kernel_address(): safely attempt to read from a location
diff --git a/mm/maccess.c b/mm/maccess.c
index ec00be51a24f..19c8c3dc14df 100644
--- a/mm/maccess.c
+++ b/mm/maccess.c
@@ -5,8 +5,20 @@
 #include <linux/mm.h>
 #include <linux/uaccess.h>
 
+static __always_inline long
+probe_read_common(void *dst, const void __user *src, size_t size)
+{
+	long ret;
+
+	pagefault_disable();
+	ret = __copy_from_user_inatomic(dst, src, size);
+	pagefault_enable();
+
+	return ret ? -EFAULT : 0;
+}
+
 /**
- * probe_kernel_read(): safely attempt to read from a location
+ * probe_kernel_read(): safely attempt to read from a kernel-space location
  * @dst: pointer to the buffer that shall take the data
  * @src: address to read from
  * @size: size of the data chunk
@@ -29,16 +41,40 @@ long __probe_kernel_read(void *dst, const void *src, size_t size)
 	mm_segment_t old_fs = get_fs();
 
 	set_fs(KERNEL_DS);
-	pagefault_disable();
-	ret = __copy_from_user_inatomic(dst,
-			(__force const void __user *)src, size);
-	pagefault_enable();
+	ret = probe_read_common(dst, (__force const void __user *)src, size);
 	set_fs(old_fs);
 
-	return ret ? -EFAULT : 0;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(probe_kernel_read);
 
+/**
+ * probe_user_read(): safely attempt to read from a user-space location
+ * @dst: pointer to the buffer that shall take the data
+ * @src: address to read from. This must be a user address.
+ * @size: size of the data chunk
+ *
+ * Safely read from user address @src to the buffer at @dst. If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+
+long __weak probe_user_read(void *dst, const void __user *src, size_t size)
+    __attribute__((alias("__probe_user_read")));
+
+long __probe_user_read(void *dst, const void __user *src, size_t size)
+{
+	long ret = -EFAULT;
+	mm_segment_t old_fs = get_fs();
+
+	set_fs(USER_DS);
+	if (access_ok(src, size))
+		ret = probe_read_common(dst, src, size);
+	set_fs(old_fs);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(probe_user_read);
+
 /**
  * probe_kernel_write(): safely attempt to write to a location
  * @dst: address to write to
@@ -66,6 +102,7 @@ long __probe_kernel_write(void *dst, const void *src, size_t size)
 }
 EXPORT_SYMBOL_GPL(probe_kernel_write);
 
+
 /**
  * strncpy_from_unsafe: - Copy a NUL terminated string from unsafe address.
  * @dst:   Destination address, in kernel space.  This buffer must be at
@@ -105,3 +142,76 @@ long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count)
 
 	return ret ? -EFAULT : src - unsafe_addr;
 }
+
+/**
+ * strncpy_from_unsafe_user: - Copy a NUL terminated string from unsafe user
+ *				address.
+ * @dst:   Destination address, in kernel space.  This buffer must be at
+ *         least @count bytes long.
+ * @unsafe_addr: Unsafe user address.
+ * @count: Maximum number of bytes to copy, including the trailing NUL.
+ *
+ * Copies a NUL-terminated string from unsafe user address to kernel buffer.
+ *
+ * On success, returns the length of the string INCLUDING the trailing NUL.
+ *
+ * If access fails, returns -EFAULT (some data may have been copied
+ * and the trailing NUL added).
+ *
+ * If @count is smaller than the length of the string, copies @count-1 bytes,
+ * sets the last byte of @dst buffer to NUL and returns @count.
+ */
+long strncpy_from_unsafe_user(char *dst, const void __user *unsafe_addr,
+			      long count)
+{
+	mm_segment_t old_fs = get_fs();
+	long ret;
+
+	if (unlikely(count <= 0))
+		return 0;
+
+	set_fs(USER_DS);
+	pagefault_disable();
+	ret = strncpy_from_user(dst, unsafe_addr, count);
+	pagefault_enable();
+	set_fs(old_fs);
+
+	if (ret >= count) {
+		ret = count;
+		dst[ret - 1] = '\0';
+	} else if (ret > 0) {
+		ret++;
+	}
+
+	return ret;
+}
+
+/**
+ * strnlen_unsafe_user: - Get the size of a user string INCLUDING final NUL.
+ * @unsafe_addr: The string to measure.
+ * @count: Maximum count (including NUL)
+ *
+ * Get the size of a NUL-terminated string in user space without pagefault.
+ *
+ * Returns the size of the string INCLUDING the terminating NUL.
+ *
+ * If the string is too long, returns a number larger than @count. User
+ * has to check the return value against "> count".
+ * On exception (or invalid count), returns 0.
+ *
+ * Unlike strnlen_user, this can be used from IRQ handler etc. because
+ * it disables pagefaults.
+ */
+long strnlen_unsafe_user(const void __user *unsafe_addr, long count)
+{
+	mm_segment_t old_fs = get_fs();
+	int ret;
+
+	set_fs(USER_DS);
+	pagefault_disable();
+	ret = strnlen_user(unsafe_addr, count);
+	pagefault_enable();
+	set_fs(old_fs);
+
+	return ret;
+}


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH -tip v9 3/6] tracing/probe: Add ustring type for user-space string
  2019-05-15  5:37 [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Masami Hiramatsu
  2019-05-15  5:38 ` [PATCH -tip v9 1/6] x86/uaccess: Allow access_ok() in irq context if pagefault_disabled Masami Hiramatsu
  2019-05-15  5:38 ` [PATCH -tip v9 2/6] uaccess: Add non-pagefault user-space read functions Masami Hiramatsu
@ 2019-05-15  5:38 ` Masami Hiramatsu
  2019-05-15  5:38 ` [PATCH -tip v9 4/6] tracing/probe: Support user-space dereference Masami Hiramatsu
                   ` (3 subsequent siblings)
  6 siblings, 0 replies; 13+ messages in thread
From: Masami Hiramatsu @ 2019-05-15  5:38 UTC (permalink / raw)
  To: Steven Rostedt, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra
  Cc: mhiramat, linux-kernel, Andy Lutomirski, Ingo Molnar,
	Andrew Morton, Changbin Du, Jann Horn, Kees Cook,
	Andy Lutomirski, Alexei Starovoitov, Nadav Amit, Joel Fernandes,
	yhs

Add "ustring" type for fetching user-space string from kprobe event.
User can specify ustring type at uprobe event, and it is same as
"string" for uprobe.

Note that probe-event provides this option but it doesn't choose the
correct type automatically since we have not way to decide the address
is in user-space or not on some arch (and on some other arch, you can
fetch the string by "string" type). So user must carefully check the
target code (e.g. if you see __user on the target variable) and
use this new type.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

---
 Changes in v9:
  - Fix other style & coding issues (Thanks Ingo!)
  - Update fetch_store_string() for style consistency.
 Changes in v8:
  - Fix style issues according to Ingo's comment (Thanks!)
 Changes in v5:
 - Use strnlen_unsafe_user() in fetch_store_strlen_user().
 Changes in v2:
 - Use strnlen_user() instead of open code for fetch_store_strlen_user().
---
 Documentation/trace/kprobetrace.rst |    9 ++++++--
 kernel/trace/trace.c                |    2 +-
 kernel/trace/trace_kprobe.c         |   42 +++++++++++++++++++++++++++++++++--
 kernel/trace/trace_probe.c          |   14 +++++++++---
 kernel/trace/trace_probe.h          |    1 +
 kernel/trace/trace_probe_tmpl.h     |   14 +++++++++++-
 kernel/trace/trace_uprobe.c         |   12 ++++++++++
 7 files changed, 84 insertions(+), 10 deletions(-)

diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst
index 235ce2ab131a..a3ac7c9ac242 100644
--- a/Documentation/trace/kprobetrace.rst
+++ b/Documentation/trace/kprobetrace.rst
@@ -55,7 +55,8 @@ Synopsis of kprobe_events
   NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
   FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
 		  (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types
-		  (x8/x16/x32/x64), "string" and bitfield are supported.
+		  (x8/x16/x32/x64), "string", "ustring" and bitfield
+		  are supported.
 
   (\*1) only for the probe on function entry (offs == 0).
   (\*2) only for return probe.
@@ -77,7 +78,11 @@ apply it to registers/stack-entries etc. (for example, '$stack1:x8[8]' is
 wrong, but '+8($stack):x8[8]' is OK.)
 String type is a special type, which fetches a "null-terminated" string from
 kernel space. This means it will fail and store NULL if the string container
-has been paged out.
+has been paged out. "ustring" type is an alternative of string for user-space.
+Note that kprobe-event provides string/ustring types, but doesn't change it
+automatically. So user has to decide if the targe string in kernel or in user
+space carefully. On some arch, if you choose wrong one, it always fails to
+record string data.
 The string array type is a bit different from other types. For other base
 types, <base-type>[1] is equal to <base-type> (e.g. +0(%di):x32[1] is same
 as +0(%di):x32.) But string[1] is not equal to string. The string type itself
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ec439999f387..69687ad83228 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4812,7 +4812,7 @@ static const char readme_msg[] =
 	"\t           $stack<index>, $stack, $retval, $comm\n"
 #endif
 	"\t     type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"
-	"\t           b<bit-width>@<bit-offset>/<container-size>,\n"
+	"\t           b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
 	"\t           <type>\\[<array-size>\\]\n"
 #ifdef CONFIG_HIST_TRIGGERS
 	"\t    field: <stype> <name>;\n"
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 5d5129b05df7..b24c87713f70 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -871,6 +871,15 @@ fetch_store_strlen(unsigned long addr)
 	return (ret < 0) ? ret : len;
 }
 
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline int
+fetch_store_strlen_user(unsigned long addr)
+{
+	const void __user *uaddr =  (__force const void __user *)addr;
+
+	return strnlen_unsafe_user(uaddr, MAX_STRING_SIZE);
+}
+
 /*
  * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
  * length and relative data location.
@@ -879,19 +888,46 @@ static nokprobe_inline int
 fetch_store_string(unsigned long addr, void *dest, void *base)
 {
 	int maxlen = get_loc_len(*(u32 *)dest);
-	u8 *dst = get_loc_data(dest, base);
+	void *__dest;
 	long ret;
 
 	if (unlikely(!maxlen))
 		return -ENOMEM;
+
+	__dest = get_loc_data(dest, base);
+
 	/*
 	 * Try to get string again, since the string can be changed while
 	 * probing.
 	 */
-	ret = strncpy_from_unsafe(dst, (void *)addr, maxlen);
+	ret = strncpy_from_unsafe(__dest, (void *)addr, maxlen);
+	if (ret >= 0)
+		*(u32 *)dest = make_data_loc(ret, __dest - base);
+
+	return ret;
+}
 
+/*
+ * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
+ * with max length and relative data location.
+ */
+static nokprobe_inline int
+fetch_store_string_user(unsigned long addr, void *dest, void *base)
+{
+	const void __user *uaddr =  (__force const void __user *)addr;
+	int maxlen = get_loc_len(*(u32 *)dest);
+	void *__dest;
+	long ret;
+
+	if (unlikely(!maxlen))
+		return -ENOMEM;
+
+	__dest = get_loc_data(dest, base);
+
+	ret = strncpy_from_unsafe_user(__dest, uaddr, maxlen);
 	if (ret >= 0)
-		*(u32 *)dest = make_data_loc(ret, (void *)dst - base);
+		*(u32 *)dest = make_data_loc(ret, __dest - base);
+
 	return ret;
 }
 
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 8f8411e7835f..30054136cfde 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -73,6 +73,8 @@ static const struct fetch_type probe_fetch_types[] = {
 	/* Special types */
 	__ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1,
 			    "__data_loc char[]"),
+	__ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1,
+			    "__data_loc char[]"),
 	/* Basic types */
 	ASSIGN_FETCH_TYPE(u8,  u8,  0),
 	ASSIGN_FETCH_TYPE(u16, u16, 0),
@@ -455,7 +457,8 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 		goto fail;
 
 	/* Store operation */
-	if (!strcmp(parg->type->name, "string")) {
+	if (!strcmp(parg->type->name, "string") ||
+	    !strcmp(parg->type->name, "ustring")) {
 		if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM &&
 		    code->op != FETCH_OP_COMM) {
 			pr_info("string only accepts memory or address.\n");
@@ -474,7 +477,11 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 				goto fail;
 			}
 		}
-		code->op = FETCH_OP_ST_STRING;	/* In DEREF case, replace it */
+		/* If op == DEREF, replace it with STRING */
+		if (!strcmp(parg->type->name, "ustring"))
+			code->op = FETCH_OP_ST_USTRING;
+		else
+			code->op = FETCH_OP_ST_STRING;
 		code->size = parg->type->size;
 		parg->dynamic = true;
 	} else if (code->op == FETCH_OP_DEREF) {
@@ -499,7 +506,8 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 	/* Loop(Array) operation */
 	if (parg->count) {
 		if (scode->op != FETCH_OP_ST_MEM &&
-		    scode->op != FETCH_OP_ST_STRING) {
+		    scode->op != FETCH_OP_ST_STRING &&
+		    scode->op != FETCH_OP_ST_USTRING) {
 			pr_info("array only accepts memory or address\n");
 			ret = -EINVAL;
 			goto fail;
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 2177c206de15..94cdcfdaced0 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -96,6 +96,7 @@ enum fetch_op {
 	FETCH_OP_ST_RAW,	/* Raw: .size */
 	FETCH_OP_ST_MEM,	/* Mem: .offset, .size */
 	FETCH_OP_ST_STRING,	/* String: .offset, .size */
+	FETCH_OP_ST_USTRING,	/* User String: .offset, .size */
 	// Stage 4 (modify) op
 	FETCH_OP_MOD_BF,	/* Bitfield: .basesize, .lshift, .rshift */
 	// Stage 5 (loop) op
diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h
index 4737bb8c07a3..7526f6f8d7b0 100644
--- a/kernel/trace/trace_probe_tmpl.h
+++ b/kernel/trace/trace_probe_tmpl.h
@@ -59,6 +59,9 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs,
 static nokprobe_inline int fetch_store_strlen(unsigned long addr);
 static nokprobe_inline int
 fetch_store_string(unsigned long addr, void *dest, void *base);
+static nokprobe_inline int fetch_store_strlen_user(unsigned long addr);
+static nokprobe_inline int
+fetch_store_string_user(unsigned long addr, void *dest, void *base);
 static nokprobe_inline int
 probe_mem_read(void *dest, void *src, size_t size);
 
@@ -91,6 +94,10 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
 			ret += fetch_store_strlen(val + code->offset);
 			code++;
 			goto array;
+		} else if (code->op == FETCH_OP_ST_USTRING) {
+			ret += fetch_store_strlen_user(val + code->offset);
+			code++;
+			goto array;
 		} else
 			return -EILSEQ;
 	}
@@ -106,6 +113,10 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
 		loc = *(u32 *)dest;
 		ret = fetch_store_string(val + code->offset, dest, base);
 		break;
+	case FETCH_OP_ST_USTRING:
+		loc = *(u32 *)dest;
+		ret = fetch_store_string_user(val + code->offset, dest, base);
+		break;
 	default:
 		return -EILSEQ;
 	}
@@ -123,7 +134,8 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
 		total += ret;
 		if (++i < code->param) {
 			code = s3;
-			if (s3->op != FETCH_OP_ST_STRING) {
+			if (s3->op != FETCH_OP_ST_STRING &&
+			    s3->op != FETCH_OP_ST_USTRING) {
 				dest += s3->size;
 				val += s3->size;
 				goto stage3;
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index be78d99ee6bc..f4e37c4f8a21 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -173,6 +173,12 @@ fetch_store_string(unsigned long addr, void *dest, void *base)
 	return ret;
 }
 
+static nokprobe_inline int
+fetch_store_string_user(unsigned long addr, void *dest, void *base)
+{
+	return fetch_store_string(addr, dest, base);
+}
+
 /* Return the length of string -- including null terminal byte */
 static nokprobe_inline int
 fetch_store_strlen(unsigned long addr)
@@ -185,6 +191,12 @@ fetch_store_strlen(unsigned long addr)
 	return (len > MAX_STRING_SIZE) ? 0 : len;
 }
 
+static nokprobe_inline int
+fetch_store_strlen_user(unsigned long addr)
+{
+	return fetch_store_strlen(addr);
+}
+
 static unsigned long translate_user_vaddr(unsigned long file_offset)
 {
 	unsigned long base_addr;


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH -tip v9 4/6] tracing/probe: Support user-space dereference
  2019-05-15  5:37 [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Masami Hiramatsu
                   ` (2 preceding siblings ...)
  2019-05-15  5:38 ` [PATCH -tip v9 3/6] tracing/probe: Add ustring type for user-space string Masami Hiramatsu
@ 2019-05-15  5:38 ` Masami Hiramatsu
  2019-05-15  5:38 ` [PATCH -tip v9 5/6] selftests/ftrace: Add user-memory access syntax testcase Masami Hiramatsu
                   ` (2 subsequent siblings)
  6 siblings, 0 replies; 13+ messages in thread
From: Masami Hiramatsu @ 2019-05-15  5:38 UTC (permalink / raw)
  To: Steven Rostedt, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra
  Cc: mhiramat, linux-kernel, Andy Lutomirski, Ingo Molnar,
	Andrew Morton, Changbin Du, Jann Horn, Kees Cook,
	Andy Lutomirski, Alexei Starovoitov, Nadav Amit, Joel Fernandes,
	yhs

Support user-space dereference syntax for probe event arguments
to dereference the data-structure or array in user-space.

The syntax is just adding 'u' before an offset value.

 +|-u<OFFSET>(<FETCHARG>)

e.g. +u8(%ax), +u0(+0(%si))

For example, if you probe do_sched_setscheduler(pid, policy,
param) and record param->sched_priority, you can add new
probe as below;

 p do_sched_setscheduler priority=+u0($arg3)

Note that kprobe event provides this and it doesn't change the
dereference method automatically because we do not know whether
the given address is in userspace or kernel on some archs.

So as same as "ustring", this is an option for user, who has to
carefully choose the dereference method.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 Changes in v9:
  - Remove an unneeded line break.
  - Move || and && in if-condition at the end of line.
 Changes in v7:
  - Fix typos and update document according to Steve's comment.
 Changes in v4:
  - Fix a bug for parsing argument and simplify code.
  - Fix documents accroding to Steve's comment.
 Changes in v3:
  - Add a section for user memory access to the document.
---
 Documentation/trace/kprobetrace.rst  |   27 ++++++++++++++++++++++-----
 Documentation/trace/uprobetracer.rst |   10 ++++++----
 kernel/trace/trace.c                 |    5 +++--
 kernel/trace/trace_kprobe.c          |    6 ++++++
 kernel/trace/trace_probe.c           |   25 ++++++++++++++++++-------
 kernel/trace/trace_probe.h           |    2 ++
 kernel/trace/trace_probe_tmpl.h      |   22 +++++++++++++++++-----
 kernel/trace/trace_uprobe.c          |    7 +++++++
 8 files changed, 81 insertions(+), 23 deletions(-)

diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst
index a3ac7c9ac242..09ff474493e1 100644
--- a/Documentation/trace/kprobetrace.rst
+++ b/Documentation/trace/kprobetrace.rst
@@ -51,7 +51,7 @@ Synopsis of kprobe_events
   $argN		: Fetch the Nth function argument. (N >= 1) (\*1)
   $retval	: Fetch return value.(\*2)
   $comm		: Fetch current task comm.
-  +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(\*3)
+  +|-[u]OFFS(FETCHARG) : Fetch memory at FETCHARG +|- OFFS address.(\*3)(\*4)
   NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
   FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
 		  (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types
@@ -61,6 +61,7 @@ Synopsis of kprobe_events
   (\*1) only for the probe on function entry (offs == 0).
   (\*2) only for return probe.
   (\*3) this is useful for fetching a field of data structures.
+  (\*4) "u" means user-space dereference. See :ref:`user_mem_access`.
 
 Types
 -----
@@ -79,10 +80,7 @@ wrong, but '+8($stack):x8[8]' is OK.)
 String type is a special type, which fetches a "null-terminated" string from
 kernel space. This means it will fail and store NULL if the string container
 has been paged out. "ustring" type is an alternative of string for user-space.
-Note that kprobe-event provides string/ustring types, but doesn't change it
-automatically. So user has to decide if the targe string in kernel or in user
-space carefully. On some arch, if you choose wrong one, it always fails to
-record string data.
+See :ref:`user_mem_access` for more info..
 The string array type is a bit different from other types. For other base
 types, <base-type>[1] is equal to <base-type> (e.g. +0(%di):x32[1] is same
 as +0(%di):x32.) But string[1] is not equal to string. The string type itself
@@ -97,6 +95,25 @@ Symbol type('symbol') is an alias of u32 or u64 type (depends on BITS_PER_LONG)
 which shows given pointer in "symbol+offset" style.
 For $comm, the default type is "string"; any other type is invalid.
 
+.. _user_mem_access:
+User Memory Access
+------------------
+Kprobe events supports user-space memory access. For that purpose, you can use
+either user-space dereference syntax or 'ustring' type.
+
+The user-space dereference syntax allows you to access a field of a data
+structure in user-space. This is done by adding the "u" prefix to the
+dereference syntax. For example, +u4(%si) means it will read memory from the
+address in the register %si offset by 4, and the memory is expected to be in
+user-space. You can use this for strings too, e.g. +u0(%si):string will read
+a string from the address in the register %si that is expected to be in user-
+space. 'ustring' is a shortcut way of performing the same task. That is,
++0(%si):ustring is equivalent to +u0(%si):string.
+
+Note that kprobe-event provides the user-memory access syntax but it doesn't
+use it transparently. This means if you use normal dereference or string type
+for user memory, it might fail, and may always fail on some archs. The user
+has to carefully check if the target data is in kernel or user space.
 
 Per-Probe Event Filtering
 -------------------------
diff --git a/Documentation/trace/uprobetracer.rst b/Documentation/trace/uprobetracer.rst
index 4346e23e3ae7..ab13319c66ac 100644
--- a/Documentation/trace/uprobetracer.rst
+++ b/Documentation/trace/uprobetracer.rst
@@ -42,16 +42,18 @@ Synopsis of uprobe_tracer
    @+OFFSET	: Fetch memory at OFFSET (OFFSET from same file as PATH)
    $stackN	: Fetch Nth entry of stack (N >= 0)
    $stack	: Fetch stack address.
-   $retval	: Fetch return value.(*)
+   $retval	: Fetch return value.(\*1)
    $comm	: Fetch current task comm.
-   +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
+   +|-[u]OFFS(FETCHARG) : Fetch memory at FETCHARG +|- OFFS address.(\*2)(\*3)
    NAME=FETCHARG     : Set NAME as the argument name of FETCHARG.
    FETCHARG:TYPE     : Set TYPE as the type of FETCHARG. Currently, basic types
 		       (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types
 		       (x8/x16/x32/x64), "string" and bitfield are supported.
 
-  (*) only for return probe.
-  (**) this is useful for fetching a field of data structures.
+  (\*1) only for return probe.
+  (\*2) this is useful for fetching a field of data structures.
+  (\*3) Unlike kprobe event, "u" prefix will just be ignored, becuse uprobe
+        events can access only user-space memory.
 
 Types
 -----
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 69687ad83228..a5ec61866cd6 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4807,10 +4807,11 @@ static const char readme_msg[] =
 	"\t     args: <name>=fetcharg[:type]\n"
 	"\t fetcharg: %<register>, @<address>, @<symbol>[+|-<offset>],\n"
 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
-	"\t           $stack<index>, $stack, $retval, $comm, $arg<N>\n"
+	"\t           $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
 #else
-	"\t           $stack<index>, $stack, $retval, $comm\n"
+	"\t           $stack<index>, $stack, $retval, $comm,\n"
 #endif
+	"\t           +|-[u]<offset>(<fetcharg>)\n"
 	"\t     type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"
 	"\t           b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
 	"\t           <type>\\[<array-size>\\]\n"
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index b24c87713f70..0ecd20364cbe 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -937,6 +937,12 @@ probe_mem_read(void *dest, void *src, size_t size)
 	return probe_kernel_read(dest, src, size);
 }
 
+static nokprobe_inline int
+probe_mem_read_user(void *dest, void *src, size_t size)
+{
+	return probe_user_read(dest, src, size);
+}
+
 /* Note that we don't verify it, since the code does not come from user space */
 static int
 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 30054136cfde..cbf19685d213 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -253,6 +253,7 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
 {
 	struct fetch_insn *code = *pcode;
 	unsigned long param;
+	int deref = FETCH_OP_DEREF;
 	long offset = 0;
 	char *tmp;
 	int ret = 0;
@@ -315,9 +316,14 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
 		break;
 
 	case '+':	/* deref memory */
-		arg++;	/* Skip '+', because kstrtol() rejects it. */
-		/* fall through */
 	case '-':
+		if (arg[1] == 'u') {
+			deref = FETCH_OP_UDEREF;
+			arg[1] = arg[0];
+			arg++;
+		}
+		if (arg[0] == '+')
+			arg++;	/* Skip '+', because kstrtol() rejects it. */
 		tmp = strchr(arg, '(');
 		if (!tmp)
 			return -EINVAL;
@@ -343,7 +349,7 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
 				return -E2BIG;
 			*pcode = code;
 
-			code->op = FETCH_OP_DEREF;
+			code->op = deref;
 			code->offset = offset;
 		}
 		break;
@@ -459,13 +465,14 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 	/* Store operation */
 	if (!strcmp(parg->type->name, "string") ||
 	    !strcmp(parg->type->name, "ustring")) {
-		if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM &&
-		    code->op != FETCH_OP_COMM) {
+		if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
+		    code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM) {
 			pr_info("string only accepts memory or address.\n");
 			ret = -EINVAL;
 			goto fail;
 		}
-		if (code->op != FETCH_OP_DEREF || parg->count) {
+		if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM) ||
+		     parg->count) {
 			/*
 			 * IMM and COMM is pointing actual address, those must
 			 * be kept, and if parg->count != 0, this is an array
@@ -478,7 +485,8 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 			}
 		}
 		/* If op == DEREF, replace it with STRING */
-		if (!strcmp(parg->type->name, "ustring"))
+		if (!strcmp(parg->type->name, "ustring") ||
+		    code->op == FETCH_OP_UDEREF)
 			code->op = FETCH_OP_ST_USTRING;
 		else
 			code->op = FETCH_OP_ST_STRING;
@@ -487,6 +495,9 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 	} else if (code->op == FETCH_OP_DEREF) {
 		code->op = FETCH_OP_ST_MEM;
 		code->size = parg->type->size;
+	} else if (code->op == FETCH_OP_UDEREF) {
+		code->op = FETCH_OP_ST_UMEM;
+		code->size = parg->type->size;
 	} else {
 		code++;
 		if (code->op != FETCH_OP_NOP) {
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 94cdcfdaced0..0feac0a81f82 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -92,9 +92,11 @@ enum fetch_op {
 	FETCH_OP_FOFFS,		/* File offset: .immediate */
 	// Stage 2 (dereference) op
 	FETCH_OP_DEREF,		/* Dereference: .offset */
+	FETCH_OP_UDEREF,	/* User-space Dereference: .offset */
 	// Stage 3 (store) ops
 	FETCH_OP_ST_RAW,	/* Raw: .size */
 	FETCH_OP_ST_MEM,	/* Mem: .offset, .size */
+	FETCH_OP_ST_UMEM,	/* Mem: .offset, .size */
 	FETCH_OP_ST_STRING,	/* String: .offset, .size */
 	FETCH_OP_ST_USTRING,	/* User String: .offset, .size */
 	// Stage 4 (modify) op
diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h
index 7526f6f8d7b0..a1b58ccdba9a 100644
--- a/kernel/trace/trace_probe_tmpl.h
+++ b/kernel/trace/trace_probe_tmpl.h
@@ -64,6 +64,8 @@ static nokprobe_inline int
 fetch_store_string_user(unsigned long addr, void *dest, void *base);
 static nokprobe_inline int
 probe_mem_read(void *dest, void *src, size_t size);
+static nokprobe_inline int
+probe_mem_read_user(void *dest, void *src, size_t size);
 
 /* From the 2nd stage, routine is same */
 static nokprobe_inline int
@@ -77,14 +79,21 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
 
 stage2:
 	/* 2nd stage: dereference memory if needed */
-	while (code->op == FETCH_OP_DEREF) {
-		lval = val;
-		ret = probe_mem_read(&val, (void *)val + code->offset,
-					sizeof(val));
+	do {
+		if (code->op == FETCH_OP_DEREF) {
+			lval = val;
+			ret = probe_mem_read(&val, (void *)val + code->offset,
+					     sizeof(val));
+		} else if (code->op == FETCH_OP_UDEREF) {
+			lval = val;
+			ret = probe_mem_read_user(&val,
+				 (void *)val + code->offset, sizeof(val));
+		} else
+			break;
 		if (ret)
 			return ret;
 		code++;
-	}
+	} while (1);
 
 	s3 = code;
 stage3:
@@ -109,6 +118,9 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
 	case FETCH_OP_ST_MEM:
 		probe_mem_read(dest, (void *)val + code->offset, code->size);
 		break;
+	case FETCH_OP_ST_UMEM:
+		probe_mem_read_user(dest, (void *)val + code->offset, code->size);
+		break;
 	case FETCH_OP_ST_STRING:
 		loc = *(u32 *)dest;
 		ret = fetch_store_string(val + code->offset, dest, base);
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index f4e37c4f8a21..5bc8c3686f6f 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -140,6 +140,13 @@ probe_mem_read(void *dest, void *src, size_t size)
 
 	return copy_from_user(dest, vaddr, size) ? -EFAULT : 0;
 }
+
+static nokprobe_inline int
+probe_mem_read_user(void *dest, void *src, size_t size)
+{
+	return probe_mem_read(dest, src, size);
+}
+
 /*
  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
  * length and relative data location.


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH -tip v9 5/6] selftests/ftrace: Add user-memory access syntax testcase
  2019-05-15  5:37 [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Masami Hiramatsu
                   ` (3 preceding siblings ...)
  2019-05-15  5:38 ` [PATCH -tip v9 4/6] tracing/probe: Support user-space dereference Masami Hiramatsu
@ 2019-05-15  5:38 ` Masami Hiramatsu
  2019-05-15  5:39 ` [PATCH -tip v9 6/6] perf-probe: Add user memory access attribute support Masami Hiramatsu
  2019-05-15  5:55 ` [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Ingo Molnar
  6 siblings, 0 replies; 13+ messages in thread
From: Masami Hiramatsu @ 2019-05-15  5:38 UTC (permalink / raw)
  To: Steven Rostedt, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra
  Cc: mhiramat, linux-kernel, Andy Lutomirski, Ingo Molnar,
	Andrew Morton, Changbin Du, Jann Horn, Kees Cook,
	Andy Lutomirski, Alexei Starovoitov, Nadav Amit, Joel Fernandes,
	yhs

Add a user-memory access syntax testcase which checks
new user-memory access syntax and ustring type.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 Changes in v6:
  - Add $argN availability check
---
 .../ftrace/test.d/kprobe/kprobe_args_user.tc       |   32 ++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc
new file mode 100644
index 000000000000..0f60087583d8
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc
@@ -0,0 +1,32 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Kprobe event user-memory access
+
+[ -f kprobe_events ] || exit_unsupported # this is configurable
+
+grep -q '\$arg<N>' README || exit_unresolved # depends on arch
+grep -A10 "fetcharg:" README | grep -q 'ustring' || exit_unsupported
+grep -A10 "fetcharg:" README | grep -q '\[u\]<offset>' || exit_unsupported
+
+:;: "user-memory access syntax and ustring working on user memory";:
+echo 'p:myevent do_sys_open path=+0($arg2):ustring path2=+u0($arg2):string' \
+	> kprobe_events
+
+grep myevent kprobe_events | \
+	grep -q 'path=+0($arg2):ustring path2=+u0($arg2):string'
+echo 1 > events/kprobes/myevent/enable
+echo > /dev/null
+echo 0 > events/kprobes/myevent/enable
+
+grep myevent trace | grep -q 'path="/dev/null" path2="/dev/null"'
+
+:;: "user-memory access syntax and ustring not working with kernel memory";:
+echo 'p:myevent vfs_symlink path=+0($arg3):ustring path2=+u0($arg3):string' \
+	> kprobe_events
+echo 1 > events/kprobes/myevent/enable
+ln -s foo $TMPDIR/bar
+echo 0 > events/kprobes/myevent/enable
+
+grep myevent trace | grep -q 'path=(fault) path2=(fault)'
+
+exit 0


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH -tip v9 6/6] perf-probe: Add user memory access attribute support
  2019-05-15  5:37 [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Masami Hiramatsu
                   ` (4 preceding siblings ...)
  2019-05-15  5:38 ` [PATCH -tip v9 5/6] selftests/ftrace: Add user-memory access syntax testcase Masami Hiramatsu
@ 2019-05-15  5:39 ` Masami Hiramatsu
  2019-05-15  5:55 ` [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Ingo Molnar
  6 siblings, 0 replies; 13+ messages in thread
From: Masami Hiramatsu @ 2019-05-15  5:39 UTC (permalink / raw)
  To: Steven Rostedt, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra
  Cc: mhiramat, linux-kernel, Andy Lutomirski, Ingo Molnar,
	Andrew Morton, Changbin Du, Jann Horn, Kees Cook,
	Andy Lutomirski, Alexei Starovoitov, Nadav Amit, Joel Fernandes,
	yhs

Add user memory access attribute for kprobe event arguments.
If a given 'local variable' is in user-space, User can
specify memory access method by '@user' suffix. This is
not only for string but also for data structure.

If we access a field of data structure in user memory from
kernel on some arch, it will fail. e.g.

 perf probe -a "sched_setscheduler param->sched_priority"

This will fail to access the "param->sched_priority" because
the param is __user pointer. Instead, we can now specify
@user suffix for such argument.

 perf probe -a "sched_setscheduler param->sched_priority@user"

Note that kernel memory access with "@user" must always fail
on any arch.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 Changes in v8
  - Fix a typo and rename user field to user_access field. (Thanks Ingo!)
---
 tools/perf/Documentation/perf-probe.txt |    3 ++-
 tools/perf/util/probe-event.c           |   11 +++++++++++
 tools/perf/util/probe-event.h           |    2 ++
 tools/perf/util/probe-file.c            |    7 +++++++
 tools/perf/util/probe-file.h            |    1 +
 tools/perf/util/probe-finder.c          |   19 ++++++++++++-------
 6 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index b6866a05edd2..ed3ecfa422e1 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -194,12 +194,13 @@ PROBE ARGUMENT
 --------------
 Each probe argument follows below syntax.
 
- [NAME=]LOCALVAR|$retval|%REG|@SYMBOL[:TYPE]
+ [NAME=]LOCALVAR|$retval|%REG|@SYMBOL[:TYPE][@user]
 
 'NAME' specifies the name of this argument (optional). You can use the name of local variable, local data structure member (e.g. var->field, var.field2), local array with fixed index (e.g. array[1], var->array[0], var->pointer[2]), or kprobe-tracer argument format (e.g. $retval, %ax, etc). Note that the name of this argument will be set as the last member name if you specify a local data structure member (e.g. field2 for 'var->field1.field2'.)
 '$vars' and '$params' special arguments are also available for NAME, '$vars' is expanded to the local variables (including function parameters) which can access at given probe point. '$params' is expanded to only the function parameters.
 'TYPE' casts the type of this argument (optional). If omitted, perf probe automatically set the type based on debuginfo (*). Currently, basic types (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal integers (x/x8/x16/x32/x64), signedness casting (u/s), "string" and bitfield are supported. (see TYPES for detail)
 On x86 systems %REG is always the short form of the register: for example %AX. %RAX or %EAX is not valid.
+"@user" is a special attribute which means the LOCALVAR will be treated as a user-space memory. This is only valid for kprobe event.
 
 TYPES
 -----
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 198e09ff611e..a7ca17be5fc5 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1577,6 +1577,17 @@ static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
 		str = tmp + 1;
 	}
 
+	tmp = strchr(str, '@');
+	if (tmp && tmp != str && strcmp(tmp + 1, "user")) { /* user attr */
+		if (!user_access_is_supported()) {
+			semantic_error("ftrace does not support user access\n");
+			return -EINVAL;
+		}
+		*tmp = '\0';
+		arg->user_access = true;
+		pr_debug("user_access ");
+	}
+
 	tmp = strchr(str, ':');
 	if (tmp) {	/* Type setting */
 		*tmp = '\0';
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 05c8d571a901..96a319cd2378 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -37,6 +37,7 @@ struct probe_trace_point {
 struct probe_trace_arg_ref {
 	struct probe_trace_arg_ref	*next;	/* Next reference */
 	long				offset;	/* Offset value */
+	bool				user_access;	/* User-memory access */
 };
 
 /* kprobe-tracer and uprobe-tracer tracing argument */
@@ -82,6 +83,7 @@ struct perf_probe_arg {
 	char				*var;	/* Variable name */
 	char				*type;	/* Type name */
 	struct perf_probe_arg_field	*field;	/* Structure fields */
+	bool				user_access;	/* User-memory access */
 };
 
 /* Perf probe probing event (point + arg) */
diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
index 4062bc4412a9..89ce1a9c3798 100644
--- a/tools/perf/util/probe-file.c
+++ b/tools/perf/util/probe-file.c
@@ -1015,6 +1015,7 @@ enum ftrace_readme {
 	FTRACE_README_PROBE_TYPE_X = 0,
 	FTRACE_README_KRETPROBE_OFFSET,
 	FTRACE_README_UPROBE_REF_CTR,
+	FTRACE_README_USER_ACCESS,
 	FTRACE_README_END,
 };
 
@@ -1027,6 +1028,7 @@ static struct {
 	DEFINE_TYPE(FTRACE_README_PROBE_TYPE_X, "*type: * x8/16/32/64,*"),
 	DEFINE_TYPE(FTRACE_README_KRETPROBE_OFFSET, "*place (kretprobe): *"),
 	DEFINE_TYPE(FTRACE_README_UPROBE_REF_CTR, "*ref_ctr_offset*"),
+	DEFINE_TYPE(FTRACE_README_USER_ACCESS, "*[u]<offset>*"),
 };
 
 static bool scan_ftrace_readme(enum ftrace_readme type)
@@ -1087,3 +1089,8 @@ bool uprobe_ref_ctr_is_supported(void)
 {
 	return scan_ftrace_readme(FTRACE_README_UPROBE_REF_CTR);
 }
+
+bool user_access_is_supported(void)
+{
+	return scan_ftrace_readme(FTRACE_README_USER_ACCESS);
+}
diff --git a/tools/perf/util/probe-file.h b/tools/perf/util/probe-file.h
index 2a249182f2a6..986c1c94f64f 100644
--- a/tools/perf/util/probe-file.h
+++ b/tools/perf/util/probe-file.h
@@ -70,6 +70,7 @@ int probe_cache__show_all_caches(struct strfilter *filter);
 bool probe_type_is_available(enum probe_type type);
 bool kretprobe_offset_is_supported(void);
 bool uprobe_ref_ctr_is_supported(void);
+bool user_access_is_supported(void);
 #else	/* ! HAVE_LIBELF_SUPPORT */
 static inline struct probe_cache *probe_cache__new(const char *tgt __maybe_unused, struct nsinfo *nsi __maybe_unused)
 {
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index c37fbef1711d..c202027716d0 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -294,7 +294,7 @@ static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 
 static int convert_variable_type(Dwarf_Die *vr_die,
 				 struct probe_trace_arg *tvar,
-				 const char *cast)
+				 const char *cast, bool user_access)
 {
 	struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 	Dwarf_Die type;
@@ -334,7 +334,8 @@ static int convert_variable_type(Dwarf_Die *vr_die,
 	pr_debug("%s type is %s.\n",
 		 dwarf_diename(vr_die), dwarf_diename(&type));
 
-	if (cast && strcmp(cast, "string") == 0) {	/* String type */
+	if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
+		/* String type */
 		ret = dwarf_tag(&type);
 		if (ret != DW_TAG_pointer_type &&
 		    ret != DW_TAG_array_type) {
@@ -357,6 +358,7 @@ static int convert_variable_type(Dwarf_Die *vr_die,
 				pr_warning("Out of memory error\n");
 				return -ENOMEM;
 			}
+			(*ref_ptr)->user_access = user_access;
 		}
 		if (!die_compare_name(&type, "char") &&
 		    !die_compare_name(&type, "unsigned char")) {
@@ -411,7 +413,7 @@ static int convert_variable_type(Dwarf_Die *vr_die,
 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 				    struct perf_probe_arg_field *field,
 				    struct probe_trace_arg_ref **ref_ptr,
-				    Dwarf_Die *die_mem)
+				    Dwarf_Die *die_mem, bool user_access)
 {
 	struct probe_trace_arg_ref *ref = *ref_ptr;
 	Dwarf_Die type;
@@ -448,6 +450,7 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 				*ref_ptr = ref;
 		}
 		ref->offset += dwarf_bytesize(&type) * field->index;
+		ref->user_access = user_access;
 		goto next;
 	} else if (tag == DW_TAG_pointer_type) {
 		/* Check the pointer and dereference */
@@ -519,17 +522,18 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 		}
 	}
 	ref->offset += (long)offs;
+	ref->user_access = user_access;
 
 	/* If this member is unnamed, we need to reuse this field */
 	if (!dwarf_diename(die_mem))
 		return convert_variable_fields(die_mem, varname, field,
-						&ref, die_mem);
+						&ref, die_mem, user_access);
 
 next:
 	/* Converting next field */
 	if (field->next)
 		return convert_variable_fields(die_mem, field->name,
-					field->next, &ref, die_mem);
+				field->next, &ref, die_mem, user_access);
 	else
 		return 0;
 }
@@ -555,11 +559,12 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 	else if (ret == 0 && pf->pvar->field) {
 		ret = convert_variable_fields(vr_die, pf->pvar->var,
 					      pf->pvar->field, &pf->tvar->ref,
-					      &die_mem);
+					      &die_mem, pf->pvar->user_access);
 		vr_die = &die_mem;
 	}
 	if (ret == 0)
-		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
+		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
+					    pf->pvar->user_access);
 	/* *expr will be cached in libdw. Don't free it. */
 	return ret;
 }


^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access
  2019-05-15  5:37 [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Masami Hiramatsu
                   ` (5 preceding siblings ...)
  2019-05-15  5:39 ` [PATCH -tip v9 6/6] perf-probe: Add user memory access attribute support Masami Hiramatsu
@ 2019-05-15  5:55 ` Ingo Molnar
  2019-05-15  8:49   ` Masami Hiramatsu
  2019-05-20 15:26   ` Steven Rostedt
  6 siblings, 2 replies; 13+ messages in thread
From: Ingo Molnar @ 2019-05-15  5:55 UTC (permalink / raw)
  To: Masami Hiramatsu
  Cc: Steven Rostedt, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra, linux-kernel,
	Andy Lutomirski, Andrew Morton, Changbin Du, Jann Horn,
	Kees Cook, Andy Lutomirski, Alexei Starovoitov, Nadav Amit,
	Joel Fernandes, yhs


* Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Hi,
> 
> Here is the v9 series of probe-event to support user-space access.
> Previous version is here.
> 
> https://lkml.kernel.org/r/155741476971.28419.15837024173365724167.stgit@devnote2
> 
> In this version, I fixed more typos/style issues.
> 
> Changes in v9:
>  [3/6]
>       - Fix other style & coding issues (Thanks Ingo!)
>       - Update fetch_store_string() for style consistency.
>  [4/6]
>       - Remove an unneeded line break.
>       - Move || and && in if-condition at the end of line.

LGTM:

Acked-by: Ingo Molnar <mingo@kernel.org>

Thanks,

	Ingo

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access
  2019-05-15  5:55 ` [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Ingo Molnar
@ 2019-05-15  8:49   ` Masami Hiramatsu
  2019-05-20 15:26   ` Steven Rostedt
  1 sibling, 0 replies; 13+ messages in thread
From: Masami Hiramatsu @ 2019-05-15  8:49 UTC (permalink / raw)
  To: Ingo Molnar
  Cc: Steven Rostedt, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra, linux-kernel,
	Andy Lutomirski, Andrew Morton, Changbin Du, Jann Horn,
	Kees Cook, Andy Lutomirski, Alexei Starovoitov, Nadav Amit,
	Joel Fernandes, yhs

Hi Ingo,

On Wed, 15 May 2019 07:55:34 +0200
Ingo Molnar <mingo@kernel.org> wrote:

> 
> * Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 
> > Hi,
> > 
> > Here is the v9 series of probe-event to support user-space access.
> > Previous version is here.
> > 
> > https://lkml.kernel.org/r/155741476971.28419.15837024173365724167.stgit@devnote2
> > 
> > In this version, I fixed more typos/style issues.
> > 
> > Changes in v9:
> >  [3/6]
> >       - Fix other style & coding issues (Thanks Ingo!)
> >       - Update fetch_store_string() for style consistency.
> >  [4/6]
> >       - Remove an unneeded line break.
> >       - Move || and && in if-condition at the end of line.
> 
> LGTM:
> 
> Acked-by: Ingo Molnar <mingo@kernel.org>

Thank you for your Ack!

> 
> Thanks,
> 
> 	Ingo


-- 
Masami Hiramatsu <mhiramat@kernel.org>

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access
  2019-05-15  5:55 ` [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Ingo Molnar
  2019-05-15  8:49   ` Masami Hiramatsu
@ 2019-05-20 15:26   ` Steven Rostedt
  2019-05-21  8:28     ` Ingo Molnar
  1 sibling, 1 reply; 13+ messages in thread
From: Steven Rostedt @ 2019-05-20 15:26 UTC (permalink / raw)
  To: Ingo Molnar
  Cc: Masami Hiramatsu, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra, linux-kernel,
	Andy Lutomirski, Andrew Morton, Changbin Du, Jann Horn,
	Kees Cook, Andy Lutomirski, Alexei Starovoitov, Nadav Amit,
	Joel Fernandes, yhs

On Wed, 15 May 2019 07:55:34 +0200
Ingo Molnar <mingo@kernel.org> wrote:

> * Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 
> > Hi,
> > 
> > Here is the v9 series of probe-event to support user-space access.
> > Previous version is here.
> > 
> > https://lkml.kernel.org/r/155741476971.28419.15837024173365724167.stgit@devnote2
> > 
> > In this version, I fixed more typos/style issues.
> > 
> > Changes in v9:
> >  [3/6]
> >       - Fix other style & coding issues (Thanks Ingo!)
> >       - Update fetch_store_string() for style consistency.
> >  [4/6]
> >       - Remove an unneeded line break.
> >       - Move || and && in if-condition at the end of line.  
> 
> LGTM:
> 
> Acked-by: Ingo Molnar <mingo@kernel.org>
> 

Hi Ingo,

Do you want me to take this through my tree, or do you want to take it
through yours?

Thanks,

-- Steve

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access
  2019-05-20 15:26   ` Steven Rostedt
@ 2019-05-21  8:28     ` Ingo Molnar
  2019-05-21 12:57       ` Steven Rostedt
  0 siblings, 1 reply; 13+ messages in thread
From: Ingo Molnar @ 2019-05-21  8:28 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: Masami Hiramatsu, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra, linux-kernel,
	Andy Lutomirski, Andrew Morton, Changbin Du, Jann Horn,
	Kees Cook, Andy Lutomirski, Alexei Starovoitov, Nadav Amit,
	Joel Fernandes, yhs


* Steven Rostedt <rostedt@goodmis.org> wrote:

> On Wed, 15 May 2019 07:55:34 +0200
> Ingo Molnar <mingo@kernel.org> wrote:
> 
> > * Masami Hiramatsu <mhiramat@kernel.org> wrote:
> > 
> > > Hi,
> > > 
> > > Here is the v9 series of probe-event to support user-space access.
> > > Previous version is here.
> > > 
> > > https://lkml.kernel.org/r/155741476971.28419.15837024173365724167.stgit@devnote2
> > > 
> > > In this version, I fixed more typos/style issues.
> > > 
> > > Changes in v9:
> > >  [3/6]
> > >       - Fix other style & coding issues (Thanks Ingo!)
> > >       - Update fetch_store_string() for style consistency.
> > >  [4/6]
> > >       - Remove an unneeded line break.
> > >       - Move || and && in if-condition at the end of line.  
> > 
> > LGTM:
> > 
> > Acked-by: Ingo Molnar <mingo@kernel.org>
> > 
> 
> Hi Ingo,
> 
> Do you want me to take this through my tree, or do you want to take it
> through yours?

Since these changes are more heavy on the kernel/tracing/ side I suspect 
your tree is the better match for this series?

Thanks,

	Ingo

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access
  2019-05-21  8:28     ` Ingo Molnar
@ 2019-05-21 12:57       ` Steven Rostedt
  2019-05-21 15:57         ` Masami Hiramatsu
  0 siblings, 1 reply; 13+ messages in thread
From: Steven Rostedt @ 2019-05-21 12:57 UTC (permalink / raw)
  To: Ingo Molnar
  Cc: Masami Hiramatsu, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra, linux-kernel,
	Andy Lutomirski, Andrew Morton, Changbin Du, Jann Horn,
	Kees Cook, Andy Lutomirski, Alexei Starovoitov, Nadav Amit,
	Joel Fernandes, yhs

On Tue, 21 May 2019 10:28:09 +0200
Ingo Molnar <mingo@kernel.org> wrote:

> > Hi Ingo,
> > 
> > Do you want me to take this through my tree, or do you want to take it
> > through yours?  
> 
> Since these changes are more heavy on the kernel/tracing/ side I suspect 
> your tree is the better match for this series?

No problem. Will do, and thanks for the Ack.

-- Steve

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access
  2019-05-21 12:57       ` Steven Rostedt
@ 2019-05-21 15:57         ` Masami Hiramatsu
  0 siblings, 0 replies; 13+ messages in thread
From: Masami Hiramatsu @ 2019-05-21 15:57 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: Ingo Molnar, Masami Hiramatsu, Linus Torvalds, Shuah Khan,
	Arnaldo Carvalho de Melo, Peter Zijlstra, linux-kernel,
	Andy Lutomirski, Andrew Morton, Changbin Du, Jann Horn,
	Kees Cook, Andy Lutomirski, Alexei Starovoitov, Nadav Amit,
	Joel Fernandes, yhs

On Tue, 21 May 2019 08:57:41 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Tue, 21 May 2019 10:28:09 +0200
> Ingo Molnar <mingo@kernel.org> wrote:
> 
> > > Hi Ingo,
> > > 
> > > Do you want me to take this through my tree, or do you want to take it
> > > through yours?  
> > 
> > Since these changes are more heavy on the kernel/tracing/ side I suspect 
> > your tree is the better match for this series?
> 
> No problem. Will do, and thanks for the Ack.

Thank you Steve for picking it up!


-- 
Masami Hiramatsu <mhiramat@kernel.org>

^ permalink raw reply	[flat|nested] 13+ messages in thread

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-- links below jump to the message on this page --
2019-05-15  5:37 [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Masami Hiramatsu
2019-05-15  5:38 ` [PATCH -tip v9 1/6] x86/uaccess: Allow access_ok() in irq context if pagefault_disabled Masami Hiramatsu
2019-05-15  5:38 ` [PATCH -tip v9 2/6] uaccess: Add non-pagefault user-space read functions Masami Hiramatsu
2019-05-15  5:38 ` [PATCH -tip v9 3/6] tracing/probe: Add ustring type for user-space string Masami Hiramatsu
2019-05-15  5:38 ` [PATCH -tip v9 4/6] tracing/probe: Support user-space dereference Masami Hiramatsu
2019-05-15  5:38 ` [PATCH -tip v9 5/6] selftests/ftrace: Add user-memory access syntax testcase Masami Hiramatsu
2019-05-15  5:39 ` [PATCH -tip v9 6/6] perf-probe: Add user memory access attribute support Masami Hiramatsu
2019-05-15  5:55 ` [PATCH -tip v9 0/6] tracing/probes: uaccess: Add support user-space access Ingo Molnar
2019-05-15  8:49   ` Masami Hiramatsu
2019-05-20 15:26   ` Steven Rostedt
2019-05-21  8:28     ` Ingo Molnar
2019-05-21 12:57       ` Steven Rostedt
2019-05-21 15:57         ` Masami Hiramatsu

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git