Messages in this thread Patch in this message | | | Date | Mon, 2 Jan 2017 14:36:57 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH v2 perf/core] perf script: fix a use after free crash. |
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Em Mon, Jan 02, 2017 at 02:35:30PM -0300, Arnaldo Carvalho de Melo escreveu: > Em Mon, Jan 02, 2017 at 12:15:14PM -0300, Arnaldo Carvalho de Melo escreveu: > > Tried it again with what is in Linus' tree + your patch and got the same > > problem: > > > > [acme@jouet linux]$ git remote -v | grep torvalds.*fetch > > torvalds git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git (fetch) > > [acme@jouet linux]$ git checkout -b test-branch torvalds/master > > Branch test-branch set up to track remote branch master from torvalds. > > Switched to a new branch 'test-branch' > > [acme@jouet linux]$ git cherry-pick f7347a33099dbad7e9fb3c22cea211f238bfd320 > > [test-branch 7d786f548b62] perf callchain: Fix a use after free crash due to refcounting bug > > Author: Krister Johansen <kjlx@templeofstupid.com> > > Date: Mon Jan 2 12:06:55 2017 -0300 > > 3 files changed, 19 insertions(+), 2 deletions(-) > > [acme@jouet linux]$ rm -rf /tmp/build/perf/ ; mkdir -p /tmp/build/perf ; make O=/tmp/build/perf -C tools/perf install-bin > > make: Entering directory '/home/acme/git/linux/tools/perf' > > BUILD: Doing 'make -j4' parallel build > > HOSTCC /tmp/build/perf/fixdep.o > > <SNIP> > > > > Then I run it with a higher frequency and no delay in refreshing the screen, to > > stress the refcounting code: > > > > # perf top -F 10000 -g -d 0 > > > > Do it while running something like 'make -j32 allmodconfig' to create lots of > > short lived processes (or use stress-ng, etc). > > Back to acme/perf/core and with debugging, we're getting a refcount hitting zero > while the map is still in a rbtree:
And this was introduced by your patch:
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c index 6770a9645609..72f5c82798e9 100644 --- a/tools/perf/util/hist.c +++ b/tools/perf/util/hist.c @@ -1,6 +1,7 @@ #include "util.h" #include "build-id.h" #include "hist.h" +#include "map.h" #include "session.h" #include "sort.h" #include "evlist.h" @@ -979,6 +980,7 @@ iter_finish_cumulative_entry(struct hist_entry_iter *iter, { zfree(&iter->priv); iter->he = NULL; + map__zput(al->map); return 0; } > perf: util/map.c:246: map__exit: Assertion `!(!((&map->rb_node)->__rb_parent_color == (unsigned long)(&map->rb_node)))' failed. > > Thread 1 "perf" received signal SIGABRT, Aborted. > 0x00007ffff522691f in raise () from /lib64/libc.so.6 > (gdb) bt > #0 0x00007ffff522691f in raise () from /lib64/libc.so.6 > #1 0x00007ffff522851a in abort () from /lib64/libc.so.6 > #2 0x00007ffff521eda7 in __assert_fail_base () from /lib64/libc.so.6 > #3 0x00007ffff521ee52 in __assert_fail () from /lib64/libc.so.6 > #4 0x0000000000504e57 in map__exit (map=0x2393790) at util/map.c:246 > #5 0x0000000000504ea5 in map__delete (map=0x2393790) at util/map.c:252 > #6 0x0000000000504f0a in map__put (map=0x2393790) at util/map.c:259 > #7 0x000000000052fa01 in __map__zput (map=0x7fffffff8230) at util/map.h:161 > #8 0x000000000053295b in iter_finish_cumulative_entry (iter=0x7fffffff8260, al=0x7fffffff8220) at util/hist.c:983 > #9 0x0000000000532b53 in hist_entry_iter__add (iter=0x7fffffff8260, al=0x7fffffff8220, max_stack_depth=127, arg=0x7fffffffa7b0) at util/hist.c:1059 > #10 0x000000000044f5cf in perf_event__process_sample (tool=0x7fffffffa7b0, event=0x7ffff7e24578, evsel=0x21515d0, sample=0x7fffffff8410, machine=0x21b2bf8) > at builtin-top.c:774 > #11 0x000000000044f8ee in perf_top__mmap_read_idx (top=0x7fffffffa7b0, idx=2) at builtin-top.c:840 > #12 0x000000000044fa0d in perf_top__mmap_read (top=0x7fffffffa7b0) at builtin-top.c:857 > #13 0x0000000000450080 in __cmd_top (top=0x7fffffffa7b0) at builtin-top.c:1002 > #14 0x00000000004514e0 in cmd_top (argc=0, argv=0x7fffffffe130, prefix=0x0) at builtin-top.c:1330 > #15 0x00000000004b5af5 in run_builtin (p=0xa0baf8 <commands+312>, argc=6, argv=0x7fffffffe130) at perf.c:358 > #16 0x00000000004b5d62 in handle_internal_command (argc=6, argv=0x7fffffffe130) at perf.c:420 > #17 0x00000000004b5ea7 in run_argv (argcp=0x7fffffffdf8c, argv=0x7fffffffdf80) at perf.c:466 > #18 0x00000000004b6290 in main (argc=6, argv=0x7fffffffe130) at perf.c:610 > (gdb) fr 4 > #4 0x0000000000504e57 in map__exit (map=0x2393790) at util/map.c:246 > 246 BUG_ON(!RB_EMPTY_NODE(&map->rb_node)); > (gdb) p map > $1 = (struct map *) 0x2393790 > (gdb) p *map > $2 = {{rb_node = {__rb_parent_color = 37304353, rb_right = 0x0, rb_left = 0x0}, node = {next = 0x2393821, prev = 0x0}}, start = 140434683187200, > end = 140434690723840, type = 0 '\000', erange_warned = false, priv = 0, prot = 5, flags = 2, pgoff = 0, reloc = 0, maj = 253, min = 0, ino = 132875, > ino_generation = 3472328296227680304, map_ip = 0x504125 <map__map_ip>, unmap_ip = 0x504174 <map__unmap_ip>, dso = 0x22b3890, groups = 0x2385290, refcnt = { > counter = 0}} > (gdb)
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