From: Pu Hou Date: Tue, 5 Sep 2017 03:17:24 +0000 (+0200) Subject: s390/perf: fix bug when creating per-thread event X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=fc3100d64f0ae383ae8d845989103da06d62763b;p=openwrt%2Fstaging%2Fblogic.git s390/perf: fix bug when creating per-thread event A per-thread event could not be created correctly like below: perf record --per-thread -e rB0000 -- sleep 1 Error: The sys_perf_event_open() syscall returned with 19 (No such device) for event (rB0000). /bin/dmesg may provide additional information. No CONFIG_PERF_EVENTS=y kernel support configured? This bug was introduced by: commit c311c797998c1e70eade463dd60b843da4f1a203 Author: Alexey Dobriyan Date: Mon May 8 15:56:15 2017 -0700 cpumask: make "nr_cpumask_bits" unsigned If a per-thread event is not attached to any CPU, the cpu field in struct perf_event is -1. The above commit converts the CPU number to unsigned int, which result in an illegal CPU number. Fixes: c311c797998c ("cpumask: make "nr_cpumask_bits" unsigned") Cc: # v4.12+ Cc: Alexey Dobriyan Acked-by: Heiko Carstens Signed-off-by: Pu Hou Signed-off-by: Martin Schwidefsky --- diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c index c1bf75ffb875..7e1e40323b78 100644 --- a/arch/s390/kernel/perf_cpum_sf.c +++ b/arch/s390/kernel/perf_cpum_sf.c @@ -823,9 +823,12 @@ static int cpumsf_pmu_event_init(struct perf_event *event) } /* Check online status of the CPU to which the event is pinned */ - if ((unsigned int)event->cpu >= nr_cpumask_bits || - (event->cpu >= 0 && !cpu_online(event->cpu))) - return -ENODEV; + if (event->cpu >= 0) { + if ((unsigned int)event->cpu >= nr_cpumask_bits) + return -ENODEV; + if (!cpu_online(event->cpu)) + return -ENODEV; + } /* Force reset of idle/hv excludes regardless of what the * user requested.