- Linux-kselftest-mirror - lists.linaro.org

[PATCH selftests 0/2] Add checkbashisms meta-testcase

by Masami Hiramatsu

Hi, Here are patches for making sure the ftracetest testcases are checkbashisms clean. This actually needs a patch from Juerg, "selftests/ftrace: Make the coloring POSIX compliant" to complete the work. http://lkml.kernel.org/r/20190220161333.28109-1-juergh@canonical.com (Note that this is still under development) So as Juerg pointed, recently ftracetest becomes not POSIX compliant, and such kind of issues happened repeatedly. To avoid those anymore, I decided to introduce a testcase which runs checkbasisms on ftracetest and its testcases. I think this can help us to find out whether it was written in a way out of POSIX. Thank you, --- Masami Hiramatsu (2): selftests/ftrace: Make a script checkbashisms clean selftests/ftrace: Add checkbashisms meta-testcase tools/testing/selftests/ftrace/ftracetest | 1 + .../ftrace/test.d/kprobe/kprobe_ftrace.tc | 2 +- .../selftests/ftrace/test.d/selftest/bashisms.tc | 21 ++++++++++++++++++++ 3 files changed, 23 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/ftrace/test.d/selftest/bashisms.tc -- Masami Hiramatsu (Linaro) <mhiramat(a)kernel.org>

6 years, 6 months

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[PATCH] selftests: add missing include linux/sockios

by Alakesh Haloi

Including <linux/sockios.h> fixes the following compiler warning timestamping.c: In function ‘printpacket’: timestamping.c:261:19: error: ‘SIOCGSTAMP’ undeclared (first use in this function); did you mean ‘SIOCGSTAMPNS’? if (ioctl(sock, SIOCGSTAMP, &tv)) ^~~~~~~~~~ SIOCGSTAMPNS Signed-off-by: Alakesh Haloi <alakesh.haloi(a)gmail.com> --- tools/testing/selftests/networking/timestamping/timestamping.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/networking/timestamping/timestamping.c b/tools/testing/selftests/networking/timestamping/timestamping.c index 5cdfd743447b..62f03bcc9432 100644 --- a/tools/testing/selftests/networking/timestamping/timestamping.c +++ b/tools/testing/selftests/networking/timestamping/timestamping.c @@ -44,6 +44,7 @@ #include <asm/types.h> #include <linux/net_tstamp.h> #include <linux/errqueue.h> +#include <linux/sockios.h> #ifndef SO_TIMESTAMPING # define SO_TIMESTAMPING 37 -- 2.17.1

6 years, 6 months

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[PATCH] selftests: kselftest: fix function return type

by Alakesh Haloi

ksft_test_num function returns sum of unsigned ints and hence should return unsigned int. This fixes the following compiler warning In file included from sync_test.c:37:0: ../kselftest.h: In function ‘ksft_print_cnts’: ../kselftest.h:73:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ksft_plan != ksft_test_num()) ^~ Signed-off-by: Alakesh Haloi <alakesh.haloi(a)gmail.com> --- tools/testing/selftests/kselftest.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h index ec15c4f6af55..5a98c80e079e 100644 --- a/tools/testing/selftests/kselftest.h +++ b/tools/testing/selftests/kselftest.h @@ -35,7 +35,7 @@ struct ksft_count { static struct ksft_count ksft_cnt; static unsigned int ksft_plan; -static inline int ksft_test_num(void) +static inline unsigned int ksft_test_num(void) { return ksft_cnt.ksft_pass + ksft_cnt.ksft_fail + ksft_cnt.ksft_xfail + ksft_cnt.ksft_xpass + -- 2.17.1

6 years, 6 months

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[PATCH 0/2] kselftest: fix rtctest timeout

by Alexandre Belloni

Hi, Commit a745f7af3cbd ("selftests/harness: Add 30 second timeout per test") wrongly assumed that no individual test would run for more than 30 seconds and this silently broke rtctest. Please consider the following patches as fixes for v5.2 to avoid having any non working release. Thanks, Alexandre Belloni (2): selftests/harness: Allow test to configure timeout selftests: rtc: rtctest: specify timeouts tools/testing/selftests/kselftest_harness.h | 17 ++++++++++++----- tools/testing/selftests/rtc/rtctest.c | 6 +++--- 2 files changed, 15 insertions(+), 8 deletions(-) -- 2.21.0

6 years, 6 months

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[PATCH 5.1 075/122] ftrace/x86_64: Emulate call function while updating in breakpoint handler

by Greg Kroah-Hartman

From: Peter Zijlstra <peterz(a)infradead.org> commit 9e298e8604088a600d8100a111a532a9d342af09 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/ftrace.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) --- 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 } 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_fun 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 * 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(struc 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 { unsigned char *new; + ftrace_update_func_call = 0UL; new = ftrace_jmp_replace(ip, (unsigned long)func); return update_ftrace_func(ip, new);

6 years, 6 months

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[PATCH 5.1 074/122] x86_64: Allow breakpoints to emulate call instructions

by Greg Kroah-Hartman

From: Peter Zijlstra <peterz(a)infradead.org> commit 4b33dadf37666c0860b88f9e52a16d07bf6d0b03 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/include/asm/text-patching.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) --- 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_r 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 */

6 years, 6 months

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[PATCH 5.0 066/139] ftrace/x86_64: Emulate call function while updating in breakpoint handler

by Greg Kroah-Hartman

From: Peter Zijlstra <peterz(a)infradead.org> commit 9e298e8604088a600d8100a111a532a9d342af09 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/ftrace.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) --- 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 } 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_fun 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 * 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; } static int ftrace_write(unsigned long ip, const char *val, int size) @@ -858,6 +877,8 @@ void arch_ftrace_update_trampoline(struc 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); @@ -959,6 +980,7 @@ static int ftrace_mod_jmp(unsigned long { unsigned char *new; + ftrace_update_func_call = 0UL; new = ftrace_jmp_replace(ip, (unsigned long)func); return update_ftrace_func(ip, new);

6 years, 6 months

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[PATCH 5.0 065/139] x86_64: Allow breakpoints to emulate call instructions

by Greg Kroah-Hartman

From: Peter Zijlstra <peterz(a)infradead.org> commit 4b33dadf37666c0860b88f9e52a16d07bf6d0b03 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/include/asm/text-patching.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) --- 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_r 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 */

6 years, 6 months

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[PATCH 4.14 34/77] ftrace/x86_64: Emulate call function while updating in breakpoint handler

by Greg Kroah-Hartman

From: Peter Zijlstra <peterz(a)infradead.org> commit 9e298e8604088a600d8100a111a532a9d342af09 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/ftrace.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -30,6 +30,7 @@ #include <asm/sections.h> #include <asm/ftrace.h> #include <asm/nops.h> +#include <asm/text-patching.h> #ifdef CONFIG_DYNAMIC_FTRACE @@ -229,6 +230,7 @@ int ftrace_modify_call(struct dyn_ftrace } static unsigned long ftrace_update_func; +static unsigned long ftrace_update_func_call; static int update_ftrace_func(unsigned long ip, void *new) { @@ -257,6 +259,8 @@ int ftrace_update_ftrace_func(ftrace_fun 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); @@ -292,13 +296,28 @@ int ftrace_int3_handler(struct pt_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; } static int ftrace_write(unsigned long ip, const char *val, int size) @@ -869,6 +888,8 @@ void arch_ftrace_update_trampoline(struc 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); @@ -965,6 +986,7 @@ static int ftrace_mod_jmp(unsigned long { unsigned char *new; + ftrace_update_func_call = 0UL; new = ftrace_jmp_replace(ip, (unsigned long)func); return update_ftrace_func(ip, new);

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[PATCH 4.19 053/114] ftrace/x86_64: Emulate call function while updating in breakpoint handler

by Greg Kroah-Hartman

From: Peter Zijlstra <peterz(a)infradead.org> commit 9e298e8604088a600d8100a111a532a9d342af09 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/ftrace.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) --- 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 @@ -228,6 +229,7 @@ int ftrace_modify_call(struct dyn_ftrace } static unsigned long ftrace_update_func; +static unsigned long ftrace_update_func_call; static int update_ftrace_func(unsigned long ip, void *new) { @@ -256,6 +258,8 @@ int ftrace_update_ftrace_func(ftrace_fun 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); @@ -291,13 +295,28 @@ int ftrace_int3_handler(struct pt_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; } static int ftrace_write(unsigned long ip, const char *val, int size) @@ -868,6 +887,8 @@ void arch_ftrace_update_trampoline(struc 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); @@ -964,6 +985,7 @@ static int ftrace_mod_jmp(unsigned long { unsigned char *new; + ftrace_update_func_call = 0UL; new = ftrace_jmp_replace(ip, (unsigned long)func); return update_ftrace_func(ip, new);

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