Messages in this thread |  | | Date | Sat, 21 Apr 2018 11:29:10 -0700 | From | Eric Biggers <> | Subject | Re: possible deadlock in ftrace_profile_set_filter (2) |
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On Mon, Jan 22, 2018 at 09:49:00AM -0800, syzbot wrote: > syzbot has found reproducer for the following crash on > git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/master commit > ebdd7b491b8a65d65936e07004caabca4a3c94a0 (Sun Jan 21 23:21:31 2018 +0000) > Merge branch 'mlxsw-Add-support-for-mirror-action-with-flower' > > So far this crash happened 3 times on > git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/master, > linux-next. > C reproducer is attached. > syzkaller reproducer is attached. > Raw console output is attached. > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: > syzbot+7b44b47914a5b3dc2038ff8f39e13a0e0f9e5f78@syzkaller.appspotmail.com > It will help syzbot understand when the bug is fixed. > > > ====================================================== > WARNING: possible circular locking dependency detected > 4.15.0-rc8+ #1 Not tainted > ------------------------------------------------------ > syzkaller301315/3887 is trying to acquire lock: > (event_mutex){+.+.}, at: [<00000000dfa1326b>] > ftrace_profile_set_filter+0x7a/0x270 kernel/trace/trace_events_filter.c:2266 > > but task is already holding lock: > (&cpuctx_mutex){+.+.}, at: [<00000000e276bad6>] > perf_event_ctx_lock_nested+0x21b/0x450 kernel/events/core.c:1249 > > which lock already depends on the new lock. > > > the existing dependency chain (in reverse order) is: > > -> #4 (&cpuctx_mutex){+.+.}: > __mutex_lock_common kernel/locking/mutex.c:756 [inline] > __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 > mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 > perf_event_init_cpu+0xb6/0x160 kernel/events/core.c:11076 > perf_event_init+0x4e9/0x549 kernel/events/core.c:11123 > start_kernel+0x4cc/0x819 init/main.c:627 > x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:378 > x86_64_start_kernel+0x77/0x7a arch/x86/kernel/head64.c:359 > secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 > > -> #3 (pmus_lock){+.+.}: > __mutex_lock_common kernel/locking/mutex.c:756 [inline] > __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 > mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 > perf_event_init_cpu+0x2f/0x160 kernel/events/core.c:11070 > cpuhp_invoke_callback+0x2ea/0x1d20 kernel/cpu.c:182 > cpuhp_up_callbacks kernel/cpu.c:477 [inline] > _cpu_up+0x216/0x510 kernel/cpu.c:1036 > do_cpu_up+0x73/0xa0 kernel/cpu.c:1066 > cpu_up+0x18/0x20 kernel/cpu.c:1074 > smp_init+0x13a/0x152 kernel/smp.c:578 > kernel_init_freeable+0x2fe/0x521 init/main.c:1067 > kernel_init+0x13/0x180 init/main.c:999 > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:541 > > -> #2 (cpu_hotplug_lock.rw_sem){++++}: > percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 > [inline] > percpu_down_read include/linux/percpu-rwsem.h:59 [inline] > cpus_read_lock+0x42/0x90 kernel/cpu.c:293 > static_key_slow_inc+0x9d/0x3c0 kernel/jump_label.c:123 > tracepoint_add_func kernel/tracepoint.c:223 [inline] > tracepoint_probe_register_prio+0x80d/0x9a0 kernel/tracepoint.c:283 > tracepoint_probe_register+0x2a/0x40 kernel/tracepoint.c:304 > trace_event_reg+0x167/0x320 kernel/trace/trace_events.c:305 > perf_trace_event_reg kernel/trace/trace_event_perf.c:122 [inline] > perf_trace_event_init kernel/trace/trace_event_perf.c:197 [inline] > perf_trace_init+0x4ef/0xab0 kernel/trace/trace_event_perf.c:221 > perf_tp_event_init+0x7d/0xf0 kernel/events/core.c:7959 > perf_try_init_event+0xc9/0x1f0 kernel/events/core.c:9192 > perf_init_event kernel/events/core.c:9230 [inline] > perf_event_alloc+0x1cc6/0x2b00 kernel/events/core.c:9494 > SYSC_perf_event_open+0x84e/0x2e00 kernel/events/core.c:9949 >
No longer occurring, fix was commit 43fa87f7deed52e8c8:
#syz fix: perf/core: Fix another perf,trace,cpuhp lock inversion
- Eric
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