https://github.com/torvalds/linux
Revision 573b3aa6940661dc50c383213d428c27df78be7c authored by Yonghong Song on 30 July 2018, 15:49:03 UTC, committed by Daniel Borkmann on 30 July 2018, 22:37:09 UTC
I hit the following problem when I tried to use bpftool
to dump a percpu array.
$ sudo ./bpftool map show
61: percpu_array name stub flags 0x0
key 4B value 4B max_entries 1 memlock 4096B
...
$ sudo ./bpftool map dump id 61
bpftool: malloc.c:2406: sysmalloc: Assertion
`(old_top == initial_top (av) && old_size == 0) || \
((unsigned long) (old_size) >= MINSIZE && \
prev_inuse (old_top) && \
((unsigned long) old_end & (pagesize - 1)) == 0)'
failed.
Aborted
Further debugging revealed that this is due to
miscommunication between bpftool and kernel.
For example, for the above percpu_array with value size of 4B.
The map info returned to user space has value size of 4B.
In bpftool, the values array for lookup is allocated like:
info->value_size * get_possible_cpus() = 4 * get_possible_cpus()
In kernel (kernel/bpf/syscall.c), the values array size is
rounded up to multiple of 8.
round_up(map->value_size, 8) * num_possible_cpus()
= 8 * num_possible_cpus()
So when kernel copies the values to user buffer, the kernel will
overwrite beyond user buffer boundary.
This patch fixed the issue by allocating and stepping through
percpu map value array properly in bpftool.
Fixes: 71bb428fe2c19 ("tools: bpf: add bpftool")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
1 parent 61f4b23
Tip revision: 573b3aa6940661dc50c383213d428c27df78be7c authored by Yonghong Song on 30 July 2018, 15:49:03 UTC
tools/bpftool: fix a percpu_array map dump problem
tools/bpftool: fix a percpu_array map dump problem
Tip revision: 573b3aa
double.h
/* Software floating-point emulation.
Definitions for IEEE Double Precision
Copyright (C) 1997,1998,1999 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson (rth@cygnus.com),
Jakub Jelinek (jj@ultra.linux.cz),
David S. Miller (davem@redhat.com) and
Peter Maydell (pmaydell@chiark.greenend.org.uk).
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#ifndef __MATH_EMU_DOUBLE_H__
#define __MATH_EMU_DOUBLE_H__
#if _FP_W_TYPE_SIZE < 32
#error "Here's a nickel kid. Go buy yourself a real computer."
#endif
#if _FP_W_TYPE_SIZE < 64
#define _FP_FRACTBITS_D (2 * _FP_W_TYPE_SIZE)
#else
#define _FP_FRACTBITS_D _FP_W_TYPE_SIZE
#endif
#define _FP_FRACBITS_D 53
#define _FP_FRACXBITS_D (_FP_FRACTBITS_D - _FP_FRACBITS_D)
#define _FP_WFRACBITS_D (_FP_WORKBITS + _FP_FRACBITS_D)
#define _FP_WFRACXBITS_D (_FP_FRACTBITS_D - _FP_WFRACBITS_D)
#define _FP_EXPBITS_D 11
#define _FP_EXPBIAS_D 1023
#define _FP_EXPMAX_D 2047
#define _FP_QNANBIT_D \
((_FP_W_TYPE)1 << (_FP_FRACBITS_D-2) % _FP_W_TYPE_SIZE)
#define _FP_IMPLBIT_D \
((_FP_W_TYPE)1 << (_FP_FRACBITS_D-1) % _FP_W_TYPE_SIZE)
#define _FP_OVERFLOW_D \
((_FP_W_TYPE)1 << _FP_WFRACBITS_D % _FP_W_TYPE_SIZE)
#if _FP_W_TYPE_SIZE < 64
union _FP_UNION_D
{
double flt;
struct {
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned sign : 1;
unsigned exp : _FP_EXPBITS_D;
unsigned frac1 : _FP_FRACBITS_D - (_FP_IMPLBIT_D != 0) - _FP_W_TYPE_SIZE;
unsigned frac0 : _FP_W_TYPE_SIZE;
#else
unsigned frac0 : _FP_W_TYPE_SIZE;
unsigned frac1 : _FP_FRACBITS_D - (_FP_IMPLBIT_D != 0) - _FP_W_TYPE_SIZE;
unsigned exp : _FP_EXPBITS_D;
unsigned sign : 1;
#endif
} bits __attribute__((packed));
};
#define FP_DECL_D(X) _FP_DECL(2,X)
#define FP_UNPACK_RAW_D(X,val) _FP_UNPACK_RAW_2(D,X,val)
#define FP_UNPACK_RAW_DP(X,val) _FP_UNPACK_RAW_2_P(D,X,val)
#define FP_PACK_RAW_D(val,X) _FP_PACK_RAW_2(D,val,X)
#define FP_PACK_RAW_DP(val,X) \
do { \
if (!FP_INHIBIT_RESULTS) \
_FP_PACK_RAW_2_P(D,val,X); \
} while (0)
#define FP_UNPACK_D(X,val) \
do { \
_FP_UNPACK_RAW_2(D,X,val); \
_FP_UNPACK_CANONICAL(D,2,X); \
} while (0)
#define FP_UNPACK_DP(X,val) \
do { \
_FP_UNPACK_RAW_2_P(D,X,val); \
_FP_UNPACK_CANONICAL(D,2,X); \
} while (0)
#define FP_PACK_D(val,X) \
do { \
_FP_PACK_CANONICAL(D,2,X); \
_FP_PACK_RAW_2(D,val,X); \
} while (0)
#define FP_PACK_DP(val,X) \
do { \
_FP_PACK_CANONICAL(D,2,X); \
if (!FP_INHIBIT_RESULTS) \
_FP_PACK_RAW_2_P(D,val,X); \
} while (0)
#define FP_ISSIGNAN_D(X) _FP_ISSIGNAN(D,2,X)
#define FP_NEG_D(R,X) _FP_NEG(D,2,R,X)
#define FP_ADD_D(R,X,Y) _FP_ADD(D,2,R,X,Y)
#define FP_SUB_D(R,X,Y) _FP_SUB(D,2,R,X,Y)
#define FP_MUL_D(R,X,Y) _FP_MUL(D,2,R,X,Y)
#define FP_DIV_D(R,X,Y) _FP_DIV(D,2,R,X,Y)
#define FP_SQRT_D(R,X) _FP_SQRT(D,2,R,X)
#define _FP_SQRT_MEAT_D(R,S,T,X,Q) _FP_SQRT_MEAT_2(R,S,T,X,Q)
#define FP_CMP_D(r,X,Y,un) _FP_CMP(D,2,r,X,Y,un)
#define FP_CMP_EQ_D(r,X,Y) _FP_CMP_EQ(D,2,r,X,Y)
#define FP_TO_INT_D(r,X,rsz,rsg) _FP_TO_INT(D,2,r,X,rsz,rsg)
#define FP_TO_INT_ROUND_D(r,X,rsz,rsg) _FP_TO_INT_ROUND(D,2,r,X,rsz,rsg)
#define FP_FROM_INT_D(X,r,rs,rt) _FP_FROM_INT(D,2,X,r,rs,rt)
#define _FP_FRAC_HIGH_D(X) _FP_FRAC_HIGH_2(X)
#define _FP_FRAC_HIGH_RAW_D(X) _FP_FRAC_HIGH_2(X)
#else
union _FP_UNION_D
{
double flt;
struct {
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned sign : 1;
unsigned exp : _FP_EXPBITS_D;
unsigned long frac : _FP_FRACBITS_D - (_FP_IMPLBIT_D != 0);
#else
unsigned long frac : _FP_FRACBITS_D - (_FP_IMPLBIT_D != 0);
unsigned exp : _FP_EXPBITS_D;
unsigned sign : 1;
#endif
} bits __attribute__((packed));
};
#define FP_DECL_D(X) _FP_DECL(1,X)
#define FP_UNPACK_RAW_D(X,val) _FP_UNPACK_RAW_1(D,X,val)
#define FP_UNPACK_RAW_DP(X,val) _FP_UNPACK_RAW_1_P(D,X,val)
#define FP_PACK_RAW_D(val,X) _FP_PACK_RAW_1(D,val,X)
#define FP_PACK_RAW_DP(val,X) \
do { \
if (!FP_INHIBIT_RESULTS) \
_FP_PACK_RAW_1_P(D,val,X); \
} while (0)
#define FP_UNPACK_D(X,val) \
do { \
_FP_UNPACK_RAW_1(D,X,val); \
_FP_UNPACK_CANONICAL(D,1,X); \
} while (0)
#define FP_UNPACK_DP(X,val) \
do { \
_FP_UNPACK_RAW_1_P(D,X,val); \
_FP_UNPACK_CANONICAL(D,1,X); \
} while (0)
#define FP_PACK_D(val,X) \
do { \
_FP_PACK_CANONICAL(D,1,X); \
_FP_PACK_RAW_1(D,val,X); \
} while (0)
#define FP_PACK_DP(val,X) \
do { \
_FP_PACK_CANONICAL(D,1,X); \
if (!FP_INHIBIT_RESULTS) \
_FP_PACK_RAW_1_P(D,val,X); \
} while (0)
#define FP_ISSIGNAN_D(X) _FP_ISSIGNAN(D,1,X)
#define FP_NEG_D(R,X) _FP_NEG(D,1,R,X)
#define FP_ADD_D(R,X,Y) _FP_ADD(D,1,R,X,Y)
#define FP_SUB_D(R,X,Y) _FP_SUB(D,1,R,X,Y)
#define FP_MUL_D(R,X,Y) _FP_MUL(D,1,R,X,Y)
#define FP_DIV_D(R,X,Y) _FP_DIV(D,1,R,X,Y)
#define FP_SQRT_D(R,X) _FP_SQRT(D,1,R,X)
#define _FP_SQRT_MEAT_D(R,S,T,X,Q) _FP_SQRT_MEAT_1(R,S,T,X,Q)
/* The implementation of _FP_MUL_D and _FP_DIV_D should be chosen by
the target machine. */
#define FP_CMP_D(r,X,Y,un) _FP_CMP(D,1,r,X,Y,un)
#define FP_CMP_EQ_D(r,X,Y) _FP_CMP_EQ(D,1,r,X,Y)
#define FP_TO_INT_D(r,X,rsz,rsg) _FP_TO_INT(D,1,r,X,rsz,rsg)
#define FP_TO_INT_ROUND_D(r,X,rsz,rsg) _FP_TO_INT_ROUND(D,1,r,X,rsz,rsg)
#define FP_FROM_INT_D(X,r,rs,rt) _FP_FROM_INT(D,1,X,r,rs,rt)
#define _FP_FRAC_HIGH_D(X) _FP_FRAC_HIGH_1(X)
#define _FP_FRAC_HIGH_RAW_D(X) _FP_FRAC_HIGH_1(X)
#endif /* W_TYPE_SIZE < 64 */
#endif /* __MATH_EMU_DOUBLE_H__ */
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