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author | Yonghong Song <yhs@fb.com> | 2018-08-14 11:01:12 -0700 |
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committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-08-16 21:55:32 +0200 |
commit | 965931e3a803a506482616f89239eff6901c17b8 (patch) | |
tree | 22c2ccac1861446a76c794422aa6a57a7c360b69 /net/ipv4/tcp_ulp.c | |
parent | 817b89beb9d8876450fcde9155e17425c329569d (diff) | |
download | linux-965931e3a803a506482616f89239eff6901c17b8.tar.bz2 |
bpf: fix a rcu usage warning in bpf_prog_array_copy_core()
Commit 394e40a29788 ("bpf: extend bpf_prog_array to store pointers
to the cgroup storage") refactored the bpf_prog_array_copy_core()
to accommodate new structure bpf_prog_array_item which contains
bpf_prog array itself.
In the old code, we had
perf_event_query_prog_array():
mutex_lock(...)
bpf_prog_array_copy_call():
prog = rcu_dereference_check(array, 1)->progs
bpf_prog_array_copy_core(prog, ...)
mutex_unlock(...)
With the above commit, we had
perf_event_query_prog_array():
mutex_lock(...)
bpf_prog_array_copy_call():
bpf_prog_array_copy_core(array, ...):
item = rcu_dereference(array)->items;
...
mutex_unlock(...)
The new code will trigger a lockdep rcu checking warning.
The fix is to change rcu_dereference() to rcu_dereference_check()
to prevent such a warning.
Reported-by: syzbot+6e72317008eef84a216b@syzkaller.appspotmail.com
Fixes: 394e40a29788 ("bpf: extend bpf_prog_array to store pointers to the cgroup storage")
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'net/ipv4/tcp_ulp.c')
0 files changed, 0 insertions, 0 deletions