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suspicious RCU usage at ./include/linux/rcupdate.h:LINE (4)

Status: fixed on 2018/02/12 17:26
Subsystems: perf
[Documentation on labels]
Reported-by: syzbot+7dbcd2d3b85f9b608b23@syzkaller.appspotmail.com
Fix commit: 0911287ce32b bpf: fix bpf_prog_array_copy_to_user() issues
First crash: 2828d, last: 2824d
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH bpf] bpf: fix bpf_prog_array_copy_to_user() issues 2 (2) 2018/02/03 01:25
suspicious RCU usage at ./include/linux/rcupdate.h:LINE (4) 1 (2) 2018/02/02 23:29
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream suspicious RCU usage at ./include/linux/rcupdate.h:LINE (2) net -1 C 174 2840d 2920d 4/29 fixed on 2018/01/22 13:19
upstream suspicious RCU usage at ./include/linux/rcupdate.h:LINE (3) bpf -1 C 5087 2830d 2839d 4/29 fixed on 2018/02/01 04:00
upstream suspicious RCU usage at ./include/linux/rcupdate.h:LINE -1 1 2988d 2988d 0/29 closed as invalid on 2017/08/27 08:48

Sample crash report:
audit: type=1400 audit(1517546098.866:9): avc:  denied  { prog_run } for  pid=4159 comm="syzkaller076311" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=bpf permissive=1

=============================
WARNING: suspicious RCU usage
4.15.0+ #10 Not tainted
-----------------------------
./include/linux/rcupdate.h:302 Illegal context switch in RCU read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
3 locks held by syzkaller076311/4159:
 #0:  (&ctx->mutex){+.+.}, at: [<0000000027c8872d>] perf_event_ctx_lock_nested+0x21b/0x450 kernel/events/core.c:1253
 #1:  (bpf_event_mutex){+.+.}, at: [<0000000092294d8c>] perf_event_query_prog_array+0x10e/0x280 kernel/trace/bpf_trace.c:876
 #2:  (rcu_read_lock){....}, at: [<000000002b518ca0>] bpf_prog_array_copy_to_user+0x0/0x4d0 kernel/bpf/core.c:1568

stack backtrace:
CPU: 0 PID: 4159 Comm: syzkaller076311 Not tainted 4.15.0+ #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 lockdep_rcu_suspicious+0x123/0x170 kernel/locking/lockdep.c:4592
 rcu_preempt_sleep_check include/linux/rcupdate.h:301 [inline]
 ___might_sleep+0x385/0x470 kernel/sched/core.c:6079
 __might_sleep+0x95/0x190 kernel/sched/core.c:6067
 __might_fault+0xab/0x1d0 mm/memory.c:4532
 _copy_to_user+0x2c/0xc0 lib/usercopy.c:25
 copy_to_user include/linux/uaccess.h:155 [inline]
 bpf_prog_array_copy_to_user+0x217/0x4d0 kernel/bpf/core.c:1587
 bpf_prog_array_copy_info+0x17b/0x1c0 kernel/bpf/core.c:1685
 perf_event_query_prog_array+0x196/0x280 kernel/trace/bpf_trace.c:877
 _perf_ioctl kernel/events/core.c:4737 [inline]
 perf_ioctl+0x3e1/0x1480 kernel/events/core.c:4757
 vfs_ioctl fs/ioctl.c:46 [inline]
 do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x43ffd9
RSP: 002b:00007ffde8594aa8 EFLAGS: 00000217 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 000000000043ffd9
RDX: 0000000020a40000 RSI: 00000000c008240a RDI: 0000000000000004
RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000217 R12: 0000000000401900
R13: 0000000000401990 R14: 0000000000000000 R15: 0000000000000000
BUG: sleeping function called from invalid context at lib/usercopy.c:25
in_atomic(): 1, irqs_disabled(): 0, pid: 4159, name: syzkaller076311
3 locks held by syzkaller076311/4159:
 #0:  (&ctx->mutex){+.+.}, at: [<0000000027c8872d>] perf_event_ctx_lock_nested+0x21b/0x450 kernel/events/core.c:1253
 #1:  (bpf_event_mutex){+.+.}, at: [<0000000092294d8c>] perf_event_query_prog_array+0x10e/0x280 kernel/trace/bpf_trace.c:876
 #2:  (rcu_read_lock){....}, at: [<000000002b518ca0>] bpf_prog_array_copy_to_user+0x0/0x4d0 kernel/bpf/core.c:1568
CPU: 0 PID: 4159 Comm: syzkaller076311 Not tainted 4.15.0+ #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 ___might_sleep+0x2b2/0x470 kernel/sched/core.c:6114
 __might_sleep+0x95/0x190 kernel/sched/core.c:6067
 __might_fault+0xab/0x1d0 mm/memory.c:4532
 _copy_to_user+0x2c/0xc0 lib/usercopy.c:25
 copy_to_user include/linux/uaccess.h:155 [inline]
 bpf_prog_array_copy_to_user+0x217/0x4d0 kernel/bpf/core.c:1587
 bpf_prog_array_copy_info+0x17b/0x1c0 kernel/bpf/core.c:1685
 perf_event_query_prog_array+0x196/0x280 kernel/trace/bpf_trace.c:877
 _perf_ioctl kernel/events/core.c:4737 [inline]
 perf_ioctl+0x3e1/0x1480 kernel/events/core.c:4757
 vfs_ioctl fs/ioctl.c:46 [inline]
 do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x43ffd9
RSP: 002b:00007ffde8594aa8 EFLAGS: 00000217 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 000000000043ffd9
RDX: 0000000020a40000 RSI: 00000000c008240a RDI: 0000000000000004
RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000

Crashes (7264):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/02/02 04:37 bpf-next b2fe5fa68642 826b35d6 .config console log report syz C ci-upstream-bpf-next-kasan-gce
2018/02/02 11:14 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:13 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:13 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:13 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:12 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:12 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:12 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:11 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:11 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:11 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:10 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:10 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:09 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:09 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:08 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:08 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:08 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:07 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:07 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:07 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:07 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:06 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:06 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:05 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:05 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:04 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:03 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:03 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:03 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:03 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:02 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:02 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:01 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:01 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:00 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:00 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:00 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 11:00 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 10:59 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
2018/02/02 10:59 bpf-next b2fe5fa68642 826b35d6 .config console log report ci-upstream-bpf-next-kasan-gce
* Struck through repros no longer work on HEAD.