On Sun, Apr 09, 2023 at 04:15:25PM +0800, Rong Tao wrote: > From: Rong Tao <rongtao@xxxxxxxx> > > When the number of symbols is greater than MAX_SYMS (300000), the access > array struct ksym syms[MAX_SYMS] goes out of bounds, which will result in > a segfault. > > Resolve this issue by judging the maximum number and exiting the loop, and > increasing the default size appropriately. (6.2.9 = 329839 below) > > $ cat /proc/kallsyms | wc -l > 329839 > > GDB debugging: > $ cd linux/samples/bpf > $ sudo gdb ./sampleip > ... > (gdb) r > ... > Program received signal SIGSEGV, Segmentation fault. > 0x00007ffff7e2debf in malloc () from /lib64/libc.so.6 > Missing separate debuginfos, use: dnf debuginfo-install > elfutils-libelf-0.189-1.fc37.x86_64 glibc-2.36-9.fc37.x86_64 > libzstd-1.5.4-1.fc37.x86_64 zlib-1.2.12-5.fc37.x86_64 > (gdb) bt > #0 0x00007ffff7e2debf in malloc () from /lib64/libc.so.6 > #1 0x00007ffff7e33f8e in strdup () from /lib64/libc.so.6 > #2 0x0000000000403fb0 in load_kallsyms_refresh() from trace_helpers.c > #3 0x00000000004038b2 in main () > > Signed-off-by: Rong Tao <rongtao@xxxxxxxx> I had to apply by hand, there was some fuzz: patching file tools/testing/selftests/bpf/trace_helpers.c Hunk #1 succeeded at 18 with fuzz 2 (offset 4 lines). Hunk #2 succeeded at 48 (offset 4 lines). but other than that looks good Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx> jirka > --- > tools/testing/selftests/bpf/trace_helpers.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c > index 09a16a77bae4..a9d589c560d2 100644 > --- a/tools/testing/selftests/bpf/trace_helpers.c > +++ b/tools/testing/selftests/bpf/trace_helpers.c > @@ -14,7 +14,7 @@ > > #define DEBUGFS "/sys/kernel/debug/tracing/" > > -#define MAX_SYMS 300000 > +#define MAX_SYMS 400000 > static struct ksym syms[MAX_SYMS]; > static int sym_cnt; > > @@ -44,7 +44,8 @@ int load_kallsyms_refresh(void) > continue; > syms[i].addr = (long) addr; > syms[i].name = strdup(func); > - i++; > + if (++i >= MAX_SYMS) > + break; > } > fclose(f); > sym_cnt = i; > -- > 2.39.2 >
