In Linux terms, the runtime verification monitors are encapsulated
inside the "RV monitor" abstraction. The "RV monitor" includes a set
of instances of the monitor (per-cpu monitor, per-task monitor, and
so on), the helper functions that glue the monitor to the system
reference model, and the trace output as a reaction for event parsing
and exceptions, as depicted below:
Linux +----- RV Monitor ----------------------------------+ Formal
Realm | | Realm
+-------------------+ +----------------+ +-----------------+
| Linux kernel | | Monitor | | Reference |
| Tracing | -> | Instance(s) | <- | Model |
| (instrumentation) | | (verification) | | (specification) |
+-------------------+ +----------------+ +-----------------+
| | |
| V |
| +----------+ |
| | Reaction | |
| +--+--+--+-+ |
| | | | |
| | | +-> trace output ? |
+------------------------|--|----------------------+
| +----> panic ?
+-------> <user-specified>
Add the rv/da_monitor.h, enabling automatic code generation for the
*Monitor Instance(s)* using C macros, and code to support it.
The benefits of the usage of macro for monitor synthesis are 3-fold as it:
- Reduces the code duplication;
- Facilitates the bug fix/improvement;
- Avoids the case of developers changing the core of the monitor code
to manipulate the model in a (let's say) non-standard way.
This initial implementation presents three different types of monitor
instances:
- DECLARE_DA_MON_GLOBAL(name, type)
- DECLARE_DA_MON_PER_CPU(name, type)
- DECLARE_DA_MON_PER_TASK(name, type)
The first declares the functions for a global deterministic automata monitor,
the second for monitors with per-cpu instances, and the third with per-task
instances.
Link: https://lkml.kernel.org/r/51b0bf425a281e226dfeba7401d2115d6091f84e.1659052063.git.bristot@kernel.org
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Gabriele Paoloni <gpaoloni@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Tao Zhou <tao.zhou@linux.dev>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
RV is a lightweight (yet rigorous) method that complements classical
exhaustive verification techniques (such as model checking and
theorem proving) with a more practical approach to complex systems.
RV works by analyzing the trace of the system's actual execution,
comparing it against a formal specification of the system behavior.
RV can give precise information on the runtime behavior of the
monitored system while enabling the reaction for unexpected
events, avoiding, for example, the propagation of a failure on
safety-critical systems.
The development of this interface roots in the development of the
paper:
De Oliveira, Daniel Bristot; Cucinotta, Tommaso; De Oliveira, Romulo
Silva. Efficient formal verification for the Linux kernel. In:
International Conference on Software Engineering and Formal Methods.
Springer, Cham, 2019. p. 315-332.
And:
De Oliveira, Daniel Bristot. Automata-based formal analysis
and verification of the real-time Linux kernel. PhD Thesis, 2020.
The RV interface resembles the tracing/ interface on purpose. The current
path for the RV interface is /sys/kernel/tracing/rv/.
It presents these files:
"available_monitors"
- List the available monitors, one per line.
For example:
# cat available_monitors
wip
wwnr
"enabled_monitors"
- Lists the enabled monitors, one per line;
- Writing to it enables a given monitor;
- Writing a monitor name with a '!' prefix disables it;
- Truncating the file disables all enabled monitors.
For example:
# cat enabled_monitors
# echo wip > enabled_monitors
# echo wwnr >> enabled_monitors
# cat enabled_monitors
wip
wwnr
# echo '!wip' >> enabled_monitors
# cat enabled_monitors
wwnr
# echo > enabled_monitors
# cat enabled_monitors
#
Note that more than one monitor can be enabled concurrently.
"monitoring_on"
- It is an on/off general switcher for monitoring. Note
that it does not disable enabled monitors or detach events,
but stop the per-entity monitors of monitoring the events
received from the system. It resembles the "tracing_on" switcher.
"monitors/"
Each monitor will have its one directory inside "monitors/". There
the monitor specific files will be presented.
The "monitors/" directory resembles the "events" directory on
tracefs.
For example:
# cd monitors/wip/
# ls
desc enable
# cat desc
wakeup in preemptive per-cpu testing monitor.
# cat enable
0
For further information, see the comments in the header of
kernel/trace/rv/rv.c from this patch.
Link: https://lkml.kernel.org/r/a4bfe038f50cb047bfb343ad0e12b0e646ab308b.1659052063.git.bristot@kernel.org
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Gabriele Paoloni <gpaoloni@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Tao Zhou <tao.zhou@linux.dev>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Currently when creating a specific group of trace events,
take kprobe event as example, the user must use the following format:
p:GRP/EVENT [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS],
which means user must enter EVENT name, one example is:
echo 'p:usb_gadget/config_usb_cfg_link config_usb_cfg_link $arg1' >> kprobe_events
It is not simple if there are too many entries because the event name is
the same as symbol name.
This change allows user to specify no EVENT name, format changed as:
p:GRP/ [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
It will generate event name automatically and one example is:
echo 'p:usb_gadget/ config_usb_cfg_link $arg1' >> kprobe_events.
Link: https://lore.kernel.org/all/1656296348-16111-4-git-send-email-quic_linyyuan@quicinc.com/
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Daniel Borkmann says:
====================
bpf-next 2022-07-22
We've added 73 non-merge commits during the last 12 day(s) which contain
a total of 88 files changed, 3458 insertions(+), 860 deletions(-).
The main changes are:
1) Implement BPF trampoline for arm64 JIT, from Xu Kuohai.
2) Add ksyscall/kretsyscall section support to libbpf to simplify tracing kernel
syscalls through kprobe mechanism, from Andrii Nakryiko.
3) Allow for livepatch (KLP) and BPF trampolines to attach to the same kernel
function, from Song Liu & Jiri Olsa.
4) Add new kfunc infrastructure for netfilter's CT e.g. to insert and change
entries, from Kumar Kartikeya Dwivedi & Lorenzo Bianconi.
5) Add a ksym BPF iterator to allow for more flexible and efficient interactions
with kernel symbols, from Alan Maguire.
6) Bug fixes in libbpf e.g. for uprobe binary path resolution, from Dan Carpenter.
7) Fix BPF subprog function names in stack traces, from Alexei Starovoitov.
8) libbpf support for writing custom perf event readers, from Jon Doron.
9) Switch to use SPDX tag for BPF helper man page, from Alejandro Colomar.
10) Fix xsk send-only sockets when in busy poll mode, from Maciej Fijalkowski.
11) Reparent BPF maps and their charging on memcg offlining, from Roman Gushchin.
12) Multiple follow-up fixes around BPF lsm cgroup infra, from Stanislav Fomichev.
13) Use bootstrap version of bpftool where possible to speed up builds, from Pu Lehui.
14) Cleanup BPF verifier's check_func_arg() handling, from Joanne Koong.
15) Make non-prealloced BPF map allocations low priority to play better with
memcg limits, from Yafang Shao.
16) Fix BPF test runner to reject zero-length data for skbs, from Zhengchao Shao.
17) Various smaller cleanups and improvements all over the place.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (73 commits)
bpf: Simplify bpf_prog_pack_[size|mask]
bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)
bpf, x64: Allow to use caller address from stack
ftrace: Allow IPMODIFY and DIRECT ops on the same function
ftrace: Add modify_ftrace_direct_multi_nolock
bpf/selftests: Fix couldn't retrieve pinned program in xdp veth test
bpf: Fix build error in case of !CONFIG_DEBUG_INFO_BTF
selftests/bpf: Fix test_verifier failed test in unprivileged mode
selftests/bpf: Add negative tests for new nf_conntrack kfuncs
selftests/bpf: Add tests for new nf_conntrack kfuncs
selftests/bpf: Add verifier tests for trusted kfunc args
net: netfilter: Add kfuncs to set and change CT status
net: netfilter: Add kfuncs to set and change CT timeout
net: netfilter: Add kfuncs to allocate and insert CT
net: netfilter: Deduplicate code in bpf_{xdp,skb}_ct_lookup
bpf: Add documentation for kfuncs
bpf: Add support for forcing kfunc args to be trusted
bpf: Switch to new kfunc flags infrastructure
tools/resolve_btfids: Add support for 8-byte BTF sets
bpf: Introduce 8-byte BTF set
...
====================
Link: https://lore.kernel.org/r/20220722221218.29943-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
IPMODIFY (livepatch) and DIRECT (bpf trampoline) ops are both important
users of ftrace. It is necessary to allow them work on the same function
at the same time.
First, DIRECT ops no longer specify IPMODIFY flag. Instead, DIRECT flag is
handled together with IPMODIFY flag in __ftrace_hash_update_ipmodify().
Then, a callback function, ops_func, is added to ftrace_ops. This is used
by ftrace core code to understand whether the DIRECT ops can share with an
IPMODIFY ops. To share with IPMODIFY ops, the DIRECT ops need to implement
the callback function and adjust the direct trampoline accordingly.
If DIRECT ops is attached before the IPMODIFY ops, ftrace core code calls
ENABLE_SHARE_IPMODIFY_PEER on the DIRECT ops before registering the
IPMODIFY ops.
If IPMODIFY ops is attached before the DIRECT ops, ftrace core code calls
ENABLE_SHARE_IPMODIFY_SELF in __ftrace_hash_update_ipmodify. Owner of the
DIRECT ops may return 0 if the DIRECT trampoline can share with IPMODIFY,
so error code otherwise. The error code is propagated to
register_ftrace_direct_multi so that onwer of the DIRECT trampoline can
handle it properly.
For more details, please refer to comment before enum ftrace_ops_cmd.
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/all/20220602193706.2607681-2-song@kernel.org/
Link: https://lore.kernel.org/all/20220718055449.3960512-1-song@kernel.org/
Link: https://lore.kernel.org/bpf/20220720002126.803253-3-song@kernel.org
When I look into implements of create_hist_fields(), I think there can be
following two simplifications:
1. If something wrong happened in parse_var_defs(), free_var_defs() would
have been called in it, so no need goto free again after calling it;
2. After calling create_key_fields(), regardless of the value of 'ret', it
then always runs into 'out: ', so the judge of 'ret' is redundant.
Link: https://lkml.kernel.org/r/20220630013152.164871-1-zhengyejian1@huawei.com
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Reviewed-by: Tom Rix <trix@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
It was brought up that on ARMv7, that because the FUNCTION_TRACER does not
use nops to keep function tracing disabled because of the use of a link
register, it does have some performance impact.
The start of functions when -pg is used to compile the kernel is:
push {lr}
bl 8010e7c0 <__gnu_mcount_nc>
When function tracing is tuned off, it becomes:
push {lr}
add sp, sp, #4
Which just puts the stack back to its normal location. But these two
instructions at the start of every function does incur some overhead.
Be more honest in the Kconfig FUNCTION_TRACER description and specify that
the overhead being in the noise was x86 specific, but other architectures
may vary.
Link: https://lore.kernel.org/all/20220705105416.GE5208@pengutronix.de/
Link: https://lkml.kernel.org/r/20220706161231.085a83da@gandalf.local.home
Reported-by: Sascha Hauer <sha@pengutronix.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
If you drop into kdb and type "ftdump" you'll get a sleeping while
atomic warning from memory allocation in trace_find_next_entry().
This appears to have been caused by commit ff895103a8 ("tracing:
Save off entry when peeking at next entry"), which added the
allocation in that path. The problematic commit was already fixed by
commit 8e99cf91b9 ("tracing: Do not allocate buffer in
trace_find_next_entry() in atomic") but that fix missed the kdb case.
The fix here is easy: just move the assignment of the static buffer to
the place where it should have been to begin with:
trace_init_global_iter(). That function is called in two places, once
is right before the assignment of the static buffer added by the
previous fix and once is in kdb.
Note that it appears that there's a second static buffer that we need
to assign that was added in commit efbbdaa22b ("tracing: Show real
address for trace event arguments"), so we'll move that too.
Link: https://lkml.kernel.org/r/20220708170919.1.I75844e5038d9425add2ad853a608cb44bb39df40@changeid
Fixes: ff895103a8 ("tracing: Save off entry when peeking at next entry")
Fixes: efbbdaa22b ("tracing: Show real address for trace event arguments")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This reverts commit 46bbe5c671.
As commit 46bbe5c671 ("tracing: fix double free") said, the
"double free" problem reported by clang static analyzer is:
> In parse_var_defs() if there is a problem allocating
> var_defs.expr, the earlier var_defs.name is freed.
> This free is duplicated by free_var_defs() which frees
> the rest of the list.
However, if there is a problem allocating N-th var_defs.expr:
+ in parse_var_defs(), the freed 'earlier var_defs.name' is
actually the N-th var_defs.name;
+ then in free_var_defs(), the names from 0th to (N-1)-th are freed;
IF ALLOCATING PROBLEM HAPPENED HERE!!! -+
\
|
0th 1th (N-1)-th N-th V
+-------------+-------------+-----+-------------+-----------
var_defs: | name | expr | name | expr | ... | name | expr | name | ///
+-------------+-------------+-----+-------------+-----------
These two frees don't act on same name, so there was no "double free"
problem before. Conversely, after that commit, we get a "memory leak"
problem because the above "N-th var_defs.name" is not freed.
If enable CONFIG_DEBUG_KMEMLEAK and inject a fault at where the N-th
var_defs.expr allocated, then execute on shell like:
$ echo 'hist:key=call_site:val=$v1,$v2:v1=bytes_req,v2=bytes_alloc' > \
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
Then kmemleak reports:
unreferenced object 0xffff8fb100ef3518 (size 8):
comm "bash", pid 196, jiffies 4295681690 (age 28.538s)
hex dump (first 8 bytes):
76 31 00 00 b1 8f ff ff v1......
backtrace:
[<0000000038fe4895>] kstrdup+0x2d/0x60
[<00000000c99c049a>] event_hist_trigger_parse+0x206f/0x20e0
[<00000000ae70d2cc>] trigger_process_regex+0xc0/0x110
[<0000000066737a4c>] event_trigger_write+0x75/0xd0
[<000000007341e40c>] vfs_write+0xbb/0x2a0
[<0000000087fde4c2>] ksys_write+0x59/0xd0
[<00000000581e9cdf>] do_syscall_64+0x3a/0x80
[<00000000cf3b065c>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
Link: https://lkml.kernel.org/r/20220711014731.69520-1-zhengyejian1@huawei.com
Cc: stable@vger.kernel.org
Fixes: 46bbe5c671 ("tracing: fix double free")
Reported-by: Hulk Robot <hulkci@huawei.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Daniel Borkmann says:
====================
pull-request: bpf-next 2022-07-09
We've added 94 non-merge commits during the last 19 day(s) which contain
a total of 125 files changed, 5141 insertions(+), 6701 deletions(-).
The main changes are:
1) Add new way for performing BTF type queries to BPF, from Daniel Müller.
2) Add inlining of calls to bpf_loop() helper when its function callback is
statically known, from Eduard Zingerman.
3) Implement BPF TCP CC framework usability improvements, from Jörn-Thorben Hinz.
4) Add LSM flavor for attaching per-cgroup BPF programs to existing LSM
hooks, from Stanislav Fomichev.
5) Remove all deprecated libbpf APIs in prep for 1.0 release, from Andrii Nakryiko.
6) Add benchmarks around local_storage to BPF selftests, from Dave Marchevsky.
7) AF_XDP sample removal (given move to libxdp) and various improvements around AF_XDP
selftests, from Magnus Karlsson & Maciej Fijalkowski.
8) Add bpftool improvements for memcg probing and bash completion, from Quentin Monnet.
9) Add arm64 JIT support for BPF-2-BPF coupled with tail calls, from Jakub Sitnicki.
10) Sockmap optimizations around throughput of UDP transmissions which have been
improved by 61%, from Cong Wang.
11) Rework perf's BPF prologue code to remove deprecated functions, from Jiri Olsa.
12) Fix sockmap teardown path to avoid sleepable sk_psock_stop, from John Fastabend.
13) Fix libbpf's cleanup around legacy kprobe/uprobe on error case, from Chuang Wang.
14) Fix libbpf's bpf_helpers.h to work with gcc for the case of its sec/pragma
macro, from James Hilliard.
15) Fix libbpf's pt_regs macros for riscv to use a0 for RC register, from Yixun Lan.
16) Fix bpftool to show the name of type BPF_OBJ_LINK, from Yafang Shao.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (94 commits)
selftests/bpf: Fix xdp_synproxy build failure if CONFIG_NF_CONNTRACK=m/n
bpf: Correctly propagate errors up from bpf_core_composites_match
libbpf: Disable SEC pragma macro on GCC
bpf: Check attach_func_proto more carefully in check_return_code
selftests/bpf: Add test involving restrict type qualifier
bpftool: Add support for KIND_RESTRICT to gen min_core_btf command
MAINTAINERS: Add entry for AF_XDP selftests files
selftests, xsk: Rename AF_XDP testing app
bpf, docs: Remove deprecated xsk libbpf APIs description
selftests/bpf: Add benchmark for local_storage RCU Tasks Trace usage
libbpf, riscv: Use a0 for RC register
libbpf: Remove unnecessary usdt_rel_ip assignments
selftests/bpf: Fix few more compiler warnings
selftests/bpf: Fix bogus uninitialized variable warning
bpftool: Remove zlib feature test from Makefile
libbpf: Cleanup the legacy uprobe_event on failed add/attach_event()
libbpf: Fix wrong variable used in perf_event_uprobe_open_legacy()
libbpf: Cleanup the legacy kprobe_event on failed add/attach_event()
selftests/bpf: Add type match test against kernel's task_struct
selftests/bpf: Add nested type to type based tests
...
====================
Link: https://lore.kernel.org/r/20220708233145.32365-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
drivers/net/ethernet/microchip/sparx5/sparx5_switchdev.c
9c5de246c1 ("net: sparx5: mdb add/del handle non-sparx5 devices")
fbb89d02e3 ("net: sparx5: Allow mdb entries to both CPU and ports")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull block fixes from Jens Axboe:
- Series fixing issues with sysfs locking and name reuse (Christoph)
- NVMe pull request via Christoph:
- Fix the mixed up CRIMS/CRWMS constants (Joel Granados)
- Add another broken identifier quirk (Leo Savernik)
- Fix up a quirk because Samsung reuses PCI IDs over different
products (Christoph Hellwig)
- Remove old WARN_ON() that doesn't apply anymore (Li)
- Fix for using a stale cached request value for rq-qos throttling
mechanisms that may schedule(), like iocost (me)
- Remove unused parameter to blk_independent_access_range() (Damien)
* tag 'block-5.19-2022-06-24' of git://git.kernel.dk/linux-block:
block: remove WARN_ON() from bd_link_disk_holder
nvme: move the Samsung X5 quirk entry to the core quirks
nvme: fix the CRIMS and CRWMS definitions to match the spec
nvme: add a bogus subsystem NQN quirk for Micron MTFDKBA2T0TFH
block: pop cached rq before potentially blocking rq_qos_throttle()
block: remove queue from struct blk_independent_access_range
block: freeze the queue earlier in del_gendisk
block: remove per-disk debugfs files in blk_unregister_queue
block: serialize all debugfs operations using q->debugfs_mutex
block: disable the elevator int del_gendisk
Pull tracing fixes from Steven Rostedt:
- Check for NULL in kretprobe_dispatcher()
NULL can now be passed in, make sure it can handle it
- Clean up unneeded #endif #ifdef of the same preprocessor
check in the middle of the block.
- Comment clean up
- Remove unneeded initialization of the "ret" variable in
__trace_uprobe_create()
* tag 'trace-v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing/uprobes: Remove unwanted initialization in __trace_uprobe_create()
tracefs: Fix syntax errors in comments
tracing: Simplify conditional compilation code in tracing_set_tracer()
tracing/kprobes: Check whether get_kretprobe() returns NULL in kretprobe_dispatcher()
Daniel Borkmann says:
====================
pull-request: bpf-next 2022-06-17
We've added 72 non-merge commits during the last 15 day(s) which contain
a total of 92 files changed, 4582 insertions(+), 834 deletions(-).
The main changes are:
1) Add 64 bit enum value support to BTF, from Yonghong Song.
2) Implement support for sleepable BPF uprobe programs, from Delyan Kratunov.
3) Add new BPF helpers to issue and check TCP SYN cookies without binding to a
socket especially useful in synproxy scenarios, from Maxim Mikityanskiy.
4) Fix libbpf's internal USDT address translation logic for shared libraries as
well as uprobe's symbol file offset calculation, from Andrii Nakryiko.
5) Extend libbpf to provide an API for textual representation of the various
map/prog/attach/link types and use it in bpftool, from Daniel Müller.
6) Provide BTF line info for RV64 and RV32 JITs, and fix a put_user bug in the
core seen in 32 bit when storing BPF function addresses, from Pu Lehui.
7) Fix libbpf's BTF pointer size guessing by adding a list of various aliases
for 'long' types, from Douglas Raillard.
8) Fix bpftool to readd setting rlimit since probing for memcg-based accounting
has been unreliable and caused a regression on COS, from Quentin Monnet.
9) Fix UAF in BPF cgroup's effective program computation triggered upon BPF link
detachment, from Tadeusz Struk.
10) Fix bpftool build bootstrapping during cross compilation which was pointing
to the wrong AR process, from Shahab Vahedi.
11) Fix logic bug in libbpf's is_pow_of_2 implementation, from Yuze Chi.
12) BPF hash map optimization to avoid grabbing spinlocks of all CPUs when there
is no free element. Also add a benchmark as reproducer, from Feng Zhou.
13) Fix bpftool's codegen to bail out when there's no BTF, from Michael Mullin.
14) Various minor cleanup and improvements all over the place.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (72 commits)
bpf: Fix bpf_skc_lookup comment wrt. return type
bpf: Fix non-static bpf_func_proto struct definitions
selftests/bpf: Don't force lld on non-x86 architectures
selftests/bpf: Add selftests for raw syncookie helpers in TC mode
bpf: Allow the new syncookie helpers to work with SKBs
selftests/bpf: Add selftests for raw syncookie helpers
bpf: Add helpers to issue and check SYN cookies in XDP
bpf: Allow helpers to accept pointers with a fixed size
bpf: Fix documentation of th_len in bpf_tcp_{gen,check}_syncookie
selftests/bpf: add tests for sleepable (uk)probes
libbpf: add support for sleepable uprobe programs
bpf: allow sleepable uprobe programs to attach
bpf: implement sleepable uprobes by chaining gps
bpf: move bpf_prog to bpf.h
libbpf: Fix internal USDT address translation logic for shared libraries
samples/bpf: Check detach prog exist or not in xdp_fwd
selftests/bpf: Avoid skipping certain subtests
selftests/bpf: Fix test_varlen verification failure with latest llvm
bpftool: Do not check return value from libbpf_set_strict_mode()
Revert "bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"
...
====================
Link: https://lore.kernel.org/r/20220617220836.7373-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
There is a small chance that get_kretprobe(ri) returns NULL in
kretprobe_dispatcher() when another CPU unregisters the kretprobe
right after __kretprobe_trampoline_handler().
To avoid this issue, kretprobe_dispatcher() checks the get_kretprobe()
return value again. And if it is NULL, it returns soon because that
kretprobe is under unregistering process.
This issue has been introduced when the kretprobe is decoupled
from the struct kretprobe_instance by commit d741bf41d7
("kprobes: Remove kretprobe hash"). Before that commit, the
struct kretprob_instance::rp directly points the kretprobe
and it is never be NULL.
Link: https://lkml.kernel.org/r/165366693881.797669.16926184644089588731.stgit@devnote2
Reported-by: Yonghong Song <yhs@fb.com>
Fixes: d741bf41d7 ("kprobes: Remove kretprobe hash")
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: bpf <bpf@vger.kernel.org>
Cc: Kernel Team <kernel-team@fb.com>
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Since the rethook_recycle() will involve the call_rcu() for reclaiming
the rethook_instance, the rethook must be set up at the RCU available
context (non idle). This rethook_recycle() in the rethook trampoline
handler is inevitable, thus the RCU available check must be done before
setting the rethook trampoline.
This adds a rcu_is_watching() check in the rethook_try_get() so that
it will return NULL if it is called when !rcu_is_watching().
Fixes: 54ecbe6f1e ("rethook: Add a generic return hook")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/165461827269.280167.7379263615545598958.stgit@devnote2
Various places like I/O schedulers or the QOS infrastructure try to
register debugfs files on demans, which can race with creating and
removing the main queue debugfs directory. Use the existing
debugfs_mutex to serialize all debugfs operations that rely on
q->debugfs_dir or the directories hanging off it.
To make the teardown code a little simpler declare all debugfs dentry
pointers and not just the main one uncoditionally in blkdev.h.
Move debugfs_mutex next to the dentries that it protects and document
what it is used for.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220614074827.458955-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When user specifies symbols and cookies for kprobe_multi link
interface it's very likely the cookies will be misplaced and
returned to wrong functions (via get_attach_cookie helper).
The reason is that to resolve the provided functions we sort
them before passing them to ftrace_lookup_symbols, but we do
not do the same sort on the cookie values.
Fixing this by using sort_r function with custom swap callback
that swaps cookie values as well.
Fixes: 0236fec57a ("bpf: Resolve symbols with ftrace_lookup_symbols for kprobe multi link")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220615112118.497303-4-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
uprobes work by raising a trap, setting a task flag from within the
interrupt handler, and processing the actual work for the uprobe on the
way back to userspace. As a result, uprobe handlers already execute in a
might_fault/_sleep context. The primary obstacle to sleepable bpf uprobe
programs is therefore on the bpf side.
Namely, the bpf_prog_array attached to the uprobe is protected by normal
rcu. In order for uprobe bpf programs to become sleepable, it has to be
protected by the tasks_trace rcu flavor instead (and kfree() called after
a corresponding grace period).
Therefore, the free path for bpf_prog_array now chains a tasks_trace and
normal grace periods one after the other.
Users who iterate under tasks_trace read section would
be safe, as would users who iterate under normal read sections (from
non-sleepable locations).
The downside is that the tasks_trace latency affects all perf_event-attached
bpf programs (and not just uprobe ones). This is deemed safe given the
possible attach rates for kprobe/uprobe/tp programs.
Separately, non-sleepable programs need access to dynamically sized
rcu-protected maps, so bpf_run_prog_array_sleepables now conditionally takes
an rcu read section, in addition to the overarching tasks_trace section.
Signed-off-by: Delyan Kratunov <delyank@fb.com>
Link: https://lore.kernel.org/r/ce844d62a2fd0443b08c5ab02e95bc7149f9aeb1.1655248076.git.delyank@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The kvmalloc_array() function is safer because it has a check for
integer overflows. These sizes come from the user and I was not
able to see any bounds checking so an integer overflow seems like a
realistic concern.
Fixes: 0dcac27254 ("bpf: Add multi kprobe link")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/Yo9VRVMeHbALyjUH@kili
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pull arm64 fixes from Catalin Marinas:
"Most of issues addressed were introduced during this merging window.
- Initialise jump labels before setup_machine_fdt(), needed by commit
f5bda35fba ("random: use static branch for crng_ready()").
- Sparse warnings: missing prototype, incorrect __user annotation.
- Skip SVE kselftest if not sufficient vector lengths supported"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
kselftest/arm64: signal: Skip SVE signal test if not enough VLs supported
arm64: Initialize jump labels before setup_machine_fdt()
arm64: hibernate: Fix syntax errors in comments
arm64: Remove the __user annotation for the restore_za_context() argument
ftrace/fgraph: fix increased missing-prototypes warnings
After commit e999995c84 ("ftrace: cleanup ftrace_graph_caller enable
and disable") merged into the linux-next tree, the kernel test robot
(lkp@intel.com) has send out report that there are increased missing-prototypes
warnings caused by that commit.
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 \
O=build_dir ARCH=sh SHELL=/bin/bash kernel/trace/
warning: no previous prototype for 'ftrace_enable_ftrace_graph_caller' [-Wmissing-prototypes]
warning: no previous prototype for 'ftrace_disable_ftrace_graph_caller' [-Wmissing-prototypes]
warning: no previous prototype for 'ftrace_return_to_handler' [-Wmissing-prototypes]
warning: no previous prototype for 'ftrace_graph_sleep_time_control' [-Wmissing-prototypes]
BTW there are so many missing-prototypes warnings if build kernel with "W=1".
The increased warnings for 'ftrace_[enable,disable]_ftrace_graph_caller'
is caused by CONFIG_FUNCTION_GRAPH_TRACER && !CONFIG_DYNAMIC_FTRACE,
so the declarations in <linux/ftrace.h> can't be seen in fgraph.c.
And this warning can't reproduce on x86_64 since x86_64 select
HAVE_FUNCTION_GRAPH_TRACER only when DYNAMIC_FTRACE, so fgraph.c will
always see the declarations in <linux/ftrace.h>.
This patch fix the increased warnings by put the definitions in
CONFIG_DYNAMIC_FTRACE although there are no real problems exist.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20220506032737.23375-1-zhouchengming@bytedance.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Pull tracing updates from Steven Rostedt:
"The majority of the changes are for fixes and clean ups.
Notable changes:
- Rework trace event triggers code to be easier to interact with.
- Support for embedding bootconfig with the kernel (as suppose to
having it embedded in initram). This is useful for embedded boards
without initram disks.
- Speed up boot by parallelizing the creation of tracefs files.
- Allow absolute ring buffer timestamps handle timestamps that use
more than 59 bits.
- Added new tracing clock "TAI" (International Atomic Time)
- Have weak functions show up in available_filter_function list as:
__ftrace_invalid_address___<invalid-offset> instead of using the
name of the function before it"
* tag 'trace-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (52 commits)
ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid adding weak function
tracing: Fix comments for event_trigger_separate_filter()
x86/traceponit: Fix comment about irq vector tracepoints
x86,tracing: Remove unused headers
ftrace: Clean up hash direct_functions on register failures
tracing: Fix comments of create_filter()
tracing: Disable kcov on trace_preemptirq.c
tracing: Initialize integer variable to prevent garbage return value
ftrace: Fix typo in comment
ftrace: Remove return value of ftrace_arch_modify_*()
tracing: Cleanup code by removing init "char *name"
tracing: Change "char *" string form to "char []"
tracing/timerlat: Do not wakeup the thread if the trace stops at the IRQ
tracing/timerlat: Print stacktrace in the IRQ handler if needed
tracing/timerlat: Notify IRQ new max latency only if stop tracing is set
kprobes: Fix build errors with CONFIG_KRETPROBES=n
tracing: Fix return value of trace_pid_write()
tracing: Fix potential double free in create_var_ref()
tracing: Use strim() to remove whitespace instead of doing it manually
ftrace: Deal with error return code of the ftrace_process_locs() function
...
If an unused weak function was traced, it's call to fentry will still
exist, which gets added into the __mcount_loc table. Ftrace will use
kallsyms to retrieve the name for each location in __mcount_loc to display
it in the available_filter_functions and used to enable functions via the
name matching in set_ftrace_filter/notrace. Enabling these functions do
nothing but enable an unused call to ftrace_caller. If a traced weak
function is overridden, the symbol of the function would be used for it,
which will either created duplicate names, or if the previous function was
not traced, it would be incorrectly be listed in available_filter_functions
as a function that can be traced.
This became an issue with BPF[1] as there are tooling that enables the
direct callers via ftrace but then checks to see if the functions were
actually enabled. The case of one function that was marked notrace, but
was followed by an unused weak function that was traced. The unused
function's call to fentry was added to the __mcount_loc section, and
kallsyms retrieved the untraced function's symbol as the weak function was
overridden. Since the untraced function would not get traced, the BPF
check would detect this and fail.
The real fix would be to fix kallsyms to not show addresses of weak
functions as the function before it. But that would require adding code in
the build to add function size to kallsyms so that it can know when the
function ends instead of just using the start of the next known symbol.
In the mean time, this is a work around. Add a FTRACE_MCOUNT_MAX_OFFSET
macro that if defined, ftrace will ignore any function that has its call
to fentry/mcount that has an offset from the symbol that is greater than
FTRACE_MCOUNT_MAX_OFFSET.
If CONFIG_HAVE_FENTRY is defined for x86, define FTRACE_MCOUNT_MAX_OFFSET
to zero (unless IBT is enabled), which will have ftrace ignore all locations
that are not at the start of the function (or one after the ENDBR
instruction).
A worker thread is added at boot up to scan all the ftrace record entries,
and will mark any that fail the FTRACE_MCOUNT_MAX_OFFSET test as disabled.
They will still appear in the available_filter_functions file as:
__ftrace_invalid_address___<invalid-offset>
(showing the offset that caused it to be invalid).
This is required for tools that use libtracefs (like trace-cmd does) that
scan the available_filter_functions and enable set_ftrace_filter and
set_ftrace_notrace using indexes of the function listed in the file (this
is a speedup, as enabling thousands of files via names is an O(n^2)
operation and can take minutes to complete, where the indexing takes less
than a second).
The invalid functions cannot be removed from available_filter_functions as
the names there correspond to the ftrace records in the array that manages
them (and the indexing depends on this).
[1] https://lore.kernel.org/all/20220412094923.0abe90955e5db486b7bca279@kernel.org/
Link: https://lkml.kernel.org/r/20220526141912.794c2786@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
