From: Andy Lutomirski <luto@kernel.org> To: "Dmitry V. Levin" <ldv@altlinux.org> Cc: paul.burton@mips.com, Ralf Baechle <ralf@linux-mips.org>, jhogan@kernel.org, Oleg Nesterov <oleg@redhat.com>, Andrew Lutomirski <luto@kernel.org>, Elvira Khabirova <lineprinter@altlinux.org>, Eugene Syromiatnikov <esyr@redhat.com>, Kees Cook <keescook@chromium.org>, Jann Horn <jannh@google.com>, Linux API <linux-api@vger.kernel.org>, strace-devel@lists.strace.io, LKML <linux-kernel@vger.kernel.org> Subject: Re: [PATCH v5 24/25] ptrace: add PTRACE_GET_SYSCALL_INFO request Date: Mon, 10 Dec 2018 11:38:17 -0800 [thread overview] Message-ID: <CALCETrV4J8+_gSHONAcQHt6XFgtuW487b9DHZ8MV-xa6XhZ_Og@mail.gmail.com> (raw) In-Reply-To: <20181210160940.GF14149@altlinux.org> > On Dec 10, 2018, at 8:09 AM, Dmitry V. Levin <ldv@altlinux.org> wrote: > > Hi, things are getting too complicated and we need some advice how to deal > with this frame_pointer issue. > >> On Mon, Dec 10, 2018 at 10:26:50PM +0800, kbuild test robot wrote: >> Hi Elvira, >> >> Thank you for the patch! Yet something to improve: >> >> [auto build test ERROR on linus/master] >> [also build test ERROR on v4.20-rc6] >> [cannot apply to next-20181207] >> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] >> >> url: https://github.com/0day-ci/linux/commits/Dmitry-V-Levin/ptrace-add-PTRACE_GET_SYSCALL_INFO-request/20181210-174745 >> config: mips-malta_kvm_defconfig (attached as .config) >> compiler: mipsel-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0 >> reproduce: >> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross >> chmod +x ~/bin/make.cross >> # save the attached .config to linux build tree >> GCC_VERSION=7.2.0 make.cross ARCH=mips >> >> All errors (new ones prefixed by >>): >> >> kernel/ptrace.c: In function 'ptrace_get_syscall_info': >>>> kernel/ptrace.c:942:20: error: implicit declaration of function 'frame_pointer'; did you mean 'trace_printk'? [-Werror=implicit-function-declaration] >> .frame_pointer = frame_pointer(regs) >> ^~~~~~~~~~~~~ >> trace_printk >> cc1: some warnings being treated as errors >> >> vim +942 kernel/ptrace.c >> >> 931 >> 932 static int >> 933 ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size, >> 934 void __user *datavp) >> 935 { >> 936 struct pt_regs *regs = task_pt_regs(child); >> 937 struct ptrace_syscall_info info = { >> 938 .op = PTRACE_SYSCALL_INFO_NONE, >> 939 .arch = syscall_get_arch(child), >> 940 .instruction_pointer = instruction_pointer(regs), >> 941 .stack_pointer = user_stack_pointer(regs), >>> 942 .frame_pointer = frame_pointer(regs) >> 943 }; >> 944 unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry); >> 945 unsigned long write_size; >> 946 >> 947 /* >> 948 * This does not need lock_task_sighand() to access >> 949 * child->last_siginfo because ptrace_freeze_traced() >> 950 * called earlier by ptrace_check_attach() ensures that >> 951 * the tracee cannot go away and clear its last_siginfo. >> 952 */ >> 953 switch (child->last_siginfo ? child->last_siginfo->si_code : 0) { >> 954 case SIGTRAP | 0x80: >> 955 switch (child->ptrace_message) { >> 956 case PTRACE_EVENTMSG_SYSCALL_ENTRY: >> 957 actual_size = ptrace_get_syscall_info_entry(child, regs, >> 958 &info); >> 959 break; >> 960 case PTRACE_EVENTMSG_SYSCALL_EXIT: >> 961 actual_size = ptrace_get_syscall_info_exit(child, regs, >> 962 &info); >> 963 break; >> 964 } >> 965 break; >> 966 case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8): >> 967 actual_size = ptrace_get_syscall_info_seccomp(child, regs, >> 968 &info); >> 969 break; >> 970 } >> 971 >> 972 write_size = min(actual_size, user_size); >> 973 return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size; >> 974 } >> 975 > > We decided to add .frame_pointer to struct ptrace_syscall_info just for > consistency with .instruction_pointer and .stack_pointer; I must have been > misled by comments in asm-generic/ptrace.h into thinking that > frame_pointer() is universally available across architectures. > > Unlike .instruction_pointer and .stack_pointer that are actually needed > in strace, .frame_pointer is not used, so from strace PoV we don't really > need it. > > So the question is, does anybody need a > struct ptrace_syscall_info.frame_pointer? > > If yes, how can frame_pointer() be defined on MIPS? > Or should we just forget about making sense of frame_pointer() and remove > struct ptrace_syscall_info.frame_pointer from the proposed API? > I would suggest getting rid of frame_pointer. Anyone who needs that degree of debugging can use existing ptrace APIs for it. > > -- > ldv
WARNING: multiple messages have this Message-ID (diff)
From: Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> To: "Dmitry V. Levin" <ldv-u2l5PoMzF/Vg9hUCZPvPmw@public.gmane.org> Cc: LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>, Jann Horn <jannh-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, jhogan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Ralf Baechle <ralf-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>, Eugene Syromiatnikov <esyr-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, paul.burton-8NJIiSa5LzA@public.gmane.org, Andrew Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Linux API <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, strace-devel-3+4lAyCyj6AWlMsSdNXQLw@public.gmane.org Subject: Re: [PATCH v5 24/25] ptrace: add PTRACE_GET_SYSCALL_INFO request Date: Mon, 10 Dec 2018 11:38:17 -0800 [thread overview] Message-ID: <CALCETrV4J8+_gSHONAcQHt6XFgtuW487b9DHZ8MV-xa6XhZ_Og@mail.gmail.com> (raw) In-Reply-To: <20181210160940.GF14149-u2l5PoMzF/Vg9hUCZPvPmw@public.gmane.org> > On Dec 10, 2018, at 8:09 AM, Dmitry V. Levin <ldv-u2l5PoMzF/Vg9hUCZPvPmw@public.gmane.org> wrote: > > Hi, things are getting too complicated and we need some advice how to deal > with this frame_pointer issue. > >> On Mon, Dec 10, 2018 at 10:26:50PM +0800, kbuild test robot wrote: >> Hi Elvira, >> >> Thank you for the patch! Yet something to improve: >> >> [auto build test ERROR on linus/master] >> [also build test ERROR on v4.20-rc6] >> [cannot apply to next-20181207] >> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] >> >> url: https://github.com/0day-ci/linux/commits/Dmitry-V-Levin/ptrace-add-PTRACE_GET_SYSCALL_INFO-request/20181210-174745 >> config: mips-malta_kvm_defconfig (attached as .config) >> compiler: mipsel-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0 >> reproduce: >> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross >> chmod +x ~/bin/make.cross >> # save the attached .config to linux build tree >> GCC_VERSION=7.2.0 make.cross ARCH=mips >> >> All errors (new ones prefixed by >>): >> >> kernel/ptrace.c: In function 'ptrace_get_syscall_info': >>>> kernel/ptrace.c:942:20: error: implicit declaration of function 'frame_pointer'; did you mean 'trace_printk'? [-Werror=implicit-function-declaration] >> .frame_pointer = frame_pointer(regs) >> ^~~~~~~~~~~~~ >> trace_printk >> cc1: some warnings being treated as errors >> >> vim +942 kernel/ptrace.c >> >> 931 >> 932 static int >> 933 ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size, >> 934 void __user *datavp) >> 935 { >> 936 struct pt_regs *regs = task_pt_regs(child); >> 937 struct ptrace_syscall_info info = { >> 938 .op = PTRACE_SYSCALL_INFO_NONE, >> 939 .arch = syscall_get_arch(child), >> 940 .instruction_pointer = instruction_pointer(regs), >> 941 .stack_pointer = user_stack_pointer(regs), >>> 942 .frame_pointer = frame_pointer(regs) >> 943 }; >> 944 unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry); >> 945 unsigned long write_size; >> 946 >> 947 /* >> 948 * This does not need lock_task_sighand() to access >> 949 * child->last_siginfo because ptrace_freeze_traced() >> 950 * called earlier by ptrace_check_attach() ensures that >> 951 * the tracee cannot go away and clear its last_siginfo. >> 952 */ >> 953 switch (child->last_siginfo ? child->last_siginfo->si_code : 0) { >> 954 case SIGTRAP | 0x80: >> 955 switch (child->ptrace_message) { >> 956 case PTRACE_EVENTMSG_SYSCALL_ENTRY: >> 957 actual_size = ptrace_get_syscall_info_entry(child, regs, >> 958 &info); >> 959 break; >> 960 case PTRACE_EVENTMSG_SYSCALL_EXIT: >> 961 actual_size = ptrace_get_syscall_info_exit(child, regs, >> 962 &info); >> 963 break; >> 964 } >> 965 break; >> 966 case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8): >> 967 actual_size = ptrace_get_syscall_info_seccomp(child, regs, >> 968 &info); >> 969 break; >> 970 } >> 971 >> 972 write_size = min(actual_size, user_size); >> 973 return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size; >> 974 } >> 975 > > We decided to add .frame_pointer to struct ptrace_syscall_info just for > consistency with .instruction_pointer and .stack_pointer; I must have been > misled by comments in asm-generic/ptrace.h into thinking that > frame_pointer() is universally available across architectures. > > Unlike .instruction_pointer and .stack_pointer that are actually needed > in strace, .frame_pointer is not used, so from strace PoV we don't really > need it. > > So the question is, does anybody need a > struct ptrace_syscall_info.frame_pointer? > > If yes, how can frame_pointer() be defined on MIPS? > Or should we just forget about making sense of frame_pointer() and remove > struct ptrace_syscall_info.frame_pointer from the proposed API? > I would suggest getting rid of frame_pointer. Anyone who needs that degree of debugging can use existing ptrace APIs for it. > > -- > ldv -- Strace-devel mailing list Strace-devel-3+4lAyCyj6AWlMsSdNXQLw@public.gmane.org https://lists.strace.io/mailman/listinfo/strace-devel
next prev parent reply other threads:[~2018-12-10 19:38 UTC|newest] Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-12-10 4:23 [PATCH v5 00/25] ptrace: add PTRACE_GET_SYSCALL_INFO request Dmitry V. Levin 2018-12-10 4:23 ` Dmitry V. Levin 2018-12-10 4:23 ` Dmitry V. Levin 2018-12-10 4:23 ` [OpenRISC] " Dmitry V. Levin 2018-12-10 4:23 ` Dmitry V. Levin 2018-12-10 4:23 ` Dmitry V. Levin 2018-12-10 4:23 ` Dmitry V. Levin 2018-12-10 4:27 ` [PATCH v5 01/25] alpha: define remaining syscall_get_* functions Dmitry V. Levin 2018-12-10 4:28 ` [PATCH v5 02/25] Move EM_ARCOMPACT and EM_ARCV2 to uapi/linux/elf-em.h Dmitry V. Levin 2018-12-10 4:28 ` Dmitry V. Levin 2018-12-10 4:29 ` [PATCH v5 03/25] arc: define syscall_get_arch() Dmitry V. Levin 2018-12-10 4:29 ` Dmitry V. Levin 2018-12-10 4:29 ` [PATCH v5 04/25] c6x: " Dmitry V. Levin 2018-12-11 22:40 ` Mark Salter 2018-12-10 4:29 ` [PATCH v5 05/25] elf-em.h: add EM_CSKY Dmitry V. Levin 2018-12-10 4:29 ` [PATCH v5 06/25] csky: define syscall_get_arch() Dmitry V. Levin 2018-12-10 4:29 ` [PATCH v5 07/25] h8300: define remaining syscall_get_* functions Dmitry V. Levin 2018-12-10 4:29 ` [PATCH v5 08/25] Move EM_HEXAGON to uapi/linux/elf-em.h Dmitry V. Levin 2018-12-10 4:29 ` [PATCH v5 09/25] hexagon: define remaining syscall_get_* functions Dmitry V. Levin 2018-12-10 4:29 ` [PATCH v5 10/25] Move EM_NDS32 to uapi/linux/elf-em.h Dmitry V. Levin 2018-12-10 4:29 ` [PATCH v5 11/25] nds32: define syscall_get_arch() Dmitry V. Levin 2018-12-10 4:30 ` [PATCH v5 12/25] nios2: " Dmitry V. Levin 2018-12-10 4:30 ` [PATCH v5 13/25] m68k: add asm/syscall.h Dmitry V. Levin 2018-12-10 8:45 ` Geert Uytterhoeven 2018-12-10 12:40 ` Dmitry V. Levin 2018-12-10 13:06 ` Geert Uytterhoeven 2018-12-10 13:30 ` Dmitry V. Levin 2018-12-12 8:55 ` Dmitry V. Levin 2018-12-12 9:01 ` Geert Uytterhoeven 2018-12-12 9:27 ` Dmitry V. Levin 2018-12-12 9:43 ` Geert Uytterhoeven 2018-12-12 12:04 ` Dmitry V. Levin 2018-12-12 12:27 ` Geert Uytterhoeven 2018-12-12 12:37 ` Dmitry V. Levin 2018-12-12 12:54 ` Geert Uytterhoeven 2018-12-12 13:07 ` Dmitry V. Levin 2018-12-12 23:12 ` Dmitry V. Levin 2019-03-29 22:04 ` Dmitry V. Levin 2019-03-30 20:57 ` Geert Uytterhoeven 2018-12-10 4:30 ` [PATCH v5 14/25] mips: define syscall_get_error() Dmitry V. Levin 2018-12-10 4:30 ` [PATCH v5 15/25] parisc: " Dmitry V. Levin 2018-12-10 4:30 ` [PATCH v5 16/25] powerpc: " Dmitry V. Levin 2018-12-10 4:30 ` Dmitry V. Levin 2018-12-10 4:30 ` [PATCH v5 17/25] riscv: define syscall_get_arch() Dmitry V. Levin 2018-12-10 4:30 ` Dmitry V. Levin 2018-12-10 4:30 ` [PATCH v5 18/25] Move EM_XTENSA to uapi/linux/elf-em.h Dmitry V. Levin 2018-12-10 4:30 ` [PATCH v5 19/25] xtensa: define syscall_get_* functions Dmitry V. Levin 2018-12-10 5:02 ` Max Filippov 2018-12-10 12:53 ` Dmitry V. Levin 2018-12-10 20:14 ` Max Filippov 2018-12-10 20:24 ` Dmitry V. Levin 2018-12-10 20:30 ` Dmitry V. Levin 2018-12-10 21:29 ` Max Filippov 2018-12-12 10:45 ` kbuild test robot 2018-12-19 5:58 ` kbuild test robot 2018-12-10 4:30 ` [PATCH v5 20/25] Move EM_UNICORE to uapi/linux/elf-em.h Dmitry V. Levin 2018-12-10 4:30 ` [PATCH v5 21/25] unicore32: add asm/syscall.h Dmitry V. Levin 2018-12-10 4:31 ` [PATCH v5 22/25] syscall_get_arch: add "struct task_struct *" argument Dmitry V. Levin 2018-12-10 4:31 ` [OpenRISC] " Dmitry V. Levin 2018-12-10 4:31 ` Dmitry V. Levin 2018-12-10 4:31 ` Dmitry V. Levin 2018-12-10 4:31 ` Dmitry V. Levin 2018-12-10 4:31 ` Dmitry V. Levin 2018-12-10 4:31 ` Dmitry V. Levin 2018-12-10 17:29 ` Kees Cook 2018-12-11 22:44 ` Mark Salter 2018-12-10 4:31 ` [PATCH v5 23/25] powerpc/ptrace: replace ptrace_report_syscall() with a tracehook call Dmitry V. Levin 2018-12-10 4:31 ` Dmitry V. Levin 2018-12-10 4:31 ` [PATCH v5 24/25] ptrace: add PTRACE_GET_SYSCALL_INFO request Dmitry V. Levin 2018-12-10 4:31 ` Dmitry V. Levin 2018-12-10 14:11 ` Oleg Nesterov 2018-12-10 16:21 ` Dmitry V. Levin 2018-12-10 16:21 ` Dmitry V. Levin 2018-12-11 15:29 ` Oleg Nesterov 2018-12-11 16:23 ` Dmitry V. Levin 2018-12-11 16:23 ` Dmitry V. Levin 2018-12-11 20:27 ` Dmitry V. Levin 2018-12-12 18:00 ` Oleg Nesterov 2018-12-10 14:26 ` kbuild test robot 2018-12-10 16:09 ` Dmitry V. Levin 2018-12-10 16:09 ` Dmitry V. Levin 2018-12-10 18:04 ` Paul Burton 2018-12-10 21:04 ` Palmer Dabbelt 2018-12-10 19:38 ` Andy Lutomirski [this message] 2018-12-10 19:38 ` Andy Lutomirski 2018-12-10 17:44 ` Kees Cook 2018-12-12 9:28 ` kbuild test robot 2018-12-10 4:31 ` [PATCH v5 25/25] selftests/ptrace: add a test case for PTRACE_GET_SYSCALL_INFO Dmitry V. Levin 2018-12-10 4:31 ` Dmitry V. Levin 2018-12-10 4:31 ` ldv
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