This example shows using a kprobe to act as a dnat mechanism to divert
traffic for arbitrary endpoints. It rewrite the arguments to a syscall
while they're still in userspace, and before the syscall has a chance
to copy the argument into kernel space.
Although this is an example, it also acts as a test because the mapped
address is 255.255.255.255:555 -> real address, and that's not a legal
address to connect to. If the helper is broken, the example will fail
on the intermediate steps, as well as the final step to verify the
rewrite of userspace memory succeeded.
Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This allows user memory to be written to during the course of a kprobe.
It shouldn't be used to implement any kind of security mechanism
because of TOC-TOU attacks, but rather to debug, divert, and
manipulate execution of semi-cooperative processes.
Although it uses probe_kernel_write, we limit the address space
the probe can write into by checking the space with access_ok.
We do this as opposed to calling copy_to_user directly, in order
to avoid sleeping. In addition we ensure the threads's current fs
/ segment is USER_DS and the thread isn't exiting nor a kernel thread.
Given this feature is meant for experiments, and it has a risk of
crashing the system, and running programs, we print a warning on
when a proglet that attempts to use this helper is installed,
along with the pid and process name.
Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The naming choice of index is not terribly descriptive, and dropcnt is
in fact incorrect for xdp2. Pick better names for these: ipproto and
rxcnt.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a sample that rewrites and forwards packets out on the same
interface. Observed single core forwarding performance of ~10Mpps.
Since the mlx4 driver under test recycles every single packet page, the
perf output shows almost exclusively just the ring management and bpf
program work. Slowdowns are likely occurring due to cache misses.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
test_cgrp2_array_pin.c:
A userland program that creates a bpf_map (BPF_MAP_TYPE_GROUP_ARRAY),
pouplates/updates it with a cgroup2's backed fd and pins it to a
bpf-fs's file. The pinned file can be loaded by tc and then used
by the bpf prog later. This program can also update an existing pinned
array and it could be useful for debugging/testing purpose.
test_cgrp2_tc_kern.c:
A bpf prog which should be loaded by tc. It is to demonstrate
the usage of bpf_skb_in_cgroup.
test_cgrp2_tc.sh:
A script that glues the test_cgrp2_array_pin.c and
test_cgrp2_tc_kern.c together. The idea is like:
1. Load the test_cgrp2_tc_kern.o by tc
2. Use test_cgrp2_array_pin.c to populate a BPF_MAP_TYPE_CGROUP_ARRAY
with a cgroup fd
3. Do a 'ping -6 ff02::1%ve' to ensure the packet has been
dropped because of a match on the cgroup
Most of the lines in test_cgrp2_tc.sh is the boilerplate
to setup the cgroup/bpf-fs/net-devices/netns...etc. It is
not bulletproof on errors but should work well enough and
give enough debug info if things did not go well.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
add few tests for "pointer to packet" logic of the verifier
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
parse_simple.c - packet parser exapmle with single length check that
filters out udp packets for port 9
parse_varlen.c - variable length parser that understand multiple vlan headers,
ipip, ipip6 and ip options to filter out udp or tcp packets on port 9.
The packet is parsed layer by layer with multitple length checks.
parse_ldabs.c - classic style of packet parsing using LD_ABS instruction.
Same functionality as parse_simple.
simple = 24.1Mpps per core
varlen = 22.7Mpps
ldabs = 21.4Mpps
Parser with LD_ABS instructions is slower than full direct access parser
which does more packet accesses and checks.
These examples demonstrate the choice bpf program authors can make between
flexibility of the parser vs speed.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
net/ipv4/ip_gre.c
Minor conflicts between tunnel bug fixes in net and
ipv6 tunnel cleanups in net-next.
Signed-off-by: David S. Miller <davem@davemloft.net>
Users are likely to manually compile both LLVM 'llc' and 'clang'
tools. Thus, also allow redefining CLANG and verify command exist.
Makefile implementation wise, the target that verify the command have
been generalized.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is not intuitive that 'make' must be run from the top level
directory with argument "samples/bpf/" to compile these eBPF samples.
Introduce a kbuild make file trick that allow make to be run from the
"samples/bpf/" directory itself. It basically change to the top level
directory and call "make samples/bpf/" with the "/" slash after the
directory name.
Also add a clean target that only cleans this directory, by taking
advantage of the kbuild external module setting M=$PWD.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Getting started with using examples in samples/bpf/ is not
straightforward. There are several dependencies, and specific
versions of these dependencies.
Just compiling the example tool is also slightly obscure, e.g. one
need to call make like:
make samples/bpf/
Do notice the "/" slash after the directory name.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make compiling samples/bpf more user friendly, by detecting if LLVM
compiler tool 'llc' is available, and also detect if the 'bpf' target
is available in this version of LLVM.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is practical to be-able-to redefine the location of the LLVM
command 'llc', because not all distros have a LLVM version with bpf
target support. Thus, it is sometimes required to compile LLVM from
source, and sometimes it is not desired to overwrite the distros
default LLVM version.
This feature was removed with 128d1514be ("samples/bpf: Use llc in
PATH, rather than a hardcoded value").
Add this features back. Note that it is possible to redefine the LLC
on the make command like:
make samples/bpf/ LLC=~/git/llvm/build/bin/llc
Fixes: 128d1514be ("samples/bpf: Use llc in PATH, rather than a hardcoded value")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
llvm cannot always recognize memset as builtin function and optimize
it away, so just delete it. It was a leftover from testing
of bpf_perf_event_output() with large data structures.
Fixes: 39111695b1 ("samples: bpf: add bpf_perf_event_output example")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This adds test cases mostly around ARG_PTR_TO_RAW_STACK to check the
verifier behaviour.
[...]
#84 raw_stack: no skb_load_bytes OK
#85 raw_stack: skb_load_bytes, no init OK
#86 raw_stack: skb_load_bytes, init OK
#87 raw_stack: skb_load_bytes, spilled regs around bounds OK
#88 raw_stack: skb_load_bytes, spilled regs corruption OK
#89 raw_stack: skb_load_bytes, spilled regs corruption 2 OK
#90 raw_stack: skb_load_bytes, spilled regs + data OK
#91 raw_stack: skb_load_bytes, invalid access 1 OK
#92 raw_stack: skb_load_bytes, invalid access 2 OK
#93 raw_stack: skb_load_bytes, invalid access 3 OK
#94 raw_stack: skb_load_bytes, invalid access 4 OK
#95 raw_stack: skb_load_bytes, invalid access 5 OK
#96 raw_stack: skb_load_bytes, invalid access 6 OK
#97 raw_stack: skb_load_bytes, large access OK
Summary: 98 PASSED, 0 FAILED
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove the zero initialization in the sample programs where appropriate.
Note that this is an optimization which is now possible, old programs
still doing the zero initialization are just fine as well. Also, make
sure we don't have padding issues when we don't memset() the entire
struct anymore.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
the first microbenchmark does
fd=open("/proc/self/comm");
for() {
write(fd, "test");
}
and on 4 cpus in parallel:
writes per sec
base (no tracepoints, no kprobes) 930k
with kprobe at __set_task_comm() 420k
with tracepoint at task:task_rename 730k
For kprobe + full bpf program manully fetches oldcomm, newcomm via bpf_probe_read.
For tracepint bpf program does nothing, since arguments are copied by tracepoint.
2nd microbenchmark does:
fd=open("/dev/urandom");
for() {
read(fd, buf);
}
and on 4 cpus in parallel:
reads per sec
base (no tracepoints, no kprobes) 300k
with kprobe at urandom_read() 279k
with tracepoint at random:urandom_read 290k
bpf progs attached to kprobe and tracepoint are noop.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
modify offwaketime to work with sched/sched_switch tracepoint
instead of kprobe into finish_task_switch
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Recognize "tracepoint/" section name prefix and attach the program
to that tracepoint.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add the necessary definitions for building bpf samples on ppc.
Since ppc doesn't store function return address on the stack, modify how
PT_REGS_RET() and PT_REGS_FP() work.
Also, introduce PT_REGS_IP() to access the instruction pointer.
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
While at it, remove the generation of .s files and fix some typos in the
related comment.
Cc: Alexei Starovoitov <ast@fb.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Building BPF samples is failing with the below error:
samples/bpf/map_perf_test_user.c: In function ‘main’:
samples/bpf/map_perf_test_user.c:134:9: error: variable ‘r’ has
initializer but incomplete type
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
^
samples/bpf/map_perf_test_user.c:134:21: error: ‘RLIM_INFINITY’
undeclared (first use in this function)
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
^
samples/bpf/map_perf_test_user.c:134:21: note: each undeclared
identifier is reported only once for each function it appears in
samples/bpf/map_perf_test_user.c:134:9: warning: excess elements in
struct initializer [enabled by default]
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
^
samples/bpf/map_perf_test_user.c:134:9: warning: (near initialization
for ‘r’) [enabled by default]
samples/bpf/map_perf_test_user.c:134:9: warning: excess elements in
struct initializer [enabled by default]
samples/bpf/map_perf_test_user.c:134:9: warning: (near initialization
for ‘r’) [enabled by default]
samples/bpf/map_perf_test_user.c:134:16: error: storage size of ‘r’
isn’t known
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
^
samples/bpf/map_perf_test_user.c:139:2: warning: implicit declaration of
function ‘setrlimit’ [-Wimplicit-function-declaration]
setrlimit(RLIMIT_MEMLOCK, &r);
^
samples/bpf/map_perf_test_user.c:139:12: error: ‘RLIMIT_MEMLOCK’
undeclared (first use in this function)
setrlimit(RLIMIT_MEMLOCK, &r);
^
samples/bpf/map_perf_test_user.c:134:16: warning: unused variable ‘r’
[-Wunused-variable]
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
^
make[2]: *** [samples/bpf/map_perf_test_user.o] Error 1
Fix this by including the necessary header file.
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
performance tests for hash map and per-cpu hash map
with and without pre-allocation
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
increase stress by also calling bpf_get_stackid() from
various *spin* functions
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
this test calls bpf programs from different contexts:
from inside of slub, from rcu, from pretty much everywhere,
since it kprobes all spin_lock functions.
It stresses the bpf hash and percpu map pre-allocation,
deallocation logic and call_rcu mechanisms.
User space part adding more stress by walking and deleting map elements.
Note that due to nature bpf_load.c the earlier kprobe+bpf programs are
already active while loader loads new programs, creates new kprobes and
attaches them.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
extend test coveraged to include pre-allocated and run-time alloc maps
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
note old loader is compatible with new kernel.
map_flags are optional
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
move ksym search from offwaketime into library to be reused
in other tests
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
map creation is typically the first one to fail when rlimits are
too low, not enough memory, etc
Make this failure scenario more verbose
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is simplified version of Brendan Gregg's offwaketime:
This program shows kernel stack traces and task names that were blocked and
"off-CPU", along with the stack traces and task names for the threads that woke
them, and the total elapsed time from when they blocked to when they were woken
up. The combined stacks, task names, and total time is summarized in kernel
context for efficiency.
Example:
$ sudo ./offwaketime | flamegraph.pl > demo.svg
Open demo.svg in the browser as FlameGraph visualization.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
A sanity test for BPF_MAP_TYPE_PERCPU_ARRAY
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
A sanity test for BPF_MAP_TYPE_PERCPU_HASH.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
commit 338d4f49d6
("arm64: kernel: Add support for Privileged Access Never") includes sysreg.h
into futex.h and uaccess.h. But, the inline assembly used by asm/sysreg.h is
incompatible with llvm so it will cause BPF samples build failure for ARM64.
Since sysreg.h is useless for BPF samples, just exclude it from Makefile via
defining __ASM_SYSREG_H.
Signed-off-by: Yang Shi <yang.shi@linaro.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Define aarch64 specific registers for building bpf samples correctly.
Signed-off-by: Yang Shi <yang.shi@linaro.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Performance test and example of bpf_perf_event_output().
kprobe is attached to sys_write() and trivial bpf program streams
pid+cookie into userspace via PERF_COUNT_SW_BPF_OUTPUT event.
Usage:
$ sudo ./bld_x64/samples/bpf/trace_output
recv 2968913 events per sec
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add new tests samples/bpf/test_verifier:
unpriv: return pointer
checks that pointer cannot be returned from the eBPF program
unpriv: add const to pointer
unpriv: add pointer to pointer
unpriv: neg pointer
checks that pointer arithmetic is disallowed
unpriv: cmp pointer with const
unpriv: cmp pointer with pointer
checks that comparison of pointers is disallowed
Only one case allowed 'void *value = bpf_map_lookup_elem(..); if (value == 0) ...'
unpriv: check that printk is disallowed
since bpf_trace_printk is not available to unprivileged
unpriv: pass pointer to helper function
checks that pointers cannot be passed to functions that expect integers
If function expects a pointer the verifier allows only that type of pointer.
Like 1st argument of bpf_map_lookup_elem() must be pointer to map.
(applies to non-root as well)
unpriv: indirectly pass pointer on stack to helper function
checks that pointer stored into stack cannot be used as part of key
passed into bpf_map_lookup_elem()
unpriv: mangle pointer on stack 1
unpriv: mangle pointer on stack 2
checks that writing into stack slot that already contains a pointer
is disallowed
unpriv: read pointer from stack in small chunks
checks that < 8 byte read from stack slot that contains a pointer is
disallowed
unpriv: write pointer into ctx
checks that storing pointers into skb->fields is disallowed
unpriv: write pointer into map elem value
checks that storing pointers into element values is disallowed
For example:
int bpf_prog(struct __sk_buff *skb)
{
u32 key = 0;
u64 *value = bpf_map_lookup_elem(&map, &key);
if (value)
*value = (u64) skb;
}
will be rejected.
unpriv: partial copy of pointer
checks that doing 32-bit register mov from register containing
a pointer is disallowed
unpriv: pass pointer to tail_call
checks that passing pointer as an index into bpf_tail_call
is disallowed
unpriv: cmp map pointer with zero
checks that comparing map pointer with constant is disallowed
unpriv: write into frame pointer
checks that frame pointer is read-only (applies to root too)
unpriv: cmp of frame pointer
checks that R10 cannot be using in comparison
unpriv: cmp of stack pointer
checks that Rx = R10 - imm is ok, but comparing Rx is not
unpriv: obfuscate stack pointer
checks that Rx = R10 - imm is ok, but Rx -= imm is not
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Existing bpf_clone_redirect() helper clones skb before redirecting
it to RX or TX of destination netdev.
Introduce bpf_redirect() helper that does that without cloning.
Benchmarked with two hosts using 10G ixgbe NICs.
One host is doing line rate pktgen.
Another host is configured as:
$ tc qdisc add dev $dev ingress
$ tc filter add dev $dev root pref 10 u32 match u32 0 0 flowid 1:2 \
action bpf run object-file tcbpf1_kern.o section clone_redirect_xmit drop
so it receives the packet on $dev and immediately xmits it on $dev + 1
The section 'clone_redirect_xmit' in tcbpf1_kern.o file has the program
that does bpf_clone_redirect() and performance is 2.0 Mpps
$ tc filter add dev $dev root pref 10 u32 match u32 0 0 flowid 1:2 \
action bpf run object-file tcbpf1_kern.o section redirect_xmit drop
which is using bpf_redirect() - 2.4 Mpps
and using cls_bpf with integrated actions as:
$ tc filter add dev $dev root pref 10 \
bpf run object-file tcbpf1_kern.o section redirect_xmit integ_act classid 1
performance is 2.5 Mpps
To summarize:
u32+act_bpf using clone_redirect - 2.0 Mpps
u32+act_bpf using redirect - 2.4 Mpps
cls_bpf using redirect - 2.5 Mpps
For comparison linux bridge in this setup is doing 2.1 Mpps
and ixgbe rx + drop in ip_rcv - 7.8 Mpps
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are two improvements in this patch:
1. Fix the build warnings;
2. Add function read_trace_pipe() to print the result on
the screen;
Before this patch, we can get the result through /sys/kernel/de
bug/tracing/trace_pipe and get nothing on the screen.
By applying this patch, the result can be printed on the screen.
$ ./tracex6
...
tracex6-705 [003] d..1 131.428593: : CPU-3 19981414
sshd-683 [000] d..1 131.428727: : CPU-0 221682321
sshd-683 [000] d..1 131.428821: : CPU-0 221808766
sshd-683 [000] d..1 131.428950: : CPU-0 221982984
sshd-683 [000] d..1 131.429045: : CPU-0 222111851
tracex6-705 [003] d..1 131.429168: : CPU-3 20757551
sshd-683 [000] d..1 131.429170: : CPU-0 222281240
sshd-683 [000] d..1 131.429261: : CPU-0 222403340
sshd-683 [000] d..1 131.429378: : CPU-0 222561024
...
Signed-off-by: Kaixu Xia <xiakaixu@huawei.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is a simple example and shows how to use the new ability
to get the selected Hardware PMU counter value.
Signed-off-by: Kaixu Xia <xiakaixu@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
mov %rsp, %r1 ; r1 = rsp
add $-8, %r1 ; r1 = rsp - 8
store_q $123, -8(%rsp) ; *(u64*)r1 = 123 <- valid
store_q $123, (%r1) ; *(u64*)r1 = 123 <- previously invalid
mov $0, %r0
exit ; Always need to exit
And we'd get the following error:
0: (bf) r1 = r10
1: (07) r1 += -8
2: (7a) *(u64 *)(r10 -8) = 999
3: (7a) *(u64 *)(r1 +0) = 999
R1 invalid mem access 'fp'
Unable to load program
We already know that a register is a stack address and the appropriate
offset, so we should be able to validate those references as well.
Signed-off-by: Alex Gartrell <agartrell@fb.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The trace bpf samples do not compile on s390x because they use x86
specific fields from the "pt_regs" structure.
Fix this and access the fields via new PT_REGS macros.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
eBPF programs attached to kprobes need to filter based on
current->pid, uid and other fields, so introduce helper functions:
u64 bpf_get_current_pid_tgid(void)
Return: current->tgid << 32 | current->pid
u64 bpf_get_current_uid_gid(void)
Return: current_gid << 32 | current_uid
bpf_get_current_comm(char *buf, int size_of_buf)
stores current->comm into buf
They can be used from the programs attached to TC as well to classify packets
based on current task fields.
Update tracex2 example to print histogram of write syscalls for each process
instead of aggregated for all.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
allow programs read/write skb->mark, tc_index fields and
((struct qdisc_skb_cb *)cb)->data.
mark and tc_index are generically useful in TC.
cb[0]-cb[4] are primarily used to pass arguments from one
program to another called via bpf_tail_call() which can
be seen in sockex3_kern.c example.
All fields of 'struct __sk_buff' are readable to socket and tc_cls_act progs.
mark, tc_index are writeable from tc_cls_act only.
cb[0]-cb[4] are writeable by both sockets and tc_cls_act.
Add verifier tests and improve sample code.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
