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Thomas Richter 5069211e2f perf trace: Use the right bpf_probe_read(_str) variant for reading user data

Perf test case 111 Check open filename arg using perf trace + vfs_getname
fails on s390. This is caused by a failing function
bpf_probe_read() in file util/bpf_skel/augmented_raw_syscalls.bpf.c.

The root cause is the lookup by address. Function bpf_probe_read()
is used. This function works only for architectures
with ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE.

On s390 is not possible to determine from the address to which
address space the address belongs to (user or kernel space).

Replace bpf_probe_read() by bpf_probe_read_kernel()
and bpf_probe_read_str() by bpf_probe_read_user_str() to
explicity specify the address space the address refers to.

Output before:
 # ./perf trace -eopen,openat -- touch /tmp/111
 libbpf: prog 'sys_enter': BPF program load failed: Invalid argument
 libbpf: prog 'sys_enter': -- BEGIN PROG LOAD LOG --
 reg type unsupported for arg#0 function sys_enter#75
 0: R1=ctx(off=0,imm=0) R10=fp0
 ; int sys_enter(struct syscall_enter_args *args)
 0: (bf) r6 = r1           ; R1=ctx(off=0,imm=0) R6_w=ctx(off=0,imm=0)
 ; return bpf_get_current_pid_tgid();
 1: (85) call bpf_get_current_pid_tgid#14      ; R0_w=scalar()
 2: (63) *(u32 *)(r10 -8) = r0 ; R0_w=scalar() R10=fp0 fp-8=????mmmm
 3: (bf) r2 = r10              ; R2_w=fp0 R10=fp0
 ;
 .....
 lines deleted here
 .....
 23: (bf) r3 = r6              ; R3_w=ctx(off=0,imm=0) R6=ctx(off=0,imm=0)
 24: (85) call bpf_probe_read#4
 unknown func bpf_probe_read#4
 processed 23 insns (limit 1000000) max_states_per_insn 0 \
	 total_states 2 peak_states 2 mark_read 2
 -- END PROG LOAD LOG --
 libbpf: prog 'sys_enter': failed to load: -22
 libbpf: failed to load object 'augmented_raw_syscalls_bpf'
 libbpf: failed to load BPF skeleton 'augmented_raw_syscalls_bpf': -22
 ....

Output after:
 # ./perf test -Fv 111
 111: Check open filename arg using perf trace + vfs_getname          :
 --- start ---
     1.085 ( 0.011 ms): touch/320753 openat(dfd: CWD, filename: \
	"/tmp/temporary_file.SWH85", \
	flags: CREAT|NOCTTY|NONBLOCK|WRONLY, mode: IRUGO|IWUGO) = 3
 ---- end ----
 Check open filename arg using perf trace + vfs_getname: Ok
 #

Test with the sleep command shows:
Output before:
 # ./perf trace -e *sleep sleep 1.234567890
     0.000 (1234.681 ms): sleep/63114 clock_nanosleep(rqtp: \
         { .tv_sec: 0, .tv_nsec: 0 }, rmtp: 0x3ffe0979720) = 0
 #

Output after:
 # ./perf trace -e *sleep sleep 1.234567890
     0.000 (1234.686 ms): sleep/64277 clock_nanosleep(rqtp: \
         { .tv_sec: 1, .tv_nsec: 234567890 }, rmtp: 0x3fff3df9ea0) = 0
 #

Fixes: 14e4b9f4289a ("perf trace: Raw augmented syscalls fix libbpf 1.0+ compatibility")
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Co-developed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: gor@linux.ibm.com
Cc: hca@linux.ibm.com
Cc: sumanthk@linux.ibm.com
Cc: svens@linux.ibm.com
Link: https://lore.kernel.org/r/20231019082642.3286650-1-tmricht@linux.ibm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

2023-10-19 22:41:46 -07:00

accounting

…

arch

tools arch x86: Sync the msr-index.h copy with the kernel sources

2023-09-13 08:53:37 -03:00

bootconfig

…

bpf

bpftool: Fix build warnings with -Wtype-limits

2023-08-30 08:39:00 +02:00

build