The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 9e298e8604088a600d8100a111a532a9d342af09 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz(a)infradead.org>
Date: Wed, 1 May 2019 15:11:17 +0200
Subject: [PATCH] ftrace/x86_64: Emulate call function while updating in
breakpoint handler
Nicolai Stange discovered[1] that if live kernel patching is enabled, and the
function tracer started tracing the same function that was patched, the
conversion of the fentry call site during the translation of going from
calling the live kernel patch trampoline to the iterator trampoline, would
have as slight window where it didn't call anything.
As live kernel patching depends on ftrace to always call its code (to
prevent the function being traced from being called, as it will redirect
it). This small window would allow the old buggy function to be called, and
this can cause undesirable results.
Nicolai submitted new patches[2] but these were controversial. As this is
similar to the static call emulation issues that came up a while ago[3].
But after some debate[4][5] adding a gap in the stack when entering the
breakpoint handler allows for pushing the return address onto the stack to
easily emulate a call.
[1] http://lkml.kernel.org/r/20180726104029.7736-1-nstange@suse.de
[2] http://lkml.kernel.org/r/20190427100639.15074-1-nstange@suse.de
[3] http://lkml.kernel.org/r/3cf04e113d71c9f8e4be95fb84a510f085aa4afa.154171145…
[4] http://lkml.kernel.org/r/CAHk-=wh5OpheSU8Em_Q3Hg8qw_JtoijxOdPtHru6d+5K8TWM=…
[5] http://lkml.kernel.org/r/CAHk-=wjvQxY4DvPrJ6haPgAa6b906h=MwZXO6G8OtiTGe=N7_…
[
Live kernel patching is not implemented on x86_32, thus the emulate
calls are only for x86_64.
]
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Nicolai Stange <nstange(a)suse.de>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Ingo Molnar <mingo(a)redhat.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: "H. Peter Anvin" <hpa(a)zytor.com>
Cc: the arch/x86 maintainers <x86(a)kernel.org>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Miroslav Benes <mbenes(a)suse.cz>
Cc: Petr Mladek <pmladek(a)suse.com>
Cc: Joe Lawrence <joe.lawrence(a)redhat.com>
Cc: Shuah Khan <shuah(a)kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de>
Cc: Mimi Zohar <zohar(a)linux.ibm.com>
Cc: Juergen Gross <jgross(a)suse.com>
Cc: Nick Desaulniers <ndesaulniers(a)google.com>
Cc: Nayna Jain <nayna(a)linux.ibm.com>
Cc: Masahiro Yamada <yamada.masahiro(a)socionext.com>
Cc: Joerg Roedel <jroedel(a)suse.de>
Cc: "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest(a)vger.kernel.org>
Cc: stable(a)vger.kernel.org
Fixes: b700e7f03df5 ("livepatch: kernel: add support for live patching")
Tested-by: Nicolai Stange <nstange(a)suse.de>
Reviewed-by: Nicolai Stange <nstange(a)suse.de>
Reviewed-by: Masami Hiramatsu <mhiramat(a)kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
[ Changed to only implement emulated calls for x86_64 ]
Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index ef49517f6bb2..bd553b3af22e 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -29,6 +29,7 @@
#include <asm/kprobes.h>
#include <asm/ftrace.h>
#include <asm/nops.h>
+#include <asm/text-patching.h>
#ifdef CONFIG_DYNAMIC_FTRACE
@@ -231,6 +232,7 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
}
static unsigned long ftrace_update_func;
+static unsigned long ftrace_update_func_call;
static int update_ftrace_func(unsigned long ip, void *new)
{
@@ -259,6 +261,8 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
unsigned char *new;
int ret;
+ ftrace_update_func_call = (unsigned long)func;
+
new = ftrace_call_replace(ip, (unsigned long)func);
ret = update_ftrace_func(ip, new);
@@ -294,13 +298,28 @@ int ftrace_int3_handler(struct pt_regs *regs)
if (WARN_ON_ONCE(!regs))
return 0;
- ip = regs->ip - 1;
- if (!ftrace_location(ip) && !is_ftrace_caller(ip))
- return 0;
+ ip = regs->ip - INT3_INSN_SIZE;
- regs->ip += MCOUNT_INSN_SIZE - 1;
+#ifdef CONFIG_X86_64
+ if (ftrace_location(ip)) {
+ int3_emulate_call(regs, (unsigned long)ftrace_regs_caller);
+ return 1;
+ } else if (is_ftrace_caller(ip)) {
+ if (!ftrace_update_func_call) {
+ int3_emulate_jmp(regs, ip + CALL_INSN_SIZE);
+ return 1;
+ }
+ int3_emulate_call(regs, ftrace_update_func_call);
+ return 1;
+ }
+#else
+ if (ftrace_location(ip) || is_ftrace_caller(ip)) {
+ int3_emulate_jmp(regs, ip + CALL_INSN_SIZE);
+ return 1;
+ }
+#endif
- return 1;
+ return 0;
}
NOKPROBE_SYMBOL(ftrace_int3_handler);
@@ -859,6 +878,8 @@ void arch_ftrace_update_trampoline(struct ftrace_ops *ops)
func = ftrace_ops_get_func(ops);
+ ftrace_update_func_call = (unsigned long)func;
+
/* Do a safe modify in case the trampoline is executing */
new = ftrace_call_replace(ip, (unsigned long)func);
ret = update_ftrace_func(ip, new);
@@ -960,6 +981,7 @@ static int ftrace_mod_jmp(unsigned long ip, void *func)
{
unsigned char *new;
+ ftrace_update_func_call = 0UL;
new = ftrace_jmp_replace(ip, (unsigned long)func);
return update_ftrace_func(ip, new);
The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 9e298e8604088a600d8100a111a532a9d342af09 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz(a)infradead.org>
Date: Wed, 1 May 2019 15:11:17 +0200
Subject: [PATCH] ftrace/x86_64: Emulate call function while updating in
breakpoint handler
Nicolai Stange discovered[1] that if live kernel patching is enabled, and the
function tracer started tracing the same function that was patched, the
conversion of the fentry call site during the translation of going from
calling the live kernel patch trampoline to the iterator trampoline, would
have as slight window where it didn't call anything.
As live kernel patching depends on ftrace to always call its code (to
prevent the function being traced from being called, as it will redirect
it). This small window would allow the old buggy function to be called, and
this can cause undesirable results.
Nicolai submitted new patches[2] but these were controversial. As this is
similar to the static call emulation issues that came up a while ago[3].
But after some debate[4][5] adding a gap in the stack when entering the
breakpoint handler allows for pushing the return address onto the stack to
easily emulate a call.
[1] http://lkml.kernel.org/r/20180726104029.7736-1-nstange@suse.de
[2] http://lkml.kernel.org/r/20190427100639.15074-1-nstange@suse.de
[3] http://lkml.kernel.org/r/3cf04e113d71c9f8e4be95fb84a510f085aa4afa.154171145…
[4] http://lkml.kernel.org/r/CAHk-=wh5OpheSU8Em_Q3Hg8qw_JtoijxOdPtHru6d+5K8TWM=…
[5] http://lkml.kernel.org/r/CAHk-=wjvQxY4DvPrJ6haPgAa6b906h=MwZXO6G8OtiTGe=N7_…
[
Live kernel patching is not implemented on x86_32, thus the emulate
calls are only for x86_64.
]
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Nicolai Stange <nstange(a)suse.de>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Ingo Molnar <mingo(a)redhat.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: "H. Peter Anvin" <hpa(a)zytor.com>
Cc: the arch/x86 maintainers <x86(a)kernel.org>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Miroslav Benes <mbenes(a)suse.cz>
Cc: Petr Mladek <pmladek(a)suse.com>
Cc: Joe Lawrence <joe.lawrence(a)redhat.com>
Cc: Shuah Khan <shuah(a)kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de>
Cc: Mimi Zohar <zohar(a)linux.ibm.com>
Cc: Juergen Gross <jgross(a)suse.com>
Cc: Nick Desaulniers <ndesaulniers(a)google.com>
Cc: Nayna Jain <nayna(a)linux.ibm.com>
Cc: Masahiro Yamada <yamada.masahiro(a)socionext.com>
Cc: Joerg Roedel <jroedel(a)suse.de>
Cc: "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest(a)vger.kernel.org>
Cc: stable(a)vger.kernel.org
Fixes: b700e7f03df5 ("livepatch: kernel: add support for live patching")
Tested-by: Nicolai Stange <nstange(a)suse.de>
Reviewed-by: Nicolai Stange <nstange(a)suse.de>
Reviewed-by: Masami Hiramatsu <mhiramat(a)kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
[ Changed to only implement emulated calls for x86_64 ]
Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index ef49517f6bb2..bd553b3af22e 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -29,6 +29,7 @@
#include <asm/kprobes.h>
#include <asm/ftrace.h>
#include <asm/nops.h>
+#include <asm/text-patching.h>
#ifdef CONFIG_DYNAMIC_FTRACE
@@ -231,6 +232,7 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
}
static unsigned long ftrace_update_func;
+static unsigned long ftrace_update_func_call;
static int update_ftrace_func(unsigned long ip, void *new)
{
@@ -259,6 +261,8 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
unsigned char *new;
int ret;
+ ftrace_update_func_call = (unsigned long)func;
+
new = ftrace_call_replace(ip, (unsigned long)func);
ret = update_ftrace_func(ip, new);
@@ -294,13 +298,28 @@ int ftrace_int3_handler(struct pt_regs *regs)
if (WARN_ON_ONCE(!regs))
return 0;
- ip = regs->ip - 1;
- if (!ftrace_location(ip) && !is_ftrace_caller(ip))
- return 0;
+ ip = regs->ip - INT3_INSN_SIZE;
- regs->ip += MCOUNT_INSN_SIZE - 1;
+#ifdef CONFIG_X86_64
+ if (ftrace_location(ip)) {
+ int3_emulate_call(regs, (unsigned long)ftrace_regs_caller);
+ return 1;
+ } else if (is_ftrace_caller(ip)) {
+ if (!ftrace_update_func_call) {
+ int3_emulate_jmp(regs, ip + CALL_INSN_SIZE);
+ return 1;
+ }
+ int3_emulate_call(regs, ftrace_update_func_call);
+ return 1;
+ }
+#else
+ if (ftrace_location(ip) || is_ftrace_caller(ip)) {
+ int3_emulate_jmp(regs, ip + CALL_INSN_SIZE);
+ return 1;
+ }
+#endif
- return 1;
+ return 0;
}
NOKPROBE_SYMBOL(ftrace_int3_handler);
@@ -859,6 +878,8 @@ void arch_ftrace_update_trampoline(struct ftrace_ops *ops)
func = ftrace_ops_get_func(ops);
+ ftrace_update_func_call = (unsigned long)func;
+
/* Do a safe modify in case the trampoline is executing */
new = ftrace_call_replace(ip, (unsigned long)func);
ret = update_ftrace_func(ip, new);
@@ -960,6 +981,7 @@ static int ftrace_mod_jmp(unsigned long ip, void *func)
{
unsigned char *new;
+ ftrace_update_func_call = 0UL;
new = ftrace_jmp_replace(ip, (unsigned long)func);
return update_ftrace_func(ip, new);
The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 4b33dadf37666c0860b88f9e52a16d07bf6d0b03 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz(a)infradead.org>
Date: Wed, 1 May 2019 15:11:17 +0200
Subject: [PATCH] x86_64: Allow breakpoints to emulate call instructions
In order to allow breakpoints to emulate call instructions, they need to push
the return address onto the stack. The x86_64 int3 handler adds a small gap
to allow the stack to grow some. Use this gap to add the return address to
be able to emulate a call instruction at the breakpoint location.
These helper functions are added:
int3_emulate_jmp(): changes the location of the regs->ip to return there.
(The next two are only for x86_64)
int3_emulate_push(): to push the address onto the gap in the stack
int3_emulate_call(): push the return address and change regs->ip
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Nicolai Stange <nstange(a)suse.de>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Ingo Molnar <mingo(a)redhat.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: "H. Peter Anvin" <hpa(a)zytor.com>
Cc: the arch/x86 maintainers <x86(a)kernel.org>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Miroslav Benes <mbenes(a)suse.cz>
Cc: Petr Mladek <pmladek(a)suse.com>
Cc: Joe Lawrence <joe.lawrence(a)redhat.com>
Cc: Shuah Khan <shuah(a)kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de>
Cc: Mimi Zohar <zohar(a)linux.ibm.com>
Cc: Juergen Gross <jgross(a)suse.com>
Cc: Nick Desaulniers <ndesaulniers(a)google.com>
Cc: Nayna Jain <nayna(a)linux.ibm.com>
Cc: Masahiro Yamada <yamada.masahiro(a)socionext.com>
Cc: Joerg Roedel <jroedel(a)suse.de>
Cc: "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest(a)vger.kernel.org>
Cc: stable(a)vger.kernel.org
Fixes: b700e7f03df5 ("livepatch: kernel: add support for live patching")
Tested-by: Nicolai Stange <nstange(a)suse.de>
Reviewed-by: Nicolai Stange <nstange(a)suse.de>
Reviewed-by: Masami Hiramatsu <mhiramat(a)kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
[ Modified to only work for x86_64 and added comment to int3_emulate_push() ]
Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index e85ff65c43c3..05861cc08787 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -39,4 +39,32 @@ extern int poke_int3_handler(struct pt_regs *regs);
extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
extern int after_bootmem;
+static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
+{
+ regs->ip = ip;
+}
+
+#define INT3_INSN_SIZE 1
+#define CALL_INSN_SIZE 5
+
+#ifdef CONFIG_X86_64
+static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val)
+{
+ /*
+ * The int3 handler in entry_64.S adds a gap between the
+ * stack where the break point happened, and the saving of
+ * pt_regs. We can extend the original stack because of
+ * this gap. See the idtentry macro's create_gap option.
+ */
+ regs->sp -= sizeof(unsigned long);
+ *(unsigned long *)regs->sp = val;
+}
+
+static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func)
+{
+ int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE);
+ int3_emulate_jmp(regs, func);
+}
+#endif
+
#endif /* _ASM_X86_TEXT_PATCHING_H */
The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 4b33dadf37666c0860b88f9e52a16d07bf6d0b03 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz(a)infradead.org>
Date: Wed, 1 May 2019 15:11:17 +0200
Subject: [PATCH] x86_64: Allow breakpoints to emulate call instructions
In order to allow breakpoints to emulate call instructions, they need to push
the return address onto the stack. The x86_64 int3 handler adds a small gap
to allow the stack to grow some. Use this gap to add the return address to
be able to emulate a call instruction at the breakpoint location.
These helper functions are added:
int3_emulate_jmp(): changes the location of the regs->ip to return there.
(The next two are only for x86_64)
int3_emulate_push(): to push the address onto the gap in the stack
int3_emulate_call(): push the return address and change regs->ip
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Nicolai Stange <nstange(a)suse.de>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Ingo Molnar <mingo(a)redhat.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: "H. Peter Anvin" <hpa(a)zytor.com>
Cc: the arch/x86 maintainers <x86(a)kernel.org>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Miroslav Benes <mbenes(a)suse.cz>
Cc: Petr Mladek <pmladek(a)suse.com>
Cc: Joe Lawrence <joe.lawrence(a)redhat.com>
Cc: Shuah Khan <shuah(a)kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de>
Cc: Mimi Zohar <zohar(a)linux.ibm.com>
Cc: Juergen Gross <jgross(a)suse.com>
Cc: Nick Desaulniers <ndesaulniers(a)google.com>
Cc: Nayna Jain <nayna(a)linux.ibm.com>
Cc: Masahiro Yamada <yamada.masahiro(a)socionext.com>
Cc: Joerg Roedel <jroedel(a)suse.de>
Cc: "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest(a)vger.kernel.org>
Cc: stable(a)vger.kernel.org
Fixes: b700e7f03df5 ("livepatch: kernel: add support for live patching")
Tested-by: Nicolai Stange <nstange(a)suse.de>
Reviewed-by: Nicolai Stange <nstange(a)suse.de>
Reviewed-by: Masami Hiramatsu <mhiramat(a)kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
[ Modified to only work for x86_64 and added comment to int3_emulate_push() ]
Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index e85ff65c43c3..05861cc08787 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -39,4 +39,32 @@ extern int poke_int3_handler(struct pt_regs *regs);
extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
extern int after_bootmem;
+static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
+{
+ regs->ip = ip;
+}
+
+#define INT3_INSN_SIZE 1
+#define CALL_INSN_SIZE 5
+
+#ifdef CONFIG_X86_64
+static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val)
+{
+ /*
+ * The int3 handler in entry_64.S adds a gap between the
+ * stack where the break point happened, and the saving of
+ * pt_regs. We can extend the original stack because of
+ * this gap. See the idtentry macro's create_gap option.
+ */
+ regs->sp -= sizeof(unsigned long);
+ *(unsigned long *)regs->sp = val;
+}
+
+static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func)
+{
+ int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE);
+ int3_emulate_jmp(regs, func);
+}
+#endif
+
#endif /* _ASM_X86_TEXT_PATCHING_H */
## TLDR
I rebased the last patchset on 5.1-rc7 in hopes that we can get this in
5.2.
Shuah, I think you, Greg KH, and myself talked off thread, and we agreed
we would merge through your tree when the time came? Am I remembering
correctly?
## Background
This patch set proposes KUnit, a lightweight unit testing and mocking
framework for the Linux kernel.
Unlike Autotest and kselftest, KUnit is a true unit testing framework;
it does not require installing the kernel on a test machine or in a VM
and does not require tests to be written in userspace running on a host
kernel. Additionally, KUnit is fast: From invocation to completion KUnit
can run several dozen tests in under a second. Currently, the entire
KUnit test suite for KUnit runs in under a second from the initial
invocation (build time excluded).
KUnit is heavily inspired by JUnit, Python's unittest.mock, and
Googletest/Googlemock for C++. KUnit provides facilities for defining
unit test cases, grouping related test cases into test suites, providing
common infrastructure for running tests, mocking, spying, and much more.
## What's so special about unit testing?
A unit test is supposed to test a single unit of code in isolation,
hence the name. There should be no dependencies outside the control of
the test; this means no external dependencies, which makes tests orders
of magnitudes faster. Likewise, since there are no external dependencies,
there are no hoops to jump through to run the tests. Additionally, this
makes unit tests deterministic: a failing unit test always indicates a
problem. Finally, because unit tests necessarily have finer granularity,
they are able to test all code paths easily solving the classic problem
of difficulty in exercising error handling code.
## Is KUnit trying to replace other testing frameworks for the kernel?
No. Most existing tests for the Linux kernel are end-to-end tests, which
have their place. A well tested system has lots of unit tests, a
reasonable number of integration tests, and some end-to-end tests. KUnit
is just trying to address the unit test space which is currently not
being addressed.
## More information on KUnit
There is a bunch of documentation near the end of this patch set that
describes how to use KUnit and best practices for writing unit tests.
For convenience I am hosting the compiled docs here:
https://google.github.io/kunit-docs/third_party/kernel/docs/
Additionally for convenience, I have applied these patches to a branch:
https://kunit.googlesource.com/linux/+/kunit/rfc/v5.1-rc7/v1
The repo may be cloned with:
git clone https://kunit.googlesource.com/linux
This patchset is on the kunit/rfc/v5.1-rc7/v1 branch.
## Changes Since Last Version
None. I just rebased the last patchset on v5.1-rc7.
--
2.21.0.593.g511ec345e18-goog
From: Yonghong Song <yhs(a)fb.com>
[ Upstream commit 6cea33701eb024bc6c920ab83940ee22afd29139 ]
Test test_libbpf.sh failed on my development server with failure
-bash-4.4$ sudo ./test_libbpf.sh
[0] libbpf: Error in bpf_object__probe_name():Operation not permitted(1).
Couldn't load basic 'r0 = 0' BPF program.
test_libbpf: failed at file test_l4lb.o
selftests: test_libbpf [FAILED]
-bash-4.4$
The reason is because my machine has 64KB locked memory by default which
is not enough for this program to get locked memory.
Similar to other bpf selftests, let us increase RLIMIT_MEMLOCK
to infinity, which fixed the issue.
Signed-off-by: Yonghong Song <yhs(a)fb.com>
Signed-off-by: Alexei Starovoitov <ast(a)kernel.org>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
tools/testing/selftests/bpf/test_libbpf_open.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_libbpf_open.c b/tools/testing/selftests/bpf/test_libbpf_open.c
index 8fcd1c076add0..cbd55f5f8d598 100644
--- a/tools/testing/selftests/bpf/test_libbpf_open.c
+++ b/tools/testing/selftests/bpf/test_libbpf_open.c
@@ -11,6 +11,8 @@ static const char *__doc__ =
#include <bpf/libbpf.h>
#include <getopt.h>
+#include "bpf_rlimit.h"
+
static const struct option long_options[] = {
{"help", no_argument, NULL, 'h' },
{"debug", no_argument, NULL, 'D' },
--
2.20.1
From: Yonghong Song <yhs(a)fb.com>
[ Upstream commit 6cea33701eb024bc6c920ab83940ee22afd29139 ]
Test test_libbpf.sh failed on my development server with failure
-bash-4.4$ sudo ./test_libbpf.sh
[0] libbpf: Error in bpf_object__probe_name():Operation not permitted(1).
Couldn't load basic 'r0 = 0' BPF program.
test_libbpf: failed at file test_l4lb.o
selftests: test_libbpf [FAILED]
-bash-4.4$
The reason is because my machine has 64KB locked memory by default which
is not enough for this program to get locked memory.
Similar to other bpf selftests, let us increase RLIMIT_MEMLOCK
to infinity, which fixed the issue.
Signed-off-by: Yonghong Song <yhs(a)fb.com>
Signed-off-by: Alexei Starovoitov <ast(a)kernel.org>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
tools/testing/selftests/bpf/test_libbpf_open.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_libbpf_open.c b/tools/testing/selftests/bpf/test_libbpf_open.c
index 8fcd1c076add0..cbd55f5f8d598 100644
--- a/tools/testing/selftests/bpf/test_libbpf_open.c
+++ b/tools/testing/selftests/bpf/test_libbpf_open.c
@@ -11,6 +11,8 @@ static const char *__doc__ =
#include <bpf/libbpf.h>
#include <getopt.h>
+#include "bpf_rlimit.h"
+
static const struct option long_options[] = {
{"help", no_argument, NULL, 'h' },
{"debug", no_argument, NULL, 'D' },
--
2.20.1
From: Yonghong Song <yhs(a)fb.com>
[ Upstream commit 6cea33701eb024bc6c920ab83940ee22afd29139 ]
Test test_libbpf.sh failed on my development server with failure
-bash-4.4$ sudo ./test_libbpf.sh
[0] libbpf: Error in bpf_object__probe_name():Operation not permitted(1).
Couldn't load basic 'r0 = 0' BPF program.
test_libbpf: failed at file test_l4lb.o
selftests: test_libbpf [FAILED]
-bash-4.4$
The reason is because my machine has 64KB locked memory by default which
is not enough for this program to get locked memory.
Similar to other bpf selftests, let us increase RLIMIT_MEMLOCK
to infinity, which fixed the issue.
Signed-off-by: Yonghong Song <yhs(a)fb.com>
Signed-off-by: Alexei Starovoitov <ast(a)kernel.org>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
tools/testing/selftests/bpf/test_libbpf_open.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_libbpf_open.c b/tools/testing/selftests/bpf/test_libbpf_open.c
index 65cbd30704b5a..9e9db202d218a 100644
--- a/tools/testing/selftests/bpf/test_libbpf_open.c
+++ b/tools/testing/selftests/bpf/test_libbpf_open.c
@@ -11,6 +11,8 @@ static const char *__doc__ =
#include <bpf/libbpf.h>
#include <getopt.h>
+#include "bpf_rlimit.h"
+
static const struct option long_options[] = {
{"help", no_argument, NULL, 'h' },
{"debug", no_argument, NULL, 'D' },
--
2.20.1
clock_getres in the vDSO library has to preserve the same behaviour
of posix_get_hrtimer_res().
In particular, posix_get_hrtimer_res() does:
sec = 0;
ns = hrtimer_resolution;
and hrtimer_resolution depends on the enablement of the high
resolution timers that can happen either at compile or at run time.
A possible fix is to change the vdso implementation of clock_getres,
keeping a copy of hrtimer_resolution in vdso data and using that
directly [1].
This patchset implements the proposed fix for arm64, powerpc, s390,
nds32 and adds a test to verify that the syscall and the vdso library
implementation of clock_getres return the same values.
Even if these patches are unified by the same topic, there is no
dependency between them, hence they can be merged singularly by each
arch maintainer.
Note: arm64 and nds32 respective fixes have been merged in 5.2-rc1,
hence they have been removed from this series.
[1] https://marc.info/?l=linux-arm-kernel&m=155110381930196&w=2
Changes:
--------
v3:
- Rebased on 5.2-rc1.
- Addressed review comments.
v2:
- Rebased on 5.1-rc5.
- Addressed review comments.
Cc: Christophe Leroy <christophe.leroy(a)c-s.fr>
Cc: Benjamin Herrenschmidt <benh(a)kernel.crashing.org>
Cc: Paul Mackerras <paulus(a)samba.org>
Cc: Michael Ellerman <mpe(a)ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky(a)de.ibm.com>
Cc: Heiko Carstens <heiko.carstens(a)de.ibm.com>
Cc: Shuah Khan <shuah(a)kernel.org>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Arnd Bergmann <arnd(a)arndb.de>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino(a)arm.com>
Vincenzo Frascino (3):
powerpc: Fix vDSO clock_getres()
s390: Fix vDSO clock_getres()
kselftest: Extend vDSO selftest to clock_getres
arch/powerpc/include/asm/vdso_datapage.h | 2 +
arch/powerpc/kernel/asm-offsets.c | 2 +-
arch/powerpc/kernel/time.c | 1 +
arch/powerpc/kernel/vdso32/gettimeofday.S | 7 +-
arch/powerpc/kernel/vdso64/gettimeofday.S | 7 +-
arch/s390/include/asm/vdso.h | 1 +
arch/s390/kernel/asm-offsets.c | 2 +-
arch/s390/kernel/time.c | 1 +
arch/s390/kernel/vdso32/clock_getres.S | 12 +-
arch/s390/kernel/vdso64/clock_getres.S | 10 +-
tools/testing/selftests/vDSO/Makefile | 2 +
.../selftests/vDSO/vdso_clock_getres.c | 137 ++++++++++++++++++
12 files changed, 168 insertions(+), 16 deletions(-)
create mode 100644 tools/testing/selftests/vDSO/vdso_clock_getres.c
--
2.21.0