Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965589AbeAJPgV (ORCPT + 1 other); Wed, 10 Jan 2018 10:36:21 -0500 Received: from mail-qt0-f195.google.com ([209.85.216.195]:38658 "EHLO mail-qt0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933346AbeAJPgR (ORCPT ); Wed, 10 Jan 2018 10:36:17 -0500 X-Google-Smtp-Source: ACJfBosObstE7HF5DYcuqTaLzAeilv53xLDU5QuZepJ5OsqDcpqGf1PBz9sKXqV48Eo80aRI02yZgA== Date: Wed, 10 Jan 2018 10:36:15 -0500 From: Josef Bacik To: Masami Hiramatsu Cc: Alexei Starovoitov , Josef Bacik , rostedt@goodmis.org, mingo@redhat.com, davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ast@kernel.org, kernel-team@fb.com, daniel@iogearbox.net, linux-btrfs@vger.kernel.org, darrick.wong@oracle.com, Josef Bacik , Akinobu Mita Subject: Re: [PATCH bpf-next v3 3/5] error-injection: Separate error-injection from kprobe Message-ID: <20180110153614.3mbzmejnjlfw6lqj@destiny> References: <151557939382.6629.18074658376309258555.stgit@devbox> <151557948555.6629.8642887195554280720.stgit@devbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <151557948555.6629.8642887195554280720.stgit@devbox> User-Agent: NeoMutt/20170714 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Wed, Jan 10, 2018 at 07:18:05PM +0900, Masami Hiramatsu wrote: > Since error-injection framework is not limited to be used > by kprobes, nor bpf. Other kernel subsystems can use it > freely for checking safeness of error-injection, e.g. > livepatch, ftrace etc. > So this separate error-injection framework from kprobes. > > Some differences has been made: > > - "kprobe" word is removed from any APIs/structures. > - BPF_ALLOW_ERROR_INJECTION() is renamed to > ALLOW_ERROR_INJECTION() since it is not limited for BPF too. > - CONFIG_FUNCTION_ERROR_INJECTION is the config item of this > feature. It is automatically enabled if the arch supports > error injection feature for kprobe or ftrace etc. > > Signed-off-by: Masami Hiramatsu > --- > Changes in v3: > - Fix a build error for asmlinkage on i386 by including compiler.h > - Fix "CONFIG_FUNCTION_ERROR_INJECT" typo. > - Separate CONFIG_MODULES dependent code > - Add CONFIG_KPROBES dependency for arch_deref_entry_point() > - Call error-injection init function in late_initcall stage. > - Fix read-side mutex lock > - Some cosmetic cleanups > --- > arch/Kconfig | 2 > arch/x86/Kconfig | 2 > arch/x86/include/asm/error-injection.h | 13 ++ > arch/x86/kernel/kprobes/core.c | 14 -- > arch/x86/lib/Makefile | 1 > arch/x86/lib/error-inject.c | 19 +++ > fs/btrfs/disk-io.c | 2 > fs/btrfs/free-space-cache.c | 2 > include/asm-generic/error-injection.h | 20 +++ > include/asm-generic/vmlinux.lds.h | 14 +- > include/linux/bpf.h | 12 -- > include/linux/error-injection.h | 21 +++ > include/linux/kprobes.h | 1 > include/linux/module.h | 6 - > kernel/kprobes.c | 163 ------------------------ > kernel/module.c | 8 + > kernel/trace/Kconfig | 2 > kernel/trace/bpf_trace.c | 2 > kernel/trace/trace_kprobe.c | 3 > lib/Kconfig.debug | 4 + > lib/Makefile | 1 > lib/error-inject.c | 213 ++++++++++++++++++++++++++++++++ > 22 files changed, 315 insertions(+), 210 deletions(-) > create mode 100644 arch/x86/include/asm/error-injection.h > create mode 100644 arch/x86/lib/error-inject.c > create mode 100644 include/asm-generic/error-injection.h > create mode 100644 include/linux/error-injection.h > create mode 100644 lib/error-inject.c > > diff --git a/arch/Kconfig b/arch/Kconfig > index d3f4aaf9cb7a..97376accfb14 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -196,7 +196,7 @@ config HAVE_OPTPROBES > config HAVE_KPROBES_ON_FTRACE > bool > > -config HAVE_KPROBE_OVERRIDE > +config HAVE_FUNCTION_ERROR_INJECTION > bool > > config HAVE_NMI > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 45dc6233f2b9..366b19cb79b7 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -154,7 +154,7 @@ config X86 > select HAVE_KERNEL_XZ > select HAVE_KPROBES > select HAVE_KPROBES_ON_FTRACE > - select HAVE_KPROBE_OVERRIDE > + select HAVE_FUNCTION_ERROR_INJECTION > select HAVE_KRETPROBES > select HAVE_KVM > select HAVE_LIVEPATCH if X86_64 > diff --git a/arch/x86/include/asm/error-injection.h b/arch/x86/include/asm/error-injection.h > new file mode 100644 > index 000000000000..47b7a1296245 > --- /dev/null > +++ b/arch/x86/include/asm/error-injection.h > @@ -0,0 +1,13 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _ASM_ERROR_INJECTION_H > +#define _ASM_ERROR_INJECTION_H > + > +#include > +#include > +#include > +#include > + > +asmlinkage void just_return_func(void); > +void override_function_with_return(struct pt_regs *regs); > + > +#endif /* _ASM_ERROR_INJECTION_H */ > diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c > index b02a377d5905..bd36f3c33cd0 100644 > --- a/arch/x86/kernel/kprobes/core.c > +++ b/arch/x86/kernel/kprobes/core.c > @@ -1183,17 +1183,3 @@ int arch_trampoline_kprobe(struct kprobe *p) > { > return 0; > } > - > -asmlinkage void override_func(void); > -asm( > - ".type override_func, @function\n" > - "override_func:\n" > - " ret\n" > - ".size override_func, .-override_func\n" > -); > - > -void arch_kprobe_override_function(struct pt_regs *regs) > -{ > - regs->ip = (unsigned long)&override_func; > -} > -NOKPROBE_SYMBOL(arch_kprobe_override_function); > diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile > index 7b181b61170e..171377b83be1 100644 > --- a/arch/x86/lib/Makefile > +++ b/arch/x86/lib/Makefile > @@ -26,6 +26,7 @@ lib-y += memcpy_$(BITS).o > lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o > lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o > lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o > +lib-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o > > obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o > > diff --git a/arch/x86/lib/error-inject.c b/arch/x86/lib/error-inject.c > new file mode 100644 > index 000000000000..7b881d03d0dd > --- /dev/null > +++ b/arch/x86/lib/error-inject.c > @@ -0,0 +1,19 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +#include > +#include > + > +asmlinkage void just_return_func(void); > + > +asm( > + ".type just_return_func, @function\n" > + "just_return_func:\n" > + " ret\n" > + ".size just_return_func, .-just_return_func\n" > +); > + > +void override_function_with_return(struct pt_regs *regs) > +{ > + regs->ip = (unsigned long)&just_return_func; > +} > +NOKPROBE_SYMBOL(override_function_with_return); > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index 5da18ebc9222..5c540129ad81 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -3124,7 +3124,7 @@ int open_ctree(struct super_block *sb, > goto fail_block_groups; > goto retry_root_backup; > } > -BPF_ALLOW_ERROR_INJECTION(open_ctree); > +ALLOW_ERROR_INJECTION(open_ctree); > > static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate) > { > diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c > index fb1382893bfc..2a75e088b215 100644 > --- a/fs/btrfs/free-space-cache.c > +++ b/fs/btrfs/free-space-cache.c > @@ -333,7 +333,7 @@ static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode, > > return 0; > } > -BPF_ALLOW_ERROR_INJECTION(io_ctl_init); > +ALLOW_ERROR_INJECTION(io_ctl_init); > > static void io_ctl_free(struct btrfs_io_ctl *io_ctl) > { > diff --git a/include/asm-generic/error-injection.h b/include/asm-generic/error-injection.h > new file mode 100644 > index 000000000000..08352c9d9f97 > --- /dev/null > +++ b/include/asm-generic/error-injection.h > @@ -0,0 +1,20 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _ASM_GENERIC_ERROR_INJECTION_H > +#define _ASM_GENERIC_ERROR_INJECTION_H > + > +#if defined(__KERNEL__) && !defined(__ASSEMBLY__) > +#ifdef CONFIG_FUNCTION_ERROR_INJECTION > +/* > + * Whitelist ganerating macro. Specify functions which can be > + * error-injectable using this macro. > + */ > +#define ALLOW_ERROR_INJECTION(fname) \ > +static unsigned long __used \ > + __attribute__((__section__("_error_injection_whitelist"))) \ > + _eil_addr_##fname = (unsigned long)fname; > +#else > +#define ALLOW_ERROR_INJECTION(fname) > +#endif > +#endif > + > +#endif /* _ASM_GENERIC_ERROR_INJECTION_H */ > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index a2e8582d094a..f2068cca5206 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -136,13 +136,13 @@ > #define KPROBE_BLACKLIST() > #endif > > -#ifdef CONFIG_BPF_KPROBE_OVERRIDE > -#define ERROR_INJECT_LIST() . = ALIGN(8); \ > - VMLINUX_SYMBOL(__start_kprobe_error_inject_list) = .; \ > - KEEP(*(_kprobe_error_inject_list)) \ > - VMLINUX_SYMBOL(__stop_kprobe_error_inject_list) = .; > +#ifdef CONFIG_FUNCTION_ERROR_INJECTION > +#define ERROR_INJECT_WHITELIST() . = ALIGN(8); \ > + VMLINUX_SYMBOL(__start_error_injection_whitelist) = .;\ > + KEEP(*(_error_injection_whitelist)) \ > + VMLINUX_SYMBOL(__stop_error_injection_whitelist) = .; > #else > -#define ERROR_INJECT_LIST() > +#define ERROR_INJECT_WHITELIST() > #endif > > #ifdef CONFIG_EVENT_TRACING > @@ -573,7 +573,7 @@ > FTRACE_EVENTS() \ > TRACE_SYSCALLS() \ > KPROBE_BLACKLIST() \ > - ERROR_INJECT_LIST() \ > + ERROR_INJECT_WHITELIST() \ > MEM_DISCARD(init.rodata) \ > CLK_OF_TABLES() \ > RESERVEDMEM_OF_TABLES() \ > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > index 9e03046d1df2..ea865bb9f676 100644 > --- a/include/linux/bpf.h > +++ b/include/linux/bpf.h > @@ -16,6 +16,7 @@ > #include > #include > #include > +#include > I assume you did this because we include linux/bpf.h for the BPF_ALLOW_ERROR_INJECTION() stuff in btrfs. Can we just drop this include here, and change the users of ALLOW_ERROR_INJECTION() to include error-injection.h instead? > +/* > + * error_injection/whitelist -- shows which functions can be overridden for > + * error injection. > + */ > +static void *ei_seq_start(struct seq_file *m, loff_t *pos) > +{ > + mutex_lock(&ei_mutex); > + return seq_list_start(&error_injection_list, *pos); > +} > + > +static void ei_seq_stop(struct seq_file *m, void *v) > +{ > + mutex_unlock(&ei_mutex); > +} > + > +static void *ei_seq_next(struct seq_file *m, void *v, loff_t *pos) > +{ > + return seq_list_next(v, &error_injection_list, pos); > +} > + > +static int ei_seq_show(struct seq_file *m, void *v) > +{ > + struct ei_entry *ent = list_entry(v, struct ei_entry, list); > + > + seq_printf(m, "%pf\n", (void *)ent->start_addr); Can we bring back the sprint_symbol() thing I did originally here so it's nice and easy to sanity check stuff is working? Thanks Josef