[BUG] perf: memory leak in perf top

[Wangnan (F)]

perf top comsumes too much memory than it need.

Using following commands:

 # yes '' > /dev/null
 # perf top -e raw_syscalls:sys_enter

System will quickly become unresponsive because of out of memory.

Using GDB I find two call stacks of malloc. See below.

[call stack 1]

#0 __GI___libc_malloc (bytes=140723951319552) at malloc.c:2841
#1 0x00000000004b7246 in memdup (src=0x7f515e04b054, len=68) at 
../lib/string.c:29
#2 0x00000000004f9299 in hist_entry__init (sample_self=true, 
template=0x7ffcd9213a80, he=0xa37da50) at util/hist.c:401
#3 hist_entry__new (template=template@entry=0x7ffcd9213a80 
<mailto:%28template=template@entry=0x7ffcd9213a80>, 
sample_self=sample_self@entry=true) 
<mailto:sample_self=sample_self@entry=true%29> at util/hist.c:458
#4 0x00000000004fa13f in hists__findnew_entry (hists=0x3549d30, 
hists=0x3549d30, al=0x7ffcd9213ca0, sample_self=true, entry=0x
7ffcd9213a80) at util/hist.c:544
#5 __hists__add_entry (hists=0x3549d30, al=0x7ffcd9213ca0, 
sym_parent=<optimized out>, bi=bi@entry=0x0 <mailto:bi=bi@entry=0x0>, 
mi=mi@entry=0x0 <mailto:mi=mi@entry=0x0>, sampl
e=<optimized out>, sample_self=sample_self@entry=true 
<mailto:sample_self=sample_self@entry=true>, ops=ops@entry=0x0) 
<mailto:ops=ops@entry=0x0%29> at util/hist.c:600
#6 0x00000000004fa3d6 in hists__add_entry (sample_self=true, 
sample=<optimized out>, mi=0x0, bi=0x0, sym_parent=<optimized out
>, al=<optimized out>, hists=<optimized out>) at util/hist.c:611
#7 iter_add_single_normal_entry (iter=0x7ffcd9213ce0, al=<optimized 
out>) at util/hist.c:823
#8 0x00000000004fc3c5 in hist_entry_iter__add (iter=0x7ffcd9213ce0, 
al=0x7ffcd9213ca0, max_stack_depth=<optimized out>, arg=0x
7ffcd9214120) at util/hist.c:1030
#9 0x00000000004536d7 in perf_event__process_sample (machine=<optimized 
out>, sample=0x7ffcd9213d30, evsel=0x3549bb0, event=<o
ptimized out>, tool=0x7ffcd9214120) at builtin-top.c:800
#10 perf_top__mmap_read_idx (top=top@entry=0x7ffcd9214120 
<mailto:%28top=top@entry=0x7ffcd9214120>, idx=idx@entry=0) 
<mailto:idx=idx@entry=0%29> at builtin-top.c:866
#11 0x00000000004559fd in perf_top__mmap_read (top=0x7ffcd9214120) at 
builtin-top.c:883
#12 __cmd_top (top=0x7ffcd9214120) at builtin-top.c:1018
#13 cmd_top (argc=<optimized out>, argv=<optimized out>, 
prefix=<optimized out>) at builtin-top.c:1344
#14 0x0000000000493561 in run_builtin (p=p@entry=0x948000 
<mailto:%28p=p@entry=0x948000> <commands+288>, argc=argc@entry=4 
<mailto:argc=argc@entry=4>, argv=argv@entry=0x7ffcd92199b0) 
<mailto:argv=argv@entry=0x7ffcd92199b0%29> at
perf.c:357
#15 0x0000000000437157 in handle_internal_command (argv=0x7ffcd92199b0, 
argc=4) at perf.c:419
#16 run_argv (argv=0x7ffcd9219720, argcp=0x7ffcd921972c) at perf.c:465
#17 main (argc=4, argv=0x7ffcd92199b0) at perf.c:609

[call stack 2]

#0 __GI___libc_malloc (bytes=140723951319456) at malloc.c:2841
#1 0x00000000005766de in trace_seq_init (s=0x7ffcd92139b0) at trace-seq.c:60
#2 0x00000000004f7047 in get_trace_output (he=0x7ffcd9213a80) at 
util/sort.c:584
#3 sort__trace_cmp (left=0x40e6d30, right=0x7ffcd9213a80) at util/sort.c:606
#4 0x00000000004fa007 in hist_entry__cmp (right=0x7ffcd9213a80, 
left=0x40e6d30) at util/hist.c:1072
#5 hists__findnew_entry (hists=0x3549d30, hists=0x3549d30, 
al=0x7ffcd9213ca0, sample_self=true, entry=0x7ffcd9213a80) at util/
hist.c:509
#6 __hists__add_entry (hists=0x3549d30, al=0x7ffcd9213ca0, 
sym_parent=<optimized out>, bi=bi@entry=0x0 <mailto:bi=bi@entry=0x0>, 
mi=mi@entry=0x0 <mailto:mi=mi@entry=0x0>, sampl
e=<optimized out>, sample_self=sample_self@entry=true 
<mailto:sample_self=sample_self@entry=true>, ops=ops@entry=0x0) 
<mailto:ops=ops@entry=0x0%29> at util/hist.c:600
#7 0x00000000004fa3d6 in hists__add_entry (sample_self=true, 
sample=<optimized out>, mi=0x0, bi=0x0, sym_parent=<optimized out
>, al=<optimized out>, hists=<optimized out>) at util/hist.c:611
#8 iter_add_single_normal_entry (iter=0x7ffcd9213ce0, al=<optimized 
out>) at util/hist.c:823
#9 0x00000000004fc3c5 in hist_entry_iter__add (iter=0x7ffcd9213ce0, 
al=0x7ffcd9213ca0, max_stack_depth=<optimized out>, arg=0x
7ffcd9214120) at util/hist.c:1030
#10 0x00000000004536d7 in perf_event__process_sample (machine=<optimized 
out>, sample=0x7ffcd9213d30, evsel=0x3549bb0, event=<o
ptimized out>, tool=0x7ffcd9214120) at builtin-top.c:800
#11 perf_top__mmap_read_idx (top=top@entry=0x7ffcd9214120 
<mailto:%28top=top@entry=0x7ffcd9214120>, idx=idx@entry=0) 
<mailto:idx=idx@entry=0%29> at builtin-top.c:866
#12 0x00000000004559fd in perf_top__mmap_read (top=0x7ffcd9214120) at 
builtin-top.c:883
#13 __cmd_top (top=0x7ffcd9214120) at builtin-top.c:1018
#14 cmd_top (argc=<optimized out>, argv=<optimized out>, 
prefix=<optimized out>) at builtin-top.c:1344
#15 0x0000000000493561 in run_builtin (p=p@entry=0x948000 
<mailto:%28p=p@entry=0x948000> <commands+288>, argc=argc@entry=4 
<mailto:argc=argc@entry=4>, argv=argv@entry=0x7ffcd92199b0) 
<mailto:argv=argv@entry=0x7ffcd92199b0%29> at
perf.c:357
#16 0x0000000000437157 in handle_internal_command (argv=0x7ffcd92199b0, 
argc=4) at perf.c:419
#17 run_argv (argv=0x7ffcd9219720, argcp=0x7ffcd921972c) at perf.c:465
#18 main (argc=4, argv=0x7ffcd92199b0) at perf.c:609