On Fri, Feb 02, 2018 at 06:04:59PM -0500, Steven Rostedt wrote: SNIP > +static int create_function_event(int argc, char **argv) > +{ > + struct func_event *func_event, *fe; > + enum func_states state = FUNC_STATE_INIT; > + char *token; > + char *ptr; > + char last; > + int ret = -EINVAL; > + int i; > + > + func_event = kzalloc(sizeof(*func_event), GFP_KERNEL); > + if (!func_event) > + return -ENOMEM; > + > + INIT_LIST_HEAD(&func_event->files); > + func_event->ops.func = func_event_call; > + func_event->ops.flags = FTRACE_OPS_FL_SAVE_REGS; > + > + for (i = 0; i < argc; i++) { > + ptr = argv[i]; > + last = 0; > + for (token = next_token(&ptr, &last); token; > + token = next_token(&ptr, &last)) { > + state = process_event(func_event, token, state); > + if (state == FUNC_STATE_ERROR) > + goto fail; > + } > + } > + if (state != FUNC_STATE_END) > + goto fail; > + > + ret = -EALREADY; > + list_for_each_entry(fe, &func_events, list) { > + if (strcmp(fe->func, func_event->func) == 0) > + goto fail; > + } > + > + ret = ftrace_set_filter(&func_event->ops, func_event->func, > + strlen(func_event->func), 0); > + if (ret < 0) > + goto fail; > + > + ret = func_event_create(func_event); > + if (ret < 0) > + goto fail; > + > + list_add_tail(&func_event->list, &func_events); > + return 0; should this be done under 'func_event_mutex' ? I tried and crashed the system by running 2 scripts with: echo 'ip_rcv(u64 skb, u64 dev)' > /sys/kernel/debug/tracing/function_events echo 'SyS_openat(int dfd, string buf, x32 flags, x32 mode)' >> /sys/kernel/debug/tracing/function_events echo 'SyS_open(x8[32] buf, x32 flags, x32 mode)' >> /sys/kernel/debug/tracing/function_events jirka [ 376.727159] general protection fault: 0000 [#1] SMP PTI [ 376.732992] Modules linked in: intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul igb ghash_clmulni_intel intel_cstate ptp intel_uncore pps_core iTCO_wdt iTCO_vendor_support ipmi_ssif ipmi_si ipmi_devintf ipmi_msghandler shpchp ioatdma cdc_ether usbnet mii intel_rapl_perf i2c_i801 tpm_tis tpm_tis_core dca tpm lpc_ich wmi xfs libcrc32c mgag200 i2c_algo_bit drm_kms_helper ttm crc32c_intel drm megaraid_sas [ 376.779583] CPU: 9 PID: 1285 Comm: t.sh Not tainted 4.15.0-rc9idle+ #32 [ 376.786956] Hardware name: IBM System x3650 M4 : -[7915E2G]-/00Y7683, BIOS -[VVE124AUS-1.30]- 11/21/2012 [ 376.797545] RIP: 0010:__unregister_trace_event+0xe/0x70 [ 376.803376] RSP: 0018:ffffa643043cbc50 EFLAGS: 00010286 [ 376.809206] RAX: dead000000000100 RBX: ffff91b6340c2480 RCX: ffffffffbf2ebf50 [ 376.817170] RDX: dead000000000200 RSI: ffffffffbf2ed540 RDI: ffff91b6340c2480 [ 376.825135] RBP: ffff91b6340c2460 R08: 0000000000000001 R09: 0000000000000000 [ 376.833099] R10: ffffa643043cbc78 R11: 0000000000000000 R12: ffff91b6340c2400 [ 376.841062] R13: ffff91b6326f8600 R14: dead000000000200 R15: dead000000000100 [ 376.849028] FS: 00007ff3644bcb40(0000) GS:ffff91b63fac0000(0000) knlGS:0000000000000000 [ 376.858058] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 376.864469] CR2: 000055c83b531008 CR3: 00000004736d0003 CR4: 00000000000606e0 [ 376.872433] Call Trace: [ 376.875168] event_remove+0x72/0x120 [ 376.879159] trace_remove_event_call+0x79/0xd0 [ 376.884117] func_event_open+0xb1/0xd0 [ 376.888302] ? free_func_event+0x70/0x70 [ 376.892673] do_dentry_open+0x1b1/0x2d0 [ 376.896954] path_openat+0x602/0x14e0 [ 376.901041] do_filp_open+0x9b/0x110 [ 376.905032] ? __vfs_write+0x33/0x170 [ 376.909119] ? __check_object_size+0xaf/0x1b0 [ 376.913981] ? do_sys_open+0x1bd/0x250 [ 376.918164] do_sys_open+0x1bd/0x250 [ 376.922156] entry_SYSCALL_64_fastpath+0x20/0x83 [ 376.927299] RIP: 0033:0x7ff363ba01c0 [ 376.931287] RSP: 002b:00007ffdf21e4978 EFLAGS: 00000246 [ 376.931290] Code: e0 d9 2e bf e9 94 aa 6e 00 0f 1f 40 00 48 c7 c7 e0 d9 2e bf e9 54 5c f7 ff 0f 1f 40 00 53 48 8b 07 48 89 fb 48 8b 57 08 48 85 c0 <48> 89 02 74 04 48 89 50 08 48 b8 00 01 00 00 00 00 ad de 48 8d [ 376.958209] RIP: __unregister_trace_event+0xe/0x70 RSP: ffffa643043cbc50 [ 376.965711] ---[ end trace b3dd6064ee6bc2f4 ]--- -- To unsubscribe from this list: send the line "unsubscribe linux-trace-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html