Patch series "Add error_report_end tracepoint to KFENCE and KASAN", v3.
This patchset adds a tracepoint, error_repor_end, that is to be used by
KFENCE, KASAN, and potentially other bug detection tools, when they print
an error report. One of the possible use cases is userspace collection of
kernel error reports: interested parties can subscribe to the tracing
event via tracefs, and get notified when an error report occurs.
This patch (of 3):
Introduce error_report_end tracepoint. It can be used in debugging tools
like KASAN, KFENCE, etc. to provide extensions to the error reporting
mechanisms (e.g. allow tests hook into error reporting, ease error report
collection from production kernels). Another benefit would be making use
of ftrace for debugging or benchmarking the tools themselves.
Should we need it, the tracepoint name leaves us with the possibility to
introduce a complementary error_report_start tracepoint in the future.
Link: https://lkml.kernel.org/r/20210121131915.1331302-1-glider@google.com
Link: https://lkml.kernel.org/r/20210121131915.1331302-2-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Suggested-by: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Bug: 177201466
(cherry picked from commit ba7612c00686f204f7bca4ceb7394a9e705e84bd
https://github.com/hnaz/linux-mm v5.11-rc4-mmots-2021-01-21-20-10)
Test: CONFIG_KFENCE_KUNIT_TEST=y passes on Cuttlefish
Signed-off-by: Alexander Potapenko <glider@google.com>
Change-Id: Ic86e29982c04dad4b3b7889a424f37b22cc5f22b
There is a bug when passing zero to PTR_ERR() and return.
Fix the smatch error.
Fixes: c4d0bfb45068 ("bpf: Add bpf_snprintf_btf helper")
Change-Id: Ibddaa08258ecc2f9887f84445abac7db55a90537
Signed-off-by: Wang Qing <wangqing@vivo.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/1604735144-686-1-git-send-email-wangqing@vivo.com
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
[ Upstream commit bdb7fdb0aca8b96cef9995d3a57e251c2289322f ]
In current bpf_send_signal() and bpf_send_signal_thread() helper
implementation, irq_work is used to handle nmi context. Hao Sun
reported in [1] that the current task at the entry of the helper
might be gone during irq_work callback processing. To fix the issue,
a reference is acquired for the current task before enqueuing into
the irq_work so that the queued task is still available during
irq_work callback processing.
[1] https://lore.kernel.org/bpf/20230109074425.12556-1-sunhao.th@gmail.com/
Fixes: 8b401f9ed2 ("bpf: implement bpf_send_signal() helper")
Tested-by: Hao Sun <sunhao.th@gmail.com>
Reported-by: Hao Sun <sunhao.th@gmail.com>
Change-Id: I9caf795beeffc0041ced83cf2d7c960ce2e3a206
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230118204815.3331855-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
commit d62cc390c2e99ae267ffe4b8d7e2e08b6c758c32 upstream.
We received report [1] of kernel crash, which is caused by
using nesting protection without disabled preemption.
The bpf_event_output can be called by programs executed by
bpf_prog_run_array_cg function that disabled migration but
keeps preemption enabled.
This can cause task to be preempted by another one inside the
nesting protection and lead eventually to two tasks using same
perf_sample_data buffer and cause crashes like:
BUG: kernel NULL pointer dereference, address: 0000000000000001
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
...
? perf_output_sample+0x12a/0x9a0
? finish_task_switch.isra.0+0x81/0x280
? perf_event_output+0x66/0xa0
? bpf_event_output+0x13a/0x190
? bpf_event_output_data+0x22/0x40
? bpf_prog_dfc84bbde731b257_cil_sock4_connect+0x40a/0xacb
? xa_load+0x87/0xe0
? __cgroup_bpf_run_filter_sock_addr+0xc1/0x1a0
? release_sock+0x3e/0x90
? sk_setsockopt+0x1a1/0x12f0
? udp_pre_connect+0x36/0x50
? inet_dgram_connect+0x93/0xa0
? __sys_connect+0xb4/0xe0
? udp_setsockopt+0x27/0x40
? __pfx_udp_push_pending_frames+0x10/0x10
? __sys_setsockopt+0xdf/0x1a0
? __x64_sys_connect+0xf/0x20
? do_syscall_64+0x3a/0x90
? entry_SYSCALL_64_after_hwframe+0x72/0xdc
Fixing this by disabling preemption in bpf_event_output.
[1] https://github.com/cilium/cilium/issues/26756
Cc: stable@vger.kernel.org
Reported-by: Oleg "livelace" Popov <o.popov@livelace.ru>
Closes: https://github.com/cilium/cilium/issues/26756
Fixes: 2a916f2f546c ("bpf: Use migrate_disable/enable in array macros and cgroup/lirc code.")
Acked-by: Hou Tao <houtao1@huawei.com>
Change-Id: Icaf207af7dfb071f0adb10fe9bb7f367e25c1860
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230725084206.580930-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
'X' tells kernel to print hex with upper case letters.
/proc/net/tcp{4,6} seq_file show() used this, and
supports it in bpf_seq_printf() helper too.
Change-Id: I7c88f9f2c9088a6acb3b2085988de50535b970e6
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230807.3988014-1-yhs@fb.com
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
This makes it easy to dump stack trace in text.
Change-Id: Ia29115428a1dadf823881bfbbc793628b2fc9715
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200630062846.664389-4-songliubraving@fb.com
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
I get the following error during compilation on my side:
kernel/trace/bpf_trace.c: In function 'bpf_do_trace_printk':
kernel/trace/bpf_trace.c:386:34: error: function 'bpf_do_trace_printk' can never be inlined because it uses variable argument lists
static inline __printf(1, 0) int bpf_do_trace_printk(const char *fmt, ...)
^
Fixes: ac5a72ea5c89 ("bpf: Use dedicated bpf_trace_printk event instead of trace_printk()")
Change-Id: I105192533535b3f3cbc78c7a54f1fbbc2eb6450b
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200806182612.1390883-1-sdf@google.com
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
The bpf helper bpf_trace_printk() uses trace_printk() under the hood.
This leads to an alarming warning message originating from trace
buffer allocation which occurs the first time a program using
bpf_trace_printk() is loaded.
We can instead create a trace event for bpf_trace_printk() and enable
it in-kernel when/if we encounter a program using the
bpf_trace_printk() helper. With this approach, trace_printk()
is not used directly and no warning message appears.
This work was started by Steven (see Link) and finished by Alan; added
Steven's Signed-off-by with his permission.
Change-Id: I3644e434a2f1e99d1fa523d247ac0b19911d041b
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/r/20200628194334.6238b933@oasis.local.home
Link: https://lore.kernel.org/bpf/1594641154-18897-2-git-send-email-alan.maguire@oracle.com
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
do_strncpy_from_user() may copy some extra bytes after the NUL
terminator into the destination buffer. This usually does not matter for
normal string operations. However, when BPF programs key BPF maps with
strings, this matters a lot.
A BPF program may read strings from user memory by calling the
bpf_probe_read_user_str() helper which eventually calls
do_strncpy_from_user(). The program can then key a map with the
destination buffer. BPF map keys are fixed-width and string-agnostic,
meaning that map keys are treated as a set of bytes.
The issue is when do_strncpy_from_user() overcopies bytes after the NUL
terminator, it can result in seemingly identical strings occupying
multiple slots in a BPF map. This behavior is subtle and totally
unexpected by the user.
This commit masks out the bytes following the NUL while preserving
long-sized stride in the fast path.
Fixes: 6ae08ae3dea2 ("bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers")
Change-Id: I10d009c0e2db1ca242fbc0076fa2933f17c4a9a9
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/21efc982b3e9f2f7b0379eed642294caaa0c27a7.1605642949.git.dxu@dxuuu.xyz
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
commit 51e1bb9eeaf7868db56e58f47848e364ab4c4129 upstream.
Back then, commit 96ae522795 ("bpf: Add bpf_probe_write_user BPF helper
to be called in tracers") added the bpf_probe_write_user() helper in order
to allow to override user space memory. Its original goal was to have a
facility to "debug, divert, and manipulate execution of semi-cooperative
processes" under CAP_SYS_ADMIN. Write to kernel was explicitly disallowed
since it would otherwise tamper with its integrity.
One use case was shown in cf9b1199de ("samples/bpf: Add test/example of
using bpf_probe_write_user bpf helper") where the program DNATs traffic
at the time of connect(2) syscall, meaning, it rewrites 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. These days we have better
mechanisms in BPF for achieving the same (e.g. for load-balancers), but
without having to write to userspace memory.
Of course the bpf_probe_write_user() helper can also be used to abuse
many other things for both good or bad purpose. Outside of BPF, there is
a similar mechanism for ptrace(2) such as PTRACE_PEEK{TEXT,DATA} and
PTRACE_POKE{TEXT,DATA}, but would likely require some more effort.
Commit 96ae522795 explicitly dedicated the helper for experimentation
purpose only. Thus, move the helper's availability behind a newly added
LOCKDOWN_BPF_WRITE_USER lockdown knob so that the helper is disabled under
the "integrity" mode. More fine-grained control can be implemented also
from LSM side with this change.
Fixes: 96ae522795 ("bpf: Add bpf_probe_write_user BPF helper to be called in tracers")
Change-Id: I824213c9e94b9c0c3ce0fe6188ed82ddebab018c
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
[ Upstream commit 548f1191d86ccb9bde2a5305988877b7584c01eb ]
The commit 0d00449c7a28 ("x86: Replace ist_enter() with nmi_enter()")
converted do_int3 handler to be "NMI-like".
That made old if (in_nmi()) check abort execution of bpf programs
attached to kprobe when kprobe is firing via int3
(For example when kprobe is placed in the middle of the function).
Remove the check to restore user visible behavior.
Fixes: 0d00449c7a28 ("x86: Replace ist_enter() with nmi_enter()")
Reported-by: Nikolay Borisov <nborisov@suse.com>
Change-Id: I29ee95686ea9a51b2b59f8b06462510253036360
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/bpf/20210203070636.70926-1-alexei.starovoitov@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
Similar to __bpf_trace_run this is redundant because __bpf_trace_run() is
invoked from a trace point via __DO_TRACE() which already disables
preemption _before_ invoking any of the functions which are attached to a
trace point.
Remove it and add a cant_sleep() check.
Change-Id: I6106e5ed79cf84ae2b6e6032c7b081209a68da6c
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200224145643.059995527@linutronix.de
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
[ Upstream commit f46fab0e36e611a2389d3843f34658c849b6bd60 ]
Anastasios reported crash on stable 5.15 kernel with following
BPF attached to lsm hook:
SEC("lsm.s/bprm_creds_for_exec")
int BPF_PROG(bprm_creds_for_exec, struct linux_binprm *bprm)
{
struct path *path = &bprm->executable->f_path;
char p[128] = { 0 };
bpf_d_path(path, p, 128);
return 0;
}
But bprm->executable can be NULL, so bpf_d_path call will crash:
BUG: kernel NULL pointer dereference, address: 0000000000000018
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC NOPTI
...
RIP: 0010:d_path+0x22/0x280
...
Call Trace:
<TASK>
bpf_d_path+0x21/0x60
bpf_prog_db9cf176e84498d9_bprm_creds_for_exec+0x94/0x99
bpf_trampoline_6442506293_0+0x55/0x1000
bpf_lsm_bprm_creds_for_exec+0x5/0x10
security_bprm_creds_for_exec+0x29/0x40
bprm_execve+0x1c1/0x900
do_execveat_common.isra.0+0x1af/0x260
__x64_sys_execve+0x32/0x40
It's problem for all stable trees with bpf_d_path helper, which was
added in 5.9.
This issue is fixed in current bpf code, where we identify and mark
trusted pointers, so the above code would fail even to load.
For the sake of the stable trees and to workaround potentially broken
verifier in the future, adding the code that reads the path object from
the passed pointer and verifies it's valid in kernel space.
Fixes: 6e22ab9da793 ("bpf: Add d_path helper")
Reported-by: Anastasios Papagiannis <tasos.papagiannnis@gmail.com>
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Change-Id: I865e5c3a9c4d0268e9cbb35a74a162898c1c0a7e
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20230606181714.532998-1-jolsa@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
[ Upstream commit db52f57211b4e45f0ebb274e2c877b211dc18591 ]
Branch data available to BPF programs can be very useful to get stack traces
out of userspace application.
Commit fff7b64355ea ("bpf: Add bpf_read_branch_records() helper") added BPF
support to capture branch records in x86. Enable this feature also for other
architectures as well by removing checks specific to x86.
If an architecture doesn't support branch records, bpf_read_branch_records()
still has appropriate checks and it will return an -EINVAL in that scenario.
Based on UAPI helper doc in include/uapi/linux/bpf.h, unsupported architectures
should return -ENOENT in such case. Hence, update the appropriate check to
return -ENOENT instead.
Selftest 'perf_branches' result on power9 machine which has the branch stacks
support:
- Before this patch:
[command]# ./test_progs -t perf_branches
#88/1 perf_branches/perf_branches_hw:FAIL
#88/2 perf_branches/perf_branches_no_hw:OK
#88 perf_branches:FAIL
Summary: 0/1 PASSED, 0 SKIPPED, 1 FAILED
- After this patch:
[command]# ./test_progs -t perf_branches
#88/1 perf_branches/perf_branches_hw:OK
#88/2 perf_branches/perf_branches_no_hw:OK
#88 perf_branches:OK
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
Selftest 'perf_branches' result on power9 machine which doesn't have branch
stack report:
- After this patch:
[command]# ./test_progs -t perf_branches
#88/1 perf_branches/perf_branches_hw:SKIP
#88/2 perf_branches/perf_branches_no_hw:OK
#88 perf_branches:OK
Summary: 1/1 PASSED, 1 SKIPPED, 0 FAILED
Fixes: fff7b64355eac ("bpf: Add bpf_read_branch_records() helper")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Change-Id: Ide9c32fdd0c825e46d7a9c6872d78122e4bb9b79
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211206073315.77432-1-kjain@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
test_run.o is not built when CONFIG_NET is not set and
bpf_prog_test_run_tracing being referenced in bpf_trace.o causes the
linker error:
ld: kernel/trace/bpf_trace.o:(.rodata+0x38): undefined reference to
`bpf_prog_test_run_tracing'
Add a __weak function in bpf_trace.c to handle this.
Fixes: da00d2f117a0 ("bpf: Add test ops for BPF_PROG_TYPE_TRACING")
Change-Id: Icd0d76d484c459c235066dc28046dd6997b3d434
Signed-off-by: KP Singh <kpsingh@google.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200305220127.29109-1-kpsingh@chromium.org
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
When CONFIG_NET is not defined, I hit the following build error:
kernel/trace/bpf_trace.o:(.rodata+0x110): undefined reference to `bpf_prog_test_run_raw_tp'
Commit 1b4d60ec162f ("bpf: Enable BPF_PROG_TEST_RUN for raw_tracepoint")
added test_run support for raw_tracepoint in /kernel/trace/bpf_trace.c.
But the test_run function bpf_prog_test_run_raw_tp is defined in
net/bpf/test_run.c, only available with CONFIG_NET=y.
Adding a CONFIG_NET guard for
.test_run = bpf_prog_test_run_raw_tp;
fixed the above build issue.
Fixes: 1b4d60ec162f ("bpf: Enable BPF_PROG_TEST_RUN for raw_tracepoint")
Change-Id: Ifdaa9a4b0e6501fd432bccbd1184cd0993cb3c02
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201007062933.3425899-1-yhs@fb.com
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
No user pointers for sysctls anymore.
Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
Reported-by: build test robot <lkp@intel.com>
Change-Id: I0b23a303ac9bd880abf7797d16311183c2b40dab
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>
Instead of using the dangerous probe_kernel_read and strncpy_from_unsafe
helpers, rework probes to try a user probe based on the address if the
architecture has a common address space for kernel and userspace.
[svens@linux.ibm.com:use strncpy_from_kernel_nofault() in fetch_store_string()]
Link: http://lkml.kernel.org/r/20200606181903.49384-1-svens@linux.ibm.com
Change-Id: If507e6fc4b0a49b56877615b3a2c875c3240e464
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-15-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
User the proper helper for kernel or userspace addresses based on
TASK_SIZE instead of the dangerous strncpy_from_unsafe function.
Change-Id: I68df005984eae6d4486b0850f16760f3fecbe17b
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In bpf_seq_printf() helper, when user specified a "%s" in the
format string, strncpy_from_unsafe() is used to read the actual string
to a buffer. The string could be a format string or a string in
the kernel data structure. It is really unlikely that the string
will reside in the user memory.
This is different from Commit b2a5212fb634 ("bpf: Restrict bpf_trace_printk()'s %s
usage and add %pks, %pus specifier") which still used
strncpy_from_unsafe() for "%s" to preserve the old behavior.
If in the future, bpf_seq_printf() indeed needs to read user
memory, we can implement "%pus" format string.
Based on discussion in [1], if the intent is to read kernel memory,
strncpy_from_unsafe_strict() should be used. So this patch
changed to use strncpy_from_unsafe_strict().
[1]: https://lore.kernel.org/bpf/20200521152301.2587579-1-hch@lst.de/T/
Fixes: 492e639f0c22 ("bpf: Add bpf_seq_printf and bpf_seq_write helpers")
Change-Id: Ic3f656f9b058fd4af31833a56c4cee7c09cde7fd
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/bpf/20200529004810.3352219-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
User the proper helper for kernel or userspace addresses based on
TASK_SIZE instead of the dangerous strncpy_from_unsafe function.
Change-Id: Ifc6a91e309cbb1d2b68e8b5d77d9b1117977369d
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-13-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Split out a helper to do the fault free access to the string pointer
to get it out of a crazy indentation level.
Change-Id: Ia9dc539749f650efd8c91482037051cd5e84627d
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-12-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Except for historical confusion in the kprobes/uprobes and bpf tracers,
which has been fixed now, there is no good reason to ever allow user
memory accesses from probe_kernel_read. Switch probe_kernel_read to only
read from kernel memory.
[akpm@linux-foundation.org: update it for "mm, dump_page(): do not crash with invalid mapping pointer"]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-17-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: Id68f398b368bc4bd0f787a5a1684abf5f47504a9
Instead of using the dangerous probe_kernel_read and strncpy_from_unsafe
helpers, rework the compat probes to check if an address is a kernel or
userspace one, and then use the low-level kernel or user probe helper
shared by the proper kernel and user probe helpers. This slightly
changes behavior as the compat probe on a user address doesn't check
the lockdown flags, just as the pure user probes do.
Change-Id: I9157773cc6777b8adc18c948ae9069d5565a86cc
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-14-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This matches the naming of strncpy_from_user_nofault, and also makes it
more clear what the function is supposed to do.
Change-Id: I862c2c72cbc36c67e35434dc29cfc00fee3abd14
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-8-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Given the legacy bpf_probe_read{,str}() BPF helpers are broken on archs
with overlapping address ranges, we should really take the next step to
disable them from BPF use there.
To generally fix the situation, we've recently added new helper variants
bpf_probe_read_{user,kernel}() and bpf_probe_read_{user,kernel}_str().
For details on them, see 6ae08ae3dea2 ("bpf: Add probe_read_{user, kernel}
and probe_read_{user,kernel}_str helpers").
Given bpf_probe_read{,str}() have been around for ~5 years by now, there
are plenty of users at least on x86 still relying on them today, so we
cannot remove them entirely w/o breaking the BPF tracing ecosystem.
However, their use should be restricted to archs with non-overlapping
address ranges where they are working in their current form. Therefore,
move this behind a CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE and
have x86, arm64, arm select it (other archs supporting it can follow-up
on it as well).
For the remaining archs, they can workaround easily by relying on the
feature probe from bpftool which spills out defines that can be used out
of BPF C code to implement the drop-in replacement for old/new kernels
via: bpftool feature probe macro
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: I41c11648b4930f6bed2a299b0bab44cbd4309e0f
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/bpf/20200515101118.6508-2-daniel@iogearbox.net
Some kernels builds might inline vfs_getattr call within fstat
syscall code path, so fentry/vfs_getattr trampoline is not called.
Add security_inode_getattr to allowlist and switch the d_path test stat
trampoline to security_inode_getattr.
Keeping dentry_open and filp_close, because they are in their own
files, so unlikely to be inlined, but in case they are, adding
security_file_open.
Adding flags that indicate trampolines were called and failing
the test if any of them got missed, so it's easier to identify
the issue next time.
Fixes: e4d1af4b16f8 ("selftests/bpf: Add test for d_path helper")
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Change-Id: Ifa431c01d768bb64a3cd99742ddc22313bf209a0
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200918112338.2618444-1-jolsa@kernel.org
While auditing all module notifiers I noticed a whole bunch of fail
wrt the return value. Notifiers have a 'special' return semantics.
As is; NOTIFY_DONE vs NOTIFY_OK is a bit vague; but
notifier_from_errno(0) results in NOTIFY_OK and NOTIFY_DONE has a
comment that says "Don't care".
From this I've used NOTIFY_DONE when the function completely ignores
the callback and notifier_to_error() isn't used.
Change-Id: Iccf849c58a63828ea566c7fab578e78232c2712f
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Robert Richter <rric@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20200818135804.385360407@infradead.org
This matches the naming of strncpy_from_user, and also makes it more
clear what the function is supposed to do.
Change-Id: I549cd72491c507dcc6639fc52b836af2e1dbdf3e
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-7-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Usage of plain %s conversion specifier in bpf_trace_printk() suffers from the
very same issue as bpf_probe_read{,str}() helpers, that is, it is broken on
archs with overlapping address ranges.
While the helpers have been addressed through work in 6ae08ae3dea2 ("bpf: Add
probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers"), we need
an option for bpf_trace_printk() as well to fix it.
Similarly as with the helpers, force users to make an explicit choice by adding
%pks and %pus specifier to bpf_trace_printk() which will then pick the corresponding
strncpy_from_unsafe*() variant to perform the access under KERNEL_DS or USER_DS.
The %pk* (kernel specifier) and %pu* (user specifier) can later also be extended
for other objects aside strings that are probed and printed under tracing, and
reused out of other facilities like bpf_seq_printf() or BTF based type printing.
Existing behavior of %s for current users is still kept working for archs where it
is not broken and therefore gated through CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE.
For archs not having this property we fall-back to pick probing under KERNEL_DS as
a sensible default.
Fixes: 8d3b7dce86 ("bpf: add support for %s specifier to bpf_trace_printk()")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Christoph Hellwig <hch@lst.de>
Change-Id: I8d34f75136e535b92af4aaa3978f95b4fbb60884
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Link: https://lore.kernel.org/bpf/20200515101118.6508-4-daniel@iogearbox.net
Open access to bpf_trace monitoring for CAP_PERFMON privileged process.
Providing the access under CAP_PERFMON capability singly, without the
rest of CAP_SYS_ADMIN credentials, excludes chances to misuse the
credentials and makes operation more secure.
CAP_PERFMON implements the principle of least privilege for performance
monitoring and observability operations (POSIX IEEE 1003.1e 2.2.2.39
principle of least privilege: A security design principle that states
that a process or program be granted only those privileges (e.g.,
capabilities) necessary to accomplish its legitimate function, and only
for the time that such privileges are actually required)
For backward compatibility reasons access to bpf_trace monitoring
remains open for CAP_SYS_ADMIN privileged processes but CAP_SYS_ADMIN
usage for secure bpf_trace monitoring is discouraged with respect to
CAP_PERFMON capability.
Change-Id: Id9b2e784dbc6e07f4ce9039a7b2e23e88f495607
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Igor Lubashev <ilubashe@akamai.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: intel-gfx@lists.freedesktop.org
Cc: linux-doc@vger.kernel.org
Cc: linux-man@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: selinux@vger.kernel.org
Link: http://lore.kernel.org/lkml/c0a0ae47-8b6e-ff3e-416b-3cd1faaf71c0@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
All callers are built in. No point to export this.
Change-Id: I164f2a8f4211ca73d0cb4fc1eeb04a88d9d876cf
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
__bpf_trace_run() disables preemption around the BPF_PROG_RUN() invocation.
This is redundant because __bpf_trace_run() is invoked from a trace point
via __DO_TRACE() which already disables preemption _before_ invoking any of
the functions which are attached to a trace point.
Remove it and add a cant_sleep() check.
Change-Id: I24a64fc030fb4609e83d68a0e121373ed4309599
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200224145642.847220186@linutronix.de
Remove bpf_ prefix, which causes these helpers to be reported in verifier
dump as bpf_bpf_this_cpu_ptr() and bpf_bpf_per_cpu_ptr(), respectively. Lets
fix it as long as it is still possible before UAPI freezes on these helpers.
Fixes: eaa6bcb71ef6 ("bpf: Introduce bpf_per_cpu_ptr()")
Change-Id: Ida63849312eec819f6303bacd0e36328a4c37a6e
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add bpf_this_cpu_ptr() to help access percpu var on this cpu. This
helper always returns a valid pointer, therefore no need to check
returned value for NULL. Also note that all programs run with
preemption disabled, which means that the returned pointer is stable
during all the execution of the program.
Change-Id: I5a21c27796380af29fecd9f5650946e7477a1c30
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200929235049.2533242-6-haoluo@google.com
Add bpf_per_cpu_ptr() to help bpf programs access percpu vars.
bpf_per_cpu_ptr() has the same semantic as per_cpu_ptr() in the kernel
except that it may return NULL. This happens when the cpu parameter is
out of range. So the caller must check the returned value.
Change-Id: I8d552a56b8e6eb80a12fb89e384deb21686cb976
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200929235049.2533242-5-haoluo@google.com
A helper is added to allow seq file writing of kernel data
structures using vmlinux BTF. Its signature is
long bpf_seq_printf_btf(struct seq_file *m, struct btf_ptr *ptr,
u32 btf_ptr_size, u64 flags);
Flags and struct btf_ptr definitions/use are identical to the
bpf_snprintf_btf helper, and the helper returns 0 on success
or a negative error value.
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Change-Id: I26813fa7f57d10098528369f89dd5b99087ce53e
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/1601292670-1616-8-git-send-email-alan.maguire@oracle.com
A helper is added to support tracing kernel type information in BPF
using the BPF Type Format (BTF). Its signature is
long bpf_snprintf_btf(char *str, u32 str_size, struct btf_ptr *ptr,
u32 btf_ptr_size, u64 flags);
struct btf_ptr * specifies
- a pointer to the data to be traced
- the BTF id of the type of data pointed to
- a flags field is provided for future use; these flags
are not to be confused with the BTF_F_* flags
below that control how the btf_ptr is displayed; the
flags member of the struct btf_ptr may be used to
disambiguate types in kernel versus module BTF, etc;
the main distinction is the flags relate to the type
and information needed in identifying it; not how it
is displayed.
For example a BPF program with a struct sk_buff *skb
could do the following:
static struct btf_ptr b = { };
b.ptr = skb;
b.type_id = __builtin_btf_type_id(struct sk_buff, 1);
bpf_snprintf_btf(str, sizeof(str), &b, sizeof(b), 0, 0);
Default output looks like this:
(struct sk_buff){
.transport_header = (__u16)65535,
.mac_header = (__u16)65535,
.end = (sk_buff_data_t)192,
.head = (unsigned char *)0x000000007524fd8b,
.data = (unsigned char *)0x000000007524fd8b,
.truesize = (unsigned int)768,
.users = (refcount_t){
.refs = (atomic_t){
.counter = (int)1,
},
},
}
Flags modifying display are as follows:
- BTF_F_COMPACT: no formatting around type information
- BTF_F_NONAME: no struct/union member names/types
- BTF_F_PTR_RAW: show raw (unobfuscated) pointer values;
equivalent to %px.
- BTF_F_ZERO: show zero-valued struct/union members;
they are not displayed by default
Change-Id: Ic45d195264ae573cc1b2e1e49304edd4c91a1c65
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/1601292670-1616-4-git-send-email-alan.maguire@oracle.com
Add .test_run for raw_tracepoint. Also, introduce a new feature that runs
the target program on a specific CPU. This is achieved by a new flag in
bpf_attr.test, BPF_F_TEST_RUN_ON_CPU. When this flag is set, the program
is triggered on cpu with id bpf_attr.test.cpu. This feature is needed for
BPF programs that handle perf_event and other percpu resources, as the
program can access these resource locally.
Change-Id: I81266d3ad6b48e198f30faae2346041efcf7998e
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200925205432.1777-2-songliubraving@fb.com
Function prototypes using ARG_PTR_TO_BTF_ID currently use two ways to signal
which BTF IDs are acceptable. First, bpf_func_proto.btf_id is an array of
IDs, one for each argument. This array is only accessed up to the highest
numbered argument that uses ARG_PTR_TO_BTF_ID and may therefore be less than
five arguments long. It usually points at a BTF_ID_LIST. Second, check_btf_id
is a function pointer that is called by the verifier if present. It gets the
actual BTF ID of the register, and the argument number we're currently checking.
It turns out that the only user check_arg_btf_id ignores the argument, and is
simply used to check whether the BTF ID has a struct sock_common at it's start.
Replace both of these mechanisms with an explicit BTF ID for each argument
in a function proto. Thanks to btf_struct_ids_match this is very flexible:
check_arg_btf_id can be replaced by requiring struct sock_common.
Change-Id: I19fbb424b1299de0a1f44dfe3fec08aa4533a30a
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-5-lmb@cloudflare.com
Adding d_path helper function that returns full path for
given 'struct path' object, which needs to be the kernel
BTF 'path' object. The path is returned in buffer provided
'buf' of size 'sz' and is zero terminated.
bpf_d_path(&file->f_path, buf, size);
The helper calls directly d_path function, so there's only
limited set of function it can be called from. Adding just
very modest set for the start.
Updating also bpf.h tools uapi header and adding 'path' to
bpf_helpers_doc.py script.
Change-Id: Ic530ea9da08f5f6479bfd7a5b7c8c26d7d4aaa66
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: KP Singh <kpsingh@google.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-11-jolsa@kernel.org
Calling get_perf_callchain() on perf_events from PEBS entries may cause
unwinder errors. To fix this issue, the callchain is fetched early. Such
perf_events are marked with __PERF_SAMPLE_CALLCHAIN_EARLY.
Similarly, calling bpf_get_[stack|stackid] on perf_events from PEBS may
also cause unwinder errors. To fix this, add separate version of these
two helpers, bpf_get_[stack|stackid]_pe. These two hepers use callchain in
bpf_perf_event_data_kern->data->callchain.
Change-Id: I71bd415402ee8476596fff65d69c3190bad06d76
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723180648.1429892-2-songliubraving@fb.com
Using BTF_ID_LIST macro to define lists for several helpers
using BTF arguments.
And running resolve_btfids on vmlinux elf object during linking,
so the .BTF_ids section gets the IDs resolved.
Change-Id: I7299a611fb88195d58b2899e37d2ef5ded84e158
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200711215329.41165-5-jolsa@kernel.org
Introduce helper bpf_get_task_stack(), which dumps stack trace of given
task. This is different to bpf_get_stack(), which gets stack track of
current task. One potential use case of bpf_get_task_stack() is to call
it from bpf_iter__task and dump all /proc/<pid>/stack to a seq_file.
bpf_get_task_stack() uses stack_trace_save_tsk() instead of
get_perf_callchain() for kernel stack. The benefit of this choice is that
stack_trace_save_tsk() doesn't require changes in arch/. The downside of
using stack_trace_save_tsk() is that stack_trace_save_tsk() dumps the
stack trace to unsigned long array. For 32-bit systems, we need to
translate it to u64 array.
Change-Id: I8ed75e8c319732433a0ea1dd05951176ca81d1dd
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200630062846.664389-3-songliubraving@fb.com
/proc/net/tcp{4,6} uses jiffies for various computations.
Let us add bpf_jiffies64() helper to tracing program
so bpf_iter and other programs can use it.
Change-Id: I18cb1e7ecea12b3ffdc597fe6b97a5d2c8137e1e
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230808.3988073-1-yhs@fb.com
The helper is used in tracing programs to cast a socket
pointer to a udp6_sock pointer.
The return value could be NULL if the casting is illegal.
Change-Id: If6ef5992dcf07b5b8171c8221078d0f96fdce956
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Cc: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/bpf/20200623230815.3988481-1-yhs@fb.com
