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WARNING: suspicious RCU usage in bpf_prog_array_copy_core

Status: fixed on 2018/08/28 17:48
Subsystems: bpf
[Documentation on labels]
Reported-by: syzbot+6e72317008eef84a216b@syzkaller.appspotmail.com
Fix commit: 965931e3a803 bpf: fix a rcu usage warning in bpf_prog_array_copy_core()
First crash: 2085d, last: 2067d
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH bpf] bpf: fix a rcu usage warning in bpf_prog_array_copy_core() 6 (6) 2018/08/16 00:17
WARNING: suspicious RCU usage in bpf_prog_array_copy_core 1 (2) 2018/08/14 15:59

Sample crash report:
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)

=============================
WARNING: suspicious RCU usage
4.18.0-rc8-next-20180810+ #36 Not tainted
-----------------------------
kernel/bpf/core.c:1582 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
2 locks held by syz-executor287/4449:
 #0: 00000000d8131c0c (&ctx->mutex){+.+.}, at: perf_event_ctx_lock_nested+0x375/0x600 kernel/events/core.c:1276
 #1: 000000006c916250 (bpf_event_mutex){+.+.}, at: perf_event_query_prog_array+0x1c6/0x380 kernel/trace/bpf_trace.c:1062

stack backtrace:
CPU: 1 PID: 4449 Comm: syz-executor287 Not tainted 4.18.0-rc8-next-20180810+ #36
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
 lockdep_rcu_suspicious+0x14a/0x153 kernel/locking/lockdep.c:4562
 bpf_prog_array_copy_core+0x2d9/0x360 kernel/bpf/core.c:1582
 bpf_prog_array_copy_info+0x9a/0x110 kernel/bpf/core.c:1720
 perf_event_query_prog_array+0x22e/0x380 kernel/trace/bpf_trace.c:1063
 _perf_ioctl+0x986/0x1600 kernel/events/core.c:5079
 perf_ioctl+0x59/0x80 kernel/events/core.c:5110
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl fs/ioctl.c:707 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440409
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffc5fc1488 EFLAGS: 00000217 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440409
RDX: 0000000020000180 RSI: 00000000c008240a RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000217 R12: 0000000000401c90
R13: 0000000000401d20 R14: 0000000000000000

Crashes (22873):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/08/10 15:08 linux-next 4110b42356f3 1fb62d58 .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2018/08/19 07:37 upstream a18d783fedfe de20bcbb .config console log report ci-upstream-kasan-gce-root
2018/08/28 07:08 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 06:55 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 06:23 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 06:03 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 05:49 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 05:35 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 05:20 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 05:05 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 04:48 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 04:32 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 04:16 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 04:02 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 03:44 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 03:29 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 03:14 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 02:56 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 02:39 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 02:20 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 02:03 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 01:49 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 01:33 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 01:18 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 00:58 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 00:44 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 00:27 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/28 00:12 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/27 23:57 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/27 23:46 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/27 23:30 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/27 23:15 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/27 23:04 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/27 22:49 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/27 22:38 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/27 22:13 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/27 21:48 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/27 21:21 bpf-next 9a76aba02a37 7ef1de9e .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/27 20:52 bpf-next 9a76aba02a37 758cd203 .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/27 20:38 bpf-next 9a76aba02a37 758cd203 .config console log report ci-upstream-bpf-next-kasan-gce
2018/08/16 23:37 linux-next 3070c752f222 9ccc1d45 .config console log report ci-upstream-linux-next-kasan-gce-root
2018/08/10 08:53 linux-next 4110b42356f3 1fb62d58 .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.