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Date: Wed, 25 Apr 2012 19:59:35 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To: Prashanth Nageshappa <prashanth@...ux.vnet.ibm.com>
Cc: peterz@...radead.org, Ingo Molnar <mingo@...e.hu>,
akpm@...ux-foundation.org, torvalds@...ux-foundation.org,
ananth@...ibm.com, jkenisto@...ux.vnet.ibm.com,
linux-kernel@...r.kernel.org, linux-mm@...ck.org, oleg@...hat.com,
andi@...stfloor.org, hch@...radead.org, rostedt@...dmis.org,
acme@...radead.org, tglx@...utronix.de, anton@...hat.com,
srikar@...ux.vnet.ibm.com
Subject: Re: [PATCH-V3] perf/probe: verify instruction/offset in perf before
adding a uprobe
(2012/04/25 14:54), Prashanth Nageshappa wrote:
> This patch is to augment Srikar's perf support for uprobes patch
> (https://lkml.org/lkml/2012/4/11/191) with the following features:
>
> a. Instruction verification for user space tracing
> b. Function boundary validation support to uprobes as its kernel
> counterpart (Commit-ID: 1c1bc922).
>
> This will help in ensuring uprobe is placed at right location inside
> the intended function.
>
> To verify instructions in perf before adding a uprobe, we need to use
> arch/x86/lib/insn.c. Since perf Makefile enables -Wswitch-default flag
> it causes build warnings/failures. Masami's patch
> https://lkml.org/lkml/2012/4/12/598 addresses those warnings and it is
> a pre-req for this patch.
>
> v3 addresses Arnaldo's review comments.
>
> v2 addresses Masami's review comments: Rebuild insn.c and inat.c while
> building perf and a few other minor ones.
This looks good for me :)
>
> Signed-off-by: Prashanth Nageshappa <prashanth@...ux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Thanks!
> ---
>
> tools/perf/Makefile | 1
> tools/perf/arch/x86/Makefile | 20 ++++++++
> tools/perf/arch/x86/util/probe-event.c | 81 ++++++++++++++++++++++++++++++++
> tools/perf/util/include/linux/string.h | 1
> tools/perf/util/probe-event.c | 23 +++++++++
> tools/perf/util/probe-event.h | 2 +
> tools/perf/util/symbol.c | 2 +
> tools/perf/util/symbol.h | 1
> 8 files changed, 130 insertions(+), 1 deletions(-)
> create mode 100644 tools/perf/arch/x86/util/probe-event.c
>
> diff --git a/tools/perf/Makefile b/tools/perf/Makefile
> index 820371f..94879b9 100644
> --- a/tools/perf/Makefile
> +++ b/tools/perf/Makefile
> @@ -61,6 +61,7 @@ ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/i386/ -e s/sun4u/sparc64/ \
>
> CC = $(CROSS_COMPILE)gcc
> AR = $(CROSS_COMPILE)ar
> +AWK = awk
>
> # Additional ARCH settings for x86
> ifeq ($(ARCH),i386)
> diff --git a/tools/perf/arch/x86/Makefile b/tools/perf/arch/x86/Makefile
> index 744e629..1a7215b 100644
> --- a/tools/perf/arch/x86/Makefile
> +++ b/tools/perf/arch/x86/Makefile
> @@ -1,5 +1,25 @@
> +inat_tables_script = ../../arch/$(ARCH)/tools/gen-insn-attr-x86.awk
> +inat_tables_maps = ../../arch/$(ARCH)/lib/x86-opcode-map.txt
> +cmd_inat_tables = $(AWK) -f $(inat_tables_script) $(inat_tables_maps) > $@ || rm -f $@
> +
> +BASIC_CFLAGS += -I. -I../../arch/$(ARCH)/include
> +
> ifndef NO_DWARF
> PERF_HAVE_DWARF_REGS := 1
> LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/dwarf-regs.o
> endif
> LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/header.o
> +LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/probe-event.o
> +LIB_OBJS += $(OUTPUT)arch/$(ARCH)/inat.o
> +LIB_OBJS += $(OUTPUT)arch/$(ARCH)/insn.o
> +
> +$(OUTPUT)arch/$(ARCH)/inat.o:../../arch/$(ARCH)/lib/inat-tables.c
> +
> +../../arch/$(ARCH)/lib/inat-tables.c: $(inat_tables_script) $(inat_tables_maps)
> + $(cmd_inat_tables)
> +
> +$(OUTPUT)arch/$(ARCH)/inat.o:../../arch/$(ARCH)/lib/inat.c $(OUTPUT)PERF-CFLAGS
> + $(QUIET_CC)$(CC) -o $@ -c $(ALL_CFLAGS) $<
> +
> +$(OUTPUT)arch/$(ARCH)/insn.o:../../arch/$(ARCH)/lib/insn.c $(OUTPUT)PERF-CFLAGS
> + $(QUIET_CC)$(CC) -o $@ -c $(ALL_CFLAGS) $<
> diff --git a/tools/perf/arch/x86/util/probe-event.c b/tools/perf/arch/x86/util/probe-event.c
> new file mode 100644
> index 0000000..f1ebf90
> --- /dev/null
> +++ b/tools/perf/arch/x86/util/probe-event.c
> @@ -0,0 +1,81 @@
> +/*
> + * probe-event.c : x86 specific perf-probe definition
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
> + *
> + * Copyright (C) IBM Corporation, 2011-2012
> + * Authors:
> + * Prashanth Nageshappa
> + */
> +
> +#include <util/types.h>
> +#include <util/probe-event.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <unistd.h>
> +#include <fcntl.h>
> +#include <string.h>
> +#include <errno.h>
> +#include <asm/insn.h>
> +#include <elf.h>
> +
> +/*
> + * Check if a given offset from start of a function is valid or not
> + */
> +bool can_probe(char *name, u64 vaddr, unsigned long offset,
> + u8 class)
> +{
> + u64 eaddr, saddr;
> + unsigned long fileoffset, readbytes;
> + int fd = 0;
> + bool ret = false;
> + char *buf = NULL;
> + struct insn insn;
> +
> + fd = open(name, O_RDONLY);
> + if (fd == -1) {
> + pr_warning("Failed to open %s: %s\n", name, strerror(errno));
> + return ret;
> + }
> + buf = malloc(offset + MAX_INSN_SIZE);
> + if (buf == NULL) {
> + pr_warning("Failed to allocate memory");
> + goto out_close;
> + }
> + fileoffset = lseek(fd, vaddr, SEEK_SET);
> + if (fileoffset != vaddr) {
> + pr_warning("Failed to lseek %s: %s\n", name, strerror(errno));
> + goto out_free;
> + }
> + saddr = (u64)buf;
> + eaddr = (u64)buf + offset;
> + readbytes = read(fd, buf, offset + MAX_INSN_SIZE);
> + if (readbytes != offset + MAX_INSN_SIZE) {
> + pr_warning("Failed to read %s: %s\n", name, strerror(errno));
> + goto out_free;
> + }
> + while (saddr < eaddr) {
> + insn_init(&insn, (void *)saddr, class == ELFCLASS64);
> + insn_get_length(&insn);
> + saddr += insn.length;
> + }
> + ret = (saddr == eaddr);
> +
> +out_free:
> + free(buf);
> +out_close:
> + close(fd);
> + return ret;
> +}
> diff --git a/tools/perf/util/include/linux/string.h b/tools/perf/util/include/linux/string.h
> index 3b2f590..9d5eb21 100644
> --- a/tools/perf/util/include/linux/string.h
> +++ b/tools/perf/util/include/linux/string.h
> @@ -1 +1,2 @@
> #include <string.h>
> +#include <perf.h>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index b7dec82..57f9eae 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -2254,6 +2254,17 @@ int show_available_funcs(const char *target, struct strfilter *_filter,
> }
>
> /*
> + * Check if a given offset from start of a function is valid or not
> + */
> +bool __attribute__((weak)) can_probe(char *name __used,
> + u64 vaddr __used,
> + unsigned long offset __used,
> + u8 class __used)
> +{
> + return true;
> +}
> +
> +/*
> * uprobe_events only accepts address:
> * Convert function and any offset to address
> */
> @@ -2307,7 +2318,17 @@ static int convert_name_to_addr(struct perf_probe_event *pev, const char *exec)
>
> if (map->start > sym->start)
> vaddr = map->start;
> - vaddr += sym->start + pp->offset + map->pgoff;
> +
> + vaddr += sym->start + map->pgoff;
> + if (pp->offset) {
> + if ((vaddr + pp->offset > sym->end) ||
> + !can_probe(name, vaddr, pp->offset,
> + map->dso->class)) {
> + pr_err("Failed to insert probe, ensure offset is within function and on insn boundary.\n");
> + return -EINVAL;
> + }
> + }
> + vaddr += pp->offset;
> pp->offset = 0;
>
> if (!pev->event) {
> diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
> index f9f3de8..9ec2f8c 100644
> --- a/tools/perf/util/probe-event.h
> +++ b/tools/perf/util/probe-event.h
> @@ -137,4 +137,6 @@ extern int show_available_funcs(const char *module, struct strfilter *filter,
> /* Maximum index number of event-name postfix */
> #define MAX_EVENT_INDEX 1024
>
> +extern bool can_probe(char *name, u64 vaddr, unsigned long offset,
> + u8 class);
> #endif /*_PROBE_EVENT_H */
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index caaf75a..be58b06 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -1184,6 +1184,7 @@ static int dso__load_sym(struct dso *dso, struct map *map, const char *name,
> goto out_close;
> }
>
> + dso->class = gelf_getclass(elf);
> if (gelf_getehdr(elf, &ehdr) == NULL) {
> pr_debug("%s: cannot get elf header.\n", __func__);
> goto out_elf_end;
> @@ -1326,6 +1327,7 @@ static int dso__load_sym(struct dso *dso, struct map *map, const char *name,
> curr_dso->kernel = dso->kernel;
> curr_dso->long_name = dso->long_name;
> curr_dso->long_name_len = dso->long_name_len;
> + curr_dso->class = dso->class;
> curr_map = map__new2(start, curr_dso,
> map->type);
> if (curr_map == NULL) {
> diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
> index 9e7742c..1d0cc28 100644
> --- a/tools/perf/util/symbol.h
> +++ b/tools/perf/util/symbol.h
> @@ -174,6 +174,7 @@ struct dso {
> char *long_name;
> u16 long_name_len;
> u16 short_name_len;
> + u8 class;
> char name[0];
> };
>
>
>
> --
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--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@...achi.com
--
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